Slip Joint Construction

S

Steve Beckwith

Joined
May 29, 2004
Messages
387
I am constructing a slip joint by following the instructions in "Pocketknife Making for Beginners". I have a piece of 15N20 big enough to make both the blade and back spring. Is 15N20 capable of being heat treated sufficiently to make a proper spring? Also mentioned is using teflon spacers instead of bronze. Does anyone have a preference? Thanks, Steve B
 
15n20 will make fine spring. Heat treat it with the blade but instead of tempering it with the blade temper it with a plumbers torch by heating past blue coloring and quench in water.
 
i've used teflon washers successfully in friction folders, for the first few slipjoints I just made, I used .005 bronze washers and they work good.
I can't speak to using teflon in a slipjoint.

I only have limited experience, one thing I can mention is that I don't think I like using washers in a slipjoint.
It doesn't seem to let the spring and blade match up perfectly with no gap. I think I will not use washers and mill a relief around the blade tang instead.
 
Teflon washers are fatter than bronze, generally speaking- as HSC says, you won't get as tight a fit, but that's really a fine point for a maker striving for top drawer results- you can make a fine, serviceable knife with either. Most of the top makers actually don't use washers on slipjoints, they do some milling so that the bearing surface is the liners themselves...but that's another subject.

A lot depends on what equipment you have- you need to be able to grind both pieces dead flat to a fairly tight tolerance to achieve really tight fitup, and you'd want a well controlled furnace to really nail the heat treat.
All that said, I made some dandy folders when I first started that are still being used with pretty rudimentary gear. Have at it, let us know how it goes! Photos are always fun- folding knives are a blast to make.
 
Don, I've followed your approach since I first saw you describe it, since I don't have machinery (or maybe patience) to mill relieve the pivot area, but an .005 gap is still a gap, isn't it? I personally don't think it's enough to see, and I'll never argue with your success. Is that not enough for collectors to mind?
 
While the equipment that I have is adequate for fixes blades, I do not have a mill. I realize that what I produce will be somewhat rudimentary but hopefully functional, tight and decent looking. And yeah, pictures are certainly in order. Thanks for the replies, S
 
Here's something for all of you to think about:
Very fine slipjoint knives have been made for a couple of hundred years WITHOUT milling machines, washers, surface grinders and digital furnaces.
And, it's actually easier to make one without all that stuff.
 
elementfe said:
Don, I've followed your approach since I first saw you describe it, since I don't have machinery (or maybe patience) to mill relieve the pivot area, but an .005 gap is still a gap, isn't it? I personally don't think it's enough to see, and I'll never argue with your success. Is that not enough for collectors to mind?
Click to expand...
The .005" relief around the blade the washer creates is really no different than milling a relief in the liner. Having the blade and two washers the same thickness as the back spring, creates no gap between spring and liners. Most liner lock folders have even thicker washers and no one complains.

You can build a folder with no washers or relief milled and the sides of the blade tang will make full contact with the liners. This causes more friction and scratches on tang.

There is no right or wrong way to do any of this stuff.
 
I like the Bronze when polished on a small leather strop with Flitz silky smooth.
 
So I put the liners, blade and spring together today and opened and closed it a couple of times. I am using stainless for the liners and both the blade and liners were pretty scratched up. I don't have any bronze spacers but I do have some .008 copper foil so I made some spacers. How durable will a copper spacer be over the long haul ? Scratching problem solved for now. To Bill DeShivs, the old pocket knife that I disassembled didn't have any spacers and it would still be in service if I hadn't been using the blade as a pry bar. Don Hanson, it is knives like you make that have me wondering why I bother to do this at all. Beautiful.
 
The slipjoint Don posted it's sooooo beautiful! The striped effect on the back given by the liners and the different steel colors it's a very nice touch.
I go slowly with a foot controlled dremel and cratex wheels (rough to fine) to slightly relieve the liner area interested by the tang. The final effect it's subtle, not standing out as when milling the liners, but the tang won't be scratched. Until i'd be better equipped i'm doing like this because i feel it works, but it is a lot of hand work and the chances to ruin some liners are there.
With a surface grinder the washer method sounds nice and straightforward...without, i think it could be done with a granite plate/sandpaper, and i'll try.
You will need to oil the joints, i don't know if the teflon will hold to this, maybe with the right oil...but i'd use bronze washers.
 
Teflon washers for me just seem to be a very bad choice. Compress them once and their thickness is changed as well as the hole pushed into an oval shape.
Frank
 
That is some beautful work Don! Question about the washers, are you punching them out, or are they available commercially. Thx
 
Most older manufactured slipjoints solved the problem of lube and perhaps scratches (mostly) by using brass liners instead of harder material.
You hardly see brass liners used these days, I'm not sure if it's a fashion thing or something else, I've always meant to try them and see how bad the tang scratching would be- still seems like an easy place to have grit build up, but that could happen with an .005 washer, too.
Any thoughts on that? Anyone out there use brass or bronze without a washer or relief?
 
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