Liner lock and frame lock press fit stop pin?

Brian Avila

Brian Avila

Joined
Jan 2, 2011
Messages
1,286
I came to the realization today that my stop pin will go all the way through the liners because I have a 5/32" reamer. And that there is the possibility that after assembled, the stop pin could rotate in the liners.

The question I need help with is: if I wanted a press fit hole for my stop pin on one side of my knife what size smaller than the actual diameter of the stop pin is good? I am using 5/32" stop pins. This would keep my my stop pin from rotating correct?

-Brian-
 
Reamers are made in standard, over and under. If you want a press fit, you need a 5/32" undersize reamer.

Bob
 
When I look through the Enco website they don't specify over or under. Just all the sizes. I can get a .1560 or .1555 or .1550
 
I don't have a lathe. So the question is should I just leave the stop pin holes 5/32 so that the pin rotates?
 
5/32" is 0.15625" so technically all three that you list are undersize. I suspect they are not giving completely accurate sizes on the Enco website. I would shoot for half a thou (0.0005") under on something that small.

Bob
 
Brian Avila said:
I don't have a lathe. So the question is should I just leave the stop pin holes 5/32 so that the pin rotates?
Click to expand...

I don't see a point in press fitting the stop pin. The force of the blade hitting the pin will wear the hole and the press fit will be lost. I am just boring blind holes with a standard endmill to hold my stop pins in my framelocks. Well, all two of them.

Bob
 
RangerBobTX said:
I don't see a point in press fitting the stop pin. The force of the blade hitting the pin will wear the hole and the press fit will be lost. I am just boring blind holes with a standard endmill to hold my stop pins in my framelocks. Well, all two of them.

Bob
Click to expand...

So does your stop pin rotate freely inside your frame?
 
Brian, I think you'll find that it doesn't really matter except maybe in the very long term whether or not your stop pin rotates. Even in the worst case scenario that there's a tiny bit of slop or play in your pin, I think you'll find that your lock will act like a spring (like it should) and take up the slack.
 
Hopefully we will have ultra precise stop pins in a few weeks.

I've been waiting for the shop to finish my order since August. It took a long time to find a shop who would meet out tolerances without over-charging. We requested tolerances of +-.0002".

Chuck
 
Brian Avila said:
So does your stop pin rotate freely inside your frame?
Click to expand...

Technically, they can. The fit is pretty close tolerance but, it is not a press. I see no down side and a couple of benefits to this. When making the knives, assembly and disassembly is easier without a press fit also, the pin will wear more evenly over time if it can rotate. I don't really see the wear thing as a big deal but the test fitting is. Being new at folders, I take mine apart and reassemble dozens of times during the construction process.

Bob
 
I've never pressed fitted any of my stop pins; I don't see the point.

Press fitting the stop pin will also make it virtually impossible for the average user to disassemble their knife if desired.
 
Alpha Knife Supply said:
Hopefully we will have ultra precise stop pins in a few weeks.

I've been waiting for the shop to finish my order since August. It took a long time to find a shop who would meet out tolerances without over-charging. We requested tolerances of +-.0002".

Chuck
Click to expand...

Chuck I purchase stuff from you guys all the time.

If you get tight tolerance stop pins that are 5/32" I will get them from you.
 
Brian Avila said:
Not sure what a smooth non-sloppy fit is, which is why I was worried.
Click to expand...

If you make your holes with a 5/32" twist drill, you will have a sloppy fit. If you drill undersize and ream with a 5/32" standard reamer you will have a non-sloppy fit.

Bob
 
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