Amount of oversize for pivot head?

Brian Avila

Brian Avila

Joined
Jan 2, 2011
Messages
1,286
I have been looking around and didn't really see this covered explicitly, or if it was I missed it.

I am using Alpha Knife Supply 3/16" pivots. The heads are 0.29" diameter. This means that I can use a 19/64" (0.296875) or 5/16" (0.3125) counterbore for my recesses for the head.

I don't want to purchase tools that I am not going to use so I figured I would ask. Which size should work the best?

Does this change if I wanted to make pivot collars?

If you guys have pics of your AKS 3/16" pivots in your holes could you show them to me and let me know what counterbore size you guys use. I will probably end up using an end mill bit to do the counterboring.

-Brian-
 
If you're using a drill press instead of a mill, also look at removable piloted counterbores.

They ensure that you are lined up on the hole center
 
Yeah, that crosses my mind. I saw a set up with a plate of g10 and pins that was suppose to help with the lining up. But it might not work out

But I need to calculate the price. Which ever way is cheaper.
 
If I'm making a frame lock, I use a 9/32" bit and follow it with a modified size "L" reamer to get a light press fit for the head of a 3/16 AKS pivot on the frame side. It's pictured in the first page of my WIP here:
http://www.bladeforums.com/forums/showthread.php/916004-Virtual-BBQ-WIP-GNiCr40Al4-frame-lock-folder
If you use that method on the screw side, a little material can be removed from the side of the screw head to get clearance as shown in the WIP if you don't have a 19/64" bit.
you can see how the method of locating the pivot hole in the bolster could be used on a liner lock as well.
If all you need is a clearance hole for the pivot head, a 19/64" bit would work best for a non bolster knife. If hidden under bolsters it could even be a 5/16" end mill. It doesn't matter that much in that case, unless being larger it begins to interfere with another feature such as bolster mounting screws.
 
Salem Straub said:
If I'm making a frame lock, I use a 9/32" bit and follow it with a modified size "L" reamer to get a light press fit for the head of a 3/16 AKS pivot on the frame side. It's pictured in the first page of my WIP here:
http://www.bladeforums.com/forums/showthread.php/916004-Virtual-BBQ-WIP-GNiCr40Al4-frame-lock-folder
If you use that method on the screw side, a little material can be removed from the side of the screw head to get clearance as shown in the WIP if you don't have a 19/64" bit.
you can see how the method of locating the pivot hole in the bolster could be used on a liner lock as well.
If all you need is a clearance hole for the pivot head, a 19/64" bit would work best for a non bolster knife. If hidden under bolsters it could even be a 5/16" end mill. It doesn't matter that much in that case, unless being larger it begins to interfere with another feature such as bolster mounting screws.
Click to expand...

Good stuff, thanks!
 
^ good advice

Generally you will use a press fit or slip fit for the pivot head... I use loose slip fit at .002' over because the tooling is easy to find (.312" pivot head into 8mm/.314" counterbore done with endmill)

I press fit the shaft (.249" hole with .25" pivot shaft). The AKS pivots have a "collar" made just for this purpose.

Also consider modding the pivot by turning it down, I just use my grinder and a hand held drill. They are easy to grind and only take a few seconds to turn down to size.
 
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