Question about hole sizes on Bearing Slide Assembly

[kevperro]

A friend of mine is cutting the bearing slide assemblies for me and there are no hole dimensions in the PDF. From the downloaded Edrawing I'm showing 0.344" for the X-axis bearing slides that use the 5/16" bolts. That gives a fair amount of slop considering the bolt is about 0.304".

Is that desirable in order to align the machine on the rails? That is the only reason I can think of for that amount of wiggle.

[BobF]

The alignement comes from the fit of the angle in the grooves. The extra wiggle room allows you to be off a little on the hole location in the aluminum verses the MDF and allows for the difference in expansion due to temp.

[kevperro]

Originally Posted by BobF The alignement comes from the fit of the angle in the grooves. The extra wiggle room allows you to be off a little on the hole location in the aluminum verses the MDF and allows for the difference in expansion due to temp.

Great.... he has the machine shop and said that all tolerances would be within a couple thousands. Guess that is a little overkill. :-)

My X-axis table is nut-on. I skinned it yesterday and this thing is starting to look like a machine.