Traditional Slip Joint Folders??...Help

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Dec 11, 2000
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I am looking for information on how to make slip joint folders, also what materials to use for the spring, pins, and frame. I was going to order How to Make Folding Knives, but it seems to be out of print. Are there any other good books that cover this subjust?

Any advice on spring tempers and tolerances would also be appreciated. I am at a stage that I don’t know all the things I don’t yet know. Do the pivots for slip joints have the same bushes and o-ring arrangement as found on some linter locks?

Hope one of the experts can spare some time and point me in the right direction.

Thanks

Chris
 
The book " How to make folding knives" by Lake, Centofante, and Clay. Is about making lockback type knives.Not slip joints. I think there is another book called How to make Multi Blade Folding Knives that is supposed to be pretty informative.
If you want to make "traditional" slip joint folding knives,
they will be put together completely with pins and epoxy. No screws, bushings, bearings or O-rings :) . Generally cutlers brass or nickle silver is used as pin material and boltsers. For handle materials, the sky is the limit, bone,stag,horn,wood,micarta. Pretty much anything you want.
I'm not sure whats best for springs. It will depend alot whether you want carbon or stainless springs/blades.
 
As it happens I don’t really want to make a “traditional” slip joint knife. I know what I said in the Subject, that was for want of a better term, sorry.

The other day I got through reading the UK’s laws on knife carry, till recently the legality of locking knives was a gray area. According to recent case law it isn’t any more, any length of locking blade in now officially an offensive weapon. So, since I don’t usually have a “good reason” to carry a lock back, I was thinking of trying to make a slip joint in a similar style. I am not too keen on the traditional jack knives, that’s mostly to do with their weight, blade shape, and steel.

All that brass is really heavy, I want something lots lighter and slimmer with a pocket clip, basically a tactical folder without the lock. I was wondering if anything could be done with the blade’s cam shape to that it was easier to open and harder to close.

Thanks for the advice on books. I still think that I will try to get the Lake and Centofante book while there are still some around.

I have been playing with fixed blade knives for a year now. I know that folders are a lot harder, but I don’t reckon I will learn much if I don’t give it a try.



http://albums.photopoint.com/j/ViewPhoto?u=1748884&a=13469011&p=51549017&f=0

http://albums.photopoint.com/j/ViewPhoto?u=1748884&a=13469011&p=51549018

http://albums.photopoint.com/j/ViewPhoto?u=1748884&a=13469011&p=51549020

http://albums.photopoint.com/j/ViewPhoto?u=1748884&a=13469011&p=51598129&f=0
 
I have been playing with slipjoints for a little while learning by trial and error. Started by taking an old Case apart and looking at it, great learning experience. Not much you can do with the cam action if you want it to fit properly. Been thinking about adding a thumb stud to a weak springed slip joint for easy opening.

I am using 440C for blades and springs and hardened 440 C for integral liners. Light materials like titanium are sticky and interfere with action. G10 and carbon fibre are gritty and eventually bind up the action. Brass, gold or hardened stainless appear to be the best for liner materials so far.

These are tricky little items to fine tune though.
 
I've only made 3 folders so far, but I know that's the way I want to go. I just finished a slip joint last week.

As far as the books go.....

"How to make folding knives" has just come back into print this week. However, many places have it back-ordered, so you may still have to wait on it. I have one on order that should get here next week.

"How to make multi-blade folding knives" - This is a pretty good book for reference, but they use professional equipment in the two projects to make the knives. This book shows you how to do it if you have things like milling machines and surface grinders.

"Custom Knifemaking - 10 projects from a master craftsman" is an EXECELENT book if you are wanting to make a folding knife. Two of the projects in the book are folding knives. One is a slip joint knife, and the other is a lockback. The book takes you step by step and shows you how to use common tools in making the knives.

The first folder I made was the slip joint knife from the book. The second was the lock-back, and the latest is a slip joint design based on the "Old Timer" pocket knife look.

Here's a picture...

damascus_folder.jpg


Pick up the "Custom Knivemaking" book. I found it to be the best one so far for learning to make simple folders. Once you learn the simple ones, you can go from there.

Hope this helps! -chris
 
Thanks, that was just what I was looking for!

Now to try to digest all that information, I think that I may be at it for a while.

Thanks to everyone for all the advice.

George, you said that titanium was "sticky", so I guess that counts it out as a spring material? It's used as a liner material in liner locks, as I understand it they use teflon bushes/washers to separate blade and liner, is there anything to stop the same thing being done in a slip joint?

Apropos the blade cam, all the ones that I have seen were basically “U” shaped, so that there was about the same force holding the blade closed as there was to hold it open. Why couldn’t the cam be more like a half “D”? I would have thought that it would make it easier to open while still being hard to close. Of course someone has probably already tried this and found that it don’t answer.

 
Titanium with spacers could work I guess.

Most cams are square with the corners rounded off and sometimes the back is fully rounded, depends whether you want the knife to stop at half open. Playing with the corner geometry too much results in a poor open "lockup" or a poor closed "lockup". The shoulder of the corner acts as the final opening cam or as the final closing cam, creating the "walk and talk",
 
Wow Chris, thats a very nice little folder!! Is it as small as it looks? It sure turned out great!
 
Thanks L6Steel.

Yea, It's a pretty small knife. The knife is 2 3/4 inches long while closed, and it is 4 3/4 inches opened. It features a cable damascus blade, jigged bone scales, nickel-silver bolsters, nickel-silver pins, and an 01 carbon steel spring.

-chris
 
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