Detent ball on liner lock

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i have this book and thankfuly i got it before it was out of print but it is a wealth of info even if you kind of have to look around for it
 
On the recommendation of you guys I just used my $50 Amazon gift card plus some more $ and got that book coming. seems like a lot for a paperback but ya got to pay for knowledge. You could buy a book and follow in somebody's footsteps or spend a lot of time and $ re-inventing the wheel.
 
That Terzoula book is also available on pdf for free if you look around the internet a bit... the pics aren’t in color, but you can still see what’s going on.
 
I'd use a 1/16" ball and...

Close knife past shut (on most knives you can remove the stop pin and let it hit the spacer or standoffs)

#55 bit (stubby and carbide if possible) Drill detent through lockbar and into blade

#53 bit drill lockbar only with knife taken apart This is a good press fit for a 1/16" ball.

Set a washer or two (I like to go something like .025" tall) around the detent hole to act as a stop and set in ball, lightly hammer (best to use a pin or the likes on ball not direct hammer hit) or press in (even better) to fit. The washer enables you to hit an exact dimension easily and as a bonus stops your ball from rolling away should it roll out of the hole.


The 1/16" ball is plenty, with improper tuning you can lock a knife shut with one.
 
Daniel Fairly Knives said:
I'd use a 1/16" ball and...

Close knife past shut (on most knives you can remove the stop pin and let it hit the spacer or standoffs)

#55 bit (stubby and carbide if possible) Drill detent through lockbar and into blade

#53 bit drill lockbar only with knife taken apart This is a good press fit for a 1/16" ball.

Set a washer or two (I like to go something like .025" tall) around the detent hole to act as a stop and set in ball, lightly hammer (best to use a pin or the likes on ball not direct hammer hit) or press in (even better) to fit. The washer enables you to hit an exact dimension easily and as a bonus stops your ball from rolling away should it roll out of the hole.


The 1/16" ball is plenty, with improper tuning you can lock a knife shut with one.
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Thanks for the advice. I’m waiting on some more drill bits to show up and I’ll give it a shot.
 
Daniel Fairly Knives said:
I'd use a 1/16" ball and...

Close knife past shut (on most knives you can remove the stop pin and let it hit the spacer or standoffs)

#55 bit (stubby and carbide if possible) Drill detent through lockbar and into blade

#53 bit drill lockbar only with knife taken apart This is a good press fit for a 1/16" ball.

Set a washer or two (I like to go something like .025" tall) around the detent hole to act as a stop and set in ball, lightly hammer (best to use a pin or the likes on ball not direct hammer hit) or press in (even better) to fit. The washer enables you to hit an exact dimension easily and as a bonus stops your ball from rolling away should it roll out of the hole.


The 1/16" ball is plenty, with improper tuning you can lock a knife shut with one.
Click to expand...
Also, why do I need to close it past the stop? I would think I want the detent to hold the blade against the stop pin.
 
Matt R said:
Also, why do I need to close it past the stop? I would think I want the detent to hold the blade against the stop pin.
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I don't really get that either. There are a lot of variables there. Some knives will close a lot farther than others with the stop pin out. You could easily miss having your detent fall into the hole altogether.

I know some guys do that and have good luck with it. It isn't something I want to try. Just making sure my knife is free and clear of grit or debris and closed all the way works well for me.
 
kuraki said:
It's just to get the detent socket in the blade slightly past the end of travel at the stop pin so that you don't have to depend on perfect contact between the ball and socket. If it's slightly past, it'll keep the blade closed under tension even with some size or form discrepancy.

View attachment 872531
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I understand now since you showed a picture! So if I used the 3/32” ball, would I use the same size bit for the detent hole or does it need to be undersized?

Edit: I see Daniel has already answered my question.
 
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I understand why people do it. It just doesn't seem very precise to me.....a lot of guess work. I remember the book saying to locate the detent hole in the blade .020" past the track the bearing scratches on the blade. That could go sideways pretty quick and if you're very far off, the ball bearing won't fall in the hole at all.

Just seems more sure fire to close the knife firmly with the stop pin in and drill through the lock bar and blade at once.
 
That's right, you have to make the detent offset a bit toward more closed otherwise you will get blade play in the closed position.

Some makers locate and press in the ball, let the ball scribe a track in the blade by opening and closing a few times then shoot just past that but I found that method to be too tricky. This works well if you want to do a hidden detent though.

I'd help on the 3/32' ball but have never used one... check out a drill bit chart and compare to get something accurate.
 
Matt R said:
I understand now since you showed a picture! So if I used the 3/32” ball, would I use the same size bit for the detent hole or does it need to be undersized?
Click to expand...

I use a smaller bit.

J. Doyle said:
I understand why people do it. It just doesn't seem very precise to me.....a lot of guess work. I remember the book saying to locate the detent hole in the blade .020" past the track the bearing scratches on the blade. That could go sideways pretty quick and if you're very far off, the ball bearing won't fall in the hole at all.

Just seems more sure fire to close the knife firmly with the stop pin in and drill through the lock bar and blade at once.
Click to expand...

Yep you're 100% right. I like Daniel's method of closing without the stop pin because I'm in control of how much relief there is between the back spacer and the blade edge. Especially at that point before I've ground the bevels. That way you don't have to guess both the radial dimension from the end of the scratch AND the distance from the pivot by eyeballing. Seems the best way to get both things - location by drilling through the liner hole and over center positioning with some amount of control.
 
I suppose if the blade couldn't close too much farther with the pin out it would work out well....especially since moving the blade closed even 1/8" farther at the tip end wouldn't move it much at all at the detent/tang end.
 
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