Drive shaft support for Kossel XL, so that the shaft is supported on both sides of the belt pulley

Kossel XL

No

No

0.2mm

50%

The support is designed for a 16x5mm, 5mm id bearing. I have included the Freecad file, to allow tweaking of the hole for the bearing. If you load the file in the part workspace, and delete the cut, you can resize the cylinder that cuts the hole, then recut. The stl file has the hole with a radius of 8.08mm, which gives a tight fit for the bearing on my printer.

To fit the mount, you have to remove the belt and motor, then drop the mount in. I used hex head bolts in the 1515 groove to fix the support. I have added extensions to the arms of the mount to help with alignment - the bearing has to be exactly at 90 degrees to the motor shaft. I fitted the toothed pulley with its collar towards the motor - mounting as near the motor as possible allowing free movement. Bring the motor into position, slotting the shaft into the bearing. The mounting holes for the motor should be perfectly aligned. There is not much room to tighten the motor bolts - I cut down an old Allen key so the the short arm is about 4mm. Still quite a fiddle to get the bolts in place. Note also that I am not using a shock absorber - the shaft of my motors are just long enough when directly mounted. Once everything is tightened down, check carefully to ensure that the motor still rotates freely.
I find I can tighten the belts on the Kossel XL with much more confidence that the motor shaft is not being deflected upwards. Prints seem sharper after fitting the supports. The print of the support shown was done after fitting the supports.

Note that I added the arm extensions after fitting my original efforts to the printer. I found it a bit tricky to align the support - hopefully if it is fitted with the extensions aligning to the end of the extrusions, all should be well.