Saturday, October 19, 2013

Lathe compound nuts

Since I still have the wreckless tendency to overtighten things, it was no surprise when I stripped the T-bolts for adjusting the compound angle on my lathe.  I obviously had too much leverage with a long 14mm wrench to tighten the nuts.  Another concern when the compound has a nut to tighten it is stripping the hex off the nut, which is no fun.  I opted to repair it by making some nuts to go in the base of the compound and secure it with an Allen screw.  This way I won't be as likely to overtighten it because the Allen wrench is much shorter than a 14mm wrench, it's also less likely to be obstructed by other things.  Also the bonus of not needing a 14mm wrench, ANOTHER VICTORY FOR AMERICA

I started with some 3/4" round bar of some good type steel (my "good" criteria is anything above hot rolled).  I took it to the lathe and drilled and tapped a 5/16"-18 thread through it.  Then, I used a parting tool to slice off 4 discs about .200" thick.

Even though only 2 are needed, I made an extra pair.
Next I put the discs in the chucker lathe to face off the back sides.  The collet makes holding such a thin item in a lathe much easier than a 3 jaw chuck.
After that, I took them to the milling machine and milled the sides flat to fit into the circular T-slot in the compound base.
In order for the screws to engage the most amount of thread, I had to buy 1" long Allen screws and face them down to about .825".  If they were too long, they'd bottom out on the compound base before tightening anything.  Too short and they'd not engage enough thread.
New hardware on the left, old on the right.
Back in service.

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