ACME rod support

I am interested in the ACME rod for the x-carve. I have watched the assembly videos for the M8 and ACME rods. For the M8 rod the weight of the spindle assembly is supported by the upper nut that is screwed onto the rod. However, the ACME rod seems to be supported only by the 2 set screws in the pulley that engage the thinned down thread on the upper part of the rod. Is this really enough to support a heavier spindle like the DW611 or Colt? Compare with the ACME kit from Improbable Construct which supports the ACME rod from below.

@WernerMrazek Only a few of the first prototypes were made that way. While they have held up for months in our shop with the Dewalt without issue, we have made a change to the rod to add a nylon locking nut to the top of rod. They are currently shipping with this version.

Here is a link to the GrabCAD version.

Thank you very much for your reassuring reply. Perhaps you should indicate this in the assembly video. I am sure I am not the only one who noticed this.

Thanks, they are working on that right now.

Has anyone figured out how to calibrate the acme rod to move the correct distance? Should I change the steps per rev in tgfx (using tiny g) and is there a good starting value? Currently my z axis is moving about twice the distance it should.

Here is a link to a spreadsheet to show you how it it’s calculated. You will need to save your own copy of the read only spreadsheet.