Assembly

This document will guide you through putting together your Prusa i3.
Please read it through briefly before starting your build, and make sure you have everything you need to continue.
It's frustrating to be stuck with a half-finished machine because you are missing a part or tool.
It's recommended to do the assembly with 2 or more people. If you are doing this alone, do the instructions in order.
If there are two of you, each step is marked P1 or P2. Decide which one of you is Player 1 and act accordingly.
If there are more than two of you, split into two teams.


===Assemble the extruder (P1)===
There are multiple forms of extruder. These instructions cover two common variants.

==The gregstruder==
Plastic parts needed:
-Extruder body
-Extruder idler
-Extruder large gear
-Extruder small gear
Other parts needed:
-1 NEMA17 motor
-1 hotend
-1 M3x8 grub screw
-6 M3 nuts
-3 M3x40 bolts
-1 M8x20 grub screw
-1 M8 hobbed bolt
-4 M8 washers
-2 M8 nuts
-3 608 skateboard bearings
-3 M3x10 bolts
(optional) 2 short, stiff springs or silicone pads
Tools needed
-Wrench/spanner to fit M8 (preferably 2)
-Soldering iron
-Drill with 8mm and 3mm bits
-File
-Screwdriver or allen key to fit your M3 bolt heads and the M3 grub screw

Take the extruder body and snap off the small support piece attached to it. It should separate easily. If it leaves a messy surface, clean the surface up.
Use the drill to drill through the 8mm hole in the extruder body, the 3mm holes for the motor bolts, the 2 3mm mounting holes on the bottom and the 3mm hole for the idler (where the support piece was).
Melt two M3 nuts into the nut traps over the mounting holes.
Drill through the filament channel to make sure it's clear.
Place 1 608 bearing on the M8x20 grub screw and push it into the idler. It will only fit if the bearing is on the middle of the grub screw. It will click in place.
Attach the idler to the extruder body and fix it with the M3x40 bolt. Make sure the bolt head is on the FLAT side of the extruder body. You can put a nut on the bolt if you want, but don't tighten it very tightly.
Place an M3 nut in the small gear and fix it in place with the M3x8 grub screw. Slide the gear onto the motor shaft and fix it in place with the grub screw. Do not overtighten, and make sure the motor can turn freely with the gear in place.
Attach the motor to the extruder body with the 3 M3x10 bolts. The bolt heads go on the FLAT side of the extruder body.
Place 2 608 bearings in the recesses in the extruder body. 
Place the hobbed bolt in the large gear. If it's too loose, pad it a bit until it sits tight. Place two washers on the opposite (flat) side of the gear and slide the hobbed bolt through the two bearings into the extruder body. The gear teeth will mesh with the small gear already there. If they don't, adjust the position of the motor and/or the gear on the motor shaft until they do. Make sure the bobbing on the bolt aligns with the filament channel. If necessary, add another washer between the gear and the extruder body. Place a washer followed by 2 M8 nuts on the opposite side of the extruder body to fix the bolt in place.
If you are using springs or silicone pads, place those on the remaining two M3x40 bolts. Place two nuts into the nut recesses above the two bearings. Use the M3x40 bolts to fix the idler in place. You will adjust the tension later when you insert filament, so don't worry about that for now. 
Assemble your hotend according to your specific hotend's assembly instructions. I am assuming you have a hotend that is matched to your extruder body.
Attach the hotend to the extruder. If your hotend has a flat mounting plate, make sure the holes on it align with the holes on the extruder body so that the filament channel leads into the hotend. Redrill holes as necessary if something does not fit.

==The raldrich geared stepper extruder==

Plastic parts needed:
-Extruder body
-Extruder idler
-Extruder body spacer
Other parts needed:
-1 geared stepper motor
-1 hotend
-2 M3x30 bolt
-6 M3 nuts
-1 filament drive gear
-1 M3x8 grub screw
-1 M4 x20 bolt
-1 624 bearing
-4 M3x40 bolts
-4 M3 washers
(optional) 4 short, stiff springs or silicone pads
Tools needed
-Soldering iron
-Drill with 8mm and 3mm bits
-File
-Screwdriver or allen key to fit your M3 and M4 bolt heads and the M3 grub screw

Use the drill to drill through the 3mm holes for the motor bolts, the 2 3mm mounting holes on the bottom and the 4mm hole in the idler.
Drill through the filament channel to make sure it's clear.
Place the 624 bearing in the idler and fix it with the M4x20 bolt.
Place the spacer on the motor and make sure it aligns correctly with the extruder body.
Attach the drive gear to the motor shaft with the grub screw. Adjust the position of the drive gear to align with the filament channel.
Use the M3x30 bolts and the M3 nuts to fix the extruder body to the motor, sandwiching the spacer plate between them.
Place washers on the M3x40 bolts.
If you are using springs or silicone pads, place those on the remaining M3x40 bolts.
Place M3 nuts into the nut traps of the extruder body.
Attach the idler to the extruder body, so that the bearing presses against the drive gear.
Assemble your hotend according to your specific hotend's assembly instructions. I am assuming you have a hotend that is matched to your extruder body.
Attach the hotend to the extruder. If your hotend has a flat mounting plate, make sure the holes on it align with the holes on the extruder body so that the filament channel leads into the hotend. Redrill holes as necessary if something does not fit.


===Assemble the X axis (P2)===
Plastic parts needed:
-x axis motor end
-x axis idler end
-x carriage
Other parts needed:
-1 NEMA17 stepper motor
-1 T2.5 belt
-3 M3x10 bolt
-1 belt drive pulley
-1 M3x8 grub screw
-1 ??? bolt
-1 ??? bearing
-7 linear bearings
-7 M3x25 bolt with nut and washers
-2 smooth rods
Tools needed
-Screwdriver or allen key to fit your M3 bolt heads and the M3 grub screw

The X axis consists of 3 parts - the motor end, the idler end, and the carriage. 
Insert four linear bearings (two per part) into the motor and idler ends of the x axis, gently fix them in place with M3x25 screw
Slide a smooth rod through each pair of linear bearings to make sure they slide smoothly and don't move around. If they do move around, tighten the screw. Remove the smooth rods
Insert two smooth rods into the motor end of the X axis (the one with the three mounting points for the motor). Push them in as far as they will go.
Insert three linear bearings into the carriage. Slide the carriage onto the smooth rods and fix them with screws as with x ends.
Attach the idler bearing onto the idler end using an ??? bolt.
Push the idler onto the smooth rods, trapping the carriage in. Make sure the carriage can move along the rods with minimal effort.
Attach a NEMA17 motor to the motor end using 3 M3x10 bolts. The bolt heads will sink into the part, and the motor will be on the side opposite the linear bearings.
Place a pulley on the motor and fasten it to the shaft using a grub screw. Make sure the belt path is aligned with the gap in the x end pieces.
Insert a belt into the carriage belt holder such that it meshes with the printed teeth.
Thread the belt through the motor and idler ends, so that it runs over the bearing and the pulley. Insert the other end of the belt into the belt holder.
Do not cut the belt to size yet, as we will still have to adjust the location of the idler end along the smooth rods.

===Assemble the Y axis(P2)===
Plastic parts needed:
-y axis motor holder
-4 y corners
-y axis idler 
-y belt clamp
-3 y bearing holders
Other parts needed:
-1 23x23cm 12mm plate (9"x9" 1/2" thick for people in inchy countries) (may be thinner)
-1 heated bed PCB, with wires attached
-1 glass plate covered with Kapton or PET tape
-1 NEMA17 stepper motor
-1 T2.5 belt
-2 M3x10 bolt
-1 belt drive pulley
-1 M3x8 grub screw
-1 ??? bolt
-1 ??? bearing
-3 linear bearings
-3 M3x25 bolt with nut and washers
-2 405mm smooth rods
-22 M8 nuts (substitute 5/16" for M8 in inchland)
-22 M8 washers
-12 M10 nuts (?? in inchland)
-12 M10 washers
-4 140mm M8 (5/16") threaded rod (longer is ok)
-2 430mm M10 (??/16") threaded rod (longer is ok)
-9 3.5x12mm wood screws (or shorter if your plate is thinner)
Tools needed:
-Screwdriver to fit your wood screws
-Screwdriver or allen key to fit your M3 bolt heads and the M3 grub screw
-13mm wrench
-Another 13mm wrench (optional but violently recommended)
-17mm wrench
-Another 17mm wrench (optional, but...)
-Pencil or marker that is visible on the plate material
-Drill with 3.2mm (1/8") or 3mm drill bit
-Tape for holding things in place

Place the belt drive pulley on the motor shaft and tighten it with the grub screw.
Attach the motor to the y axis motor holder using two M3x10 bolts. (ystep1.png)
Thread two of the 140mm threaded rods through the motor holder. It should sit about 1/3 along the length of the rods, so that the motor is approximately centered.
Use 4 M8 washers and nuts to fix the motor holder in place on the rods. (ystep2.png)
Place a ??? bearing in the idler and fix it with the ??? bolt.
Attach the idler to one of the remaining 140mm rods. Fix it with a nut and washer on each side. (ystep3.png)
Place a pair of washers surrounded by nuts around the middle of each of the 430mm threaded rods.
Place a nut and a washer on one end of each of the 430mm threaded rods. (ystep4.png)
Snap a smooth rod into one of the y corners.
Thread one end of the 430mm threaded rod through the y corner piece so it goes parallel to the smooth rod with the nut and washer against the plastic part.
Put a washer and a nut on the outside of the plastic piece, fixing it to the threaded rod. (ystep5.png)
Put a nut followed by a washer onto the other end of the threaded rod.
Add another plastic y corner to the smooth and threaded rod's other end.
Put a washer and a nut on the outside of the plastic piece, fixing it to the threaded rod. 
Adjust the inner nut so the smooth rod is snugly held in place.(ystep6.png)
Repeat this procedure for the other 430mm threaded rod.(ystep7.png)
Place a nut and a washer on one end of each of the 140mm threaded rods. (ystep8.png)
Place the assembled smooth and threaded rods on the ends of the 140mm rods. Adjust the motor and idler position if necessary. (ystep9.png)
Place a nut and washer on the outside end of each of the 140mm rods. Do not tighten yet. (ystep10.png)
Place an object of 10cm width between the smooth rods. One of the frame panels might be useful for this.
Using the 10cm reference, make sure the distance between smooth rods is the same on both ends. 
Measure as close as you can to the motor, and as close as you can to the idler. 
Adjust the inner nuts and tighten the outer nuts, while checking the distance repeatedly. 
Use two wrenches to tighten the nuts without moving the plastic part along the rod.
Once done, pop the smooth rods out of the plastic parts. (ystep11.png)
Place the linear bearings in the linear bearing holders, fix them firmly with M3x25 screws
Slide them onto the rods. Two on one rod, one on the other.
Place your heated bed PCB on the plate and tape it down so it doesn't move around.
Mark and drill the 4 corner holes of the PCB with a 3.2mm (1/8") or 3mm drill.
Remove the heated bed PCB from the plate and place the plate on a flat surface.
Pop the smooth rods, with linear bearings attached, back into the plastic parts. 
The rod with two linear bearings on it should go on the side where the motor pulley is.
Place the entire assembly, upside down, onto the plate. Align it so the smooth rods are parallel to the plate edges and the assembly is approximately centered.
Position the two linear bearings that share a rod so that they are both in the middle third of the plate.
Position the last linear bearing so it's between the other two.
Mark each linear bearing holder mounting hole.
Drill all the holes and screw the linear bearing holders in with the wood screws.
Place one end of the belt into the belt clamp. Run the belt along its path over the pulley and idler and back to the belt clamp. 
Place the belt clamp in the middle of the plate along the belt path.
Mark and drill the belt clamp mounting holes and screw the belt clamp down.
Pull the belt tight and place the end into the belt clamp. Your Y axis is done.


===Assemble the frame (P1)===
The frame can be either one custom-cut plate or a box section composed of several precut pieces (you can have them cut to size at the hardware store).
If you have a custom-cut plate, skip this step and move on to the Z axis below.

Other parts needed:
-6 45x10cm 12mm plate (18"x4" 1/2" thick plate for you non-metric people)
-1 47.5x10cm 12mm plate (19"x4" 1/2" thick) (optional, needed only if you want to mount a spool on top of the machine.)
-Box of 3.5x20mm wood screws
Tools needed
-Drill with 3mm or 3.2mm bit
-Countersink bit
-Screwdriver or power screwdriver to match the wood screws
-Clamps (optional but highly recommended, can be replaced by helpful friend)
-Pencil
-A shim/spacer, 3mm wide

Place two of the 45x10 plates against each other on a flat surface, one standing up. 
Make sure the ends are aligned exactly by pressing another plate against them. Clamp them down in this position (or have your friend hold them).
Drill through the plate that is standing up into the side of the plate that is lying on the table, approximately halfway along the length of the plate. 
Countersink the hole and add a screw. Add two more screws about 3cm from each end of the plate.
Repeat this for another pair of plates.
Lay the two pairs on the table and put another 45x10 plate between them. Align the new plate with one of the edges.
Clamp the plates down and use 6 screws to attach the cross plate to the two corners.
Place the 3mm spacer on the table, and put the last remaining 45x10 on top of it.
Stand the remaining plates on end, and place them on top of the new plate. Use 8 screws to secure the bottom plate to the rest of the frame.
If you want to, place the 47.5x10 plate on top of the entire structure and attach it with 6 screws. This is a convenient place to mount accessories, such as a filament roll holder.


===Assemble the Z axis(P1)===