Drillbit counterbore

[Rythorne]

Been searching without success for a drill bit that has a 1/4 in bit that leads to a 5/6 upper portion used to make holes and counter bores for knife hardware. Any ideas?

 

[Stacy E. Apelt - Bladesmith]

I'm assuming you mean 5/16" not 5/6".


If you don't find what you want, you can make one by turning down a 5/16" bit. Use a diamond stone and turn down the end of the running bit.

My errort, I misread your dimensions. That is a standard Corby. USAKnifemakers has the counterbore, as do ost knife suppliers.

 

[Busto]

You might try searching MSC industrial for "Straight Shank Interchangeable Counterbore". As Stacy mentioned you will need to purchase 1 Counterbore(5/16)Body and 1 Pilot(1/4 which has a 3/32 stem that slides into the counterbore).

 

[gunfixrjoe]

Usaknifemaker.com has a good selection. I've also found decently priced sets on the big river site.

 

[Alan Davis Knives]

http://popsupply.bizhosting.com/counterbore_tools.html

 

[Stacy E. Apelt - Bladesmith]

I corrected my error in reading your sizes.
As I said in the edit, USAKnifemakers has a large assortment of counterbore bits. They also sell them in carbide, which is a really smart way to go if you plan on using Corby bolts in your handles. It is about four times the cost, but all the holes will be the same size forever (almost). Regular HSS counterbores wear with use and the holes get too tight for the bolts to fit easily. Carbide solves this - Buy once, Cry once.

Also, buying the bolts from the same supplier as the counterbore will assure a good fit. Each supplier has the bolts made for them. Not all Corby style bolts measure exactly the same.