Michael Webb said:
You can use the 5/16 pin, just turn the front shank of the pin, not the insert to clear the insert with a comfortable fit. The brass inserts I make for the 3/8X16. I use a solid shank @.280 for 1 inch and I leave approx. 1/2 inch of threads. I taper the first two threads. The O.D. of the brass insert in threaded all the way, I hate that shoulder B.S.
Uni loc is a good invention EXCEPT, you can't turn the insert side between centers to face correctly because it starts right away with threads, instead of a concave first. I still can't believe that part was overlooked.
Maybe it's me!
I noticed that about them, the front of the inserts are tapered, but the bottom is'nt. I like the compression feeling fit to the joint, and the way they pop if you pull them apart quicky, seems like pretty close tolerences, but as far as the taper goes Even the non-self aligning inserts usually have both sides tapered, so not sure why not Myself either.
On the shoulder, I know what you are saying, pretty much depending on that small patch of bottom threads to be perfect, and hold. I do the bore for the shoulder with a small handmade looking carbide ID tool I picked up in a lot of drills and tool bits, and use It as a mini boring bar for them. It stays really sharp. I can take really small passes with It, and bump the fit for the shoulder in as tight or loose as I want to, and it's hard to take too much off with it, so It's perfect. I can get a really snug fit without it locking the insert during installation, or blowing the shaft out, and since it's bored I know I have a straight hole to align It properly. I drill the bottom to size, ream & tap afterwards, so what little threads are there, are all good, and grip the insert well. It seems to be working pretty well for me, but only time will tell for sure.
Apprietiate all the tips on the pins Mike, having fun with It. I am going to try the 3/8 next, Maybe a 5/16-14, then would like to practice cutting My own thread after, out of brass to start with probably, then on to ss.
Thanks
Greg