chicago screws for folder pivots.

[joe9knives]

I see some liner locks that appear to have chicago screws for pivots. Is this true or am I seeing things? Are they hardened enough for this purpose?

 

[novaflare]

I would have to say like all other bolts and screws they have a specific hardening for a given purpose.

So dont go down to your local hardware store and buy the first ones you see go to someplace that deals in machine screws and choose one that a few points under the hardness of your planned blade or purchase after HT. Or even better stock some of varied rc and use one just under blade hardness.

Little off topic but also not
Ive always wondered why makers do not use a roller bearing inside the pivot hole in the blade and the pivot screw through the center of the roller bearing.

I my self do not have the tools or skill needed to make folding knives so ive never been able to try it my self.
Maybe ill take a junker i have laying here and drill out the pivot hole and try to mod one to test.

 

[Stacy E. Apelt - Bladesmith]

You mean like this:
http://www.knifekits.com/store/s-pages/kk_store_1mainframe.htm?kk_products_parts_main.htm~smain

 

[novaflare]

You mean like this:
http://www.knifekits.com/store/s-pages/kk_store_1mainframe.htm?kk_products_parts_main.htm~smain

Na those are just bushing inserts.

I ment more along these lines just non tapered ones.

http://www.timken.com/products/bearings/products/TaperedRollerBearings/singlerow.asp

The ones im thinking of are commonly used in rc cars and the like. Thats the main reason i still have like 300 of them in various sizes laying around the house heh.

Reason i think they would work nice in knives is because one thing ive seen in even the best production liner locks is blades that develop side to side movement and you need to tighten down the pivot screw. I think useing a pressed in roller bearing would lesson or get rid of this.

 

[joe9knives]

i see some linerlocks with larger than average pivot screws and they appear to be regular chicago screws like you might find on some kydex sheaths. for novaflare. i think i saw roller berings for folders in tks's catalog for around 6 bucks each.

 

[Stacy E. Apelt - Bladesmith]

Ball bearings and roller bearings have been used by several makers.Darrel Ralph uses them ,IIRC.Problem is that they will have too much slop and attract/retain too much dirt and grit. The bushings have super close tolerances, and are smooooth.

 

[joe9knives]

anyone use anything other than the usual knife supply companies folder pivots?

 

[Fellhoelter]

anyone use anything other than the usual knife supply companies folder pivots?

Personally, I make my own.
I use a 3/8" bronze bushing, similar to the picture above.

It allows you to crank down on the pivot screw, and never have play, or need adjustment, etc...

 

[joe9knives]

Personally, I make my own.
I use a 3/8" bronze bushing, similar to the picture above.

It allows you to crank down on the pivot screw, and never have play, or need adjustment, etc...

what do you use for the pin that goes through the bushing?

 

[Fellhoelter]

Precision ground 3/16" Diameter 440C drilled and tapped 6-32.
Those you can buy, though now that I think about it, I don't know if anyone stocks them with the 6-32.
I think the common thread is 4-40, and that's just silly because the head diameter on a 4-40 button head is .213
It's .260 on a 6-32

.013 per side just isn't enough shoulder for me, so I make 'em.

They give me my precise, repeatable location.
I drill and ream 3/16 through my liners/frames, so everything goes back together the same every time.

I can take them apart, and when I put them back together I can crank down on the pivot, and it's the same as it was before I started.