# What size dowels to use for joints?

I'm comfortable with the process of creating and joining wood with dowels, but I'm not sure what size dowels to use in which cases? Specifically, I'm working with 1" thick stock (3/4" actual), what size should I use?

What are the other sizes and lengths of dowels used for?

Are there any recommended grouping or spacing for wood dowels?

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When dealing with joinery I typically always deal with thirds. So I'd get whatever is closest to 1/3" that I can get. 3/8" is probably good for this, 5/16" even better. Thirds is a pretty good rule of thumb especially for furniture sized joinery.

This can be applied to all types of joinery such as mortise and tenon, splined miters, bridle joints, etc.

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+1 also. 1/3 is easier to remember, though with full-size lumber 3/8 is sometimes easier to compute and measure. :) – Alex Feinman Sep 26 '11 at 17:34
Sat in on a class of Roy Underhill's this weekend. His opinion is to use something at least 1/3rd of the thickness of the piece but less than half. – Cody C Oct 3 '11 at 19:09

Obviously depends on the type of wood (of the dowel), is the dowel in single shear or double shear, can the base wood handle the load on the dowel or will it split or deform, what is the load going through the joint, etc.

wood properties http://www.awc.org/pdf/wsdd/C1.pdf

american wood council pdf contains detailed formulas for calculating dowel size. http://www.awc.org/pdf/tr12.pdf

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Instead of just posting link resources, it would help to include enough of a description of the content to be useful without depending solely on the link. – Doresoom Jul 20 '15 at 17:55

The best work I know of on the topic was written by Tage Frid (see http://amazon.com).

The approximate rule-of-thumb, iirc, is to use a dowel no more than 3/8 the thickness of the wood to be joined (and not less than 1/4 the thickness).

### Expansion

For example, if you are joining 5/4 boards (finished thickness 1"), the dowels should be between 1/4" and 3/8" in diameter.

Likewise, if joining finished thickness 3/4" boards, use between 3/16" and 9/32" diameter dowels.

This presumes, of course, you're joining the boards on the narrow dimension (e.g. making a door frame).

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This is the publisher's page for the book I'm assuming you're referring to. Also as an ebook. – Dennis Williamson Sep 30 '10 at 18:10
@Dennis Williamson - actually, I was thinking of amazon.com/Tage-Teaches-Woodworking-Step---Step/dp/1561588261 – warren Oct 7 '10 at 18:49