Liner and Frame Lock Questions:

Hawk45

Hawk45

Joined
Jan 28, 2005
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I'm still in research on my first folder with a lock. I've made a few friction folders, now I'm going to convert that design over to either a liner or frame lock.

For liner lock version I'm going to use 410 steel and Ti if I try the frame lock. I've got a VERY basic setup of tools I've made due with so far (2x42 grinder, dremel, drill press, hand tools).

Cutting materials:
Can I use my dremel with a cutoff wheel to make the lock bar cuts? This is what I planned to do for both lock bars, Ti and steel. I have a cheap hacksaw but can't cut a straight line for my life with it even in annealed carbon steel.

410 Liner Lock:
I'm a bit confused on how the liner lock setup works. Do I bend then heat treat? Can I do the HT to get the spring with a Benzo torch (I don't have a HT oven) or will I need to send out with my blades for professional HT?

Ti Framelock:
If I try Ti, do I just need to mill out enough to allow the lock to naturally bend or does it require HT also?
I know it wouldn't be optimal, but I was going to get a end mill bit and chuck it up in my drill press and go slow, it's what I have to work with... What mill bit would you recommend?

Thanks for your help guys!
John
 
For the liner lock, if you use something like spring temper shim stock(usually something like 301 stainless,) you don't have to heat treat: you just cut it to shape, and bend it enough past where you want it to spring to.
 
Seems like all the online shops only have 410 liner steel.. is this similar enough to 301 and not need a HT?
 
Some things for you to consider
I have made a couple of liner locks using 410 and have had no issues at all regarding its spring or lack thereof.
However I've noticed that the front of the lockbar has started to wear against the hardened steel of the lockface. I did a quick HT with a torch to harden it up a bit, hopefully that will fix the issues.

The dremel wheel in the drill press works for the lockbar cuts. A little slow for my taste though.
You can use an angle grinder and ultra thin cutoff wheel if you clamp a piece of 1/4"+ mild to the liner, with the edge being where you want the cut.
 
I have an angle grinder so I can pickup some ultra thin cutoff wheels.. I planned on this in time anyway.
 
I have no experience in using steels for liner locks but it seems to me that its more complicated than using Ti, because steel needs to be hardened to a certain degree. I use Ti (6al4v) which does not need to be HT´ed and has exelent spring properties. I suggest you give it a try.
You can use your Dremel and cutoff wheels but you need a steady hand to get the lines straigt and keep the discs from breaking. This is how I do it: I mount a 1 mm thick disc for an angle grinder, in my drill press and clamp the liner in the vise. Adjust the heigt of the drill press table, and cut the long leg of the spring, guiding the vise with your hands (taking care not to cut your hands off). The short leg can be cut with a hacksaw. Clean up the cuts with abrasive shop role afterwards. A slitting saw in a milling machine would be even better but this setup has worked fine for me.

Come to think of it, I did actually make an inlayed spring in an interframe folder, from Damasteel once just cause I wanted it to match the Damasteel blade. I milled it down to .050 ", bent it and sent it of for HT along with the blades. This means it came out way too hard at 59-60 HRC but its worked flawlessly none the less. A hardness of approx 50-52 would probably be better for locks though.

Edit: I type too slowly, others were down the same road before me:p
Brian
 
Last edited:
Brian, thanks for the response. I like your method of making the cut better than trying to do free hand. Cheers.
 
As far as lock face wear, carbidizing is very helpful for that. You can also carbidize the cutting faces of drill bits, end mills, HSS lathe bits, etc. to increase their life, which helps ease the sting of paying $250 for a carbidizer.
 
I have read that you need to grind say a 7 degree or so angle on the lock face on the blade. Do you just leave the face of the lock bar flat and perpendicular?
 
jdm61 said:
I have read that you need to grind say a 7 degree or so angle on the lock face on the blade. Do you just leave the face of the lock bar flat and perpendicular?
Click to expand...

In Bob Terzuola's The Tactical Folding Knife, he states his preference for a positive or matching angle on the lock bar. YMMV.
 
You can download it on google play for 10.00
It's worth every penny of the amazon price. Everything you need to know is there.
 
Well, I do make lots of liner locks, but no frame locks.
Get some .050 titanium for your liners if making a liner lock, from Alpha Knife Supply. They sell small pieces too. It is THE metal for this job and if you want thicker for a frame lock, they have that too. No face hardening required.
On the blade surface where the spring will go grind this about 11 degrees with a 120 grit belt or use a course file if doing by hand. There is no need to heat treat the face of the leaf spring. No need for carbidizing either. I cut by hand lots of leaf spings with a dremel and cut off wheels. Check back later once you are making the folder. Regards. Frank
 
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