Bearing pocket for folders

K

Kevin Powers

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Jul 23, 2015
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411
I'm getting ready to start 5 folders for Christmas presents. A bit ambitious since I've only made 2 folders, but nonetheless I'm making time to do it. My question comes to bearing pockets. Do you makers prefer to bore liners, blades, or a combination of both? So far I did one with both, and one with just the liners bored. I don't know how far I can bore into the titanium (.070") and maintain strength. Boring the blade and liner gives more opportunity for something to get out of square. Lastly, what gap do you prefer between the blade and liner in the finished knife?
 
Never done the ball bearing thing, but if I were, I'd likely cut the radius in the blade. I really do not like milling titanium. I'd also shoot for .020-.030 clearance between blade and liners. Hope this helps a little.
 
If for liner locks, I've only drilled the titanium leaf and used a compression fit on the ball. I use a 1/16" ball and set it into a hole drilled with a no. 54 drill bit. .015 bronze washers work well. Use one over top of the ho0le when setting the the ball to get it at the proper depth.
Frank
 
I do my pockets at .050". I don't believe it makes a difference whether it's in the scale or blade as long as your happy with the gap between the tang and the scale, which I like at .015".

If you do .050" in a .070" scale it obviously doesn't leave a lot but IMHO I don't think you need a lot. There will be material backing it up so the only real pressure (from lateral stress) shouldn't be an issue.

ETA: FWIW - long day at NYCKS and my math was off. My depth of .050" will leave a gap of .125" with .0625" bearings.
 
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I prefer a .010" gap between the blade and liners as I feel, everything else being equal, smaller gaps give a cleaner, more refined look. I only use bearings on flippers and then I only pocket into the liners.

Bob
 
You could skip the bearings all together. Use bronze washers and polish them super smooth. Save you on milling the liners and/or blade. Yes of course if you want to use bearings that's good too. Google a zt bearing folder tones how they are made. The zt 0560. 0561 or 0562.
 
Frank Niro said:
If for liner locks, I've only drilled the titanium leaf and used a compression fit on the ball. I use a 1/16" ball and set it into a hole drilled with a no. 54 drill bit. .015 bronze washers work well. Use one over top of the ho0le when setting the the ball to get it at the proper depth.
Frank
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That's how I set the detent ball, thanks frank.
 
Varga Knives said:
I do my pockets at .050". I don't believe it makes a difference whether it's in the scale or blade as long as your happy with the gap between the tang and the scale, which I like at .015".

If you do .050" in a .070" scale it obviously doesn't leave a lot but IMHO I don't think you need a lot. There will be material backing it up so the only real pressure (from lateral stress) shouldn't be an issue.
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.020" is not a lot of meat on the bone. I guess it's titanium so it should be fine.
 
Bob, I also like .010" between blade and liners on liner locks, & .005" on slip joints.

I said .020-.030" above thinking room for ball bearings, but I don't use em on my liner locks, so don't know?

I use bronze washers.
 
I just ordered bronze and nylatron washers for the Christmas knives I'm making. I'll keep the bearings for flippers. Thanks everyone.
 
On Ti I would not go below .040" thickness, you are going to have the bearings galling the soft ti and the compression from the pivot. If you go past that, you really need some cold rolled races. I use .0625" bearings and .020" cold rolled races. My gap is .015" each side, sometimes .020". If I use thick handles I CB .0625 or .0675 into the handle, you have to remember to leave room to CB for the pivot as well. If I am doing a thin handle I CB the blade but leave a little to do the final depth after I heat treat. This knife I am working on now, I CB both the handle and blade so I can get more depth on the pivot, it was extra work but turned out very well. If you ask why I did that, it's because I don't like the races sticking out, so I set them into the ti handles.
 
Pittknife said:
On Ti I would not go below .040" thickness, you are going to have the bearings galling the soft ti and the compression from the pivot. If you go past that, you really need some cold rolled races. I use .0625" bearings and .020" cold rolled races. My gap is .015" each side, sometimes .020". If I use thick handles I CB .0625 or .0675 into the handle, you have to remember to leave room to CB for the pivot as well. If I am doing a thin handle I CB the blade but leave a little to do the final depth after I heat treat. This knife I am working on now, I CB both the handle and blade so I can get more depth on the pivot, it was extra work but turned out very well. If you ask why I did that, it's because I don't like the races sticking out, so I set them into the ti handles.
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I have hardened washers from AKS for that but have not used them yet. I started my 3rd and 4th folder today, also the first non-flippers that I've done. I'm trying to get a big batch so I can do all my heat treat in one shot.

Here's my second folder/flipper. It's very narrow and will be a nice ladies knife. I don't like where I ended up putting the scale screws so I addressed that on the next design.
87A04A82-342F-443A-90E3-D6878138248A_zpsjuw1y9la.jpg

And here's the 2 I started today so far. This is the most thorough design that I've done. Designed completely in cad and accounted for all screw holes prior to cutting anything out. The pin tracks are a little rough but I don't have a rotary table yet.
52FE7BCE-3120-45FD-97C0-561330BE81CA_zpsjpiuepxg.jpg
 
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There's no shame is using slightly thicker materials if need be, to compensate for counterboring/bearing pockets. Also, I everything is near perfectly flat and square, bearings may not even gain you that much over a good set of nylon or pb bushings.
 
Kevin,
If I understand your question correctly. I use .072 Ti for my liner locks. Counter-bore .050 for the .0625 caged bearings. This will give you .0125 clearance. Leaving me .022 for the thickness of Ti where the bearing will track. a couple of things worth noting. It is really important to get the bottom of the counter-bore a smooth as possible. I use a 3/8" piloted counter bore for the 3/16 caged bearings. I turn the counter-bore at around 195 to 225 RPM for Ti. If I go much faster it seams to chatter.
I have used .010 bronze washers in some of my earlier folders. With good to great results. For flippers my clients prefer /demand bearings.

As you may already have found out. There are as many ways to do this as there are makers doing it.

Hope this helps

Good luck

By the way I like your design :thumbup:

Bing
 
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