relieving slip joint liners

I have not normalized the bolsters yet. I tried the etching last night to see if it would work. I ran the liners over my granite plate and sandpaper and could see a difference in hardness from the spots it was welded. Hopefully I'll get the new liners with sharper lines on the etch done tonight. From there I will normalize the bolsters. Thanks Ryan
Bill Burke said:
I am also relieving my liners on a mill but I am making my slipjoints with integral bolsters and liners. I do the relief cuts before milling out the area for the scales. I have a presision ground plate that pivots on another plate clamped in the vise.

One thing. Are you normalizing your bolsters and liners after spotwelding? This will need to be done if you are going to do any engraving or filing on the bolsters to avoid hard spots. Also on damascus bolsters you need to normalize and the harden to get the best looking etch with out the welds showing.
Click to expand...
 
To make .005 washers you buy a piece of bronze sheet from MSC and punch them out with a punch set. They sell all thicknesses of sheet stock.
 
The best fit is to have only .001" clearance. The liners need to be relieved about .005" each. Tony Bose does this and uses a block like Bill Burke is talking about. I am going to make one and try it again. I aint letting no little slip joint get the best of me. :)
 
Ryan, I tried the etch and was able to relieve the liners by .005 in a short period of time. Thanks for the tip.
 
Thanks for the advice about punching out shim stock I'll have to try it out.

Jim glad it worked for you. I had to be a little carefull about pouring the coals to it with the etcher because I blew a fuse. Once I figured out how long I could etch for it seemed like a good way to relieve the liners.
 
"Bill,
How does relieving the liners make the blade more prone to wobble? The area where the tang rides is the same thickness as the rest of the liner. It is the area around the pivot area that is relieved so the tang does not get scratched."
I said "theoretically." There is not as much support of the tang.
 
Just a note or two about relieving the liners of a folder. All, or at least 99% of comercial folders have brass liners and are assembled by machine, the liners are deburred and polished prior to assemly.

If you are using brass liners for folders, as I do on some folders; you do not necessarly have to mill out the liners for clearance where the will not scratch up the tang area of the blade. When the liners are deburred and polished they should not mar the blade tang. But, all things being equal that will not happen very easily.

Jerry Fisk explained it this way: mark the liners with die marker (I use a Shapie to do this); next place the spring onto the liner and scribe a line at the end of the spring, and along the bottom of the spring; take a compass and set it for 1/8" from the closest part of the liner to the pivot either the end of the liner of the fsce side of the liner opposite of the spring, then mark circle from the spring scribed lines to the other side of the spring mark (from the end of the spring to the far side of the spring bottom); the next part is to scribe a part of a circle for the relief of the tang area in the closed position (set the compass for 1/8" past the farthest area of the pivot area to the tang this will give you an area relieved where the as the tang pivots it will not touch any areas that will not be relieved, thus no scratches on the blade tang). You only need to relieve 0.003" for this to be able to happen. The washer area left after this relief will be more than enough to support the blade, and spring when it is peened togather, (it's like using a washer on a liner lock).

One other thing Ryan is to mark the area not being relieved with an industrial Sharpie this way you should not have to worry about masking off the area while you use the electro etch to relief the area of the liners. The Sharpie should hold while you are doing this then just remove the Mark with alcohol, and polish the area.

I hope this is of some help as well as of some use to the folder makers out there. Knowledge if not shared is wasted,and is lost to the world.

There are no pro's or con's on this or any subject as long as one person learns just one thing. For this is the reason for any forum.
Curtis Wilson
 
Bill, if the liners and the blade tang are flat, and the holes drilled are squared up there should be no wobble even on a relieved area of the liner, (as long as the pins are peened evenly). The way to do that is to take time when peening them.
Curtis Wilson
 
You mentioned thinning the blade to be a bit thinner than the spring.
Why not make the spring thicker than the blade to begin with, then thin the spring to the right thickness?
Should be easier, as the spring is softer than the blade steel.
 
howiesatwork said:
You mentioned thinning the blade to be a bit thinner than the spring.
Why not make the spring thicker than the blade to begin with, then thin the spring to the right thickness?
Should be easier, as the spring is softer than the blade steel.
Click to expand...

The problem I most often run into is I can't keep the thickness even throughout the blade or spring not matter which one it is. The hardness of the two isn't as much as a factor because I use ceramic belts. If anything I seem to have more control over flattening and evening out heat treated blade steel over the soft annealed steel. Frank Niro emailed me a couple of tips and they help big time.
The other problem with making the spring bigger to begin with is I buy cpm-154 in 3/32 barstock so making the spring thicker to begin with would be buying cpm-154 in 1/8" thick steel. Either way I'm going to have to remove material on spring or blade one seems about as difficult as the other for me without a surface grinder or mill. Some makers can pull it off, but for now I can't. I've come closer to getting an even thickness using Mr. Niro's tips and I suspect if I try it more than once the results will get better. But for now the etched liners seemed to work better than I had hoped.

I thought about doing the etch after realizing my other methods weren't cutting it. Other makers use a mill to relieve their liners I just so happen to use the etcher. It's fairly quick and more accurate than I expected, and if I did have a mill I'm guessing my inexperience with one would cause the helicopter liner mentioned earlier.
 
It appears that the etching process can be used very successfully and if done in combination with the information supplied by Curtis Wilson will give very satisfactory results. Finger nail polish works very well as a resist, by the way. Frank
 
Back when I was still chopping up liners with a die grinder and carbide bur you can bet if the wild idea of etching the relief crossed my mind I would have tried it. I used a rotary table for a while in my mill but now I use a fixture similar to the one in T.B."s tutorial that Bill Vining talked about --really slick Thank God for mills and surface grinders but as Gene Shadley said in his book a gob of folders came out of my shop prior to that.
Ken.
 
Ryan,
Since your dabbling in slip-joints why not switch to a cheaper steel while you are learning. Why waste your expensive 154 CPM on a learning curve.

Switch to some O-1. At flatstock.com you can buy some precision ground stock and some oversize precision ground stock. The oversize stuff is about .020 oversize. This would be perfect and you could put 1 .010 washers on either side and you will have no need to grind anything down.
Yes the gap between the blade and liners would be slightly larger but who cares? It would make learning easier for you till you got comfortable grinding down stock or got a surface grinder. The Heat treat would be easier and if you heat treat the spring wrong you can just re-harden it and temper it again.
It's all about making things easier while you are learning so you stick with it.
 
howiesatwork said:
You mentioned thinning the blade to be a bit thinner than the spring.
Why not make the spring thicker than the blade to begin with, then thin the spring to the right thickness?
Should be easier, as the spring is softer than the blade steel.
Click to expand...

Just a note about spring and blade thickness for whomever: The Blade and the Spring should be of the same thickness except for an area of roughly 1/8" past the locking point of the spring and the blade (toward the center pin), ((This is the area wherethe spring sets in against the blade)). This area should be relieved about 0.001" to 0.005" preferred is 0.003" (this is for the clearance of the sprong during the opening and closing of the blade). This can be accomplished very easily by takin a couple of swipes against the sides of the spring against a 320 or 400 grit belt, (make sure to debur and polish this area after this has been done).
The reason for doing this is where the blade Will Not Bind; Thus the infamous walk and talk will result.
You see the walk and talk is the ultimate goal for a working folder. If it doesn't walk and talk it might as well be a fixed blade.
I may not be making myself real clear, but I hope that I did. If you need to contact me feel free and I might be able to explain to you a little bit better.
Not to play on forums, but Don Robinson did a toothpick build on the KnifeNetworkForums and I have been going along and helping showing the same build. This way makers can get a different perspective for doing the same thing by different makers, and doing it a little bit different. This type of build along with the info on this thread is a perfect example of makers helping makers. It's not about someone making a better knife than someone else, but about keeping the knowledge from being lost.

I hope that this is of some help.
cwknifeman2026@att.net or if you need to talk to me by phone call: 817-676-2105 Cell
Curtis Wilson
 
Not the best picture, my bride, secretary, photographer ect will take some better pictures tomorrow that I will post in the gallery. This is the knife I have been working on. The blade is hollow ground cpm154 hand rubbed finish and a ground swedge, half stop, the nail pull is fine silver and has three small studs on each side. The bolsters are 416 stainless and the handle is the customer's request of mesquite. I've made 5 slip joints I guess so far and the first 4 where 3 years ago and I've tried to buy them back to no avail. I did another set of relieved liners with the etcher on this knife and seemed to work great.

knives442.jpg

knives443.jpg

knives446.jpg
 
Chuck Gedraitis Knives said:
How does relieving the liners make the blade more prone to wobble? The area where the tang rides is the same thickness as the rest of the liner. It is the area around the pivot area that is relieved so the tang does not get scratched.
Click to expand...

When the blade is opened, it does not have support all the way to the end of the liners/bolsters any more. And as I'm sure you know, the further you get from the pivot, the more dramatic a difference this support can make. Imagine for a moment if you were using washers only half a milimeter wider than the pivot pin. (not thickness, but diameter) Even if it's nice and tight as made, with heavy use this small area can wear down, and light prying will exert all its force on this tiny area.

In practice it's a matter of degrees, and whatever compromise you're comfortable with. I'm interested in it because I plumb wore out a bunch of folders on the farm; they all get blade play sooner or later (assuming they're not lost or broken outright before then).

Edit-
I'm adding a quick sketch to illustrate what I mean. The shaded areas represent where the tang is actually making contact with the liners/washers.
foldertangsupport.jpg
 
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