RepRapPro Huxley y axis assembly

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Revision as of 13:50, 26 October 2012 by Dysgenio (talk | contribs) (Step 1: Sled assembly)
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Introduction | Frame assembly | Y axis assembly | X axis assembly | Z axis assembly | Heated bed assembly | Extruder drive assembly | Hot end assembly | Wiring | Commissioning | Printing | Maintenance | Troubleshooting | Improvements

A notice about these instructions!

These instructions are open to editing by everyone and anyone.
For the official, and most up to date, instructions, see the RepRapPro wiki here


By the end of this stage, your machine will look like this:



You will need the following tools:

  • Phillips screwdriver
  • Adjustable spanner
  • 1.5mm hex key (Allen) for M3 socket set screw (grub)

Step 1: Sled assembly

RP parts Quantity Reprappro-huxley-section-1-components.jpg
Reprappro-huxley-bearing-holder-fixed.png 1
Reprappro-huxley-bearing-holder-float.png 1
Reprappro-huxley-belt-clamp.jpg 2
Reprappro-huxley-belt-tensioner.jpg 1
Hardware Quantity
Lasercut frog 1
M6 smooth rods 270 mm 2
LM6UU Linear bearings 3
M3 x 12 screw 4
M3 x 25 screw 4
M3 nyloc nuts 5
M3 nuts 4

Assemble the parts of the Y sled as shown:


Push the bearings in from the side. Don't try to clip them in from the top. They should be an interference fit and should stay where they are put.

Reprappro-huxley-bearings-from-the-side.jpg Reprappro-huxley-bearings-from-the-side-b.jpg

When correctly fitted, the linear bearing should protrude by the same amount from each end of the bearing holders.

The screws should be inserted from the top of the frog (the side without the markings). Use the 12mm M3 screws and nuts for the bearing holders and the 25mm M3 screws and nylock nuts for the Y Belt Clamps. This image is showing the bottom of the frog (the side with the markings).


Fit an M3 nyloc nut inside the hexagonal recess of the belt tensioner, then loosely attach this to the frog assembly using four M3 nyloc nuts. The belt tensioner has a boss at one end. This should be fitted nearest the camera as shown in the image below.


Adjust the gap between the 270mm Y rods at both ends so they are parallel and their inner edges are 103mm apart. Don't tighten their clamps yet.

Slide the 270mm Y rods partly out of the machine, put the sled onto them, and refit their free ends into the frame:


Ensure the linear bearings slide freely along the smooth rods. If the bearings are a little tight, insert the smooth rod into a power drill, then spin the rod for a few seconds whilst holding a scouring pad over it. Clean the rod with a cloth, then try the bearing fit again.

Slide the Y sled back and forth. It should run completely freely. If it doesn't, that means that the rods are not quite parallel - move their ends a little bit using the nuts either side.

Gradually tighten the ends of the rods, checking for free running right from end to end all the while as you do so.

Step 2: Y motor and idler brackets

RP parts Quantity Reprappro-huxley-y-section-2-components.jpg
Reprappro-huxley-y-idler-cad-1.png 1
Reprappro-huxley-y-idler-cad-2.png 1
Reprappro-huxley-y-motor-cad-1.png 1
Reprappro-huxley-y-motor-cad-2.png 1
Hardware Quantity
623 bearing 1
M3 x 16mm screw 4
M3 washer 5
M3 nut 1
NEMA 14 stepper motor 1
M3x10mm socket set screw (grub) 1
14 Tooth moulded pulley 1

Later versions of Huxley have printed pulleys like this:


These simply push onto the motor shaft (see below).

The next stage is to fit the Y axis idler and motor assemblies. Each end is made up of two printed parts and some hardware. Each end is in two parts to enable printing these components without the need for support material.

Motor end

If you have a moulded pulley, screw the set screw into the toothed-belt pulley. Take care not to cross the threads - the plastic is not hard. Screw it in far enough to project into the hole down the middle, then back it off so it is no longer projecting. Blow any displaced pieces of plastic from the central hole. Put the pulley on the motor shaft with its hub outermost, as shown. Use the toothed belt to get it roughly the right distance along the shaft. Align the set screw with the flat on the shaft, and tighten it. Do not over tighten it - the pulley has an internal embedded nut, and over tightening will cause this to fracture the pulley.

If you have a printed pulley push it onto the shaft. It should be a tight fit, and you may have to tap it into place. Use a soft hammer, or a wood block. If you place a tube against the pulley that will fit over the motor shaft, you can tap the end of the tube to place the pulley. Support the motor shaft, not the motor body, from the other end as you tap. You can secure it with a drop of superglue if you like (make sure the shaft is completely free of grease). Take care that no glue gets near the shaft's entry to the motor.

When you fit the 14-tooth pulley to the Y axis stepper motor, ensure that the teeth face in towards the motor (the Y axis belt will not fit with the pulley the other way around). Leave about a millimetre at the bottom of the shaft so that the pulley can turn freely.


Screw the motor to the Y motor bracket using the three M3x16mm screws with washers under their heads (if the screws are a little short leave out the washers).


The Y motor goes at the back of the machine, with the motor to the left when looking from the front of the machine and the wires pointing in towards the 626 bearing slot.

Fit the the Y motor bracket either side of the 626 bearing, and between the serrated washers on the top cross bar.

Move the Y sled to be at the same end, and make sure that the motor is positioned so that the bearings line up with the centre of the two holes in the sled that will hold the toothed-belt clamp.

The Y axis motor end will now look like this:

Reprappro-huxley-y-motor-fitted.jpg Reprappro-huxley-y-motor-fitted-b.jpg

Note the orientation of the stepper motor, with the wires pointing in towards the machine and the motor on the left of the bracket when looking at the machine from this end.

Idler end


The Y axis idler end is also constructed from two printed parts. Screw them together with the bearing inside as shown. If the 16mm screw is a little short for the idler part, leave the washer off.

Move the Y sled to the front of the machine (i.e. the opposite end to the Y motor you just fitted) and use the Y belt holes to get the idler bracket in roughly the right place.

Measure the gap from one of nuts holding the motor bracket to the nut along from it that holds one of the smooth Y bar clamps.

Adjust the idler bracket so that the gap between its corresponding nut and its Y-bar-clamp nut is the same. Tighten the nuts to hold the Y idler bracket.

Reprappro-huxley-y-idler-fitted.jpg Reprappro-huxley-y-idler-fitted-b.jpg

Step 3: Y axis belt

For this step you just need one 600mm T2.5 PU toothed belt. Your T2.5 belt may have been supplied as a single piece used for both the Y axis and X axis assemblies, so when you cut off the excess belt you'll want to retain as much as possible of the remainder.

Reprappro-huxley-y-belt-fitted 2.jpg Reprappro-huxley-y-belt-fitted 3.jpgReprappro-huxley-y-belt-fitted.jpg

Route the belt through the Y axis motor end, around the 14-tooth pulley, under the bearing, along to the idler end with one twist so that the flat edge then goes under the 626 bearing, around the 623 bearing and back to the belt clamp. Feed the ends through and overlap the two ends of the belt by pulling it lightly and overlapping by about 5 or 6 teeth. Secure in the belt clamp by tightening the screws.

Line the belt up by eye. The top should be in line with the bottom and the belt should be square where it sits under the clamps.

Hand-turn the Y motor by holding the hub of the 14-tooth pulley between your fingers. You will be able to feel the clicks as the motor's rotor magnets run past the ends of its stator coils. Make sure everything on the Y axis stays in line and runs freely right from one end to the other and back.

You should have some M3 grub screws in the kit which are left over from when we used the older style of pulley. One of these can now be used in the belt tensioner.

Next step

X axis assembly