Prusa i3 Single Sheet Laser Cut Build Log

This post will grow as I continue the build of my Prusa i3 3D Printer.

I'm currently working on getting things wired up.


Power supply

Power supply: 12V 30A

Power Cable

Wire an AC cord to the L (line), N (neutral) and ground.

Plug in the supply and test the 12V output.




Prusa i3 LC w/ Side Supports

6 M3x25mm Machine Screws

12 M3 Flat Washers

6 M3 Nylon Lock Nuts

Slide the tabs of the side supports into the main frame. Attach with screws and nuts. I used a washer on each side as well and used nylon lock nuts This step takes 6 M3x25mm screws, 6 M3 Nyloc nuts and 12 M3 washers. This step took a little while due to the small space available to hold the lock nuts. I ended up using regular hex nuts for the middle sets. The frame ends up being very solid.

5D-20130127-6959 5D-20130127-6960



Rod – Smooth and Threaded.

I got the rod and cut it to length.  I used an angle grinder with a cutoff wheel that I borrowed from my dad.  It cut through even the hardened smooth rod fairly easily. I used a clamp hanging from the ceiling to hold the pieces that were being cut so they didn't bounce off the concrete floor.



The Y-axis consists of 6 threaded rod and 2 smooth rod, along with the printed parts.

I used rod lengths as follows:


3 – 215 mm x 8mm – front and back (bottom)

1 – 310 mm x 8mm – back (top)

2 – 435 mm x 8mm – sides


2 – 405 mm x 8mm hardened

The rod lengths here are a bit bigger than the "normal" size.


Take one short (215mm) threaded rod and put the y idler on it and thread washers and nuts to both sides of it.

Next, thread two nuts and washers on far enough that the plastic pieces will fit on with room for a washer and nyloc nut. The plastic pieces will hold the smooth rod, so they should be the same distance apart at the linear bearings on the y carriage. I am just hand tightening things at this point to make adjustment easier when we put things together. 5D-20130202-6974
Thread two nuts and washers onto another piece of (215 mm) threaded rod and add to the assembly. Add washers and nyloc nuts to the ends of all the shafts. 5D-20130202-6979

Now for the back section.

Take a 215 mm threaded rod and a 310 mm threaded rod and thread a washer and nut about halfway or so (this will be adjusted later). Slide the Y-motor holder up to that and thread a washer and nut on the other side (both top and bottom. Thread nuts and washers for the inside of the plastic pieces, put the plastic pieces on and thread washers and nuts (nyloc on the bottom) on both ends of both rods.. Thread a nut and two washers and a nyloc nut on each end of the top (long) piece for attachment to the frame.

Connect the front and back pieces with the 425 mm threaded rod, one on each side. Thread two nuts and two washers (between the nuts) onto the threads for connecting to the frame. Use washers and nuts on the inside and washers and nyloc nuts on the outside of each plastic corner piece. Lay the smooth rod in place to get the dimensions set and begin to tighten down the corners. Once everything is tight, check the frame for square. 5D-20130202-6984




Assemble the Y-Carriage by using M3 Machine screws, washers and nuts to attach the bearing holders and the belt holder to the laser cut carriage. Don't tighten completely to allow some give when you put the rod through. Mount the bearings into the bearing holders.





Slide the smooth rod through the bearings and mount to the Y Corners. It takes a bit of pressure to get them to seat fully. Then zip tie the rods in place. Then tighten the Y-Carriage bearing holder fasteners. You can also mount the Y stepper at this point.




Assemble the X Axis



Small zip tie 6
LM8UU Linear Bearing 7
M3 X 25mm Screw 1
M3 Nyloc nut 1
M3 nut 2
M3 x 40mm Screw 2
M3 Washer 3


Place the LM8UU bearings in the X-Carriage and use zip ties to fasten them.

Insert the M5 Nuts into the X-Motor Mount and X-Idler
I heated the nuts over a small flame and then stuck them in with a pliers.  Make sure they fit well and are square with everything.  You will also want to make sure the M5 threaded rod easily runs through the assembly.  I had to ream the hole out slightly.
Place the smooth rod into the X-Idler. Mine went in quite tightly and I used a hammer to drive them in. I should have reamed out the holes a bit so that they wouldn't be so tight.

Put the 623 Bearing inside the belt guide plastic pieces and screw into the X-idler end. Fasten with M3x25, washer and nyloc.

Now Build Add the Extruder Adapter to the X-Carriage

Place two M3 nuts in the nut holders in the adapter.  Make sure you can screw the M3 bolts into them.  Then remove the screws.
Screw the M3x40 Screws through the X-Carriage with M3 washers.  Mine were a fairly tight fit so I just screwed them through. 5D-20130215-7034
Attach the Adapter as shown and tighten the screws. 5D-20130215-7035
Slide the X-Carriage Assembly onto the smooth rods. 5D-20130215-7044
Slide the X-Motor Mount onto the smooth rod.  Adjust this to the width of the Z smooth rod (mine is 369mm outside to outside of the smooth rod) 5D-20130215-7046


Assemble the Z Axis



M3 X 20mm Screw 10
M3 Nyloc nut 10
M3 x 10mm Screw 9
M3 Washer 10
.17" ID tubing - ~25-30 mm 2

Mount the top Z brackets and slide the rod through. (M3x20, washer and nyloc in each hole) I had to ream the rod holes to make sure they were tight but not making the bracket bend.

Attach the bottom Z brackets

(M3x20, washer and nyloc in each hole)

Slide the X axis on to the Z rods and slide the rods into the bottom brackets. 

Attach the Z motors with M3x10 screws 5D-20130216-7055
Thread the M5 rod through the X ends and down to the motor. Slide the tubing over the motor shaft and the threaded rod 5D-20130216-7057
Mount the X motor with 3 M3x10mm screws 5D-20130217-7075






8mm Hobbed Bolt 1
8mm washer 5 – depends on the hobbed bolt
M4x60mm screws 2
M4 nut 2
M4 Washer 4
Spring 2
20mm Smooth Rod 1
608 Bearing 3
M3 Nut 2
M3x10 Screw 4

Put the 20mm smooth rod through one of the 608 bearings.  Mine was pretty tight and I used a hammer/punch to get it into place.  Snap that into the idler plastic part. Make sure it snaps in all the way and the bearing turns smoothly.

Slide a M3 nut into the nut holder on the small gear.  Drive a screw into the nut. 5D-20130216-7065
Attach the small gear to the motor

Mount the motor with 3 M3x10mm screws. Do not tighten completely at this point.
Mount two 608 bearings into each side of the body. 5D-20130216-7067
Now you need to <<put the bolt through the gear, spacing washers, bearings>>
Screw a M3x25mm screw to act as a hinge for the idler. 5D-20130216-7070
Drop the M4 nuts into the nut traps at the top.

Slide a washer, spring and washer on the M4 screws. 

Attach through the idler into the nuts.
Attach through the idler into the nuts. 5D-20130217-7072


Mount Y to Z

You are now ready to mount the Y-axis to the Z Axis. Line things up and tighten everything in place.