Corby problem

SBranson

SBranson

Joined
Oct 29, 2006
Messages
2,912
I'm sure this isn't too tough an issue but on my first knife with corby rivets I had one blow through and had to "fix" it with a little 1/8" stainless rod. :rolleyes:

I shortened the threading on both halves to try to avoid this but obviously not enough.

Any tips for setting up to avoid this in the future? Any sense of how little material in the bottom of the hole is enough not to blow apart when tightening the corbys?

Luckily this one was for a personal edc.

StuartEDC_3.JPG
 
I usually try to leave about 3/32 of the handle material for the corby to rest against. That is deep enough that you can take the edges of the handle material all the way down to the steel if you want and round the handle up to a 1/4 inch or slightly less on the rivets.
You don't have to worry about pulling through the handle material unless you drilled an oversize hole for the post of the corby through the blade.
 
denim said:
...You don't have to worry about pulling through the handle material unless you drilled an oversize hole for the post of the corby through the blade.
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Yoiks! :o That's so obvious it's painful I didn't think of that. Thanks!!!

I did slightly oversize the hole just to make up for the angle of the tapered tang. I guess I was thinking of this from the point of view of a woodworker forgetting the steel plate of the tang.
 
I was the same way first time I used them, then it dawned on me that they couldn't pull through with the blade backing them.
If you drill your holes before tapering you won't have to worry about oversizing them. The rivets will go in just fine.
 
denim said:
I was the same way first time I used them, then it dawned on me that they couldn't pull through with the blade backing them.
If you drill your holes before tapering you won't have to worry about oversizing them. The rivets will go in just fine.
Click to expand...

And once again I forgot simple geometry:o:o The micarta slabs, being parallel to what was the tang before tapering, the cylinder of the hole in the tang (drilled before tapering) is still perpendicular to the micarta... section of a cylinder... Duh...:rolleyes:

Thanks again. I drilled the holes before I tapered the tang but confused myself unnecessarily... Stay in school kids.. :p:p
 
I always make one of the counter bored holes deeper than the other and put the female side in that one not much about an 1/8" or so.
test fit them first! Use a tooth pick or piece of wire and stick it in the hole to see how deep the threads go and mark them on the side with a scribe or sharpie.
 
Yep that's why I love this place, always something to learn, another thing is on tapered tangs it is easy to counter drill to deep, then the male will bottom out before snugging up the scales. If the female part of the rivet sticks out past the tang on the other side you'll be grinding off threads to make it work.
 
I ground them down quite a bit. In fact I ground one down so much that during glue up it wouldn't grab so I had to fight to remove it and put in a new one. Yes I did test fit but I think I reversed the order of assembly and the torque of the micarta on the taper was enough to cause the threads not to quite line up.

I think in the end, the hole was just not deep enough but as this was the first time using these and shaping this kind of handle...

Thanks for the tips. I'm sure next time will be much easier.
 
Why are you tightning them that much. Just like in woodworking, use minimal clamping pressure to assure you don't squeze out all your glue. No way to blow through that way.
 
remember that on Corby bolts. Sometimes the hole might be drilled a little deeper into the female side on some bolts, so you have to be careful and give yourself enough wiggle room.
 
jdm61 said:
remember that on Corby bolts. Sometimes the hole might be drilled a little deeper into the female side on some bolts, so you have to be careful and give yourself enough wiggle room.
Click to expand...

Very good point.

As far as tightening and losing epoxy, I hollowed the tang a little and put a lot of marks and stuff on the inside of the micarta to both give room for the epoxy to go and to get better adhesion.
 
I did exactly the same thing on the first knife I ever made. I fixed it in the same manner you did. Then I drilled a small hole in the other Corby and put a pin in there too, to make it look like it was supposed to be that way.;)

I countersink so that .080 of material is left on the bottom of the c-sink. I have a scrap piece of .080 material that I've drilled a hole in that's slightly larger than the pilot on my countersink. I just put this on the drill press, lower the (already secured in the chuck) c-sink until the flutes come to rest on the material, and set the depth stop on the drill press. Your c-sink will now automatically stop at the proper depth.
 
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