Liner lock help

Sean Cochran

Sean Cochran

Well-Known Member
Ok, so Ive finally got some time to work on knives and I thought I would make the switch from slipjoints to liner/frame locks. Well....maybe not switch but at least give it a try.:biggrin: but I need some help (Frank, Les, Les, Ed....somebody????:31::3:)

Ive looked at several tutorials and the question I have deals with the detent. I know some makers drill from the backside of the lock so the detent hole is all the way through. Ive seen some who drill from the front and use the scribe method for the hole in the blade. If the hole is all the way through how do you keep from setting the ball too far in the lock?

What are some of your secrets guys? Ill trade some slipjoint mojo if anyone is interested.:biggrin:


Sean
 
(for a 1/16" detent ball) With the blade assembled in the liners (no handle scales on) I gently hold the blade in the closed position. Using a #55 Hi Roc bit, I drill though the liner/lock and into the blade...depth isn't critical, as long as it's deep enough for approx. 1/3 the diameter of the ball. I then place a Popsicle/craft stick between the blade and the liner/lock and drill the liner with a #53 bit. I "set" the detent ball with a very small hammer...a couple of taps and then I measure with a set of calipers...tap and measure until the detent ball is seated just just less than the washer thickness plus any "relief" cut made in the handle scale.

I've tried the scribe method, and for me its generally about a 50% success rate....the method I described above is the LAST thing I do to a folder, and for me it works every time.
 
2 things i have done for setting the depth of the ball is use 2 washers and set tyhe depth then ajust a bit if needed to clear everything

the other is use a vice or soem other screw closing jig to "press" the ball in jsut how far you need it

for me also the nearly last step in making the knife
 
Drill a small hole in a piece of shim stock that is a couple of thousandths thinner than your washer.
Place that over the ball and press it in.
I use an .018" Shim for .020" washers.

I'm a hole all the way through the liner guy because every now and then, you need to remove the detent.
Much easier to remove if you can press it out.

I quit doing any relief in the handle of a liner lock when I went to .020" washers.
You want as much of the ball protruding as you can, so the contact between hole and ball is steep.
Every last thousandth makes a big difference, since that is where the ball is getting steep.
The further the ball goes in the hole, the less spring pressure is required to keep the knife shut, and so you can make your spring feel much "softer" and still be secure.

I learned in the Terzuola shop a few months ago, that .020" washers are about perfect.

It's very interesting to actually draw the ball/hole relationship out in CAD, from the edge perspective, and see the difference hole diameters make in the apparent angular contact made by the ball and the hole.
 
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I don't mean to hi-jack this thread, but since we're talking detent balls, I would like everyones take on the location of the detent for a flipper, I've heard that the location is more critical for flippers because they have to have such a smooth action, my first folder of any kind is on the bench right now, and as soon as I finish up on Christmas orders it is my next project. Also any good web sites for beginners would be awesome as well!!!!!
Thanks Everyone, and again, sorry to butt in with my problems! Rex
 
You don't have many choices on location.

It's gotta go on the lockbar, in a place that won't fall off the blade.

How well it seats is very important though.
 
That "snap" that so many folks like on "flippers" has more to do with the pivot system than the detent. When it comes to the "snappy" action often associated with flippers, pressure on the lock/detent, in the closed position is the key. The problem with most common pivot systems is that ANY side play detracts from that "snap". Because of the way it works, the IKBS would be my choice for a pivot system in a flipper. With a standard pivot arrangement such as a threaded barrel with washers, it's next to impossible to keep everything tight enough for that opening "snap" on a blade....as the blade will shift ever so slightly side to side. And if this type pivot system is tightened down enough to prevent the slight side play, it's not "fee" enough to allow for easy blade travel. So in reality, it's combination of several factors that make a flipper work, or not work well.
 
Great info guys. Thanks.

Ed, Ive looked at your tutorial and I think Im going to try your method because to me it seems most logical. I have Bob T's book, in it he says that the scribe method does not require as much presicion as the way you do it. Frankly that doesnt make sense to me. It seems that by drilling through with a smaller bit would make concentric holes that when the detent hole is drilled larger makes the holes ecentric without having to measure or place them.

Brian, If I follow correctly you are setting the ball .002?

Thanks again for the help guys, its really cool to be able to have makers of your qualtiy answer my questions.

Sean
 
What I do is drill the hold the blade held closed by hand or a clamp and drill a 55 hole through the leaf and into the blade. This depth is not important other than to be about .020 into the blade. I take the assembly apart and re drill the hole in the leaf with a 53 drill bit the size needed to accept the 1/16 detent ball. To install the ball I place iit on the hole , put a washer of the size I use overtop and tap it into place with a large flat punch. I now take the liner with the ball installed, place a wedge between the spring and the rest of the liner and remove say .010 off of the scale side at the ball end,on an angle back about half the length of the leaf. Frank
 
I also do the drill through method but use a #60 drill bit for the original hole and the depression into the blade. Follow with the # 53 through the lockbar for seating the ball itself.
Steve
 
Sean Cochran said:
Brian, If I follow correctly you are setting the ball .002?
Click to expand...
I leave the balls .018" proud of the lockbar.

To do this, I have a piece of .018" shim stock with a hole drilled in it.

I place the ball on the hole in the lock, and then the shim stock over it, with the ball in the shims hole.

I have a 3/8" carbide rod (non-cutting side of an endmill) in my arbor press, and press down hard, until the carbide is in contact with the shim.

My ball now protrudes .018"

FWIW if you use ceramic balls, drill with a 1.55mm drill to captivate the ball.
 
Fellhoelter said:
I leave the balls .018" proud of the lockbar.

To do this, I have a piece of .018" shim stock with a hole drilled in it.

I place the ball on the hole in the lock, and then the shim stock over it, with the ball in the shims hole.


I have a 3/8" carbide rod (non-cutting side of an endmill) in my arbor press, and press down hard, until the carbide is in contact with the shim.

My ball now protrudes .018"

FWIW if you use ceramic balls, drill with a 1.55mm drill to captivate the ball.
Click to expand...

Thanks, that sounds simple enough.
Thanks for all the help guys, Im sure Ill have more questions.
Sean
 
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