What size drill bit for a detent hole (more details in thread)

H

hazy

Joined
Mar 1, 2013
Messages
328
Hey guys I have a production knife that does not have a detent hole, the knife is a flipper so I want a strong detent for good flipping action. I want to drill one myself but I don't know what size drill bit to use, and what type of bit is best. Price is not a factor I want the best one for the job I don't care the price (within reason of course, I'm not spending $80 on a bit :P)

The knife has a 1/16" detent ball (according to manufacturer), the blade is hardened Elmax.

I'm going to be using a drill press, don't know much about it but I can get more info from the owner of the press if necessary.

Please feel free to treat me like a noob guys, I am not a knife maker this is just a one shot deal for me so any advice or words of warning/wisdom are extremely welcome. Thanks!
 
Last edited:
Word of warning: Don't do it. It sure isn't easy and unless you're used to working in thousandths of an inch increments you should send it back to the manufacturer. If there really is no detent hole but there is a detent ball then they will absolutely make it right.

However, we all like to mess with stuff now and then and the worst thing that could happen is you srew up the hole and it won't work or be warrantied. Use a number 55 carbide bit. If you want to go the route of taking the blade apart and marking the tang with some Dykem or whatever then prepare for the worst. That procedure will be to mark and reassemble. Open and close a bunch and drill a divot just past the end of the path, about .020" IIRC. I failed at this method.

If the detent hole in the lockbar is drilled all the way through then you can punch it out with the backside of a number 53 bit in your press and start over. Hold the blade tightly closed and redrill right through the existing hole and into the tang. Make sure you have your stop set. I'd buy a new ball but you can probably reuse the old one. Lightly tap the ball back in place with a hammer. You really should have some calipers to measure the amount protruding but you can just overlay one of the washers around the ball after you've given it an initial tap so it doesn't get all squirrelly on you and disappear. Lay a flat piece of hard and thick metal over the ball and tap some more. The washer will act as a spacer so the ball won't go in too far.

This was an abbreviated version of Ed Caffrey's method (and I'm sure others) and it works well. You can find more with Google.

Mark
 
Last edited:
Varga Knives said:
Word of warning: Don't do it. It sure isn't easy and unless you're used to working in thousandths of an inch increments you should send it back to the manufacturer. If there really is no detent hole but there is a detent ball then they will absolutely make it right.

However, we all like to mess with stuff now and then and the worst thing that could happen is you srew up the hole and it won't work or be warrantied. Use a number 55 carbide bit. If you want to go the route of taking the blade apart and marking the tang with some Dykem or whatever then prepare for the worst. That procedure will be to mark and reassemble. Open and close a bunch and drill a divot just past the end of the path, about .020" IIRC. I failed at this method.

If the detent hole in the lockbar is drilled all the way through then you can punch it out with the backside of a number 53 bit in your press and start over. Hold the blade tightly closed and redrill right through the existing hole and into the tang. Make sure you have your stop set. I'd buy a new ball but you can probably reuse the old one. Lightly tap the ball back in place with a hammer. You really should have some calipers to measure the amount protruding but you can just overlay one of the washers around the ball after you've given it an initial tap so it doesn't get all squirrelly on you and disappear. Lay a flat piece of hard and thick metal over the ball and tap some more. The washer will act as a spacer so the ball won't go in too far.

This was an abbreviated version of Ed Caffrey's method (and I'm sure others) and it works well. You can find more with Google.

Mark
Click to expand...

Thanks for the reply Varga, you make it sound a lot more involved then I thought it would be. Tbh I thought it was just drilling a hole at the end of the detent ball path. I might just sell it, I'm not much of a machinist I would probably screw it up. Thanks for taking the time to reply I think I will heed your advice. :)

PS: unfortunately the manufacturer will not put a detent in it for me (I already asked), I could send it to a guy who would do it for me but, it might not even be worth the aggravation.
 
hazy said:
PS: unfortunately the manufacturer will not put a detent in it for me (I already asked)
Click to expand...

You're welcome. Am I miss something? There is a 1/16" ball already in it from the manufacturer but no hole in the tang to make any use of it and they won't remedy this? Could you explain how they answered you?

Is the hole all the way through the lock? If so, it's not that hard and I can either walk you through it over the phone or you can send it to me and I'll take care of it. All you need are two drill bits (really just the #55). I didn't mean to scare you off from it but rather to steer you towards getting resolution from the maker.
 
Varga Knives said:
You're welcome. Am I miss something? There is a 1/16" ball already in it from the manufacturer but no hole in the tang to make any use of it and they won't remedy this? Could you explain how they answered you?

Is the hole all the way through the lock? If so, it's not that hard and I can either walk you through it over the phone or you can send it to me and I'll take care of it. All you need are two drill bits (really just the #55). I didn't mean to scare you off from it but rather to steer you towards getting resolution from the maker.
Click to expand...

But that has to be a solid carbide drill, the blade is hard.


It's interesting that the knife has a ball in the liner, but no detent hole in the blade.

I'd call that a warranty issue.
 
Varga Knives said:
You're welcome. Am I miss something? There is a 1/16" ball already in it from the manufacturer but no hole in the tang to make any use of it and they won't remedy this? Could you explain how they answered you?

Is the hole all the way through the lock? If so, it's not that hard and I can either walk you through it over the phone or you can send it to me and I'll take care of it. All you need are two drill bits (really just the #55). I didn't mean to scare you off from it but rather to steer you towards getting resolution from the maker.
Click to expand...

Long story short it's a ZT 0566, apparently the earlier batches did have a detent hole. According to the KAI warranty rep I spoke to on the phone there were "problems with the detent holes," so they stopped drilling them. There actually is a hole drilled all the way through the lockbar for the detent ball. I currently have the knife up on the for sale section so if it sells then I won't worry about it, if for whatever reason I can't move it I will consider taking you up on your offer to do it (and compensate you of course). Don't feel like you scared me away, more informed me of the reality of the task. Like I said I'm not much of a machinist and measuring, then drilling holes in exact locations is not my expertise. There's a very high chance I would have screwed it up. Thanks for the follow up, I do appreciate it :)
 
You must log in or register to reply here.
Back
Top