Thread: how to drill 2 large counter bore holes for vice jaw

Greetings,
Counterbore_Cross-Section.png
I'm a bit confused by your use of the term "counter bore". A "counter bore" usually refers to a situation where you have a through hole (or a blind hole) of say 1 inch diameter, with a larger diameter hole bored concentric with the first hole, and to a partial depth, as in the drawing at the left.4XK80_AS01.jpg

I suspect that what you need to mount your vice is to bore tw0 through holes, 2 and 5/16 inches in diameter. The easiest way of boring a hole that large would be to use an adjustable spade bit. Irwin make something they call the Irwin Speedbore. The Irwin Speedbore is an adjustable Spade Bit that can bore a hole any diameter between 7/8 inch and 3 inches. Other manufacturers also make adjustable spade bits that are less expensive, so a hunt round your favourite tool suppliers should find one that will do the job.

I've used a 25mm to 50mm adjustable spade bit, that I bought off a Chinese web site, to bore some 45mm holes in Hoop Pine. It worked quickly, and a battery pistol drill was able to drive it OK, provided you didn't push too hard. With this type of bit you do get a lot of tear out on the back surface when the bit breaks through. I found that the best way to prevent the tear out on the back surface, was to bore through just until the auger on the tip of the bit just breaks through, and then complete the hole by boring from the back side.

If what you really need is a "counter bore", then bore the larger diameter part of the hole first, and then complete the smaller diameter second.

Hope that helps,

RoyG

Have you got your hands on the vice yet?
I don't believe the one from thewoodworks has the support collets like the Veritas one seen here on the right
Veritas Front Vices - Woodworking Vices - Vices - Benches, Vices & Storage | Axminster Tools & Machinery

If it does, then it's totally different to the one in their catalogue.

Thanks Roy,

Yes these holes are actually counter bores. See the diagram on the second page of this: http://veritastools.com/Content/Asse.../70G0801AI.pdf

thanks for the tip regarding those spade bits. I'll see if I can find one.

Thanks,

Jason

Yes, I have the vice, it does have the support collet just like the right hand one in the image you link to. In fact to my eye it looks exactly the same as that except painted black rather than green.

Use a router and a template to bore the large holes