Thursday, August 25, 2011

Banjo Bolt Prototype

Played around tonight with making a pre-production prototype banjo bolt. Here are a couple of pix:

Everything went smoothly (turning, drilling) except that I am having a helluva time getting the 3/8 x 16 die started. Nothing I tired worked. I need to learn more about thread cutting, and then I could just cut the threads on the lathe... You can see that I tried cutting light threads with the lathe to get the die started...

I would face the end after threading... If you have any brilliant suggestions, I am all ears!


BitMonkey said...


I took a quick look and it appears the OD for a 3/8-16 die should be .339/.344. Is that about what you have? Are you having probs with the die because it's too hard to turn or the bolt is too short to get it started. Sometimes it helps to back the die with a live center in the tailstock, just to get it started straight. It's been too long to offer much add advice on lathe threading. When I did it once in a while it didn't seem like a big deal. I remember grinding a decent tool to be the only tough part. You need
one of these suckers.

There are a couple of real machinists that check in here once in a while. If you are out there, any advice?

Flathead45 said...

The problem is probably the o.d. I should have checked that... I am surprised it's that much smaller than 0.375... I am at about 0.365. If this is the case, I should be able to easily turn down the shank and try again...

Funny that you mention backing the die with the live center in the tailstock. I eventually improvised that method last night. Still didn't start, but probably because of the o.d. issue.

I'm Cossacking most of today and tomorrow. Stay tuned.