How big does the drill have to be?

[cigi]

Hey Luthiers,

I'm starting a little project in which I need to drill out a hole and fill it with a dowel. I finally got my 6,5mm (1/4") dowels. The only drills I have are 6 mm and 8 mm. I've seen 7mm ones on internet.

What does the diameter of my drill has to be to make a good hole for the 6,5mm dowel? Does it have to be 6,5mm? Or is 7mm good?

Thanks,

Timothy

[mikeyswood]

Fluted dowels expand with glue. 7mm is good.

[barnaclebeau]

Where are you writing from? Are 1/4" drill bits not available?

If you live somewhere that Metric is the standard (it's not in the US, but it should be...) I would recommend ordering a set of SAE-sized drill bits for doing guitar and bass work, from 1/8" to at least 3/4" in 1/8" increments. a set of forstner bits from 1/4" to 1", in 1/8" increments, would also be valuable. You can find both sets on eBay, and DeWalt and Porter-Cable are cheap and perfectly serviceable.

[bassbodger]

FWIW im in the UK. i use 6mm dowels with a 6mm auger drill bit. you want as snug a fit as you can get. failing this, use the 7mm but use expanding wood glue.