Milling Lockbacks ?

Matt Shade

Matt Shade

Joined
Nov 24, 1999
Messages
4,981
I've been trying to make some decent folders for awhile now and its going alright but I'm having trouble with the locking mechanisms. I'm making lockbacks because I don't have a milling machine, and I can shape the different parts with needle files and a dremel(its slow, but a mill doesn't fit into my budget right now)For those of you who have milling machines, what kind of bit or cutter are you using, and what is the shape of the cut it makes?
I tried making the notch on knife #1 perfectly square, it has a pretty solid lockup, but sticks really bad when you try to release it. So on try #2, I tried making the notch taper from top to bottom so it would release easier, then the angle on it was wrong and it didn't lock at all. So I'm on try #3 and am trying it a little differently again. I'm making it completly square but with less depth to the notch in the tang. Am I going in the wrong direction completly or will I eventually get this worked out? Thanks for any help.

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It'll feel better when it stops hurting.
 
Matt you need a 4-5 degree face angle and a 6-8 degree rear angle on the blades lock notch. It also matters where the piviot hole is in relation to the notch. I would recomend a book by "How to Make Folding Knives" by Lake, Centofante, and Clay. They explain how to make the notch.


 
Thanks, I have that book. I guess I need to take some more time and read it over again. Its hard to make exact angles like that with the files, but I can get pretty close. When you say 4-5 degrees and 6-8 degrees, you mean it should be that far off of being a 90 degree angle with the bottom of the notch right? And the angle needs to be faced outwards on both sides so that the top of the notch is slightly longer across than the bottom of the notch right ? or does it need to be set up so that the lock bar is hooked backwards slightly ( both angles set off of 90 degrees towards the point of the blade) Thanks

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It'll feel better when it stops hurting.
 
matt,

i put the 5-6 degree angle to the face of the lock bar but only 2-3 at the back. if you put more angle on the back with heavy pressure on the top of the blade, it will slip and onlock!
a squar slot has no room for any wear at all and will get sloppy in time. with thw angles you will always have room for wear and still get a no play lockup.
hope this helps
 
These angles can be milled on with tapered end mills. they are available at most supply houses. :]
They can used for the back of the blade and the lock bar both.
biggrin.gif


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Web Site At www.darrelralph.com
 
Thanks guys
I think I'm ready to get back at it as soon as I get some free time. I've got my horse at the county fair this week and thats keeping me pretty busy. I'll let you know how try #3 turns out later on.

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It'll feel better when it stops hurting.
 
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