Some Driveline Enhancements

Variations Too, again

So. I've been dragging my feet -- once again -- because everything just seemed too hard over the holidays, but I have made progress none-the-less....

While doing limited in-camera demos I found that the Variations second arm linkage just tore itself apart pretty consistently. This was due to there being nothing but a bit of stickyness holding the axle into the arm. I originally used two pins through the whole sandwich to keep the gear from spinning, but I didn't have anything really holding the layers together, and there was too much torque for the sticky to manage.

This has, perhaps, been remedied:

Improved(?) axle mounting

After the arm was all re-assembled, I drilled a hole longitudinally through the circular backing plate and the axle, and glued a 1" long by ~1/32" diameter nail into the hole. This of course requires solid drill press, or mill, mounting and careful attention to not breaking the (@$!@#) miniature drill. Here you can also see the two pins (little brass brads, also about 1/32" dia) that pierce the entire sandwich to prevent the gear from spinning on it's own.

Compare to the previous layout, where the above photo is looking straight on from the bottom:

So. After assembling and gluing all the little bits into their sandwich, one needs to fire up the machine shop and drill two transverse holes almost through all of plate-arm-gear layers -- the almost part being that we don't want to completely pierce the gear itself, thus the pins need to be shorter than the full thickness (which may vary according to the arm material). Then rotate the arm and drill a longitudinal hole through the backing plate and axle -- basically straight down, centered where the "Plexiglas backing plate" arrow points in the above -- Gear Linkage -- photo. THEN glue the relevant pins into the holes. I've tried both: Goop, which is a bit hard to get schmushed into the holes but sticks to the pins; and: filled acrylic-solvent glue, which can be squirted into the holes but only sticks to the pins in an advisory way. Fortunately the sticky provides little in the way of mechanical advantage, it only needs to keep the pins in place.

I did this for the two lower arm linkages and made the executive decision that the torque on the smallest, upper, arm did not merit the extra effort. YMMV...

 

So.

I think this may be the end of the mechanical portion of our time together, save perhaps for cable routing which is still rather ad-hoc.