Actually all yall can give me feedback,

Over in the knifekits forum a new guy has a question about press fit pivots. Would you be so kind as to check it out and tell me from a machinist background the way it should be done.
http://www.knifenetwork.com/forum/showthread.php?p=228258#post228258

I'm still looking forward to checking out your shop (if the invite is still standing), maybe after I get a few of your designs actually put together:)

Thanks for taking the time,

Bill

Hope you and you wife had an awesome Thanksgiving!

Bill, Dennis Greenbaum has already given good advise if I understand the thread correctly.

I doubt that anyone makes a step drill that would fit precisely. In any case, its necessary to use a 3/16" reamer.

As a last result, I could make the guy a step drill for less than $500.00.

He sounds like he's building hundreds of those kits at once.


Take note of the announcement for the new knifemaking school.

Thanks Don,

My question was more of "how" does the press pin work than how to make the hole. I was saying that the head was the part that was pressed in (and the barrel being more of a slip fit) and Dennis seems to be saying that the head just rests on the counterbored lip of the hole. I agree that it ends up there but with a bigger diameter hole than the head the pivot functions more like a smoothed out cap screw without external threads if you will.

If the diameter of the pivot is .1875 and my hole is reamed out to .1875, will I have a press fit or a slip fit? How much bigger should a slip fit hole be than the piece that needs to slip? And normally (for future reference) how much smaller should my hole be than the part I'm trying to "press" in? The head of this pivot is supposed to be .204-.205.

Doesn't the material of the pin either shear off a few thousandths or compress in order to slide into the hole? On my Barlow, after I pressed the bronze bushing in, I had to ream out the ID for the 1/8 pivot to slide in where it had freely done so before being installed. With a stainless pivot I wouldn't think that the threads would be affected adversely.

Have you already posted something for the school? I haven't seen anything yet.

Bill

Bill, I never use a press fit pivot. The ones I've seen have a standard size barrel with a slightly oversized portion under the head that is intended to be pressed into the reamed hole in the liner on one side.

In other words, if the pivot has a 3/16" diameter, you would ream both liners to 3/16", then force the head end of the pivot into the liner on one side. That would require pressing the oversized portion of the pin under the head thru the liner.

I would never do that, since it's necessary to disassemble a linerlock several times while fitting and finishing all the parts. If you had a press fit, then knocked the pin out and put it back several times, you'd just end up with a slip fit again.

As for what a slip fit is, the ideal close slip fit would be where the pin must be pushed thru the hole in a liner with your finger. That's great when it happens, but a loose slip fit obtained by a standard size reamer works fine for folding knives.

All you need to do is drill the hole .005 to .010" smaller than the reamer, use cutting oil, and ream with a standard reamer. No big deal. :eek:

For the school announcement, go to the list of forums and look for the school of knifemaking.

I'll look forward to having you participate. :D

Awesome! Now I know how it works. I had the right idea but didn't know the barrel had a raised portion. I've never used one either but if I spent $30 for 10 of em I'd want to do it right. Think I'll stick with the ones you use too.

I'm cheking out the school forum next!

Thanks again,

Bill