pivot bolt size

[joe sangster]

I am relatively new at folder knife construction. Is there any rule of thumb regarding what pivot bolt size to use ? Thanks, Joe

[didtas]

HI JOE,

Re pivot pin size ,I use 3/16 pivot pins for the folders i make.the blades on the knives being 3 inches long.hope this helps.the pivots i use are hardened 316 stainless.


Regards Daniel DIDTAS .

[Brett Schaller]

For locking-liner folders, I use 1/8" for small-to-medium sized knives, 3/16" for larger knives.

[joe sangster]

Brett, thanks for your reply . Thats what I've been using but got to thinking that I should be using 7/32 on the med / large liner-lock. Joe

[Jeremy Krammes]

I build alot of folders with 3.5" or bigger blades, and I use 7/32" pivots. I also use alot of .080, or .100 Ti for my liners, and 3/16" stop pins. All of that is overkill, but that is how I want it to be. When I do the smaller gents/art knives I will use 3/16" pivots. It's all in what you want.

Jeremy

[DaveL]

I know one maker, a very good one, that uses 1/8 inch pins but he sets that in a 1/4 inch bushing which he leaves just wider than the blade. He says the action is on the bushing and not the pin.

[Messinger]

Originally Posted by DaveL

I know one maker, a very good one, that uses 1/8 inch pins but he sets that in a 1/4 inch bushing which he leaves just wider than the blade. He says the action is on the bushing and not the pin.

The action is on the bushing, but the shear forces are still on the pivot pin. But...even a 1/8" threaded stainless pivot pin is a whole lot stronger than any of the little soft peened pins in a slipjoint and they seem to hold up pretty well.

-Ben M.

[Frank Niro]

You could use a 1/8" pivot and if you hammered on the back of the knife over the pivot it would not break, but the small screws would allow it to spring apart. Try it some time. So for tackicals and large working folders I use 3/16 and 1/8 for other folders. Frank

[joe sangster]

Does a smaller pivot give more lateral strength ? Joe

[Messinger]

Originally Posted by Frank Niro

...if you hammered on the back of the knife over the pivot it would not break, but the small screws would allow it to spring apart.

What small screws? [sly grin] I have to confess that I'm a Donvert (Don Robinson convert). I'm using four big barrels to hold mine together. This little guy (2.75" blade) has four 3/16" barrel pins holding it together under the scales/bolsters. The only little screws are the ones holding the scales/bolsters on. 3/16" on this little folder was overkill - I should have used 1/8" but didn't have any in inventory at the time. My EDC is from the same patern but done as a framelock and I've actually been thinking about doing a yield test on it (how sick is that). It would be an excuse to have to make another one.

-Ben M.


EDITED TO ADD: Frank, I assumed at first you were talking about the small screws many makers use to hold the spine and liners together. Is that what you meant, or were you talking about the pivot-pin screws? Maybe I made the wrong assumption. By the way, I think your work is AMAZING.

[Frank Niro]

Yes it's the pivot in screws I was reffering to. As to my work I thank you for your compliment. Appreciation from fellow makers is important to me. Frank