A platform for the evolution of the maker movement

F3 Prusa Air Build Instructions

Created by Erik Moon & Rich Martin – Last Revised: 2012-10-28
@ F3 Labs℠, LLLP

Purpose:

This document is meant to fill a gap in the RepRap community. Currently, there is no single source of assembly instructions for the RepRap Prusa Air v2 3D-Printer (awesome design by Mecano), so builders have had to rely on instructions for the Prusa Mendel (excellent instructions available here: http://garyhodgson.com/reprap/prusa-mendel-visual-instructions/)

Also, this build replaces several of the parts from the original Bill of Materials (BoM) with improved designs that help with either ease-of-build or improved reliability / repeatability.

Note: This set of instructions is not consistent with the YouTube video that I posted earlier – the steps here are optimized to reduce the chance for mistakes and repeated work.

FOLLOW THE WRITTEN INSTRUCTIONS - not the video. It will save you time and effort.


Step 1: Gather Parts and Tools

1.1. F3-Labs Prusa Air Printed Parts BoM (Bill of Materials):



X-axis
Description Qty URL Image
X-end Motor-side 1 thing:18384
X-axis Belt T5 Pulley (10 tooth) 1 thing:11256
X-end Idler-side 1 thing:18384
X-axis Cart 1 x-carriage.stl
X-axis Cart Belt Clamp 2 x-carriage.stl


Y-axis
Description Qty URL Image
Y-axis Motor Mount 1 thing:29150
Y-axis Belt T5 Pulley (10 tooth) 1 thing:11256
Y-axis LM8UU holder 3 y-bushing.stl
Smooth Rod Clamp 4 thing:18637
Y-axis Cart Belt Clamp 2 thing:13479
Y-axis T5 Adjustable Belt Clamp (Optional) 1 (Opt) thing:23882


Z-axis
Description Qty URL Image
Z-axis Motor / Rod Coupler 1 thing:20137
Smooth Rod Clamp 2 thing:18637
Z-axis Adjustable Endstop Actuator Kit
(Optional)
1 (Opt) thing:16168


Extruder
Description Qty URL Image
Greg’s Wade Reloaded Extruder Body 1 thing:20413
Herringbone Gear (9 tooth) 1 download:59457
Herringbone Gear (47 tooth) 1 download:59456


Electronics
Description Qty URL Image
End-stop switch clamp 3 thing:26797
PCB Holder 1 Not yet defined N/A



1.2. F3-Labs Prusa Air Vitamins Parts BoM (Bill of Materials):

  • (1) F3-Labs Prusa Air Laser Cut Frame Kit (mirrored symmetrical design with handle mounting holes)
  • (1) F3-Labs Prusa Air Printed Parts Kit (modified BoM for ease of assembly and increased repeatability)
  • (3) 25 mm x 19 mm Stanley Chair Braces (purchased at Lowes)
  • (1) 5” drawer pull (carrying handle - this is an individualized choice that adds distinct personality to your machine)
  • (2) M8 Threaded Rod - 210 mm (be sure to order 1.25 mm or standard thread pitch)
  • (4) M8 Threaded Rod - 285 mm
  • (1) M8 Threaded Rod - 430 mm
  • (2) M8 Smooth Rod - 345 mm
  • (4) M8 Smooth Rod - 410 mm
  • (49) M8 Nut (be sure to buy 1.25 aka standard thread pitch)
  • (~50) M8 Flat Washer (you may need an extra here or there to acheive proper spacing)
  • (~8) M8 Fender Washer (you may need an extra here or there to acheive proper spacing)
    • Note: If you can find M8 x 30mm Fender Washers, that size is more helpful than the M8 x 24mm Fender Washers that we ended up using.
  • (1) M8 x 30 mm SHCS or Hex Bolt (or M8 x 35 mm) (be sure to buy 1.25 aka standard thread pitch)
  • (6) M4 x 20 mm FHCSS
  • (5) M4 x 40 mm SHCS
  • (2) M4 x 60 mm SHCS
  • (10) M4 Nut
  • (6) M4 Nylon-filled Lock Nut
  • (8) M4 Flat Washer
  • (14) M4 Fender Washer
  • (??) M3 x 10 mm SHCS
  • (??) M3 x 16 mm SHCS
  • (3) M3 x 20 mm SHCS
  • (1) M3 x 25 mm SHCS
  • (??) M3 Nut
  • (??) M3 Flat Washer
  • (4) M3 Fender Washer
  • (2) #1 Compression Spring
  • (4) #111 Compression Spring

You will need the following tools:

  • Metric Ruler (metal is better - minimum 40 cm length)
  • Digital Micrometer (12” is better)
  • Hex Key, 1.5 mm (for M3 SSS)
  • Hex Key, 2.0 mm (for M2.5 SHCS)
  • Hex Key, 2.5 mm (for M3 SHCS and M4 FHCSS)
  • Hex Key, 3.0 mm (for M4 SHCS)
  • Hex Open End Wrench, 5.5 mm (for M3 Nuts)
  • Hex Open End Wrench, 7.0 mm (for M4 Nuts)
  • Hex Open End Wrench, 13 mm (for M8 nuts - you really need 2)
  • Drill Bit, 3 mm
  • Drill Bit, 4 mm
  • Drill Bit, 8 mm

Optional tools to save you time:

  • Hex Nut Driver, 5.5 mm (for M3 Nuts)
  • Hex Nut Driver, 7.0 mm (for M4 Nuts)
  • Hex Nut Driver, 13 mm (for M8 Nuts)

Note: If you cut your own rods (or someone sends you freshly cut rods that have not been dressed), you will need to use a grinder to deburr the ends of the rods. A bench grinder or Dremel tool with grinding stone will work fine. Be sure to round all the edges and remove any jagged burrs. This well help with inserting the rods and minimize your chances of injury.

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Step 2: Assemble Frame Rods

Step 2 BoM (Bill of Materials):

  • (4) Printed Bar Clamps (from Printed Parts Kit)
  • (1) Printed Y-axis Motor Mount (from Printed Parts Kit)
  • (1) M4 x 40 mm SHCS
  • (1) M4 Nut
  • (2) M8 Threaded Rod - 210 mm
  • (4) M8 Threaded Rod - 285 mm
  • (1) M8 Threaded Rod - 430 mm
  • (22) M8 Nut
  • (25) M8 Flat Washer
  • (3) M8 Fender Washer
  • (2) 608ZZ Ball Bearing

Build steps:

Note: During these steps, precise location of the components on the threaded rod are not critical. However, ensuring ALL the components are on the rod in the correct order is critical.

2.1. Pre-assemble lower front M8 Threaded Rod

Start with (1) M8 Threaded Rod - 285 mm – then place 1 M8 nut, about 2” (~50 mm) from each end of the rod.

1
2
3
4
5
-- Approx 2" (~50mm)
- M8 Nut
-- Gap --
- M8 Nut
-- Approx 2" (~50mm)

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2.2. Pre-assemble lower center M8 Threaded Rod

This is also the Z-axis Lower Support Rod. Start with (1) M8 Threaded Rod - 430 mm – then place 1 M8 nut, about 4” (~100 mm) from each end of the rod.

1
2
3
4
5
6
-- Approx 4" (~100mm)
- M8 Nut
-- Gap --
- M8 Nut
-- Approx 4" (~100mm)

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2.3. Pre-assemble upper front M8 Threaded Rod

Start with (1) M8 Threaded Rod - 285 mm – then place the following components on the rod in order:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
-- Approx 2" (~50mm)
- M8 Nut
-- Gap --
- M8 Nut
- M8 Flat Washer
- Printed Bar Clamp 
- M8 Flat Washer
- M8 Nut
-- Gap --
- M8 Nut
- M8 Fender Washer
- M8 Flat Washer
- 608ZZ Ball Bearing
- M8 Flat Washer
- M8 Fender Washer
- M8 Nut
-- Gap -- 
- M8 Nut
- M8 Flat Washer
- Printed Bar Clamp 
- M8 Flat Washer
- M8 Nut
-- Gap --
- M8 Nut
-- Approx 2" (~50mm)

prusa air

2.4. Prepare the Y-axis Motor Mount

Start with (1) Printed Y-axis Motor Mount and (1) M4 Nut – insert the M4 Nut into the nut trap slot at the top rear of the printed part. The nut should fit very snugly. If too tight, you can use a little force to press it into place, but ensure that the sides of the nut slide against the sides of the nut trap, otherwise you could damage the part by elongating the nut trap.

Once in place, screw an (1) M4 x 40 mm SHCS into the hole on the back edge of the part – if the hole is too tight, use a 4 mm drill bit (do this by hand – no drills!!) and twist into the hole to loosen it up A LITTLE. If you use a drill, you will likely damage the part. Insert the M4 x 40 mm screw until you can just barely see the tip protruding into the upper rod slot.

LATER, you will tighten this screw to apply tension to the Y-axis belt.

2.5. Pre-assemble the upper rear M8 Threaded Rod

Start with (1) M8 Threaded Rod - 285 mm – then place the following components on the rod in order:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
-- Approx 2" (~50mm)
- M8 Nut
-- Gap --
- M8 Nut
- M8 Flat Washer
- Printed Bar Clamp 
- M8 Flat Washer
- M8 Nut
-- Gap --
- M8 Nut
- M8 Fender Washer
- M8 Flat Washer
- 608ZZ Ball Bearing
- M8 Flat Washer
- Printed Y-axis Motor Mount (ensure you thread through the upper hole)
- M8 Flat Washer
- M8 Nut
-- Gap -- 
- M8 Nut
- M8 Flat Washer
- Printed Bar Clamp 
- M8 Flat Washer
- M8 Nut
-- Gap --
- M8 Nut
-- Approx 2" (~50mm)

prusa air prusa air

2.6. Add the lower rear M8 Threaded Rod to the upper rear Threaded Rod assembly

Start with (1) M8 Threaded Rod - 285 mm – then place the following components on the rod in order:

1
2
3
4
5
6
7
8
9
10
11
-- Approx 2" (~50mm)
- M8 Nut
-- Gap --
- M8 Nut
- M8 Flat Washer
- Printed Y-axis Motor Mount (ensure you thread through the lower hole)
- M8 Flat Washer
- M8 Nut
-- Gap -- 
- M8 Nut
-- Approx 2" (~50mm)

prusa air prusa air


Step 3: Assemble Acrylic Frame

Step 3 BoM (Bill of Materials):

  • Completed Assemblies from Step 2
  • (10) M8 Nut
  • (10) M8 Flat Washer
  • (1) F3-Labs Prusa Air Laser Cut Frame Kit (improved symmetrical design with handle mounting holes)
  • (3) 25 mm x 19 mm Chair Braces
  • (6) M4 x 20 mm FHCSS
  • (6) M4 Nylon-filled Lock Nut
  • (6) M4 Fender Washer
  • (1) 5” Drawer Pull (carrying handle)

Build steps:

3.1. Peel protective paper / plastic sheeting

Peel protective sheeting off of acrylic pieces. Be careful to set peeled sheets down on a soft surface. They will scratch very easily.

If you have an pieces that are still attached to the “parent” material (e.g. the laser didn’t cut all the way through), DO NOT try to push them out – they will chip the acrylic. Return your acrylic parts to the vendor and get them re-cut.

Note: BEFORE you start Step 3.2, ENSURE that all your Threaded Rod assemblies have all the correct components on the rods – you will save a lot of frustration if you heed this caution.

3.2. Insert Threaded Rod assmeblies from Step 2 to Left Vertical Frame

Be sure to place an M8 Flat Washer on the ends of each rod BEFORE inserting into the acrylic sheet. There should ALWAYS be a washer (either flat or fender washer) between a nut and the acrylic sheet. Be sure to insert the correct rods in the correct pre-drilled holes. Add an additional (1) M8 Flat Washer and (1) M8 Nut to the outside of each rod. You do not need to tighten these nuts yet, just put them on the ends of the rods to ensure nothing falls off the rods.

prusa air prusa air prusa air prusa air

3.3 Attach Right Vertical Frame to Threaded Rod Assemblies

Again, be sure to place an M8 Flat Washer on the ends of each rod BEFORE inserting into the acrylic sheet. Add an additional (1) M8 Flat Washer and (1) M8 Nut to the outside of each rod. You do not need to tighten these nuts yet, just put them on the ends of the rods to ensure nothing falls off the rods.

When this step is complete, you should have two (2) Vertical frames, loosely held together by (5) threaded rod assemblies.

Note: At this point, it is IMPORTANT that the nuts are NOT tighened against the acrylic parts – we will be additing additional components that require the frame to remain flexible for a few more steps.

3.4 Install Backer Plate

Insert Backer Plate tabs into both left and right Vertical Frame slots then slide Backer Plate upwards – if fit is too loose, you can wedge one of your scrap acrylic pieces (or something soft like a wood pencil) into the gap under the lowest Backer Plate tab – it will hold the Backer Plate in the upper position.

Note: It is important to ensure the Backer Plate is supported – because the tabs face upwards, if left unsupported, it could easily fall out and get scratched.

prusa air

3.5. Attach Top Z-Motor Mount Plate

Place the Z-Motor Mount Plate on top of the Vertical Frame members and slide forward. The slots on the top front edge should engage with the tabs on the Vertical Frame members.

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3.6. Install Chair Braces (angle brackets)

Using M4 x 20 mm FHCSS and M4 Nyloc Nuts, attach the 3 Chair Braces to the Top Z-Motor Mount Plate and the rear Backer Plate – lightly snug the screws, but do not fully tighten yet.

prusa air

3.7. Square the acrylic frame

Using a small 90º square, ruler or level, ensure that the Vertical Frame sides are parallel to each other and perpendicular to both the center Backer and the Top Z-Motor Mount plate. If using a ruler, measure on the diagonal to ensure the frame is square. If using a level, ensure that the Z-Motor Mount Plate AND THE TABLE you are working on are both level – then check the vertical members for level.

Once the frame is square, ensure the center Backer is in the highest possible position, then tighten the M4 Nyloc Nuts. You will need to use an M2.5 Hex Key to keep the M4 x 20 FHCSScrews from rotating – then using a 7 mm Nut Driver or Hex Wrench, tighten the Nyloc Nuts.

Be sure to keep checking square as you tighten these nuts – and make adjustments as necessary – to keep the frame square.

When this step is completed, all four (4) of your Vertical Frame feet should be level on the same plane. If your table is flat, the frame should have all four (4) feet in contact with the table surface – the frame should not rock back and forth on uneven feet.

If your frame is not stable, loosen the M4 Nyloc Nuts on the Chair Braces and repeat Step 3.7.

3.8. Measure frame width

Measure the distance between the two Vertical Frame members along the Top Z-Motor Mount – be sure to write down this measurement as you will need it in future assembly Steps.

prusa-air

3.9. Attach carrying handle

Attach Drawer Pull to Top Z-Motor Mount Plate – we recommend that you use the screws provided with the drawer pull – but install in the following sequence from the top: Drawer Pull / M4 Fender Washer / Top Z-Motor Mount Plate / Drilled Top Plate Cutout (long narrow acrylic piece with 2 holes in it) / M8 Flat Washer (one on each side) / M4 Fender Washer / Insert screw included with Drawer Pull. If the screws are too long (e.g. you can’t get them to snug), add additional M4 Fender Washers as needed between the bottom M4 Washer and the head of the screw)

Note: It is important to use the drilled acrylic bar under the Top Z-Motor Mount Plate to ensure that the stress from the “carrying handle”” is distributed over as wide an area as possible to avoid cracking of the Top Plate. If you don’t have this acrylic piece, you will need to find some other way to distribute the weight of the machine as much as possible.

prusa air


Step 4: Square the frame (yup, again)

This procedure is so important it has its own section in the assembly instructions. The goal of this step is to ensure that your rods are set to the right width, ensuring that your acrylic frame is both square and rigid. The acrylic sheet is fairly flexible, so without the threaded rod providing the correct tension or support, your frame would not be stiff enough to generate repeatable and reliable results.

4.1. Set rod widths (by hand)

Starting from the upper rear Threaded Rod assembly, measure the distance between the Vertical Frame members. Move the inside nuts on the outermost pairs to the correct location on the Threaded Rod to set the width between the Vertical Frame members. Use the frame width that you wrote down in Step 3.8 (my machine measures 250 mm, but your frame may be slightly wider or narrower) and match that distance. Once your inside nuts are in the correct location, slowly tighten the outer nuts against the outside of the Vertical Frame members – ensure that the rod itself is not rotating. The rod should have an equal amount of excess rod on the left and right sides of the frame.

When the nuts are finger snug, measure again to ensure your width is correct.

Repeat this step for the remaining 4 rods. It is easier to do the upper rods first, then the lower center rod, then the front and back lower rods.

Remember, the exact location of OTHER components on the rod are not important yet – so if any other nuts or parts get in your way, move them toward the center of the rods.

4.2. Check square

Put the frame back on its feet (on a flat and level surface) and ensure that all 4 feet are firmly against the table. This will help ensure the frame remains square. If not, loosen the nuts on the Threaded Rod ends and repeat Step 4.1.

4.3. Tighten frame nuts

Flip the frame over so you can easily access the bottom. Consider setting the frame on a towel or other soft surface to prevent damage to the beautiful acrylic.

Using (2) 13 mm Open End wrenches, simultaneously torque the frame nuts against each other with equal pressure (turn the inside nut so it moves outward and turn the outside nut so it moves inward). This tightening will create a strong clamping force and will drastically improve rigidity of the frame.

After tightening EACH pair of nuts, measure the distance between Vertical Frame members at that rod, to ensure that you are maintaining consistent distance between the Vertical Frame members at all Threaded Rod joints. If done properly, your Vertical Frame members will be perfectly parallel.

4.4. Check square (not the last time)

Flip the frame back on its feet (on a flat and level surface) and ensure that all 4 feet are firmly against the table. Using a small 90º square, ruler or level, ensure that the Vertical Frame sides are parallel to each other and perpendicular to both the center Backer and the Top Z-Motor Mount plate. If using a ruler, measure on the diagonal to ensure the frame is square. If using a level, ensure that the Z-Motor Mount Plate AND THE TABLE you are working on are both level – then check the vertical members for level.

If not, loosen BOTH the outer and inner nuts and repeat Step 4.3.


Step 5: Install Y-axis & Z-axis Smooth Rods

Step 5 BoM (Bill of Materials):

  • (1) Completed Frame from Step 4
  • (2) Printed Bar Clamps (from Printed Parts Kit)
  • (2) M8 Smooth Rod - 345 mm
  • (2) M8 Smooth Rod - 410 mm
  • (4) M8 Nut
  • (4) M8 Flat Washer
  • (7) LM8UU Linear Motion Bearings

Build Steps: ###5.1. Align Y-axis Bar Clamps As stated before, the exact location of the Y-axis bar clamps is not yet critical. However, the front and rear pair need to be approximately lined up with each other.

If necessary, move the Bar Clamps (and their associated nuts / washers) to approximately the 1/4 and 3/4 positions inside the frame and leave them loose – again exact position is not critical. You can measure if you want, just make the front and rear distance from the Vertical Frame members consistent. Do this for both the right and left pairs.

Do NOT snug the nuts at this time.

5.2. Install Y-axis Smooth Rods

Wipe the (2) M8 Smooth Rods - 410 mm clean with a dry paper towel or lint-free cloth. DO NOT use water or water-based cleaners as they can cause corrosion. These rods will likely have an oil coating – that is ok to leave on the rod, but excess oil will attact dust and dirt. It is important to remove any dirt or grit to prolong the life of your bearings.

Slide (1) M8 Smooth Rod - 410 mm into the left front printed Rod Clamp. The Smooth Rod should be installed BELOW the Threaded Rod. The Rod Clamp will likely be very tight – so proceed with patience and firm, smooth pressure.

If you hear any cracking, STOP – pull out the M8 Smooth Rod and assess the situation. Forcing the rod will likely break the printed part.

ONLY if the hole in the Bar Clamp is too small, CAREFULLY use an 8 mm Drill Bit to increase the bore size of the Bar Clamp. DO THIS BY HAND – NO POWER TOOLS. The Smooth Rod is more than likely NARROWER than the drill bit, so it is important that this hole is not made too big.

Once the tip of the Smooth Rod is through the Bar Clamp, slide about halfway up the rod’s length. WIPE THE ROD CLEAN (again) with a paper towel. There is likely to be a fair amount of plastic dust on the rod. The goal is to keep this junk out of your bearings.

Install (2) LM8UU Linear Motion Bearings on the left Smooth Rod and (1) LM8UU Linear Motion Bearing on the right Smooth Rod. Don’t play with them yet. Just slide them down the cleaned rod and leave them alone!

Slide the M8 Smooth Rod all the way to the rear of the frame and press into the rear Bar Clamp. Again, observe the same precautions to prevent breaking the part.

No need to tighten the Bar Clamps at this time.

WIPE THE ROD CLEAN (again) with a paper towel – there is probably more plastic dust on the rod from having slid through the Bar Clamp.

Repeat with the right-side Smooth Rod.

Now you can play with the LM8UU Linear Motion Bearings. They are usually internally lubricated, so don’t be surprised if they deposit some of their own oil on the rods – this is normal. If they seem a little rough, that is usually normal – they should “break-in” with a little use and become quite smooth.

Note: You should periodically inspect your smooth rods for any pitting or scoring. If you see any marks like this or metal filings around the ends of your LM8UU bearings, it is quite possible that a bearing has failed. It is important to replace failed bearings as soon as possible to prevent damage to the Smooth Rods (or in extreme cases, to printed parts and/or motors). If you notice squeaking or binding from your LM8UU bearings, you may need to lubricate them – use a light machine oil (like sewing machine oil), but not too much as excess lubricant will attract dirt to the rods.

5.3. Align Z-axis Bar Clamps

We will now install the Z-axis Bar Clamps as accurately as possible. The Z-axis Smooth Rods need to be as parallel as possible to ensure smooth and linear movement of the X-carriage. The tops of the Z-axis Smooth Rods are defined by the 8 mm holes in the Top Z-Motor Mount Plate – this location is fixed.

Measure the distance from the nearest Vertical Frame member to the inside edge of the 8 mm hole. Write this number down.

Set the position of the lower Z-axis Bar Clamp directly below the 8 mm hole. Measure the distance from the inside edge of the Bar Clamp to the Vertical Frame member. Move the Bar Clamp as needed to match the upper distance. Lightly finger snug the nuts against the sides of the Bar Clamp – not enough to apply any clamping pressure, just enough to prevent it from moving.

Ensure that the Bar Clamps are turned to the FRONT side of the center Threaded Rod.

5.4. Install Z-axis Smooth Rods

Wipe the (2) M8 Smooth Rods - 345 mm clean with a dry paper towel or lint-free cloth. DO NOT use water or water-based cleaners as they can cause corrosion. These rods will likely have an oil coating – that is ok to leave on the rod, but excess oil will attact dust and dirt. It is important to remove any dirt or grit to prolong the life of your bearings.

Insert (1) M8 Smooth Rod - 345 mm into the left 8 mm hole in the Top Z-axis Motor Mount Plate. Slide it downwards toward the Bar Clamp - DO NOT insert it into the Bar Clamp yet.

Wipe the Smooth Rod again, just to ensure no acrylic dust is on the rod. Slide (2) LM8UU Linear Motion Bearings on to the bottom of the Smooth Rod.

Press the Smooth Rod into the lower Bar Clamp. Again, observe the same precautions as in Step 5.2 to prevent breaking the part. When fully inserted, the top of the Smooth Rod should be flush with the upper surface of the Top Z-Motor Mount Plate. Ensure it is flush – not below the surface.

Repeat with right side.

Using (2) 13 mm Open End wrenches, simultaneously torque the Z-axis Bar Clamp nuts (on one side of the frame) against each other with equal pressure (turn the inside nut so it moves outward and turn the outside nut so it moves inward). This tightening will create a strong clamping force and will compress the Bar Clamp. DO NOT OVER TIGHTEN – the Bar Clamp does NOT need to be squished closed to provide adequate clamping force. Tighten just past the point where the Smooth Rod will no longer rotate or slide.

After tightening EACH pair of nuts, measure the distance between Vertical Frame member and the Z-axis Smooth Rod, to ensure that you are maintaining parallel distance between the Vertical Frame member and the Z-axis Smooth Rod. If done properly, your Z-axis Smooth Rods will be perfectly parallel.

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5.5. Check square (sound familiar?)

Ensure that all 4 feet are firmly against the table.

Follow the same procedure as in 4.4 to ensure the frame is square.

Additionally, measure the distance between the Z-axis Smooth Rods at the top and the bottom of the frame. This distance should be identical, ensuring that the rods are indeed parallel.

If you have any non-square or non-parallel problems, fix them now.


Step 6: Install X-axis Carriage & Z-axis Threaded Rods

Step 6 BoM (Bill of Materials):

  • (1) Completed Frame from Step 5
  • (1) Printed X-axis End Motor-side (from Printed Parts Kit)
  • (1) Printed X-axis End Idler-side (from Printed Parts Kit)
  • (1) Printed X-axis Cart (from Printed Parts Kit)
  • (2) Printed Z-axis Coupler (from Printed Parts Kit)
  • (1) Printed Z-axis Adjustable Endstop Kit
    • Includes: (1) Endstop Bar Frame, (1)Endstop Trigger Shoe, (1) M3 x 25 mm SHCS, (2) M3 x 20 mm SHCS, (2) M3 Nut, (2) M3 Flat Washer and (1) Ball-point Pen Spring
  • (8) M3 x 20 mm SHCS
  • (8) M3 Nut
  • (4) M3 Flat Washer
  • (2) M8 Smooth Rod - 410 mm
  • (2) M8 Threaded Rod - 210 mm
  • (1) M8 x 30 mm (or M8 x 35 mm) Hex Bolt
  • (5) M8 Nut
  • (3) M8 Flat Washer
  • (3) M8 Fender Washer
  • (2) Springs «< Need spring specs »>
  • (3) 4” narrow plastic Zip-ties

Build Steps: ###6.1. Test fit X-axis M8 Smooth Rods / X-axis Ends Unlike most X-axis Ends, the designs incorporated in our BoM are meant to fit loosely, then be tightened using a clamping M3 x 20 SHCS. This allows for much easier assembly and disassembly in the future. Press fit design parts are more common, but usually make it impossible to disassemble without destroying the parts.

Because of this, the M8 Smooth Rods must easily slide in and out of the X-axis Ends. Slide the rods through the printed parts to ensure a smooth and easy fit. If there is any difficulty, CAREFULLY use an 8 mm Drill Bit to increase the bore size of the X-axis End. DO THIS BY HAND – NO POWER TOOLS. The Smooth Rod is more than likely NARROWER than the drill bit, so it is important that this hole is not made too big.

Be sure to test both X-axis Ends with both Rods.

Once loose assembled, lay the completed assembly on your flat / smooth table. Ensure that the X-axis Ends lay flat – there should be no wobble or uneven lifting off the table.

If you have any problems, your holes may not be parallel. Fix any issues with the plastic parts to ensure the rods are parallel and the X-axis ends are flat against the table before proceeding.

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Disassemble the X-axis Ends / Smooth Rods.

6.2. Prep X-axis End Motor-side

Starting with the X-axis End Motor-side printed part, find the two holes in the bottom plate of the part. Insert one (1) M3 Nut into each of the two nut traps (top surface). From the bottom, insert an M3 x 20 mm SHCS with one (1) M3 Flat Washer between the head and the printed part into each of the holes. Lightly screw into the nut, just to hold together – do not tighten.

Press one (1) M8 Nut into the bottom Nut Trap.

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6.3. Prep X-axis End Idler-side

Starting with the M8 x 30 mm SHCS (can also use an M8 x 30 mm Hex Bolt, M8 x 35 mm SHCS or M8 x 35 mm Hex Bolt, but the 30 mm length is easier to work with), build up the following parts on the Bolt:

1
2
3
4
5
6
7
8
-- Bolt Head
- M8 Flat Washer
- M8 Fender Washer
- M8 Flat Washer
- 608ZZ Ball Bearing
- M8 Flat Washer
- M8 Fender Washer
-- Bolt thread

Insert this Bolt into the back side of the 8 mm hole in the X-axis End Idler-side printed part. This hole is located on the 45° strut on the back surface of the printed part.

On the other side of the printed part strut, add one (1) M8 Flat Washer and one (1) M8 Nut. Hold the inside nut stationary with a 13 mm Open End Wrench and tighten the Bolt head with a 6 mm Hex Key (or for a Hex Bolt, use a 13 mm Open End Wrench or 13 mm Nut Driver) – but do not over tighten or you will crush the plastic and/or ball bearing.

Next, like we just did with the Motor-side, find the two holes in the bottom plate of the part. Insert one (1) M3 Nut into each of the two nut traps (top surface). From the bottom, insert an M3 x 20 mm SHCS with one (1) M3 Flat Washer between the head and the printed part into each of the holes. Lightly screw into the nut, just to hold together – do not tighten.

Press one (1) M8 Nut into the bottom Nut Trap.

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6.4. Mount X-axis Ends

Start on the left side and move both the LM8UU Linear Bearings on the Z-axis Smooth Rods to the upper half of the rod. Slide the X-axis End Motor-side assembly around the Z-axis Smooth Rod. Move the lower LM8UU Linear Bearing down INTO the bearing clamp on the X-axis End – be sure to move one bearing at a time. Press the LM8UU Linear Bearing all the way to the bottom of the clamp – it should be flush with the BOTTOM edge of the printed part. The fit should be tight enought to maintain position. Slide the upper LM8UU Linear Bearing into the clamp – stopping so the top of the upper bearing is flush with the TOP edge of the printed part.

Insert one (1) M3 Nut into each of the two Nut Traps on the back side of the printed part. Insert one (1) M3 x 20 mm SHCS into each of the two front holes and lightly screw into the nut. Verify position of both linear bearings and tighten the screws – BE SURE NOT TO OVER TIGHTEN – these screws do not have washers and will easily break the printed part if over tightened.

Repeat on the Idler-side – but note that the M3 clamping screws insert from back to front.

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6.5 Assemble X-axis Carriage

Wipe the (2) M8 Smooth Rods - 410 mm clean with a dry paper towel or lint-free cloth. DO NOT use water or water-based cleaners as they can cause corrosion. These rods will likely have an oil coating – that is ok to leave on the rod, but excess oil will attact dust and dirt. It is important to remove any dirt or grit to prolong the life of your bearings (yup, you’ve seen this before).

Slide both (2) M8 Smooth Rods - 410 mm into the left X-axis End (Motor-side) about half way. Wipe the rods again (right side) to ensure all plastic dust is removed.

Install two (2) LM8UU Linear Motion Bearings on the REAR Smooth Rod and one (1) LM8UU Linear Motion Bearing on the FRONT Smooth Rod.

Slide the Smooth Rods into the right side X-axis End (Idler-side). Move the Linear Bearings to the right most side of the X-axis Carriage. Wipe the rods again (whole length of rods) to ensure all plastic dust is removed.

Flip the entire frame over (laying on a towel or other soft surface) – BE CAREFUL – be prepared for the X-axis Carriage to be loose. It will easily glide up and down because of the linear bearings.

Pull the X-axis carriage toward the bottom of the frame (against the Vertical Frame members) and ensure that both rods are flush against both sides of the frame. Using a 2.5 mm Hex Key, tighten the four (4) M3 x 20 mm SHCScrews (X-axis Rod Clamps) on the bottom of the X-axis Ends. This will clamp the Smooth Rods in position – pulling the rods against the frame will ensure that the X-axis is square.

Flip the frame back onto its feet. GENTLY slide the X-axis Carriage up and down – it should move easily and smoothly. There might be a slight “gritty” feeling from the Linear Bearings – this is ok.

Look for any binding, uneven friction or twisting caused by the Z-axis Smooth Rods not being parallel or the X-axis Carriage being twisted. If you encounter any of these problems, flip the frame over, loosen the X-axis Carriage Smooth Rod Clamps and try again. If you continue to have problems, re-measure your Z-axis Smooth Rods and ensure they are parallel – then repeat Steps 5.4 and 5.5.

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6.6 Attach X-axis Cart

Before mounting the X-axis cart, ensure that the small holes near the centers of the Linear Bearing slots are clear and able to hold a small 4” narrow Zip-tie. If the holes are not clear, use a 3 mm drill bit (NO POWER TOOLS!!) to clear the holes.

Flip the entire frame over (laying on a towel or other soft surface) – BE CAREFUL – be prepared for the X-axis Carriage to be loose. It will easily glide up and down because of the Linear Bearings.

Thread three (3) Zip-ties into the X-axis Cart.

Using the X-axis Cart (printed part) as a guide, move the X-axis Linear Bearings so they are in-line with the X-axis bearing holder slots. Place the X-axis Cart on top of the Linear Bearings (mind you, the machine is upside down – so you will be holding the X-axis Cart upside down and pressing upward onto the Linear Bearings). Ensure the Linear Bearings are fully seated in the X-axis Cart.

Insert the Zip-tie ends into their slotted heads and tighten. The Zip-ties should be as tight as you can possibly make them without breaking anything. The Zip-ties will hold the Linear Bearings in their slots and the grooves in the slots will ensure the Bearings stay properly aligned. Using Diagonal Wire Cutters, cut off the excess length of the Zip-ties – cutting as close to the head and as flush as possible.

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6.7 Pre-assemble Z-axis Threaded Rods

Start with both (2) M8 Threaded Rod - 210 mm and add one (1) M8 Nut to each rod about 2” (50 mm) from one end. Add an M8 Flat Washer to the short end of the rod.

Next, with both (2) Z-axis Rod Couplers (printed parts), insert one (1) M8 Nut into each of the Coupler nut traps.

Note: These Rod Couplers are usually printed with support material inside the nut traps – if your your nuts will not slide into the nut traps, be sure to look for stray support material. This can easily be removed with small needle nose pliers or a small utility knife.

Twist one (1) Threaded Rod Assembly (washer side) into the bottom of each Coupler. Twist the rod only until initial resistance is felt - DO NOT tighten. The rod should be just above the top surface of the captive nut. Using a 13 mm Open End Wrench, tighten the lower nut against the Coupler – holding the coupler by hand. DO NOT OVERTIGHTEN - the plastic on the bottom of the printed part is quite thin.

Repeat for the second set.

The finished Z-axis Threaded Rod assembly should look like this:

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-- Z-axis Threaded Rod Coupler (printed part)
-- M8 Nut (captive in Coupler)
- M8 Flat Washer
- M8 Nut
- Remaining rod thread

One last detail in this step:

On the upper part of the Coupler, insert one (1) M3 Nut into each Nut Trap. From the side, insert one (1) M3 Set Screw so that its tip is just visible in the motor shaft hole. Use an 1.5 mm Hex Key to turn this screw.

Note: It is important for the Couplers to be perfectly co-axial with the Threaded Rods – that is, the centers of the Couplers and the centers of the rods need to line up perfectly. You can test this visually by twisting a Rod in your hands and watching the Coupler. If you see the Coupler wobbling back-and-forth, you should loosen the nut, center the Rod and tighten the nut. Repeat until you are satisfied there is no wobble.

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6.8 Attach Z-axis Threaded Rods to X-axis Carriage

Insert one (1) Spring into each hexagonal nut trap column on the upper surface of the X-axis ends. Insert one (1) M8 Nut on top of the Spring in each column.

Lower the X-axis Carriage (if it isn’t already) to rest on the Vertical Frame members. Take the Z-axis Threaded Rod Assemblies from Step 6.4 and thread into each of the hexagonal columns on the X-axis Ends.

Note: The purpose of the spring inside the X-axis Ends is to apply downward pressure on the X-axis Carriage when the Z-axis moves. This insures accurate Z-axis movement and also ensures that the X-axis Carriage does not pop off of the lower nuts in the event of excessive downward Z-axis forces. When threading the Z-axis Rod Assemblies, it is important to get a little compression of the springs – but you only need a little compression. If your springs are very stiff, just try to get one thread height worth of compression – if your springs are very soft, try to get a little more compression, but you shouldn’t need more than 4-6 thread heights worth of compression. Try to get the same amount of spring tension on both the right and left side. As you press downward on the Threaded Rods, keep twisting until you feel the rod engage the bottom nut. Once the rod is threaded onto both nuts, you can release any compressive force.

Continue threading the Z-axis Rod Assemblies until you have about 1” (~25 mm) of threaded rod protruding from the bottom of the X-axis Ends.

6.9 Assemble Z-axis Adjustable Endstop (optional component)

Note: This component is completely optional. The Z-axis Endstop switch can easily be actuated by direct contact with the bottom surface of the X-axis End - Motor-side without this extra component. However, in my experience, having the ability to make fine-adjustments to the Z-axis endstop will be a major time saver.

If you choose to use this component, go ahead and assemble it now.

Starting with the plunger assembly, simply assemble the components in order (from the top) and screw into the Endstop Trigger Shoe (printed part on the bottom):

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-- M3 x 25 mm SHCS
- Spring
- M3 Flat Washer
- Endstop Bar Frame (flat side down)
- Endstop Trigger Shoe

Then insert an M3 nut into the bottom of each end of the Endstop Bar Frame clamps. Next, add one (1) M3 x 20 mm SHCScrew and one (1) M3 Flat Washer on each of the upper forks of the clamps – lightly twist into the nuts just to keep things from falling apart.

If your X-axis Carriage Rods are too short (the Smooth Rods in my kit left only about 2 cm of extra rod on the left side), you may need to modify the Endstop Bar Frame to fit in the available space. I needed to remove about half of the rear bar clamp (using a Dremel tool cutting wheel and some sandpaper). The modified Endstop Frame is strong enough and stationary enough to work without any problems.

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Step 7: Install Axis Control Motors

Step 7 BoM (Bill of Materials):

  • (1) Completed Frame from Step 6
  • (4) NEMA 17 Stepper Motors
  • (2) T5 10 Tooth Flanged Pulley (printed part)
  • (11) M3 x 10 mm SHCS
  • (3) M3 x 16 mm SHCS
  • (8) M3 Flat Washer
  • (2) M3 Nut Nyloc

Build Steps:

7.1. Install Z-axis Motors

Install one motor at a time using four (4) M3 x 10 SHCS and one (1) M3 Flat Washer for each screw. Place the motor directly on the Top Z-axis Motor Mount Plate (motor shaft pointing down into the large hole – if your motor has 2 shafts, place the longer one down). Align the screw holes with those in the plate. Insert M3 x 10 SHCS screws with washers – first install all four (4) screws snug, but not tight. After all screws are in place, tighten the screws.

Repeat with the other Z-axis Motor.

Pull the X-axis carriage upward until the first Z-axis Coupler is close to the Motor shaft. Rotate the Motor shaft (by hand) so the flat side of the shaft is aligned with the M3 Set Screw. Do this with both Motors and both Z-axis Couplers.

Note: This next sub-step is much easier if your Z-axis Threaded Rod Assemblies are set to approximately the same height before you press onto the Motor shafts. To adjust the position of the Z-axis Threaded Rod, simply twist the assembly and it will rise in one direction and fall in the other. Once the two rods are aligned, proceed with mounting to the Motor shafts.

Push the Couplers upward onto the Motor shafts until they are about 1 mm from the body of the Motor housing. Tighten the M3 Set Screws using an 1.5 mm Hex Key.

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7.2. Prep X-axis and Y-axis Motors

Insert one (1) M3 Lock Nut into the nut trap of each of the T5-10 Pulleys. Insert one (1) M3 x 6 mm SSS (headless Socket Set Screw) into the side hole of each Pulley and using a 1.5 mm Hex Key, turn until barely visible in the Motor shaft hole.

Note: The shaft holes on the Pulleys are deliberately smaller than the Motor shafts, so they will be very tight and difficult to install on the motors, so please be very careful. Also, it is CRITICAL to properly orient the Pulleys – ONLY ONE should be installed with the wide flange TOWARD the Motor body (Y-axis) and the OTHER ONE should be installed with the wide flange AWAY from the Motor body (X-axis).

Press the Pulley onto the Motor shaft so it is about 1 mm away from the Motor body – PLEASE DOUBLE CHECK PULLEY ORIENTATION. THIS PART IS CRITICAL: Install one Pulley with the wide flange TOWARD the Motor body (Y-axis). Install the second Pulley with the wide flange AWAY from the Motor body (X-axis). It is important to do this right the first time – the Pulley is so tight on the Motor shaft that it may be impossible to remove it without damaging the Pulley. Yes, it was important enough to mention twice in this document.

7.3. Install Y-axis Motor

Turn the entire frame so it is facing away from you (but right-side up with all 4 feet on the table).

Mount the Y-axis Motor on the side of the Y-axis Motor mount that is FLAT. Be sure to orient the motor so the wire harness is facing the INSIDE of the frame. This will help prevent snagging the wires.

Attach the Y-axis Motor using three (3) M3 x 16 mm SHCScrews. The screws should be inserted in the side with the COUNTERSINK. Tighten the screws, but as usual, do NOT overtighten.

7.4. Install X-axis Motor

Turn the entire frame so the left side is facing you (but right-side up with all 4 feet on the table).

Mount the X-axis Motor on the BACK side of the X-axis End Motor-side. Be sure to orient the motor so the wire harness is facing the INSIDE of the frame. This will help prevent snagging the wires.

Attach the X-axis Motor using three (3) M3 x 10 mm SHCScrews. The screws should be inserted from the FRONT. Tighten the screws, but as usual, do NOT overtighten.


Step 8: Install Y-axis Cart

Step 8 BoM (Bill of Materials):

  • (1) Completed Frame from Step 7
  • (3) LM8UU Linear Bearing Holder (printed parts)
  • (2) Y-axis Belt Clamp (printed parts)
  • (10) M3 x 16 mm SHCS
  • (10) M3 Lock Nut (Nylon filled)
  • (20) M3 Flat Washer
  • (1) T5 Belt (approx 32” or 800 mm length)
  • (3) 3/32” x 4” zip ties (2 mm wide x 100 mm long)
  • (1) Y-axis Cart (we’re using laser-cut 0.25” MDF)
  • (1) Y-axis Print Bed (also 0.25” MDF)
  • (4) M4 x 40 mm SHCS
  • (8) M4 Fender Washer
  • (4) M4 Flat Washer
  • (8) M4 Nut
  • (4) #111 Compression Spring

8.1. Prep Y-axis Cart

Insure that the zip-tie holes in the LM8UU Linear Bearing Holders are properly sized for a 3/32” zip-tie. If the holes are too small or blocked by stray plastic, use a 3 mm Drill Bit (and your fingers) to clean out the holes (NO POWER TOOLS!!).

Using the M3 x 16 SHCS, attach the LM8UU Linear Bearing Holders to the bottom of the Y-axis Cart. Install TWO Bearing Holders on the LEFT side of the plate using the FRONT and REAR set of holes. Install ONE Bearing Holder on the RIGHT side of the plate using the CENTER set of holes. Place an M3 Flat Washer between the M3 x 16 mm SHCS head and the Bearing Holder, then another washer on top of the Y-axis Cart, before attaching the M3 Lock Nut. Snug the nuts, but do not tighten – leave the nuts loose enough to adjust the precise location of the Bearing Holders on the bottom of the Y-axis Cart plate.

Note: In case you are wondering, a common question is: Why are the Linear Bearings asymmetric (two on one side, and only one on the other)? Well, it is a bit of a pessimistic solution to a common problem. If you had two bearings on both sides, the Y-axis Cart could bind and be difficult to move if your Y-axis Smooth Rods are not perfectly parallel. By putting two bearings only on one side, you are relying on that side to be your twisting constraint – then the third bearing can absorb a little “slop” before causing a jam. If the asymmetry bothers you, feel free to install the 4th Linear Bearing – but you will need to ensure your Smooth Rods are perfectly parallel. Because a triangle is inherently stable, it is unlikely that adding a fourth Linear Bearing would improve machine performance.

Helpful tip: We recommend that all the screws for the Y-axis Cart be inserted from the bottom surface, pointing upwards. This will allow you to make adjustments to these screws in the future, even after the Print Bed is attached above the the Y-axis Cart. Because you will be able to insert an open-ended 7 mm wrench in the space between the boards, you will be able to use a hex key from below to tighten / loosen Y-axis Cart components without first having to remove the Print Bed.

Insert zip-ties in each of the Linear Bearing Holders – but do not insert the loose ends into the zip-tie heads. I find that it looks better if you insert the zip-ties from the center outward. This will make it easy to rotate the zip-ties so the heads are hidden behind the Bearing Holders.

8.2. Install LM8UU Linear Bearings into LM8UU Bearing Holders

Flip the entire frame so the front is facing down and the bottom is facing you. Place the Y-axis Cart on the Y-axis Smooth Rods – ensure the side with TWO Bearing Holders is on the same side with TWO LM8UU Linear Bearings (on the Smooth Rods). Slide the LM8UU Linear Bearings to align with the Bearing Holders.

You may need to adjust the position of the Y-axis Rod Clamps (both front and back) to ensure they are set to the proper distance of the Y-axis Cart – and that they are centered in the frame.

Insert the zip-tie loose ends into the heads and loosely pull them through. Once all three zip-ties are “zippable”, ensure that the Y-axis Cart is FULLY SEATED on all three (3) LM8UU Linear Bearings. One-by-one, pull the zip-ties finger tight. The Y-axis Cart should not wobble – but only slide along the Y-axis. Use Needle Nose Pliers to pull the zip-tie ends very tight (but do not break the zip-tie). Use Diagonal Wire Cutters to snip off the excess zip-tie loose ends – but be sure to cut as close to the zip-tie head as possilbe.

Spin the zip-tie heads toward the center of the Y-axis Cart so they are no longer visible from the outside of the frame.

8.3. Align Y-axis Smooth Rods

Using TWO (2) 13 mm Open-Ended Hex Wreches (don’t use pliers – you’ll booger up the nuts and your tool – use an adjustable wrench if you do not have two (2) 13 mm Open-Ended Wrenches), slowly tighten the M8 Nuts adjacent to your Y-axis Bar Clamps. Be sure to keep them centered and parallel – measure the distance between the M8 Smooth Rods at both the FRONT and REAR M8 Threaded Rods – adjust to keep that distance identical. Also, measure all four (4) distances between the M8 Smooth Rods and the acrylic Vertical Frame members to ensure that the pair of M8 Smooth Rods are centered left-to-right. Continue to tighten the M8 Nuts until your Smooth Rods no longer move (check both left-to-right, front-to-back and rotation to ensure the clamps are tight enough).

DO NOT OVER-TIGHTEN!! If you crank down hard enough on the Bar Clamps, THEY WILL BREAK!! If you see the printed parts starting to turn white along a stress line, YOU ARE OVER TIGHTENING.

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Helpful tip: We recommend that you use two (2) 13 mm Wrenches and turn them simultaneously in opposite directions to tighten / loosen the Bar Clamps. This will insure that the position of the M8 Smooth Rods doesn’t move while you are tightening / loosening the clamps.

Flip the entire frame back onto its feet.

Slide the Y-axis Cart front-to-back in the frame. It should move very smoothly with very little resistance. Ensure that there are no “rough spots” or binding when sliding back and forth. If you have rough areas, your M8 Smooth Rods may be bent. Carefully inspect your rods. If you have binding at one end and/or the other, it is likely that your M8 Smooth Rods are not parallel. Measure again and adjust as needed.

Measure the distance between the edges of the Y-axis Cart and the Vertical Frame members – do this with the Y-axis Cart both in the forward-most position and the rear-most position. Ensure that your distances are consistent on the left and right side (ensure the Smooth Rod pair are centered) and that it is consistent when the Y-axis Cart is front-most or rear-most (ensures that the rods are parallel with the Frame Vertical members).

Only when you are satisfied that your Y-axis is parallel and square, proceed to the next Steps.

8.4. Attach T5 Belt Clamps to Y-axis Cart

The .STL file for the T5 Belt Clamps in the BoM includes a couple adjustable components. If you want, you can use these components to make the belt clamps adjustable – HOWEVER, we do not recommend using this method to adjust belt tension. Because the Adjustable Belt Clamps are so tall, they force you to position the Print Bed a lot higher than necessary.

Instead, we suggest that you omit the adjustable components (belt piston and spacer block) and simply attach the toothed Clamp and the Nut Holder directly to the Y-axis Cart. Insert the M3 x 16 mm SHCScrews from the bottom (with a washer!), then place the toothed Clamp on the UPPER surface of the Y-axis Cart plate. Then insert the end of the belt (teeth down) in between the screws so the belt meshes with the toothed Clamp. Place the Nut Holder on top of the belt, insert M3 Nut into each Nut Holder and tighten. Repeat for the opposite edge of the Y-axis Cart with the Y-axis belt taut (take out all slack that you can, but don’t worry about making it super tight).

Alternative: You can also install the toothed Clamp on the BOTTOM surface of the Y-axis Cart, pressing the flat side of the T5 Belt against the bottom of the Y-axis Cart. This is the simplest installation and the easiest to adjust later, if necessary, but this approach results in a slightly restricted Y-axis movement, a “less linear” Y-axis belt and might impact Y-axis print accuracy.

Note: It is NOT necessary to strain yourself to get this belt super tight. The Y-axis Motor Mount included in this BoM is fully adjustable and can be used to tighten the belt quite easily. prusa air prusa air

8.5. Install Y-axis Print Bed

Prep the Y-axis Print Bed (laser cut MDF or plywood piece) be inserting the following hardware in the four holes that line up with the corner holes in the Y-axis Cart (see photo):

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-- M4 x 40 mm SHCS
-- Y-axis Print Bed (larger board) --
- M4 Fender Washer
- #111 Compression Spring
- M4 Fender Washer
- M4 Nut (upper)
- M4 Flat Washer
-- Y-axis Cart (smaller board) --
- M4 Flat Washer (put on after mating with the Y-axis Cart)
- M4 Nut (lower - put on after mating with the Y-axis Cart)

For now, the critical component is the M4 Nut (upper) – you want all four (4) M4 Nuts (upper) to be in the same position. Approx 1/2” or 12 mm is fine, just try to be consistent. The spring will be compressed between the two Fender Washers, providing upward pressure for the Print Bed.

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Mate the Y-axis Print Bed assembly with the Y-axis Cart – from front to back, the Y-axis Cart should fit between the center 3 sets of holes in the Y-axis Print Bed. Attach the remaining M4 Flat Washer and M4 Nut (lower) on each of the four (4) M4 x 40 SHCScrews.

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Step 9: Install Extruder

Step 8 BoM (Bill of Materials):

  • (1) Completed Frame from Step 8
  • (1) “Greg’s Wade Reloaded” Extruder Body (printed part - ensure you have the right part for your desired filament size)
  • (1) “Greg’s Wade Reloaded” Guilder (printed part - ensure you have the right part for your desired filament size)
  • (1) “Greg’s Wade Reloaded” Large Herringbone Gear - 47 teeth (printed part)
  • (1) “Greg’s Wade Reloaded” Small Herringbone Gear - 9 teeth (printed part)
  • (1) NEMA 17 Stepper Motor
  • (1) Hot End kit of your choice (e.g. Budaschnozzle, J-Head, etc.)
  • (3) M3 x 10 SHCS
  • (1) M3 x 20 SHCS
  • (1) M3 x 25 SHCS
  • (2) M3 Nut
  • (4) M3 Flat Washer
  • (1) M3 x 6 (or M3 x 8) SSS (Socket Set Screw)
  • (2) M4 x 20 SHCS
  • (2) M4 x 60 SHCS
  • (4) M4 Nut
  • (6) M4 Flat Washer
  • (1) M8 x 60 Hobbed Bolt (ensure you have the right part for your desired filament size)
  • (1) M8 x 15 Threaded Rod (should be able to cut this from your rod scraps)
  • (2) M8 Nut
  • (2) M8 Fender Washer (Note: you might need 1 - 3 of these)
  • (2) M8 Flat Washer
  • (3) 608zz Ball Bearing
  • (2) #1 Compression Spring

9.1. Prep & Assemble Extruder Guidler

Prep the Extruder Guilder by test fitting onto the Extruder Body hinge. If the fit does not allow for easy assembly (e.g. the plastic pieces are too big to fit together), use a small file or some sandpaper to gently remove some plastic from the hinge area until the parts fit together properly.

Continue prep by inserting an M3 Nut into the nut trap in the Guidler hinge area (Note: The nut trap is only on one side). Insert M8 x 15 Threaded Rod into the center of one (1) 608zz Ball Bearing. Press the Ball Bearing into the Guilder bearing cavity. This might require a bit of force to press into place, but the short ends of the Rod should help align the Ball Bearing and prevent over insertion.

Align the hinge of the Guidler with the hinge of the Extuder Body. Insert the (1) M3 x 25 SHCS with an M3 Washer to use as a hinge pin. Once inserted up to the M3 Nut in the Guilder nut trap, turn the head of the M3 x 25 SHCS until fully inserted (snug, but not tight). The M3 Nut will ensure the hinge pin does not back out of the hinge.

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9.2. Prep Extruder Body & Large Herringbone Gear

Prep the Extruder body by press fitting (2) 608zz Ball Bearings into the Extruder Body – one (1) in the front and one (1) in the back. Next, insert the M8 x 60 Hobbed Bolt to the front side (HEX-shaped hole) of the Large Herringbone Gear. Ensure that the Hex head of the bolt is fully seated in the hex-shaped nut trap.

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9.3. Assemble Extruder Body

Insert the bolt into the front (flat) side of the Extruder Body through the 608zz Ball Bearings.

Examine the hobbed area on the bolt – align it with the funnel area inside the Extruder Body. This will help you determine how many washers you will need to properly space the rear face of the Large Herringbone Gear from the front face of the Extruder Body. You will certainly need a minimum of (1) M8 Flat Washer – add M8 Fender Washers as needed to fill the gap between the Large Herringbone Gear and the 608zz Ball Bearing to align the bolt’s hobbed area with the funnel. Once the desired alignment is acheived, add an M8 Flat Washer to the rear of the Hobbed Bolt (on the far side of the 608zz Ball Bearing) and tightent an M8 Nut onto the Hobbed Bolt. Tighten, but do not crush any components. Double-check to ensure that the hobbed area on the Hobbed Bolt is still aligned with the funnel area. If necessary, disassemble and add or remove washers as needed. When properly aligned, add a second M8 Nut to the end of the Hobbed Bolt and tighten against the first M8 Nut – this will help prevent the nuts from loosening as the extruder rotates.

Insert (1) M4 Nut in each of the two (2) nut traps in the upper surface of the Extruder Body. Try to prevent over-insertion of the nuts and try to keep them vertical. Note: These M4 nut traps are deliberately large to allow the Guidler Springs to flip upward. prusa air

9.4. Prep & Assemble Extruder Guilder Springs

Prep the Extruder Guilder Springs by placing each (1) #1 Compression Spring on an (1) M4 x 60 SHCS with an (1) M4 Flat Washer on either end of the spring.

Prep the Guidler Spring Clasp (rectangle with 3 holes) by inserting (1) M3 Nut into the nut trap on the inside face of the Guidler Spring Clasp. Partially insert the (1) M3 x 20 SHCS from the outside of the Guidler Spring Clasp (side without the nut) into the Guidler Spring Clasp and M3 Nut (just so the tip of the M3 x 20 SHCS is flush with the inside surface of the nut).

Insert the prepped Guilder Springs into the outer holes of the Guidler Spring Clasp (from the outside surface WITHOUT the M3 Nut. Note: ALL THREE SCREWS SHOULD BE POINTING IN THE SAME DIRECTION. Press the M4 x 60 SHCS into the Clasp until the washers are flush against the outer surface.

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-- M4 x 60 mm SHCS
- M4 Flat Washer
- #1 Compression Spring
- M4 Flat Washer
- Guidler Spring Clasp

With the Guidler in the fully open position, insert the Guilder Spring ends into the Extruder Body (upper surface above the Guidler). Turn the M4 x 60 SHCScrews so they are engaged with the captive M4 Nuts in the Extruder Body. Just turn until the tips of the M4 x 60 screws are flush with the nuts.

To check fit and proper mounting, flip the Guidler Clasp to the uppermost position. Close the Guidler. Pull back the Guidler Clasp (against the spring tension) and flip downware over the Guidler. Carefully tighten the CENTER M3 screw just enough to lock the Guilder Clasp in the downward position.

Note: It is NOT necessary to fully tighten the Center M3 screw – it is merely there to prevent the clasp from moving upwards inadvertently. When in the closed position, simply turn so the tip is inside the Guidler approx 1-2 mm. It is also NOT necessary to fully tighten the Guilder Spring screws. These springs hold the 608zz Ball Bearing against the incoming filament to ensure that the Hobbed Bolt is able to grip the filament and drive it downwards for extrusion (or retract it upwards). Only tighten the Guilder Spring screws enough to gain positive traction – you might not need to tighten them at all. DO NOT overtighten as it can flatten the filament, causing weakness and encouraging filament jams in the extruder or hot end.

9.5. Prep & Assemble Extruder Motor

First, prep the Small Herringbone Gear by inserting an M3 Nut into the nut trap. Lightly insert the M3 x 6 mm SSS set screw, but ensure the tip of the set screw is NOT penetrating into the shaft hole.

Prep the Extruder Guilder Motor by attaching the Small Herringbone Gear with the base of the gear (fatter side without teeth) toward the Motor body – but be careful not to over-insert the shaft. Slowly press the gear onto the Motor shaft – occassionally checking the depth of the Gear by holding the Motor on the back side of the Extruder Body. If you have a Motor with a D-shaped shaft, ensure the set screw is aligned with the FLAT side of the shaft!

Note: It is critical that the two Herringbone Gears are carefully aligned center-to-center. If they are not properly aligned, the two gears will rub against each other and gradually turn the gear teeth into dust. Increased friction can also cause skipping of the Extruder Motor, and thus create poor quality prints. Properly aligned gears will last much longer.

Once the two Herringbone Gears are properly aligned, insert one (1) M3 x 16 SHCS in the upper-left Extruder Body mount hole and attach the Motor to the Extruder Body. Be sure there is an (1) M3 Flat Washer between the head of the SHCS and the Extuder Body. Once this screw is lightly inserted, swing the Motor down until the teeth of both gears align and mesh. Insert one (1) M3 x 16 SHCS in the lower-left Extruder Body mount hole and lightly snug. Rotate the Large Herringbone Gear until the lower-right Extruder Body mount hole is visible through one of the Gear holes. Insert the final (1) M3 x 16 SHCS in the lower-right Extruder Body mount hole and tighten. Tighten the other two (2) M3 x 16 SHCS to firmly mount the Motor.

Tighten the M3 x 6 SSS set screw against the Motor Shaft. Do not overtighten as this could damage your printed gear. prusa air

9.6. Prep & Mount Extruder Hot End

Follow the instructions provided with your Hot End and mount it to the X-cart (do not use any screws yet).

*Note: Some Hot End designs do not mount directly to the X-cart, but instead mount to the bottom of the Extruder Body. If you have a Hot End like this, go ahead and mount to your Extruder Body at this time.

The following instructions / pictures are for the Budaschnozzle 1.3 hot end.

Before mounting the hot end, ensure that the PTFE tube within the hot end is the right size for the diameter of filament you will be using. If the PTFE tube needs to be changed, its a very simple process. There is a good YouTube video walking through this process located here.
prusa air prusa air

9.7. Mount Extruder to X-cart

First, prep the Extruder Body by inserting an (1) M4 Nut into each of the two (2) nut traps on the upper surface of the Extruder Body base.

Place the Extruder Body on top of the mounted Hot End and insert M4 x 20 SHCS screws from the lower side of the X-cart. Ensure that there is an M4 Flat Washer between the head of the M4 x 20 SHCS and the bottom of the X-cart. Insert screws into the M4 Nuts in the base of the Extruder Body and only very lightly snug the screws. prusa air prusa air

9.8. Test Extruder / Hot End alignment

Cut a short piece of unused filament (be sure to use the proper diameter filament for your Extruder and Hot End) approximately 5-6 inches long. With the Extruder Guilder open, feed the filament down through the funnel under the Hobbed Bolt until it enters the Hot End – eventually it will stop and not feed past the first constriction point inside the Hot End.

*Note: This can also be done with the Guilder closed. Insert the filament through the top of the Guilder groove and feed the filament downward until you feel resistance. With the Herringbone Gear facing you, rotate the Large Herringbone Gear clockwise to feed the filament downward - it should feed itself through and poke through into the Hot End.

Keep track of how much filament is feeding to determine if the filament is feeding all the way through the Extruder to the Hot End.

Optional: If you are unable to properly align the Extruder / Hot End alignment, dismount the Extruder Body from the X-cart. Then take a short piece of unused filament (5-6 inches long) and press one end into the Hot End until it stops. Do not force. Thread the other end upwards into the Extruder Body – if your Extruder Guilder is closed, you should be able to rotate the Large Herringbone Gear counter-clockwise to retract the filament upwards. Once the Extruder Body is in contact with the Hot End, proceed with mounting the Extruder to the X-cart.

Once alignment is acheived, tighten both M4 x 20 SHCS from below the X-cart until snug. DO NOT OVERTIGHTEN.


More to come soon…


Glossary:

  • 608ZZ - Radial Ball Bearing with 6 mm width and 8 mm innder diameter
  • LM8UU - Linear Motion Bearing with 8 mm inner diameter
  • FHCSS - Flat Head Counter Sunk Screw
  • SHCS - Socket Head Cap Screw
  • SSS - Socket Set Screw

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