Relief notch in Ti liners/frame folding knives

Ron Bendele

Ron Bendele

Well-Known Member
I have some .100" 6AL-4V Ti that I am using for liners. I normally use .050" or .063" and don't need to cut a relief notch for the lock. I believe I will need to cut a relief notch for the thicker liner.

What are you folks using to cut the notch with? I am thinking a round end mill, but what size? Would cobalt be better than HSS? I think I will cut it down .040" leaving .060" on the liner. Does that sound about right?
 
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I try to cut mine down to .050, I've tried leaving more that lock gets hard to operate.

I use a 1/4 solid carbide end mill, put the liner in a mill vice and take off the material from the outside of the liner and elongate the cut about 3/8" (I guess that depends on the size of the knife). Tod Rexford does something pretty cool that I might try someday, he drills 3 holes at the point where you bend the lock tab.
 
I also use a ball end mill to cut the relief notch - leaving about .050" thickness in the titanium for smaller knives and .060" thickness in the titanium on larger knives.

FLT48.jpg
 
Thanks guys for all the replies.

Les - do you happen to know what size holes Tod is drilling? This sounds like an interesting idea.

Tom - I went back to your tutorial and noticed that you are using a carbide end mill as well. Thanks for the tutorial by the way.

Stew - No I had not seen that. Thanks for sending it, it gives me some food for thought.
 
Stew said:
I'm guessing you haven't seen this before then:

STR's He Man Folder

:D
Click to expand...

Actually I have seen that before, Either STR mentioned it in another forum or someone mentioned STR's write up on his site. It's what really got me thinking about watching my cutout thickness and also got me to do things a little different that I used to.

The problem for me is customers not being able to operate the knife. He has a good point that thinning that area down is weakening the lock tab and making it easier to accidentally unlock the blade but if a guy comes to my table and picks up a knife and cant open or close it (the problem goes both was on flippers because of the detent), I can't just tell him "well you just gotta keep working with it until you develop some hand strength".

Also, STR is right on about lock tab length being improtant, but I found when I made the lock tab long enough to compensate for the thickness, then you you encountered lateral play.

It's good to play around with different things but make sure you don't create another problem while your working on this one.

Les - do you happen to know what size holes Tod is drilling? This sounds like an interesting idea.
Click to expand...

No I don't but look him up and shoot him an e-mail.
 
I'm just starting to try making something in a tactical. At this point I feel that if you can give the back of the blade a wack on the edge of the table and it doesn't close, it's got to be pretty darn secure. Perhaps the lock geometry has quite a bit to do with the concern over lock release? Frank
 
Frank Niro said:
I'm just starting to try making something in a tactical. At this point I feel that if you can give the back of the blade a wack on the edge of the table and it doesn't close, it's got to be pretty darn secure. Perhaps the lock geometry has quite a bit to do with the concern over lock release? Frank
Click to expand...

I think the accidental lock releasing that STR was referring to is when the lock is so easy to push over that it could accidentally be released by your hand while holding it, other wise the lock performs at it should. But another part of that is that if you thin the base of the lock too much and someone really tweeked on the blade that the lock could collapse, also it can allow some lateral lock movement.
 
Obviously a mill is the way to go on the lock relief, at least IMO it's the cleanest looking method.
The first locking folder I made I found myself w/ out a way to relieve the lock in .100 Ti. I've heard of some people doing it with a dremel sanding drum, I opted for a different method.

I put a piece of .40 ti in my lock cutout and then did the relief on my 10" wheel. It turned out okay, the lock works flawlessly so far. It's neither to easy or hard to release. I think next time I will use a
smaller wheel though, just to get a smaller relief. If I'm not mistaken, I think this is hoe Les George did some of his earlier FM-1 knives.

Here's a pic of the liner and knife.
C-6.jpg

c-9-1.jpg
 
That is something I never thought of jryan76. Did you put the relief on both sides or just relieve one side? I can't really tell by the pictures.

I am confused by something you say - "I put a piece of .40 ti in my lock cutout and then did the relief on my 10" wheel." Are you using the .40 ti as a shim to get the lock to stand proud while you grind it?

Thanks,
Ron
 
I did the relief on the outside of the lock, though I wouldn't suppose it mattered if you did it on the inside or outside, I don't think anyhow:)

I used the thin to act as a guard to keep me from grinding into the rest of the liner. Basically just so I could keep the relief on the lockbar only. If that makes since?:)
it just looks cleaner that way I think. The Ti sort of acts like one of those guides people use for grinding there plunges.
 
Whoops, double post...dang iPhone
 
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I grind all my lock releafs with a 3" wheel. :) I put the cut on the outside so I can contour the frame and I go down to about .050 at the thinnest point in the arch.

:D
 
I just finished a folder today with the .100 ti and milled the relief on the inside of the liner. I used a 1/4" straight HSS mill (not rounded) and milled it down to .055". It looks nice and neat and works great.

On my next folder I may try out jryan76's and Les' method. I will probably go with the 3" wheel instead of the 10" though. Doing it on the outside would be easier to do, but I might do it on the inside of the liner.

I really appreciate everybody's input on this thread. It has given me a lot of food for thought.
 
these are all ground on a 3 incher...
 

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Les, how do you avoid grinding the handle and only grind the lock? The knives you shared don't have any 'over' grinding onto the handle. The knives look great by the way.
 
Ron, I know this sounds like I am being a smarty pants, but I just dont grind the handle! :):)

If I do bump it though, it gets cleaned up when I "de-horn" the frame lock... Does that make sense?
 
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