A Few Slip Joint Questions

Brian Avila

Brian Avila

Joined
Jan 2, 2011
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I have decided that I want to make a slip joint or maybe a frame lock. I am just going to do it and start with a slip joint so I can carry a pocket knife of my own making. But I need some clarification on some aspects of them.

I want to use a stainless steel for the blade. Why not use the same type of steel for the spring...

1) I hear that 45 RC is a good spring hardness after fully hardening the spring. When I try to look for temper temps for those numbers I don't find suggested temps. I am thinking about using CTS-XHP, AEB-L. But I am open to other suggestions maybe CPM-154cm.

2) From what I can gather, the pivot pin is not glued in or anything?

3) I saw Steve Culver's tutorial about making a slip joint and he uses a Ruple Dial. Is that some special dial to buy or make? Can it be done without the Ruple Dial?

4) What are the traditional blade thicknesses and liner thicknesses for slip joints?

-Brian-
 
Brian
1--I use CPM 154 and temper springs to 48 Rc. Temper temp is 1135 in my kiln.
2--All pins are piened, no glue.
3--The Ruple dial,or rise and fall indicator is really nice to have but you can make do with a piece of steel and a couple of pins.Drill holes in the piece of steel the same as your liner,put pins in the holes and then put on your blade and spring. Set your open position and then scribe a line at the top of the spring and use that to set the other two positions.Be prepared to take the knife apart several times to get it right.
4--Most of my knives are made with .093 blade and springs. Although I have made several with 1/8" and 1/16" blades and springs.
Liner Thickness is .040

Hope this helps

Stan
 
Last edited:
Brian,
I'll try to help.
You can use stainless and make the spring from the same material as the blade. Spring tempering temperatures are going to be around 1000 degrees. If you will use a steel I'm familiar with I'll tell you haw to heat treat blade and spring. I recommend Sandvik 14C28N.
You want the spring 45-50 Rc.
You don't need a zero jig or Ruple jig.
Pivot pins are peenend in place.
3/32" is typical for slipjoints blades, 20-50 thousandths for liners.
If these are the only things you need clarification on you are already well on your way to building a slipjoint knife,congratulations!:)
 
If I can get the blade thicknesses that I want I will probably use CTS-XHP or AEB-L. Probably AEB-L. So I would need to find out the tempering temp for the spring. I would guess 1150-1200?

Thoughts on washers or barrel pivot?

The only other thing that I don't really do and can't see in my head is the peening of the pins. All the little slip joints that I have seen have bolsters and the pins blend in. So I am guessing you team the pin holes on the outside a little and then peen with a hammer and then finish and polish flush?
 
The other thing that I haven't been able to find the right terms for is the part that is like a pivot that shows when you don't have a bolster? It kind of looks like a corby bolt. John Howser made some like that.
 
I've not made a slipjoint but, I bought Weldon Whitley's video and watched it through twice now. He has an interesting technique for peening the pins so they don't swell in the blade and get too tight. He used a tiny carbide ball burr and made a small trough around the inside of the bolster pin hole. The trough allows the pin to swell into it when peened and prevent the pin from swelling beyond the cut that point.

Bob
 
Brian Avila said:
The other thing that I haven't been able to find the right terms for is the part that is like a pivot that shows when you don't have a bolster? It kind of looks like a corby bolt. John Howser made some like that.
Click to expand...

Called a bird's eye pivot. You make a small washer about .100 thick and inset into the handle material and then peen the pin in it.
 
SBuzek said:
Called a bird's eye pivot. You make a small washer about .100 thick and inset into the handle material and then peen the pin in it.
Click to expand...

interesting...

So have you guys heard of a way to do the pivot without peening the pivot pin and the other pins?

After going through the Steve Culver tutorial, I noticed that my design does not have the pivot point in the middle of the handle. This isn't a problem if you are using bolsters and you can hide the pin, but what do I need to do if I don't want bolsters?

-Brian-
 
Took me half a day of searching but I found out what the no bolster is called, it is referred to as a shadow pattern. As Stan mentioned it is indeed a washer with the pin peened.
 
You asked what the pivot was called,yes it it used on a shadow pattern knife but you can also make a shadow pattern with simply the pin and no washer.
 
Brian,
I thought you only had four things that you weren't clear on before making a slipjoint knife.:)
Seems like you keep coming up with more questions as you receive more information.:)
I hope you don't mind me funning you:)
What you don't realize is that there are about ten thousand things you are not clear on when it comes to making a slipjoint knife. But don't worry,you will get it figured out if you stick with it long enough.
 
SBuzek said:
You asked what the pivot was called,yes it it used on a shadow pattern knife but you can also make a shadow pattern with simply the pin and no washer.
Click to expand...

Brian, my apologies.:o I just re read this and I don't like the way it came out. Gonna PM you my phone # and if you wish give me a call and I'll help you all I can with slip joints.
I'm on Central time.

Stan
 
Hey Stan. No problem at all. You are right on all accounts. I keep finding new aspects of the knife making. It's a new venture from fixed blades. I will give u a call.
 
Calvin Robinson said:
Brian,
I thought you only had four things that you weren't clear on before making a slipjoint knife.:)
Seems like you keep coming up with more questions as you receive more information.:)
I hope you don't mind me funning you:)
What you don't realize is that there are about ten thousand things you are not clear on when it comes to making a slipjoint knife. But don't worry,you will get it figured out if you stick with it long enough.
Click to expand...

It is all good Calvin, and you are not kidding. More questions... each and every time... :foot:
 
I would like to hijack this thread for some basic questions on slipjoints.
1) i don't have the equipment to do a perfect nail nick and i was wondering if (for single blade) could be acceptable a "nickless" design...i mean, i don't actually use nail nicks when opening slipjoints...
2) the cut in the edge-kick area, the choil...is it really necessary? just another feature i regard as unsightable when made less than perfect. Also if the plunges/kick are a little over 90° sharpening is pretty much not an issue regardless
 
Sure, you can go that way. Lots of the making can be as you want not what you think others may wish for. Frank
 
stezann said:
I would like to hijack this thread for some basic questions on slipjoints.
1) i don't have the equipment to do a perfect nail nick and i was wondering if (for single blade) could be acceptable a "nickless" design...i mean, i don't actually use nail nicks when opening slipjoints...
2) the cut in the edge-kick area, the choil...is it really necessary? just another feature i regard as unsightable when made less than perfect. Also if the plunges/kick are a little over 90° sharpening is pretty much not an issue regardless
Click to expand...

I make some models without nail nicks and some without choil,so you have my permission to make them that way too.:)
 
Chris Crawford has a great tutorial on his website http://chriscrawfordknives.com/# I used his directions to build my first one. It's not near as complicated as it may seem at first. You don't need a Ruple dial, your fingers will tell you if things are flush. Also, if you are making a shadow pattern, you can set the "washer" centered and place the pivot pin off center of the washer. After it is sanded down, you won't know it's not centered on the washer. You can make the washer from solid stainless roundstock.
I think you should make a Bowie slipjoint! Your bowies are beautiful!
PM me if I can answer any specific questions. I'm not as good as Stan or some others but I would be happy to share what I know.
 
Haha! Yes I agree lanny's clip is a good idea for a slip joint for me. I agree!

I'll keep you guys updated. I am in the middle of collecting everything to do this.
 
Thanks for the kind reply, i do knives as a hobby so i don't have customers to disappoint, just me and my friends ;)
Grant: be careful that the finger method (vs. rupert's dial) could be of little use since when dialing, the spring is yet to be grinded flush, but the check against scribed line method is a valid one. I suggest to leave some meat to grind from the spring after the ht considering that the spring deformation when in tension could affect the final "flushness", but a nice dialed tang from the beginning is helpful to start with.
This weekend i should finalize my first slippie, nice walk and talk but i'll have to:
adjust the tang to get better flushness in 3 position and clean some leftover scratch from the blade
solder the bolsters,
make the scales
and pin everything together
The things i'll leave out for this first trial are the relieving of the liners (don't have mill or etcher), the nail nick and the acute choil
Wish me luck ;)
 
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