How dangerous is it...

if you don't mind ruining the bit and the bushing???

Think I would pass.

I figgered a 64th clearance was a bit tight. PC's bushing is steel and the walls look pretty thick. If I had a machinist cut a 32nd from the inside, do you think that would give enough clearance?

How well can you center the guide? Can you somehow have the bit protruding out of the guide so only the shaft is within it?
Out of curiosity what is the OD of the template guide?

Any wobble on start up or deflection in use and you are likely to make contact.

TWheels said:

How well can you center the guide? Can you somehow have the bit protruding out of the guide so only the shaft is within it?
Out of curiosity what is the OD of the template guide?

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I'm cutting 3/4" holes using a template with 1" holes. So, the OD of the guide bushing would be 1".

Found a 1 1/4 OD PC bushing that will work. Just need to make the template holes bigger.

Gene Howe said:

Found a 1 1/4 OD PC bushing that will work. Just need to make the template holes bigger.

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I knew you would figure it out. That is what I was going to suggest.
Herb

Don't they make brass bushings???

Herb Stoops said:

I knew you would figure it out. That is what I was going to suggest.
Herb

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The bigger OD is no problem but, I just got lucky finding it. Only Klingspor had one of all the sellers I found.

Don, I couldn't find a brass one that size.

Electric drill, piece of dowel, and emery cloth, should enlarge the hole easily enough.

JOAT said:

Electric drill, piece of dowel, and emery cloth, should enlarge the hole easily enough.

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Thanks, Theo. That would have been the next thing to try if I hadn't found the bigger one. It's 1 1/32 ID. Just needed it to be big enough to spin a 3/4 bit safely. Not following a pattern so, OD isn't critical.

Thanks, Harry. I'm just cutting bench dog holes. The reason for the template guide is to be able to use a template that assures accurate spacing.

Gene Howe said:

Thanks, Harry. I'm just cutting bench dog holes. The reason for the template guide is to be able to use a template that assures accurate spacing.

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Forstner bit...?

Check out Lee Valley: Dog Hole Bushings and Bits - Lee Valley Tools

Thanks, Tom. Definitely worth consideration.

Lee Valley used to sell a cheap French made brad point bit for drilling dog holes. The bit is about 7 inches long give or take. I drilled a hole with it through a short piece of 4 x 4 on my drill press. Then I just laid out the grid on the bench with tape and pencil and drilled free hand just enough to register the tip of the drill in the hole then I ran it through the 4 x 4 and drilled as deep as I could that way. That was maybe 3" deep with one more to go but with the hole that deep already the guide was no longer needed. Worked great and didn't take very long.

A plunge router using a plunge bit makes the cleanest holes.