Need hole drilling advice

[Jim Izat]

I have to drill two 1.5 inch diameter holes for my Veritas twin screw vise through both the front and back jaws at the same time, a total depth of about 4.25".

Trouble is my forstners aren't nearly long enough to do that. I could buy a speedbore that would do it buy I'm afraid I'd get a mighty raggedy lookin' hole.

How can I drill a smooth 1.5" by 4.25" hole (in ash)?

Jim

[Jim DeLaney]

A shank extension for the forstners will let you drill to a depth of about 6½ - 7". Most mail order catalogs have them for just a few bucks. They'll work with any bit larger than 5/8", and with a 3/8" shank.

<Center><FONT FACE="Comic Sans MS" COLOR="Blue">Jim D.</FONT></Center>
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[Ian MacDonald]

Hi Jim,

Why do you have to drill both pieces at the same time? Wouldn't a fence with a stop block allow you to drill the pieces separately while maintaining alignment?

A couple of test holes drilled into some scrap should let you know if this process is accurate enough.

Regards,

-- Ian


Originally posted by Jim Izat
I have to drill two 1.5 inch diameter holes for my Veritas twin screw vise through both the front and back jaws at the same time, a total depth of about 4.25".

Trouble is my forstners aren't nearly long enough to do that. I could buy a speedbore that would do it buy I'm afraid I'd get a mighty raggedy lookin' hole.

How can I drill a smooth 1.5" by 4.25" hole (in ash)?

Jim

[Lee Schierer]

You can easily do it in two steps. Clamp the two pieces together as if you were drilling all the way through with your forstner bit. Drill though the first piece and just start the bit in the second piece. Once you have at least the drill point in the second piece, preferrably about a 1/8" deep hole, you can remove the piece on top and finish drilling the hole through the second piece. I'd also clamp a backer board to the back side of the second piece to prevent tearout.