Bearing System Help

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Liam021

Joined
Jun 26, 2012
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133
Hey guys I'm planning on making a Knife with bearings. I want to use the Alpha Knife Supply .125 Bearings. http://www.alphaknifesupply.com/hardware.htm

My questions and where im having trouble trying to figure this out is how I should drill/mill the bearing pockets. This is the best picture I could find to describe my idea of what I would like.
IMG_0952.jpg


I need to find a way to do this using only a drill press or hand tools. I don't have a mill or any other CNC machines. I was also wondering how far down I should have the pocket go. If the bearing "Carrier" is .040 thick should I drill down .040? Or should I drill down more to accommodate the size of the ball? What I'm asking I suppose is should I be drilling so that the "Carrier" is flush with the handle material or should it be protruding out a little. Also should the "Carrier" be snug or should it be able to spin freely inside the pocket or do I have to drill the pocket to be exactly .312... witch seems odd to me.

Ive been trying to find answers for this for a couple of days and I've heard of a thing called a counterbore. I'm wondering if that's what I need to get this job done? Also where to get these. Whenever I find them they are not the right size.


Any Help would be great thanks everyone!

-Liam
 
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Check out the GTC bearings and tools on page 41 of the Jantz Knifemaker catalog pdf.

www.knifemaking.com

You use a drill press and a bearing to press into the liners

Seems easy enough although I haven't done it

Your mileage may vary

Syn
 
I've never done this with with metal, I've done counterbores with wood and plastic the later having a bearing in it, but counter boring seem the way to go. AFAIK, this is usually done with a mill just remember I don't have the metal working back ground, I'm just a hobbyist that likes to build stuff.

A quick use of the goog, show some counter bore bits for metal use. I'd think since you're in a press you could use something like this

Your bore size is odd... .312 i just a smidge under 5/16. I'm not sure if they make that size.
As for carrier fit, it depends on the bearing setup. From the looks of the picture, the carrier should be able to move. I think with the above counterbore, you should be alright. Just don't go too deep. I would imagine you would want the ball to touch both the liner and the blade.

So, if I were to be doing this, I would drill a pilot for my pivot, then swap bits, and drill the counterbore then finish off the pivot. If you got them, use hard stops when drilling your counterbore.
 
Man I must be bored... no pun intended, I think your target depth is going to be .0225

It should be greater than .040 (carrier height) but less than .0625 (bearing height)
 
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Im doing some with the GTC bearings at the moment.
A counterbore is required for sure.
The OD for the 1/4" GTC bearings is .415" and the accompanying counterbore that jantz sells is .422.
The bore is used to a depth of .05" and the ball size is .062"

I would think a 5/16 countebore for the alpha bearings would be too tight, the jantz ones just fall into the hole no pressing required and they're free to rotate. You could try a 21/64" counterbore
 
First of all, it's going to be very difficult to do without a mill. Maybe even impossible but I don't know. You may want to think about using washers instead. It's not that hard to get a smooth folder with washers, especially with teflon washers. That said, if you want to know how I do it, here goes:

Those Alpha Knife Supply bearings use .062" balls. I've used those a few times and used a 21/64" centercutting end mill to cut the pockets. You just have to do the math to figure out the depth. For example if you want a gap of .015" between your blade and liner then you'd have left .047" to hide in your blade and/or liners. Usually I'll put most of it in the blade like .020" in the liner and .027" in the blade. Plus the .015" gap that totals the ball diameter of .062". Hope this makes sense.
 
Yeah, like Ray said. I put about .035 in the blade (each side) and about .015 in the frames, leaves .012 clearance.
It's really all on how much clearance you want, and what you are comfortable with on a detent. Because of my detent style I go for .012 to .015 clearance.
 
Thanks guys. I might as well try this out on a metal test. If it works I'll come back here and let everyone know. Thanks for all the info guys!
 
Liam021 said:
Thanks guys. I might as well try this out on a metal test. If it works I'll come back here and let everyone know. Thanks for all the info guys!
Click to expand...

I know this is an old thread but wondering if this ever worked out for you? Using a drill press?
 
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