corby bolt questions

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grindemup

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Nov 9, 2013
Messages
69
Hello community.

I'm Allen and I have a question or two about corby bolts. I'v read that using two different drill bits wont exactly work because when you drill the outside hole it might not be centered. So what tool do i need to use to drill with? The hardware store told me they had a countersink bit that would do it, but they weren't sure what the bigger part of the bit size was, "it should be close" does not make me feel confident that it will work.

Also if i can find a countersink bit, do they make them where the bigger part will drill flat, instead of a bevel.I would assume a flat rivet head resting on a beveled hole would not be very strong.

Or am I way off and looking at the wrong bits?

Thanks for the help.

Allen
 
Most places will sell the drill bit along with the Corbys. then ya know you've got the right one. I'd be hesitant too on the close enough. I have the Jantz bit and use their Corbys. They work well together but there are many suppliers.
 
grindemup said:
Hello community.

I'm Allen and I have a question or two about corby bolts. I'v read that using two different drill bits wont exactly work because when you drill the outside hole it might not be centered. So what tool do i need to use to drill with? The hardware store told me they had a countersink bit that would do it, but they weren't sure what the bigger part of the bit size was, "it should be close" does not make me feel confident that it will work.

Also if i can find a countersink bit, do they make them where the bigger part will drill flat, instead of a bevel.I would assume a flat rivet head resting on a beveled hole would not be very strong.

Or am I way off and looking at the wrong bits?

Thanks for the help.

Allen
Click to expand...

Allen,
Most of the suppliers that sell Corbys or Loveless type bolts, "My Fav" also sell a step drill that will complete the drilling and countersink in one operation.
 
grindemup said:
I've read that using two different drill bits wont exactly work because when you drill the outside hole it might not be centered.
Click to expand...

Works fine for me, I've done that probably hundreds of times. The stepped drills are really nice, though. Mainly because you don't have to change bits.
 
Faron Moore said:
You'll need something along these lines: http://usaknifemaker.com/drills-tap...erbore-5-16-w-1-4-pilot-for-large-corbys.html
Click to expand...

Thanks for the link. Ill check and see if they have one for the size i was sold.

about those that i bought. Well. ebay :D. I am a little confused by the size listed on the listing tho. bigger part is 3/16. standard size. the smaller part. .124:confused:. 1/8 is .125, but this lists .124.

is it meant to be slightly smaller than the hole so it will fit the tang easier?

james terrio said:
Works fine for me, I've done that probably hundreds of times. The stepped drills are really nice, though. Mainly because you don't have to change bits.
Click to expand...

What about the drill bit drilling a point-ish hole, not a flat hole?

Thanks for the help everyone.
 
I use the step drills most of the time, but have done the 2 drill bit way. It will work and the bevel at the bottom of the hole really doesn't matter because I put epoxy around the corby and it fills to a solid mass when cured. They will tighten up fine and you don't really want to torque them down. Just get them good and snug so not to push out all the epoxy on your handle and cause a glue starved joint.

Stan
 
Looks like you've sorted it all out. Good luck!

On another note, has anyone ever found a source for silicon bronze corby bolts?
 
Now, here is another question for you. I bought corby bolts becuase the internet told me to. Seems to me that if you are epoxying the scales and rivets, corby bolts do not really offer any real advantage over rivet stock?
 
grindemup said:
Seems to me that if you are epoxying the scales and rivets, corby bolts do not really offer any real advantage over rivet stock?
Click to expand...

That's a fair question. :)

First let's make sure we're talking about the same thing... if by "rivet stock" you mean plain pins, the advantage is clear... plain un-peened pins do not hold the scales together, they just prevent them from slipping off. Bolts and true rivets or peened pins provide a mechanical joint that's not going to come apart unless you drill through them or grind them away... even if the epoxy fails for some reason. I would rather have bolts but no epoxy, than epoxy but no bolts.

The advantage of Corby bolts over true rivets/peened pins is that as long as you drill for 'em properly, they're basically idiot-proof. Smear a little epoxy on 'em, screw 'em together and once the epoxy is cured up, grind 'em flush down to the handle contours you want.

Riveting/peening requires a bit more skill, and it's possible to crack handle material or even push it away from the tang by over-peening. But when done properly, it will definitely work.
 
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Using corby's you don't have to worry as much about damaging your scales, when pining with rivets you have to smack Em with a hammer or punch and as you beat rivets they expand. Both of these things make it easier to damage the scales. At least that's the way I see it...
 
grindemup said:
Is there a need for peening if its going to be glued in?
Click to expand...

The short answer is "Yes". Adhesive joints between disparate materials range from reasonably strong to very easy to break. Mechanical fasteners are very difficult to break.
 
I think we have two topics going here. I'll try to explain the difference:

All handle construction normally has the scales epoxied to the tang. Use the best and slowest curing epoxy available. Only clamp the scales tight enough to hold them in place while the epoxy is drying. Over-clamping can cause the epoxy to all squeeze out, creating a "glue starved" joint....and potential handle failure.
The hole through the tang of the knife should be about 25% larger than the rivet or bolt shaft that goes through. This allows for some misalignment in drilling, as well as adjustment in fitting the handle.

Rivets, also called pins, are just pieces of round stock used to "pin" the handle scales in place. They provide shearing resistance strength to the handle, but only a little resistance to the scales lifting due to warp or epoxy swelling.
They are roughed up a bit on the sides with 100 grit sandpaper, and the hole through the handle material should be just a smooth slip fit....not tight, nor loose. The ends are filed to within about 1/16" of the handle, and before the epoxy sets the ends are peened with a ball peen hammer. This flares the head a bit, locking the rivet tightly in place. The hole through the handle material is usually slightly chamfered to make the rivet "head" seat properly without splitting the handle. After the epoxy cures, the excess metal is filed/sanded away.

Corby Bolts, Loveless Bolts, Chain ring bolts, and other mechanical fasteners provide solid mechanical bond to the two scales, clamping them to the tang. These type fasteners are far stronger than rivets. They install easily and don't require peening. The epoxy adds to this strength as well as seals the joint from moisture. These type of fittings use a hole in the scales with a "seat" that allows the bottom of the bolt head to apply pressure to the scales from both sides of the tang. The hole is best made with a stepped drill bit or a special bit called a counterbore. These holes must be carefully drilled to assure exact alignment, or all the handle bolts may not go in properly. Corby bolts, et.al., Are tightened with screwdrivers to just snug enough to bring the scales into contact with the tang. Do not over tighten them, as this may cause the scales to lift on the end or even crack. After the epoxy cures, the excess bolt head material is cut/filed/ground away as the handle is shaped, and the bolt becomes a smooth wide rivet.
 
If you want to watch the best install a slabbed handle on a knife watch Bob Loveless or Steve Johnson video. Or read the Bob Loveless book on knifemaking.

Once you see how they do it a lot of the worries will decrease because it eliminates a lot of the problems.
 
AVigil said:
If you want to watch the best install a slabbed handle on a knife watch Bob Loveless or Steve Johnson video. Or read the Bob Loveless book on knifemaking.

Once you see how they do it a lot of the worries will decrease because it eliminates a lot of the problems.
Click to expand...

i cant seem to find the video
 
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