Should a detent ball "roll"

[cpirtle]

This is a questions that's had me curious for a while but never got around to asking it.

I have had custom pieces on which the detent ball was peened into it's hole tightly and would not rotate, so they develop a little flat spot.

I have had others where the ball was not peened in tightly and the ball would roll freely.

I see the loose fitting ball to be an advantage to smoothness and long term wear resistance, but does it really make a difference?

How hard are they to replace if one does wear down?

 

[Peter Atwood]

Chad, if it's a ti frame they can be removed by soaking overnight in ferric chloride. A new one can then pressed in. I like to use a tiny drop of Bondini as an insurance policy.

 

[Chuck Gedraitis Knives]

If the correct type of detent ball is used it should not develop a flat. I use 440-C stainless detent balls. They are hardned and wear evenly with the knife. The blade tang after time will develop a wear pattern and the ball and wear marks should wear themselves in and be smooth. I don't see how you could get the ball to roll in the hole? That would mean that the hole is oversized and the ball is peened or burnished in. Too much work and there is the risk of it falling out.

 

[Andrew McLurkin]

If the bearing is hard in the range of the blade little to no wear will be evident. The 440c ball bearings form MSC are 60Rc and blades are usually in the 57 to 60 range. On occasion I have taken material off the the top surface of the detent bearing with an EDM stone to get a little extra clearance. This if anything seemed to make the action a little smoother with the slightly wider bearing surface.

I've heard of instances where the bearing was not hard form the manufacturer. In this case the bearing can be replaced. The procedure would differ depending on whether the hole is drilled through the liner or only from one side. A stainless steel ball will resist ferric chloride.

 

[Chuck Gedraitis Knives]

Yes a stainless steel ball will resist ferric chloride, but not anodizing. If you don't coat the ball with nail polish when you anodize the liners, it will also act like the stainless foil in your solution and get eaten away and fall out!

 

[cpirtle]

Thanks for all of the answers guys.

I was under the impression that some detent balls actually rolled in their hole, never quite knew how that would work...

I still think Chris Reeve uses a plate over his ball to hold it in place, otherwise wouldn't the ceramic ball bearing break when pressed in?