Just a follow up to my Torx Bit Broach Thread.

[astroracer]

These are the short, inverted flare plugs I made using that "broach".
I used a piece of 3/8-24 threaded rod. I faced the parts off in the lathe, drilled a 3/16th's dia. hole about 3/1th's deep and then used a 90 degree C'sink to make the chamfer.
This is the fitting spinning in the lathe.


I then turned it around in the chuck and drilled a .173 dia hole about .25" deep. This is the hole to be "broached". In the pic you can see the starting chamfer I put in with a center drill to guide the broach and help get it started.

A couple of taps from a hammer set it enough I could get it clamped in the vise.

After pressing it home It took a bit of wiggling to get it out of the brass but doing that didn't seem to hurt the fit or operation of the "new" driver.

Continued in next post.

[astroracer]

I've made a few of these now with the latest ones on the right.

I got these significantly shorter then my previous attempts and they do the job very well with no clearance issues.

I think they look a ton better then that huge plug hanging down there.

I've used three of these so far on the van build.
Mark

[Frank S]

Very nice indeed. I was wondering if you concave ground the end of the torx bit to have a cutting edge but I see now that you didn't. if you had done so it might have helped in the broaching process and would have been needed on harder material such as steel. I used to make a lot of male JIC plugs out of 12L14 then broached a hex in them but my broaches were store bought cutters

[astroracer]

Thank You.
I concave ground an Allen hex key before I tried the Torx. All it seemed to do was gall up. The untouched Torx bit worked like a charm, as you can see, and I wouldn't change a thing.