K8200/3Drag Z Axis Trapezoid Anti Wobble - Upgrade

The original kit has too much wobble on the Z axis, resulting in shifting and uneven layers.

This design is for a minimal but rigid Z axis, using a trapezoid lead screw. There are only changes to the original design, where needed.

The new replacement parts is printed in ABS. To make the trapezoid threads work properly they needs to be cleaned with a tap (can be homemade).

I plan to make a nylon print of nut block to make the construction more wear resistant and with lower friction, but the friction turned out to be fine in this ABS version.
(NB: Parts shown on the photos are printed before upgrading...)

If you try out other materials, please share your experiences :-)

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Print Settings

• 0.30mm layer height, 50-80% infill
• 2 perimeters, 4 top and 4 bottom layers
• No support needed

Post-Printing

Parts needed:

• 1x 300 - 400mm trapezoid lead screw 10mm with pitch of 2mm (TR10x2D)
• 1x Ball Bearing 6000ZZ or 6000RS2 (10x26x8mm)
• 2x M10 washer (ISO7090)
• 1x Motor coupler 10mm/5mm

The washers are used on both sides of bearing and the bearing is fixed with the two printed nuts. The bearing must take all weight of the assembly, not the coupler and motor.

Other parts are reuse.

Tools needed:

Trapezoid tap for 10x2mm (TR10x2D) to clean up the printed thread.
Alternatively a home made tap from the part of the rod can be used as the tap is only needed to clean printed thread, not making a new - the printed thread will guide the tap.

Firmware:

Change the scaling for the Z axis in the firmware from 1.25mm/rotation to 2mm/rotation to match the new pitch of the lead screw.

In my case I changed from 5120 to 3200 steps per revolution for 1/32 micro stepping (DRV8825).