Well, 1/4"=.250..... however, and corby bolt that is .250 will NOT fit into a .250" hole.....because they are both the same size. I would expect the corby to actually be .240-.245", so it would fit into a .250" hole.

OK, that being said, to eliminate the glue line around the corby head, first, you have to ensure that you use HIGH QUALITY bits... it always surprises me how folks will be so careful about buying/using high quality tooling for everything else, but when it comes to drill bits, the buy the cheapest they can find, and when they do, it causes all kinds of "little" issues like this. Next, IF the corner of the corby head that is nearest the shank is not already rounded off, then do that, and use a little glue as "lube" when installing.....as you tighten, it will pull the bolts into the holes..... then let the glue cure, and finish as normal.

More often then not, I epoxy/glue pins. I learned my lesson YEARS ago, when attempting to "gently" peen/dome pins on fossil ivory scales....one little tap too many and "POP!" Rats! Wrecked several hundred dollars worth of ivory. Afterward no peening pins in ANY natural handle materials.

|quoted:

Well, 1/4"=.250..... however, and corby bolt that is .250 will NOT fit into a .250" hole.....because they are both the same size. I would expect the corby to actually be .240-.245", so it would fit into a .250" hole.

OK, that being said, to eliminate the glue line around the corby head, first, you have to ensure that you use HIGH QUALITY bits... it always surprises me how folks will be so careful about buying/using high quality tooling for everything else, but when it comes to drill bits, the buy the cheapest they can find, and when they do, it causes all kinds of "little" issues like this. Next, IF the corner of the corby head that is nearest the shank is not already rounded off, then do that, and use a little glue as "lube" when installing.....as you tighten, it will pull the bolts into the holes..... then let the glue cure, and finish as normal.

More often then not, I epoxy/glue pins. I learned my lesson YEARS ago, when attempting to "gently" peen/dome pins on fossil ivory scales....one little tap too many and "POP!" Rats! Wrecked several hundred dollars worth of ivory. Afterward no peening pins in ANY natural handle materials.

I hope you do not mind me asking a few questions mostly out of curiosity. what do you consider quality drill bits?

Now the thing that I am curious about as I hope to one day be able to afford ivory, and I do not trust glue as much as mechanical connections as I have seen images really old step sabers with the pins still in the blade in the book a study of the eastern sword. So I am wondering if you remember what method of prep were you using for peening? my current method is to drill a slightly bigger hole about 1/4ish deep. the reason I am not sure how deep I go is I use a masking tape method I learned from a retired cabinet maker who also was my high school woodshop teacher...and it's literally just dawning on me as i type this that drill press a built in depth limiting device. I only use wood as a natural material however with the exception of when I used brass its been some time since I damaged scales. however, its been almost 3 years since I last used I used to bone.

However given the sheer cost of ivory of any form I honestly would hesitate greatly with peening them so I am wondering what is the best adhesive/epoxy to use for affixing the pins in scales, and what is the best epoxy to use to affix the scales to the blade?

Travis & Kevin, They actually make drill bits specifically for Corby bolts. Buy the correct bit for the size Corby you are using.

https://knifemaking.com/products/rivet-drills

Thank you all. Is the appropriate size drill bit the only difference. I know several custom knives I’ve picked up you can see glue around the pins. When I’ve done 1/16” pins I’ve had it as well. What other things can you do to avoid this?

Thanks,

Travis<><

I am in the "use quality drill bits" camp also. I have a harbor freight 1/4" drill that drills 0.280" holes. I ended up getting the step drill bits that Joshua was talking about.

good drills but also keep everything CLEAN, I have had oil get in a pin hole and stain the end grain, even on stabilized woods. don't heat the pin, I wont even touch a pin to the grinder anymore. After glue up I cut the pin close and file and sand to finish for flush pins or file close and dome if a domed pin, it is very easy to over heat the pin and scorch the wood/glue.

make sue you drilll press is running true, 0.001 run out on the spindle of in the chuck, will open that hole far more than you might think. If your press is out you can drill undersized and use a on size reamer.

MP

Thanks for all the advice guys. I hadn't thought about temperature when grinding the pins. I'm going to be mindful of that and I ordered a new bit to try.

Thanks again,

Travis<><

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Thanks for all the advice guys. I hadn't thought about temperature when grinding the pins. I'm going to be mindful of that and I ordered a new bit to try.

Thanks again,

Travis<><

https://smile.amazon.com/gp/product/B00D3NM3VU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 I would suggest getting one of these as drill bits do hit the bank in the long run. It's been two years since I bought drill bits, however this one is the budget model and if you can afford i i would try a higher-end as there is a risk of the shavings from sharpening getting into the electric motor which will short it out if you knock it down on accident. which is something I learned by doing it. however, at about 5 bucks a pop for a cobalt bit 10 sharpenings will basically pay for the machine itself.