View Full Version : 1st folder (slipjoint)


T. Hendrickson
04-09-2003, 02:32 PM
In order to gain more experience for my first liner lock, I am in the process of making a slip joint folder. I am using the 410 stainless I talked about earlier for liners. I think I will use brass for bolsters (not sure about the handle yet). The steel is 1095, inexpensive for my 1st try. I have learned a lot already and have some questions.

do all the interacting parts need to have a high finish on them, for better, smoother action, or is it unnecessary?

Can the lever spring pin be peined over the liners instead of the handle materials, as demonstrated in the tutorial? I have an idea to peen one side of the handle pins on the inside of both liners,, putting it together,peening the spring pin, then putting a scrap piece of steel in between the 2 liners to peen the handle on. Has this been done before?:confused:

How much does the spring need to be bent before heat treat to hold the blade in pressure?

Thanks a lot guys:D :D :) :D

Ray Rogers
04-09-2003, 04:17 PM
Well, there's no doubt that you will gain a lot of experience building that slip joint. In order to do it correctly, you will have to build a lot of them (if you're like most of us). After you have all the bugs worked out and you've mastered all the techniques for building a slip joint you'll find out most of what you learned may not apply to liner locks. Some things will like peening - although most liner locks use screws. Making the blade is the same but the geometry of the blade where it meets the lock is totally different. You will gain experience using your machines but not much about building liner locks. What I'm saying is, if you want to build a liner lock then build a liner lock. Nothing wrong with slip joints - in fact they are just as difficult to build correctly as a liner lock - but they aren't built the same way.

That said, 410 should be fine for slip joint liners. 1095 is a nice, simple, and forgiving blade material for most any kind of knife. Parts don't have to be polished but they do need to be flat and parallel especially on a slip joint (liner lock too but more lattitude). The parts can be mated with lapping compound.

As for the peening of the lever pin etc etc you can do whatever you can dream up. That's why making knives is so cool.:) Has it been done before? Everything has been done before but maybe you can do it better.

How much should the spring be bent before heat treat? Don't know. Make it fit the knife before heat treat then grind and bend it as necessary afterwards to make it fit and function the way you want it too. It's a spring, it will bend. But, see, that's a whole set of techniques you'll have to work out for that kind of spring that doesn't even exist in a liner lock...

T. Hendrickson
04-10-2003, 11:32 AM
Thanks for the very informative answer Ray. Yes I have definitely learned a lot about folders. It has been a very fun and interesting experience. It can also be very nerve wracking at times. Why just last night when I was working on it I had the blade hollow ground and ready to finish when I decided to do A little adjustments on the tang where it meets the spring. You guessed it, I ruined the fit and had to regrind a new blade.

I definitely see your point when It comes to the construction of liner locks and folders. When I acquire some titanium, I will start my liner lock, and I will use higher grade materials on that one. Fir now, however 1095 is very nice. I've been using it for years and I really like it. (Iplan to use ats34 on the liner lock).
Plus I've been able to use scrap pieces of steel which have just been sitting around.

Tanks again Ray, and I have one more question. Why is it necessary to use screws rather than pins, on liner locks, (for attaching the handle, mating the liners, etc.)
Oh yes and one more thing, is it the lock itself, pushing against the blade, which holds tension on a liner lock? Thanks8o

Ray Rogers
04-10-2003, 01:29 PM
I'm glad you found my answer informative and useful. I was afraid it might have come across a little harsh. But, it's not the first time I've heard somebody say they planned to start with slip joints and work up to liner locks and it pushes one of my buttons. Never could figure out how someone could think that learning to be a champion moto-cross rider would teach them much about being a swimming pool salesman, if you get my drift. Heck, I've been making liner locks for years and I still can't make a decent slip joint.

As for 1095, I love the stuff and recommend it to anyone who is practicing any kind of knife making. In fact, I used it just yesterday to make a blade for a prototype of a new folder I'm planning to build. It's a liner lock and the lock was made from aluminum sheet - see, you can do anything you can dream up. No, it doesn't make a good lock but it's fast, cheap, and easy to use and it works well enough to prove the design will work.

I've seen some pins used on liner locks. Maybe it's just the 'higher tech' look that usually goes with liner locks that make screws popular, I don't know. But, fitting the lock and the general process of building a liner lock requires a lot of assembly/disassemby cycles and that's much easier with screws. Customers like it because they can maintain the knife themselves that way (cleaning and tighening the pivot, etc).

Yes, the lock holds the tension on the blade by forcing it against the stop bar. Invest $50 in your liner lock education and get one of the Darrel Ralph kits. Use it to learn how everything works and then use the parts as a pattern and make your own copy of the knife (this is a good place to use 1095 and other cheap materials). Do this until you can make a knife with a good, solid lock that works well. As you build the copies, modify the shape of the handle and the blade a little bit. By the time you get the lock working right you'll probably have an entirely different knife. This is how I learned only I started with a $90 Benchmade folder...

T. Hendrickson
04-10-2003, 02:28 PM
Thanks again ray, for your expert opinion, youve been a big help to me.

No you weren't harsh I see your point and you've given me new insight on that part of it! So im kinda wasting my time with this slip joint...no actually its a great experience for me. But I do want to make some liner locks.

You might have misunderstood me about the liner though, what I'm wondering is if its the liner which holds the blade in tension when in the closed position, and when opening and closing. Its gotta have some thing to keep it tight, doesnt it?

Thanks again

Ray Rogers
04-10-2003, 05:00 PM
Oh, that tension! Another good reason to get one of those kits.:D

When the knife is open, the liner and the stop bar hold the blade.

When the knife is closed, a detent ball on the end of the lock bar holds the blade closed.

When the blade is between the fully opened and fully closed positions, the tension set by the pivot screw (screws again!) is the primary factor that determines how easily the blade will move. Very little of this tension comes from the locking bar. If the locking bar does provide a lot of tension on the side of the blade it can cause all sorts of difficulty. This area is the 'big deal' when it comes to liner locks. It determines whether your knife has a good action and a good fit or if it was made in Pakistan....

whv
04-10-2003, 05:50 PM
ckd member peter atwood has a video making a framelock folder (http://www.realrates.com/knives/video1.htm) that will give you another source of insight. many of the parts and processes are the same or similar to making a liner lock.

neil charity
04-11-2003, 02:28 AM
I use 440C or ATS34 for my spring on slip-joint folders and I use the method described in the book "How to make Multi-Blade Folders". First off I profile the blade and tang, cut out and drill liners, put blade in position with pivot pin. I then cut out spring leaving about 1/8" extra on the bottom of where the spring rests on the tang. I then insert a pin into the spring pivot hole and drop in the spring. Holding the spring at rear with finger I operate the mechanism and that will show me where I need to remove metal. When I'm almost there I heat treat the spring. I hope this is clear but if not the book has pics that demonstrate the process.

Regards from Australia.

Don Cowles
04-11-2003, 07:10 AM
Neil, good to hear from you! Are you coming to the Blade Show this year?

Shotgunone
04-11-2003, 08:22 PM
Well there must be a few ways to do the springs tension. I fit my spring to the blade. Heat treat everything. Cut my liners oversized a little. Clamp the blade and spring to the liners and drill the blade hole and center hole in the spring. Mark the back spring hole with a sharp scribe. Remove the blade and pivot the spring end up towards the blade pivot where about 1/2 to 2/3 of the rear scribed hole is visible and drill the rear hole. Then when assembling the knife I put pins through the liners and springs. Place the blade in between the liners and use a sharp tappered pin through the blade hole which has about 1/2 to 1/3 of a hole visible. Slide the sharpened pin in place puts the load on the springs.

Regards