Need help with a framelock I'm making

Justin Schmidt · Jun 3, 2020

Alright so I've been trying to make a folder forever with no success.
Made a framelock but the blade wasnt centered so I thought it was the steel. I bought some cpm154 precision ground but I'm having the same problem. The blade is shoved all the way over to the show side. If I move the lock bar out of the way then the blade centers itself. So the lockbar is pushing the blade over. I'm using a mini mill with a reamer. Checking all my tolerances with a multitayo micrometer. Desperately need some help

HSC /// · Jun 3, 2020

Well I haven’t made that kind of folder but it sounds like you Have too loose of a fit in the pivot hole? It Should be within .0005”. Too much blade play in the pivot hole

do you have pin gauges to check the pivot hole in the blade?

Mark van Elteren · Jun 4, 2020

How far did you bend the lock bar? Just touching the opposite liner is far enough, any more creates unnecessary tension, in my experience. How tight is your pivot and what does tightening it do to the centering?
Regarding accuracy, I think that reaming with a mill is plenty accurate enough. I use a drill press with a decent drill, and can still get close enough tolerances.

Keep in mind this is all experience from linerlocks, I haven't made a framelock yet.

Natlek · Jun 4, 2020

Justin Schmidt said:
Alright so I've been trying to make a folder forever with no success.
Made a framelock but the blade wasnt centered so I thought it was the steel. I bought some cpm154 precision ground but I'm having the same problem. The blade is shoved all the way over to the show side. If I move the lock bar out of the way then the blade centers itself. So the lockbar is pushing the blade over. I'm using a mini mill with a reamer. Checking all my tolerances with a multitayo micrometer. Desperately need some help

To much tolerance between pivot and hole in blade or to much tolerance between holes in frame and pivot . Are holes for pivot in frame parallel to each other ? Do you have washers/bearings between frame and blade ?

Daniel Carraher · Jun 4, 2020

How far bent over is the lockbar and how thin is the lockbar cutout?

Justin Schmidt · Jun 4, 2020

Mark van Elteren said:
How far did you bend the lock bar? Just touching the opposite liner is far enough, any more creates unnecessary tension, in my experience. How tight is your pivot and what does tightening it do to the centering?
Regarding accuracy, I think that reaming with a mill is plenty accurate enough. I use a drill press with a decent drill, and can still get close enough tolerances.

Keep in mind this is all experience from linerlocks, I haven't made a framelock yet.

Just barely bent it over so it has about 20% lockup
If I tighten the pivot the blade centers but the blade is difficult to move

Justin Schmidt · Jun 4, 2020

Just checked my pivot hole with a pin gauge and a .188 pin gauge fit in snugly. I just ordered a reamer from ticonnector where I get my pivots so hopefully that helps

HSC /// · Jun 4, 2020

Justin Schmidt said:
Just checked my pivot hole with a pin gauge and a .188 pin gauge fit in snugly. I just ordered a reamer from ticonnector where I get my pivots so hopefully that helps

What is the pivot diameter?
What do you measure for the holes in the frame for the pivot?

it’s fine that you ordered another reamer but that’s not gonna help you if you don’t really know where your problem is

Justin Schmidt · Jun 4, 2020

HSC /// said:
What is the pivot diameter?
What do you measure for the holes in the frame for the pivot?

it’s fine that you ordered another reamer but that’s not gonna help you if you don’t really know where your problem is

According to my multitayo micrometer my pivot is. 1871
I use a pin gauge set to measure the holes in the frame

Mike Read · Jun 4, 2020

In my experience centering the blade is more to do with the blade, washers and scales all being flat and parallel than pivot tolerances. Tolerances between the pivot and blade hole as well as the pivot and scale holes would have to be amazingly tight to hold the blade central.
If everything is flat and parallel and square then you should be able to tighten the pivot screw and remove all blade play without causing the blade to bind.
If you cannot do this without the blade binding then something is off. Maybe the pivot or hole in the blade is not quite square, or the scales are not parallel or the blade tang is tapered.
If this is the case then the centering can sometimes be improved by opening out the blade hole a little so you can nip up the pivot and remove the play.

Mark van Elteren · Jun 4, 2020

Justin Schmidt said:
Just barely bent it over so it has about 20% lockup
If I tighten the pivot the blade centers but the blade is difficult to move

I am not really sure, but overbending should have no effect on lockup, if I am not mistaken. If you are using washers, have you oiled them and broken them in? A stiff blade will become much smoother pretty fast (to put it simply, the blade will will not feel so tight but will stay centered).