Liner lock problem

[dan van]

I am finishing up a liner lock folder and all works well except but after cycling the blade open and closed about 30 times the lock became quite sticky. I am wearing my thumb nail down trying to unlock it. Any suggestions ? Thanks Dan

 

[Frank Niro]

Hi Dan.
This is a strange one to me and I thought I've had every problem there could be with liner locks. Perhaps the leading edge, or locking edge, of the leaf now has a burr formed on it? Sorry I couldn't be of more help. Frank

 

[Chuck Gedraitis Knives]

It could be a couple of things. Do you have too much bend in your lock? This would put more pressure on the lock and have it "bite".
Do you have too much of the lock face engaging on the blade tang?
Is the blade tang flush with the outside edge of the liners or is it inset? This would cause the blade tang to dig into the lock face.

 

[clancy]

if you could post a photo of the lock it would help.
what angle did you grind on the back of the blade?

 

[dan van]

I'll try to get a photo but I can say that I ground the lock angle on the blade at 9 degrees and is polished to about 600 grit. The lock leaf was cut with a dremel cut off disk using a drill press and a drill press vise and I stoned the locking face. The lock leaf is approx. 1.60" long bent enough to reach the left liner. I will take another look at the lock face. Thanks Dan

 

[dan van]

I was able to get rid of the sticky lock, I sanded both the lock angle on the blade and the face of the lock leaf with 800 grit paper about 6 times. It kept improving each time until it didn't stick. I also found that by working this blade soo much that the movement was quite smooth. Thanks, Dan

 

[Frank Niro]

Dan.
I leave the lock face on the blade at 120 and the face of the leaf at 400. The angle I use is more like 10- 12 degrees. Frank

 

[EdCaffreyMS]

I agree with leaving the lock face on the blade at 120 grit....finer than that and you get the type of "sticking" you mentioned. I always come off the 120 grit after cutting the lock face, and go with a few gentle touches on a med. scotchbrite wheel. Personally I use a 7 1/2 degree angle on the blade lock face.....but it really comes down to what works best of each maker.

 

[tomwatson]

If you guys will just heat the end of the lockbar that engages the blade lock face with a torch to orange/cherry red and let it cool, it will oxidize the lockbar edge and stop any sticking issues.

 

[dan van]

tom, what do you do to keep the heated area restricted to just the end of the lock bar? Thanks, Dan

 

[tomwatson]

I push the lockbar out about 3/8" from liner and heat it with a propane flame.