Slippy questions

Mark Knapp

Mark Knapp

Joined
Dec 20, 2009
Messages
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I would like to get more serious about making slip joint folders (I have been just goofing around till now). I would like to use the same damascus for the blade, spring, and bolsters, the material is going to be 1095 and 15N20 for one and some spirogragh I got from Bill Burke (Bill if you see this, what was the steel?) for another. How hard should the spring and tang of the blade be? My assumtion is they should be about the same hardness. Will I run into complecations at the bearing surface of the tang and spring, should that area be made of homogenous steel? Thanks for any help. Mark
 
When I do mine out of a similar material to this I just HT them both the same and temper them both the same, then draw back the spring with a torch until you get that familiar blue color you get when drawing back the spine on a fixed blade. Comes out to be around a 45-55 in hardness i think.
As long as you don't have any chisel edges on your pivot, have all the corners rounded just a bit, there wont be any galling. I like to use the same materials for the spring as I use for the blade But this is just me.
 
Mark it is 15n20 and 1084. harden both the same and draw the spring to 45-48. when you etch everything put fingernail polish on the bottom of the spring and the tang area and around the pivot hole so that they don't etch.
 
Rusty McDonald said:
When I do mine out of a similar material to this I just HT them both the same and temper them both the same, then draw back the spring with a torch until you get that familiar blue color you get when drawing back the spine on a fixed blade. Comes out to be around a 45-55 in hardness i think.
As long as you don't have any chisel edges on your pivot, have all the corners rounded just a bit, there wont be any galling. I like to use the same materials for the spring as I use for the blade But this is just me.
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Same here.
 
Thank you very much every one, anything else to add, things to look out for, common mistakes rookies might make? Thanks Mark
 
Mark Knapp said:
Thank you very much every one, anything else to add, things to look out for, common mistakes rookies might make? Thanks Mark
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Don't polish the contact areas of the tang and the contact area of the spring -- stop at about 400 grit. These surfaces need a bit of texture to be able to retain lubricant.
 
zerogee said:
Don't polish the contact areas of the tang and the contact area of the spring -- stop at about 400 grit. These surfaces need a bit of texture to be able to retain lubricant.
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I respectfully disagree with this. I recommend polishing this area and then before final assembly but with the knife put togehter and working properly put a little oil between the tang and the blade and work the blade back and forth until a nice burnished area on the tang and blade develops. After final assembly do this step again the goal is to develop this burnished area into a bright polished looking area that will retain a small amount of lubricant but still have a pleasing appearance.
 
Bill, I learned this from Tony Bose. Yes, working the action will burnish the points of contact somewhat - and this is good. The logic is that by finishing the contact areas to about 400 grit before final assembly, then doing a repeated working of the action (lubricated of course), you burnish the contact areas somewhat for final smoothness, but keep a texture in the steel that retains lubrication well. Polishing these areas before assembly makes the time between lubrications for optimal action far too short in my opinion, and the action too quickly gets to the point of working dry. YMMV.
 
zerogee said:
Bill, I learned this from Tony Bose. Yes, working the action will burnish the points of contact somewhat - and this is good. The logic is that by finishing the contact areas to about 400 grit before final assembly, then doing a repeated working of the action (lubricated of course), you burnish the contact areas somewhat for final smoothness, but keep a texture in the steel that retains lubrication well. Polishing these areas before assembly makes the time between lubrications for optimal action far too short in my opinion, and the action too quickly gets to the point of working dry. YMMV.
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I guess that does make some sense. I have tried it both ways and prefer to polish the areas first. Different strokes for different folks.
 
Bill Burke said:
I guess that does make some sense. I have tried it both ways and prefer to polish the areas first. Different strokes for different folks.
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Might depend on the steels used for blade and spring also. I have a few production linerless folders (midlocks/frontlocks) made by Moki that really don't have to have lubricant as long as they're kept clean (though they're still smoother with oil). Of course, with just the rocker (separate spring) to worry about, they can easily find a steel that makes a good bearing surface and is still hard enough.
 
Thanks guys, I am paying attention. How about clearance between liners, washers and tang. I am going to use a bushing in the tang so that I can sinch the pivot pin down tight, should that be .001 thicker than the tang, or a little more?
 
Well Like I said different strokes for different folks. I wonder if it matters that I use bearing steel (52100) for most of my slips. I was just at a slip class with Mike and don't remember him menyioning it but it is very possible that I missed it.

Mark there is a good tutorial on the Bose website. http://boseknives.com/pvtbushing/index.htm
 
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Chris Crawford has a great slipjoint tutorial on his site for free and a really great DVD set (4hrs) for $50 I think.
 
Mark Knapp said:
Thanks guys, I am paying attention. How about clearance between liners, washers and tang. I am going to use a bushing in the tang so that I can sinch the pivot pin down tight, should that be .001 thicker than the tang, or a little more?
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I don't use washers but when I shim mine before peening the pins I use .002 shims on either side of the blade.

And I was also told by another maker Bill Ruple, not to polish the tang because it galls the spring faster, especially if you don't have the right radius on the kick. You have to remember that there are 2 different harnesses meeting under tension. The surface area is less if it's not polished and the lube can get between the parts a bit easier. but as Mr Burke said to each his own.
Rusty
 
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Chris Crawford's DVD on slipjoints is the answer to a newbie's prayer. With his instructions , a monkey could build one !

Joe
 
Mark Knapp said:
Thanks guys, I am paying attention. How about clearance between liners, washers and tang. I am going to use a bushing in the tang so that I can sinch the pivot pin down tight, should that be .001 thicker than the tang, or a little more?
Click to expand...

Yes, most shoot for a 0.001" wider bushing than the tang. Just don't get over enthusiastic with the hammer -- you can still wedge the blade, it's just not as easy - so check your action as you peen. I assume you already have or can easily make a bushing lap?
 
Thanks for the link Bill, and Congrats on your MS stamp. My hat is off to those who work hard to earn their stamp. I am going to take several classes from Mike since we live in the same town now.
 
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