Dowel Sizes

[Darius Ferlas]

Is there any science to how select dowel sizes?
Do I use the largest diameter that will fit?
How do you decide whether to use 5/16 or 3/8 etc? Is there a standard amount of wood that should be left un-drilled around the dowel so that it is not too close to faces of the boards?

Thank you.

[Howard Acheson]

I'm a little confused. Dowel sizes are chose based on the diameter of the hole they go into.

What are you using the dowels for?

[Mike Henderson]

I don't use dowels in strength applications but my guess is that you'd size them the same as tenons. When mortising into a larger piece of wood (that is, the wood the mortise will go into is larger than the wood that has the tenon - such as an apron into a table leg) I divide the wood of the tenon by two and use that for the tenon. The other half is split on both sides of the tenon. For a 3/4" apron (for example), I use a 3/8" tenon, with 3/16" on both sides of the tenon.

If you were doweling 3/4" wood to 3/4" wood, you could use 3/8" dowels because the wood is only thin for a small part of the hole, and the holes are spaced some distance apart. You could even go a bit larger (7/16") but 5/8" would probably be too large (very thin sides for the holes).

If the dowels are for alignment and not for strength, I wouldn't go over half the size of the wood, and could go smaller.

Mike

[Darius Ferlas]

Mike,

that answers my questions. Thank you.

Darius

[glenn bradley]

I'm with Mike; same as tenons.

[Paul Demetropoulos]

I'm with Glenn..who's with Mike..don't go over half the stock thickness with the dowel size...and dowels are plenty strong in most applications.