Printrbot+ Base Assembly

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These instructions assume you have done the assembly prep step.

Any suggestions, objections and such are welcomed on this forum thread.

See the Assembly Notes for LC and Plus forum post for details. As of July, 2012, there is no exploded drawing of the Plus. If you use the LC's drawing, note that most parts are exactly the same, but not all of them are. Also, part 109 (used to mount the controller) is only for the LC. It will not exist in your Plus kit.

Step 1: Assemble ZRod Bases

First, gather all the laser cut parts of the Base Assembly.

Required parts:

  • 2x Bolt - #6-32 0.75"
  • 2x Nut - Hex - #6-32
  • 2x each of the following Laser-Cut Parts:
    • 106-RDEP, RoD End Plate
    • 107-LRDP, Lower RoD Plate
    • 108-BSTR, Base STRetcher


Pbp assy base 01 01.jpg Pbp assy base 01 02.jpg

Four of these parts have a small arrow (triangle) on them. Parts with the small arrow should face towards the front of the bot. So take care that all of the parts point the same direction.

The 106 part is not symmetrical, the wider side should go over the hole in 107.

Don't tighten the bolts yet, the plywood is not perfect so if you tighten the bolts now, you may not be able to fit in the next part.

You will need this assembly twice. But note they are not exactly same, one is mirrored. See the Assembly Notes for some important considerations regarding the orientation of the laser-cut cone-shaped holes in these parts! A small mistake here can result in ZRods which lean and are not perfectly vertical in the Finished Bot.

Step 2: Attach Front and Back Plates

Required parts:

  • 8x Nut - Hex - #6-32
  • 8x Bolt - #6-32 0.5"
  • 4x Washer - #6
  • 1x Zip Tie
  • 1x Endstop
  • Laser-Cut Parts: 102-FNTP FroNT Plus, 103-RRPL ReaR PLus, 104-ZLMT Z LiMiT switch spacer


On the laser-cut printrbots there are basically two types of plywood joints. One requires a screw with washer and for the other one a washer is not required (Some prefer to have washers on all screws. Be aware that the washer on a joint which doesn't require one can interfere with proper tightening of the parts!). When a washer is used on the joints which require it, take the time to center the washer so that it extends onto BOTH sides of the square or rectangular hole. (Note that in the picture below the washer is only covering one side.)

Pbp assy base 02 01.jpg Pbp assy base 02 02.jpg

In the next step take care on the orientation of the rear panel (laser-cut part 103-RRPL). Note the position of two holes in the middle and the pair of small holes on the top left corner. Again, don't fully tighten the bolts yet.

Pbp assy base 02 04.jpg

Before you add the top DECK, attach the z-endstop switch and its ZLMT spacer. The free end of the switch lever should point outwards. The zip-tie end needs to be outside otherwise the z-axis motor will not fit. The loose end of the metal strip on the switch should point outwards from the base.(Otherwise its position will later not match with the corresponding hole in 101-DECK.) If you have some Kapton tape or some other insulation tape, and you're paranoid, you can cover the naked contacts of the switch, but this is not necessary. It is very important that this switch be securely fastened and not shift. The free See the Assembly Notes for additional details.

Pbp assy base 02 05.jpg Pbp assy base 02 06.jpg Pbp assy base 02 03.jpg

Step 3: Add Top Deck and YRods

Required parts:

  • 16x Nut - Hex - #6-32
  • 16x Bolt - #6-32 0.5"
  • 16x Washer - #6
  • 4x LM8UU Linear Bearing (with YRods in place. See Assembly Notes for details.)
  • 8x Zip Tie
  • Laser-Cut Part: 101-DECK


First place the DECK part 101 on top of the frame, taking care that:

  • The arrows point to the front (part 102-FNTP, without holes)
  • The smaller rectangular holes (used for y-endstop later) should be on the left side
  • If the DECK doesn't fit this way you have assembled something incorrectly in previous steps. It IS possible to build the BASE assembly *inside-out*, so do take care to ensure that your build matches the pictures.

Now, if you are sure of the Deck orientation add zip-ties and linear bearings (See the Assembly Notes for reasons to consider adding bearings with the smooth YRods already inside. If you choose not to do this, don't tighten the zip-ties too much yet). Either way, Do not cut the ends of the zip-tyes yet! Add all the remaining bolts with washers and nuts and assemble snug, but NOT tight. The only screws which should be tight at this point are those four holding 106-RDEP, 107-LRDP, and 108-BSTR together. Go ahead and tighten them now, but leave the rest of the Base assembly screws snug, but loose. Use the other hand (that one that's not holding screwdriver :) ) to help the nuts "settle" in the right place (sometimes it tends to slip on the side while tightening).

Pbp assy base 03 01.jpg

Step 4: Add Y & Z Stepper Motors

Required parts:

  • 1x Zip Tie
  • 1x Endstop
  • 1x "011" Z Stepper Motor set (the two smaller ones wired together) (42BYGH011)
  • 1x "807" X, Y, E Stepper Motors (the larger one) (42BYGH4807)
  • 10x M3 x 8mm bolt


Use a zip-tie and mount the Y-Endstop, (again you can use some insulation for naked contacts of the switch) and route the wires through the square hole in the base. The loose end of the metal strip on the switch should point to the left (towards the closest linear bearing).

Pbp assy base 04 01.jpg

Attach the z-motors, use the M3x8mm bolts. The z-motors go on each end of the base. It is helpful to run the lead of the motor wires behind the front panel of the base. Brook's video shows him pointing the wires inward toward the controller board. The space around the z-endstop is really tight so after mounting the z-motor on that side check that the switch works correctly.

Attach the y-motor. There are two holes remaining where it will fit. It goes into the hole farthest from the y-endstop. Use two M3x8mm bolts only through the two holes closest to the linear bearings. Do not tighten these two bolts yet. The Y-motor must have at least the "upper half" of the shaft flattened. See assembly prep for details on adding a flat to the shaft.

Pbp assy base 04 03.jpg Pbp assy base 04 02.jpg

Step 5: Y Pulley and Belt Guide

Required parts:

  • 1x M3 x 8mm bolt
  • 1x M3 nut
  • 2x M3 x 20mm bolt
  • 4x Nut - Hex - #6-32
  • 4x Bolt - #6-32 0.75"
  • 2x Washer - 0.25"
  • 2x 608ZZ Bearings (shielded skate bearings)
  • Printed parts: GUID - Y Bearing Guide,PULY XL belt pulley
  • Laser-cut Parts: 2x 105

First take the pulley, X-Acto knife, 3mm drill bit and 5mm drill bit, maybe also some files (and a lot of patience and caution). First use the drill bits (or a file if holes really too small) and sure the hole are exactly 3mm (the one for the bolt) and 5mm (the one for the motor shaft). Use the drill bits to ensure that the sizes are correct. You want the pulley to be tight on the motor shaft, but you shouldn't have to force it on. If you only have English drill bits, your choices are probably either 3/16" or 13/64". These are 4.76 mm and 5.16 mm, respectively. 3/16" is too small to fit easily. 13/64" will make the pulley simply fall onto the shaft. If you can get a true 5mm bit, do so.

Then take the X-Acto knife and cut out the squashed (and exceeding) first layer(s) around the nut hole (maybe you will need to extend the hole a bit, if so try not to reduce or damage the other side, you need it to remain strong). Fit the M3 nut in the hole. You may need to use some force (but again be careful not to crack the pulley) in order to get the hole in the nut aligned with the hole for the bolt.

If you have the pulley with the nut and bolt. Take the Y-bearing guide, 3mm drill bit, and patiently file and fix the holes so the M3 bolt fits in them, and the shaft fits in the skate bearing (no need for free-play, but it needs to fit). (Or if you have another 3D printer (or someone who has) ask him if he can print you the pulley and the guide (and maybe the rest of the printed parts as well) more precisely according the drawings on thingiverse.  :( I did and all fits perfectly).

Pbp assy base 05 01.jpg


Assemble all as shown on pictures (Don't forget the washer between the bearing and the plywood part).

Pbp assy base 05 02.jpg Pbp assy base 05 03.jpg

Basic check

Before you put the base aside and continue with printbed consider performing following basic check in order to avoid future complications:

  • Check if the endstop switch has correct orientation and if the arm moves freely ("clicks" if pushed)
  • Check the position of y-motor. (If you put the base with the front side it should be on the right side, the left round hole should remain empty)

Turn the base around and check that the positions of the holes on the back panel are the same as in the photo (this will most probably be correct if you have the position of the end-stops correct).

Pbp assy base 05 04.jpg

Miscellaneous Notes

  • I don't see a real reason to put the electrics in the base now (and risk harming them)
  • Video showing the Base Assembly process http://youtu.be/uNZM-UeUXF8

Next Step

The next step is to assemble the Printbed.