Folder detent

[Shane Wink]

After several years of making fixed blades and with new rules at work I am looking at making some frame-locks. I have researched out several threads and designs and notice that some frame-locks have a 1/16 hole drilled into the lock for the detent. I can see how easy it would be to lock the blade in place and then drill through the lock and into the blade but for some reason the little hole in the lock just bugs me. I figure I can just lock the blade closed as before and drill from the other side through the blade and into the lock, but how do I make the detent ball stay in and is this the right way to do it?

 

[Calvin Robinson]

Yes you could do it that way. For a 1/16" ball Drill through the blade with a 3/64" bit, just spot your hole in the lock,then you would need to drill into the lock with a bigger bit to the depth you want. I can't remember the size of the bigger bit should be,if I can remember tomorrow I'll look it up and let you know. Then you would press the ball into the hole in the lock,it will be a friction fit. You will need to use a shim to make sure you get the ball to the proper depth, you want the ball to protrude the same thickness as your pivot washers. I use a staking tool to stake the ball so it can't come out,I don't think it is necessary but I do it anyway.

 

[EdCaffreyMS]

My method is to drill through the liner and into the blade with a #55 "Hi-Roc" bit, then ream the liner with a #53 bit. This will allow for a "press fit" of a 1/16" bearing/detent ball. I generally have to "tap" the detent in with a hammer.

The way you want to do it.....drill through the blade and into the liner with the #55, then ream the liner/lock bar with a #53. The only problem I can see is that it will be tough to drill through the blade and into the inside of the liner and get the location right/correct. (That's the biggest reason that most folks drill from the outside of the liner and into the blade.)

 

[BRad704]

Ed,

Thank you for putting the 55 and 53 in there. that is something I have go search for on every new liner lock.

As for actual geometry, do you drill straight through with the blade in the exact closed position? or remove the stop-pin and "over-close" the blade by a tiny bit?

I only ask because I have been told on good authority to over-close the blade before drilling, that way the detent never bottoms out when it is against the stop pin.

 

[EdCaffreyMS]

I drill straight through the liner and into the blade, while holding the blade tightly in the closed position.... the difference in the bit sizes (#55 (.0520") in the blade versus the .625" diameter of the 1/16" detent ball makes the blade "suck" into the close position. Another trick that a lot of us use is to relieve the "back edge" of the detent hole in the blade ("back" being with the blade in the closed position). This works especially well on framelock "flippers" and for reasons I cannot explain in print, will make the blade "suck" into the closed position even better/harder.

 

[BRad704]

I believe your second scenario is what I was trying to describe... that way the ball pulls harder and has nothing to "bottom out" against.

I like the idea of drilling straight with the blade held tightly closed. I will try that on my next folders.

Thanks Ed!