Todays Project - What did you do today?

[stevec]

I haven't posted much about actually doing things in the shop lately but today I launched into a little project to restore a part for one of my old Allis-Chalmers tractors (old being older than me). I had this distributor mounting device that looked like this.

   

Someone on the Allis-Chalmers forum suggested I insert a copper threaded piece and have it aluminum welded.

Soe I set about making the copper "plug".
After turning down the smallest piece of copper I had in stock I started to machine a hex head for the plug.
I only then thought of taking some pics.

   

I then put the piece back in the lathe and turned the shank to 3/8" D.

   

I then started to single point the 3/8-16 thread and found that copper behaves worse being threaded than turned,
probably due to my impatience to grind a proper cutting tool ( I had to rework the turning tool to get a nice finish to the 3/8" D
shank).
So, I decided to try the 3/8-16 threading die and with much lubrication and effort I got it to follow my ugly single point efforts.

   

Here's what I took to my "Vulcan" that welds aluminum".

   

The copper plug didn't "unscrew" as I had hoped but I had centre drilled both ends while in the lathe so I had no problem pilot drilling through from both ends and then drilling with a letter "N" drill which left me with a copper "half helicoil" that I removed with a pair of pliers.

A run through with the tap and here's what we have.

            

The newly welded aluminum did follow the "plug's" thread and so made a pretty good  "rethreaded" hole so I gues it did the job.
Maybe if I had dressed and polished the threads on the copper plug it would have un threaded all the way out? It did turn about 90°,
Next time (if there is one.)