Framelock vs Liner lock geometry

[Triple Stripe Knives]

Hi all,

I'm a fairly new maker, and have made a few folders. I made a batch of five framelocks a few months ago, and have more recently made various full liner/inset liner locks.

When I was making the framelocks, I had a lot of trouble with the locks failing under fairly light pressure. They were ground at 7-7.5*, and the lockbars are around 2" long. Even with heavy lockbar pressure, and 50-70% lockup, they would fold unexpectedly.
Once I started doing linerlocks though, the locks were solid. These were ground at the same angle, with either .062 or .040 ti, and the same 2" ish long lockbars. Does anyone have any ideas as to why the frame locks fail, but the liner locks are strong?

Thanks.

Also I've read a bunch of the previous threads on lock grinding and such, including the one by REK Knives , however I couldn't see anything that related directly to this. Issue.

 

[Daniel Carraher]

Are you sure the lockbar is cut square to frame? At 7* you shouldn’t have lock slip issues. How’d you cut the lock?

 

[Triple Stripe Knives]

Are you sure the lockbar is cut square to frame? At 7* you shouldn’t have lock slip issues. How’d you cut the lock?

I cut it in the mill, with a dremel disk. Do you think I would get better lockup if I put a backwards angle when freeing the lockbar?

 

[JRB Blades]

Yea, 7* shouldn't spontaneously unlock like that. I cut mine at 7.5* and they are rock solid. If anything, that low of an angle should have a tendency to have lock stick. I'd expect that kind of unlocking from a 10+* lock face. How are you determining the lock angle you are grinding? I use an electronic angle cube and place it on my platen and zero it out. Then place it on my work rest and get the angle to around 7.5* and I haven't had any issues with lock slip yet. I follow you on instagram, my username is @jrbblades. Feel free to message me on there if need be.

 

[Triple Stripe Knives]

Yea, 7* shouldn't spontaneously unlock like that. I cut mine at 7.5* and they are rock solid. If anything, that low of an angle should have a tendency to have lock stick. I'd expect that kind of unlocking from a 10+* lock face. How are you determining the lock angle you are grinding? I use an electronic angle cube and place it on my platen and zero it out. Then place it on my work rest and get the angle to around 7.5* and I haven't had any issues with lock slip yet. I follow you on instagram, my username is @jrbblades. Feel free to message me on there if need be.

I determined the angle with a digital protractor. On the liner locks though, I used an app on my phone.

Yeah man I follow you there! Good looking stuff!

 

[Daniel Carraher]

I determined the angle with a digital protractor. On the liner locks though, I used an app on my phone.

Yeah man I follow you there! Good looking stuff!

Get an angle cube. Far more accurate and cheap enough