framelock lockup problems

Bailey Knives

Bailey Knives

Knifemaker / Craftsman / Service Provider
Joined
Oct 18, 2004
Messages
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This is for all you folder makers out there. I am just starting making folders. I have a framelock that locks up nicely, but it is almost impossible to unlock, it is just incredibly sticky. Sometimes I have to put a butter knife in to pry the lock off. I have tried nearly everything I can think of and nothing seems to work. Any suggestions?
 
I tried 240, and even sanded them to a near mirror polish. Still sticks like superglue.
 
I just ordered a carbidizer. Hopefully that will help the titanium be less sticky
 
What percentage of lockup do you have now? What's angle did you cut it at? Can you force the lockbar further in? Does it stick only when opened hard? Is the contact only at the very outside?

Maybe just needs a good breaking in but the carbidizer will help.

Mark
 
Heat treat the lock bar , I always blast the face with fine grit abrasive then heat treat the titanium. Just bring the end of the lock bar up to.bright orange and quench in water. Titanium is only going to get so hard . Should solve your problem.
 
I heat treat prior to inserting the detent ball, the titanium is still plenty flexible so no worries about cracking or other issues when you do put it in.
 
When you have lockstick that bad it's your lock geometry.

Lock geometry is an artform and lots of stuff that can go wrong. Here are the angels I use:

8 deg angle on lockface, 1 degree draft up and down, lockbar with 3 deg. I polish to 600grit.

I got a lot of good advice from some of the top flipper makers and they all do something similar. Most of the top guys do not carbidize the lockbar. Some of them do heat it 3 times, letting it air cool but thats it.

*you want it to wear correctly so not lock rock, but you can't have sharp angles as well, it will bit in the lockbar. Only small contact point is desirable.
 
I'd check a couple of things...

- are the locking areas parallel? check where the wear is

- how much lock area? too little will cause more stick... also keep in mind that too much will eventually cause lockrock


It could be several other things but if everything has been done well these are two areas that can be easy to overlook while learning to make framelocks. Is there any movement after assembly... are you using screws to keep everything tight or does it fit together nicely without them?
 
Here is what works for me every time, all the time on titanium that is .038 or more and blades .070 or more ! I cut the lock face flat on the blade at 11degrees with a 120 grit belt and don't change that. I do this by placing a 1/8" piece of bar stock on my flat grinder table which is locked at 90 degrees and have the front edge 7/8" away from the belt. The leaf I size down with a 16 belt with a bit of relief on the back or scale side. I have done this for years. I do not use any sort of hardening.
Frank
 
Thanks for all the advice everyone. I will have to try some of these. I got frustrated with it yesterday and just started working on some fixed blades. Much easier!
 
I think I figured it out. The lock bar was not lining up flush to the blade tang. It was hitting on the bottom portion of the lock, and that was all. Are there any tips or tricks to make sure everything lines up flush?
 
For future knives I would come up with a way to take apart and put back together the knife easily so you can file the lock bar and tang slightly until you get a prefect fit, testing it after filing. Recently I made some folding knives (not great quality, it was a learning experience) and this is what I would recommend to anyone attempting to make a folder. Make sure your pins/pin holes are not angled or off center. This is only really a problem if you didn't use a drill press, but can cause the blade to try to fit in the handle at an odd angle. Make sure the lock bar is thin enough that it can be moved easily/doesn't apply too much pressure to the blade when it's opening. Also, don't file down the lock bar too much, because then the blade wobbles and you have to make a new scale with the lock bar. Filing either the tang or the end of the lock bar at a slight angle can help it wedge into place more securely, preventing wobble and allowing it to lock correctly. I would also try trial and error on scrap stuff to see what seems to work for you. I hope this helps.
 
Bailey Knives said:
I think I figured it out. The lock bar was not lining up flush to the blade tang. It was hitting on the bottom portion of the lock, and that was all. Are there any tips or tricks to make sure everything lines up flush?
Click to expand...


- Set your stop 100% (do all final grinding work for the stop relationship when the knife is open)

- mark blade with Dykem or a marker around the lockup area

- assemble and open your knife

- with the knife open use a scribe (if it fits), razor blade, feeler gauge, etc to mark a line just along the end of the lock bar between the gap in the frame

- take apart... you should now have a mark on your blade very close to where it will lock up

- grind to this line.... when you get close check for lock fit. I will literally take 50 tries to do this as just short is still OK and too far means a trashed blade.


One tip is to clamp a 1-2-3 block, carpenters square or something to your workrest so when you are grinding the lock the angle is always the same. I'm just talking about lining the knife up and clamping something down beside it so it will still slide on your workrest.
 
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I do the exact same thing as Daniel. I don't measure it but when I work to the scribed line Daniel mentioned I cant the blade slightly so as not to grind exactly parallel to that line. I want to grind a little more away from the tang towards the spine so that final contact is at the outside toward the edge side.
 
Thanks guys. That has been very helpful. Since the current knife is trashed (ground too far trying to get it to fit up) I will have to do all that on knife #2. I appreciate the time you took to help me out. This knifemaking community is great.

On a side note, I was watching Forged in Fire, and thinking to myself how different it is from other shows like that. The contestants seem to really like eachother and respect the work that the others do. I have seen enough reality TV to know that this is unheard of. In the entire season, I don't think there was any back-biting, or gossipy talk.

Having you all help me on an issue reminds me of that. No one has to take the time, yet you all seem to do it.

Just saying thanks.
 
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