Slipjoint-specific issues

R

RobbW

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Oct 15, 2003
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Slipjoints are the knife world's "beasts of another nature." I just purchased a Case Peanut and Med. Amber Stockman and have been using them for a month now. They are my first new slippies since my childhood Boy Scout knife.

Both knives were dry with tight blades when they arrived. The first thing I did was "wear" the blades in by opening and closing them a few hundred times. Then I used solvent to flush them out really good. A bunch of black stuff came out, evidence of the "wearing in." A drop of oil and they were all butter-smooth.

Then a funny thing happened. I started using them to cut fruit to get a natural patina going. The juices of the apples, pears, melons, etc. got up in the joints and I ended up rinsing the whole knife, handle and all, in hot water. This cleared out the oil, and I was cutting too much fruit to be oiling all the time so I let it go at hot rinses.

Well, the blades now cycle smoothly with no oil at all! There is no evidence of wiggle in the blade, which would really bother me. The blades just seem to be really well mated to the knife. I suspect this might be due to the natural lubricity of the brass liners against the carbon steel. That's just a guess, though. This seems to be a benefit of the classic slipjoint design that wouldn't carry over to other knives. Traditional cutlers really know what they're doing.

Has anyone else noticed this, or any other use issues specific to slipjoints?
 
You're right on the money with the brass againt the carbon steel theroy.

I'm not a metalurgist so I can't give the why of it, but I know from being a machinist that in steel to steel contact of moving parts, stainless can give you a galling problem. Its also much harder to get a smooth milled surface on some grades of stainless due to this charateristic. I remember making some of the same parts on a lathe that we had made in carbon steel, but the customer wants changed to stainless because the tool steel "darkened and didn't look as nice to the customers". The burs on the carbon steel came off with a touch on a scotchbrite wheel. The larger stringy burrs on the stainless parts need a brush on a belt sander. Look at the feel of the actions on the old blued Smith and Wesson revolvers when they were new vs the stainless revolvers when new. The stainless revolver will require a much longer "break-in" before you feel a decent trigger, if at all. In the end the stainless guns have to go back to the shop for a trigger smoothing job. And I recall an article about the stainless guns that when the LAPD switched from the blued S&W model 15, to the model 67 which was the same gun only in stainless, armorers reports of complaints with the new guns actions increased a great deal.

And theres nothing like a brass liner for smoothness. If a little wiggle developes over years of use, don't worry about it, it dosen't matter. Slippys really are a different beast.
 
All well and good, but if you don't oil the joints they will wear out.
 
Thanks for the advice. I'll use a drop of mineral oil since I use this knife on food every day.
 
RobbW said:
The first thing I did was "wear" the blades in by opening and closing them a few hundred times. Then I used solvent to flush them out really good. A bunch of black stuff came out, evidence of the "wearing in."
Click to expand...

I have a microscope on my desk at work and lately I've been taking a close look at my new knives. One thing I see a lot is what looks like buffing residue in the cracks and joints. I've since developed the habit of cleaning them all thoroughly before using them at all, because the thought of that abrasive material in the joints makes me afraid of excessive wear until it works itself out. Not all of them have it, my latest Spyderco didn't, but my last two Case canoes and Schatt trapper did.
 
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