2. X axis

x_end_motor

x_end_idler

x_end_idler_tensioner

Insert a M3x18mm socket head screw in one of the x_end_idler clamp holes. This screw helps insert the hex nut.

Using tweezers, hold a M3 hex nut so that it can be threaded onto the M3x18mm socket head screw. Tighten that screw until the M3 hex nut is firmly seated.

Remove the M3x18 socket head screw and repeat on the other clamp hole.

Insert an LM8UU linear bearing into the x_end_idler until it hits the internal stop.

The next LM8UU linear bearing will have to be inserted so that the rows of ball bearings are at 45° to the rows in the other bearing.

Insert that LM8UU linear bearing into the x_end_idler until it hits the internal stop.

Verify that the rows of balls are rotated at an angle of 45° from each other (as shown in the photograph).

Temporarily insert a 8mm smooth rod through both LM8UU linear bearings.

Engage two M3x10 socket head screws in the hex nuts, but do not tighten them at this time.

Alternately tighten the two M3x10 clamp screws to secure the linear bearings. Slide the smooth rods back and forth while tightening.

Don't over-tighten the clamp screws; they need to be just tight enough to keep the bearings from moving.

Remove the 8mm smooth rod.

Repeat the 3 previous steps on the x_end_motor

MK2(S) or MK2.5(S) only: Use two M2x12 screws to attach the x-endstop switch. Ensure the correct orientation of the switch. The microswitch should be oriented so that it is closest to the v-notch in the printed part.

MK2(S) or MK2.5(S) only: While tightening the screws, apply gentle pressure in the direction shown.

MK2(S) or MK2.5(S) only: Do not over-tighten the M2x12 screws!

MK2(S) or MK2.5(S) only: Double check the orientation of the endstop.

Check the holes for the smooth rods in the x_end_motor part and ensure that they are clean and free from obstructions.

Slide the two 370mm smooth rods in the x_end_motor.

Ensure that the smooth rods are fully inserted. You can check in the little windows on top and bottom.

If it is too hard to insert the smooth rods you can use a quality metal drill of 8mm and hand drill the first centimeter. Warning: don't drill the hole up to the end, only the first centimeter.

Insert two LM8UU linear bearings on the top smooth rod.

Insert one LM8UU linear bearing on the bottom smooth rod.

Be very careful inserting the LM8UU linear bearings.

Insert both rods simultaneously into the x_end_idler and provide even pressure to force the rods all the way in.

Ensure that the smooth rods are fully inserted by checking the little windows on top and bottom.

Take the time to double check observation windows on both x_end_idler and x_end_motor.

If it is too hard to insert the smooth rods you can use a quality metal drill of 8mm and hand drill the first centimeter. Warning: don't drill the hole up to the end, only the first centimeter.

The 2GT 16T pulley's teeth are not visible on the images.

Position the 2GT 16T pulley so that approximately 3.5 to 4 mm of the motor shaft protrudes. Ensure the pulley is not touching the motor.

Align one of the set screws on the flat side of the motor shaft and then tighten both set screws alternately until they are snug.

Attach the x-axis motor with three M3x18 screws. Don't tighten them fully yet. Note the orientation of the wires.

Finish to tighten the M3x18 screws while applying gentle pressure in the direction shown

Double check the pulley position and ensure it does not touch the motor.

Insert the idler in the x_end_idler_tensioner.

Press the dowel pin through the x_end_idler_tensioner and idler bearings.

Verify that the dowel pin is not protruding from either side.

Verify that the idler spins freely.

Insert two M3 nylock nuts in the top and bottom of the x_end_idler_tensioner. Note the orientation of the nylock nuts.

Insert the x_end_idler_tensioner in the x_end_idler.

Secure it with two M3x18 screws. Don't tighten the screws, only engage them.

Insert two M3 hex nuts in the dedicated pockets of the x_end_idler.

Note the orientation of the trapezoidal nut.

Insert a trapezoidal nut in the top of the x_end_idler.

Use two M3x18 screws, to tighten the trapezoidal nut in place. Do not over-tighten the screws.

Verify the orientation of the trapezoidal nut.

Insert two M3 hex nuts into the dedicated pockets of the x_end_motor.

Insert a trapezoidal nut in the top of the x_end_motor.

Use two M3x18 screws, to tighten the trapezoidal nut in place. Do not over-tighten the screws.

Verify the orientation of the trapezoidal nut.

These steps are using the Bear Upgrade frame 2.1 as example but can be applied to Original Prusa frames and previous Bear Upgrade frame versions.

Bear Upgrade frame only: Remove the z_end_caps.

Remove the z_tops that hold the Z smooth rods.

Carefully slide the X axis assembly on the Z-axis. Rotate both lead screws to engage the X axis with the trapezoidal nuts.

Continue to rotate both lead screws by hand, to move the X axis assembly down a few centimetres. If the X rods are not parallel with the top of the Z axis, rotate a lead screw on one side only, until the X axis assembly is parallel to the top of the Z axis.

Continue to move the X axis assembly downwards until you reach the middle of the Z axis. Keep the X axis as level as possible.

These steps are using the Bear Upgrade frame 2.1 as example but can be applied to Original Prusa frames and previous Bear Upgrade frame versions.

Install the Z axis tops and tighten them.

Bear Upgrade frame only: Make sure the z_tops are flush with the Z smooth rods on both sides

Bear Upgrade frame only: Tighten the z_ends_caps back in place.