Tuesday, June 20, 2023

Old Habits Die Hard

I started cutting the acetal inserts that go into the aluminum sleeves which will go on the Losmandy Lightweight tripod legs.

This involves cutting a 30 degree angle so the bottom of the tripod legs rests on a flat surface and non-square end of the insert is parallel to the ground where I drill and tap a hole for the caster.  The insert only needs to be long enough to allow a 1" stem to not penetrate to the bottom of the tripod leg.  As short as possible in this application to reduce the added height.

The process is simple enough.  I put the piece of acetal on the fence at 2" from the end and clamp it down, then turn the miter to 30 degrees and cut.  Then I turn it over out the sharp end at 2", put the miter at 0 degrees and cut.

I only need three of these inserts but because I was so used to doing four or five sets at a time, I did not stop until I had cut five.  There are slight discrepancies in the lengths because a chop saw is not a precision tool.  I can take the three closest in length and use the mill to get them within .01", which is adequate for this purpose.

The 2" x 3" x 0.25" wall tube is supposed to arrive tomorrow.  The same process will give me three leg envelopes.  I will then machine the inserts to be .01" smaller than needed so they are if not a true press fit, close enough to require some pressure to push in position.

Then drill through the aluminum tube with a .201" drill to make the pilot hole in the acetal to tap for 1/4"-20.  Then enlarge the holes in the aluminum to .265".  Any slight variation in position of the insert in the sleeve will get pulled into position as the screw turns into the acetal. 

I will use the Tapmatic to tap the inserts.  I use four screws on each insert, so the Tapmatic greatly speeds up the process.

Historically, I have used hex head 1/4"-20 screws to lock the sleeves in place but I think the knurled thumbscrews work well enough and look closer to the Losmandy esthetics.  I still would love to find some 1/4" diameter rubber tips to glue on the thumbscrews.  I might find something in the Ace Hardware odds and end fastener drawers.

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