Pilot Hole Size

[Jerry Lawrence]

Not sure if this is the right section for this question, so if it should be elsewhere, admin. please feel free to relocate it...thanks!
I'm looking for the right size drill bit to make pilot holes to hold #18 escutcheon pins in cocobolo. The coco. is only 1/2" thick and the holes will be within 3/16" from the edge, so hoping to prevent cracking but still have holes small enough to hold the pins tightly.
Thanks in advance for your help!

[Sam Murdoch]

This is a case for trying some holes near the edge of a scrap piece - replicating just what you intend to do. You will learn all you need to know. We? Just guessing otherwise.

[Jerry Lawrence]

That would work, was just hoping I could find the right size first so I could buy the right size the first time and not have to buy a bunch of different size tiny drill bits that I would probably never have another use for. Thanks for the reply!

[John Coloccia]

#18 is .049. You're 3/16" from the edge of Cocobolo, so I think the odds of splitting it are VERY high. I would drill a pilot for .049 and glue in the pins with a drop of epoxy or superglue. That's 1.25mm (.0492"), btw, if you're searching for the bit online.

You could try for a standard interference fit, maybe 3/64" (.0469") or even #56(.0465"). I would probably normally do #56 or #57(.0430") depending on the kind of wood for a typical situation, but I do believe that even 3/64" will be risky in this case. You might get away with it.

[Jerry Lawrence]

Thanks, John, for your very informative and very helpful answer!

[Tim Howell]

http://www.jamestowndistributors.com/userportal/show_product.do?pid=1943







Gauge

Shank Diameter (inch)

Head Diameter (inch)



#18

0.049

0.098



#16

0.065

0.136



#14

0.083

0.177













Metal:

Brass



MET / STD:

Standard



Type:

Nails



Fastener Type:

Escutcheon Pin



These are the drill number sizes in the range you are working with.






60







0.04








59







0.041








58







0.042








57







0.043








56







0.0465







3/64








0.0469










1.25





0.0492








55







0.052




You might try a drop of crazy glue on the pin. ? Don't force the drill - it will flex and walk or wander and give you a crooked hole.