Drill bit sizes

S

scherar

Well-Known Member
I have read on other threads about the need to get the correct size bits for certain holes, such as the 1/8" pin won't fit in an 1/8" hole. After reading this, I realized this might be my trouble with my 1/4" pins and holes, so I ordered a letter F bit (.2570) to see if it helped.

I found out that it drills a hole that allows the 1/4 stock to pass through much easier. Before, I was having to drill and then use a file to open up the holes a little. This was a pain, but sometimes I made the mistake of "flaring" the holes in the handle material, which would show after epoxying.

My question is how loose should a pin be in the hole? Before, it was snug. Now it passes through very easily. Is this o.k.? I guess one could say that it allows for some epoxy to bind the pin in the hole.
 
A little bit snug fit looks better after glueing than, let's say, 1/64" over. The looser hole will show more glue around it. For 1/4" pin, you could try a 6.4mm bit which is 0.2520". What you really need to do is mic your pin to see the exact size and go from there. Not all stock are exactly the nonimal size stated, for example, if the 1/4" stock mic'ed out at 0.2530 then the 6.4mm bit wouldn't be usable but the F bit would give a better fit. If it mic'ed out at something like 0.242, which was about the case with some copper pin stock that I had once, then a 1/4" bit might do the trick for you.

Doug Lester
 
I have used both the 6.4mm and the F drill for 1/4" pins. Both work. Mic'ing is a good idea. Something that I have started doing is rolling the pin stock (brass- not SS) into the band saw blade before cutting it to length. I make 3 light cuts, rough up the pin with sandpaper, and then glue. I have driven pins out before, and they came out rather easily. I haven't had to drive out a pin done as described yet, but in theory it should make for a tighter glue job.

Milt
 
Thank you both for your help. I recently finished two knives using the new bit (F) and the pins don't show much in the way of an epoxy line. After reading Doug's response, I looked in the Jantz catalog and found the metric bit that was tighter than the F. I will probably order it the next time I place an order.

My only thought is that a tight/snug fitting pin to begin with would be better than one that passes through with very little resistance. If the epoxy were to fail, or if you get hard flexing near the ricasso, then there would at least be a tighter fit with friction. This is where the metric bit might be better.

Thanks again.
 
Cut your pin material to length and chuck it up in your drill press. Use fine mill file to file the sides and it will rough it up for your epoxy. Check it against your hole size and file it again until it matches your holes in your tang. Chuck one end then flip it over to make sure you file each end evenly.
 
I drill to size, then I sand down my pins on my belt sander to fit before I cut them off. Keep it simple.
 
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I do about like Mike and Jim, rough up my pins till they just have to be pushed hard with my thumb or tapped gently with a small plastic mallet to get through the standard-size holes. Be gentle sanding anything in your drill press chuck, let speed do the work. Shallow notches here and there on the side of the pin give extra space for epoxy to "grab", too.

If the pins are a bit undersize for any reason, placing the assembled knife on a flat hard surface and giving the pin a good thump with a hammer (before the epoxy sets up) will usually upset them enough to peen them tightly. Don't beat them so hard they swell too much and crack your handle scales! With a nicely peened pin the epoxy is really only there as a bonus, it's a pretty snug mechanical bond to begin with.

FWIW I've found the 1/4" and 5/16" corby bolts I've gotten from USAknifemaker fit just right in a standard hole. Snug fit without any extra fiddling around or special bits. :thumbup:
 
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