3d Printer pt 4: Assembling the base

3d Printers:  a tool for the homestead?

3d Printer pt 2: Prusa i3 wood frame

3d Printer pt 3: Designing your parts

I know that there are plenty of blogs and videos about assembling the Prusa i3.  Why am I posting another?  Because there are several versions of the i3.  The printer I’m building is the Prusa i3 Rework.  The videos I have watched do not cover this specific version.

A word of caution:  I’m learning as I’m going.  I’ll edit my posts as I discover my mistakes, but you might duplicate them if you are building before I complete this project.  This post is probably going to be pic heavy and may take time to load.

Here’s my bill of materials for the base…

  • Heated bed mount
  • Y Belt Holder
  • 3 x Linear bearing LM8UU
  • 2 x M3x14mm screw
  • 2 x 3mm washer
  • 2 x M3 nut
  • 2 x Zip-ties
  • 4 x Y Corner
  • Y Idler
  • Y Motor
  • 1 x Ball bearing 608
  • 4 x Threaded rod M10x210mm
  • 34 x M10 nut
  • 34 x 10mm washer
  • 1 x M8x30mm screw
  • 1 x M8 nut
  • 2 x 8mm wahser
  • 1 x M4x20mm screw
  • 1 x M4 nut
  • 2 x Smooth rod 8x350mm
  • 2 x Threaded rod M10x380mm

There are some 3d printed parts in the list above.  Here’s a link to the official BOM that includes pics of the printed parts. The pics are handy but the BOM they have is incomplete.  (Zip-ties and parts to screw the frame together aren’t listed among other things)

You can find parts kits on places like eBay.  There are some websites that specialize in 3d parts, but my experiences is that most are slow or expensive or both.  You can pick up most of what you need from Amazon.  Tacoma Screw is a good source for quality rods.  Rod kits are available on eBay, but their quality may be suspect.


Prepping the Bed

  1. Put a linear bearing on the heated bed mount.  There are three slots for the bearing, pick one.
  2. Zip-tie (yes, it’s a verb) the bearing in place.
  3. Trim the zip-ties.
  4. Repeat all of the above two more times.
  5. Take 2 of the M3x14mm screws, 2 washers and put them through the top of the Y belt holder.
  6. Put the belt holder on the heatbed, open side toward the two bearings.
  7. Flip the heatbed over and put on the two nuts.  Voila!

You should have something that looks like this…


I wasn’t impressed with the use of zip-ties.  That’s something to upgrade later.

Y idler Assembly

  1. Put an M4 nut inside the Y idler assembly
  2. Screw in an M4x20mm screw from the outside.  It should look like this…20150126_122207
  3. Put a 608 bearing in the fork of the y idler.  I don’t like how my y idler holds the bearing btw.
  4. Grab the M8x30mm screw, two washers and a nut.  Put a washer on the screw, feed it through the side of the idler, through the bearing and out the other side.
  5. Put a washer on the end of the screw.  Add the nut.

The Y idler should look like this now…


Nicely done!

Transverse Assembly: Y Idler

  1. Take an M10x210mm rod and put it through the middle hole of the Y idler.  Make sure the idler is in the middle of the rod.
  2. put a washer on each end of the rod, followed by a nut on each side.  Tighten the nuts until they and the washers are almost touching the idler.
  3. Put another washer on each end of the rod.  Screw these on until they’re 30mm away from the rod ends.
  4. Add a washer to each end.
  5. Grab another M10x210mm rod and put a nut on each end, 30mm from the end.  Add a washer on each end.
  6. Take a Y corner and put the two 210mm rods through the two side holes of the Y corner.  Add another corner to the other end of the rods.  Both corners should be oriented the same way.
  7. Add a washer on each end of the rods.  Add a nut on each end as well.

It should look like this…



Transverse Assembly: Y Motor

  1. Take two of the M10x210mm rods and put them through the holes of the Y motor.  Center the motor on the rods.
  2. put a washer and nut on both sides of both rods.  snug them so that they’re close to touching the motor.
  3. Add a nut and washer to each end of the rods, about 30mm from the ends.
  4. Put Y corners on each end.
  5. Put washers and nuts to hold the corners on the rods.  Here’s what it should look like…


You should get 186mm when you measure from the outside of one Y corner to the other.

Longitudinal Assembly:

(Phew!  Almost done with this part)

  1.  Take a 380mm threaded rod and put two washers, sandwiched by two nuts somewhere in the middle(doesn’t need to be exact).  Do the same to another 380mm threaded rod.
  2. Add a nut on each end of the rods, around 30mm from each end.
  3. Add a washer to each end.
  4. put the two rod ends through the Y corners of the Y motor assembly.  The slot side of the motor should be pointing away from the rods.
  5. put a washer and nut on the rod ends to secure them against the Y corners.
  6. Grab the 350mm smooth rods.  They fit in the tops of the Y corners (Y motor assy.).  I slid them in, I didn’t pop them in from the top.
  7. Take the idler assembly.  Make sure it is oriented with the idler curved part up.  Slide it on the longitudinal threaded rods.
  8. Slide the idler assembly onto the smooth rods.
  9. put a washer and nut on the longitudinal rods to secure the idler assembly.
  10. Tighten everything.  All corners should be touching your workbench.  Make sure that your measurements between corners have stayed true.

Here’s what you should have…





2 thoughts on “3d Printer pt 4: Assembling the base

  1. Pingback: 3d Printer pt 5: X axis | This Happy Homestead

  2. Pingback: 3d Printer pt 7: Y axis motor | This Happy Homestead

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