Forging a bit of progress on the CNC project. Smoothing out nicks and surface irregularities of the structural material through a gentle file hone and fitting the bearings onto the screws as outlined following.
In preparation I stuck the screws in the freezer for the afternoon, and the bearings in an oven (initially at 250 f) for ten minutes. I forget the actual room temperature dimensions, as they were compared at ODD a while back, but it did amount to an interference fit. The hope here was that between thermal expansion and contraction a fit could be made without the necessity of an actual press.
Note the frosty condensation at left offset by the heated metal at right, the metal cylinder was the bearing race "anvil" to alleviate hammer shock from being transmitted through the bearing itself. The first two involved hammering at the coupling end. This wasn't a huge concern as the coupling end is not a super critical precision surface as it will be floating to allow drift from minor misalignments to be taken up at the coupler as opposed to premature wear on the bearing surfaces (no mushrooming occurred).
The second bearing was a bit more resistant to installation, probably due to the cooling of the bearings during the first installation; so the third bearing was heated at 350 for five additional minutes. Additional heat was the key, as the third bearing required no hammering at all.
Installed, ready to move on to structural plotting, based on actual measurements of installed screws.
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