One of the great frustrations of using dowels in woodwork is that they are rarely round and they are almost never the exact size that you require. Why are they oval? Dowels, like, all round pieces of wood, tend to become an oval shape as they lose moisture. Why are they odd sized? Because they are wood.
You can scrape or sand them, but that can be a fool’s errand to get them perfect. You can use a dowel plate, but those tools rarely offer enough sizes to achieve the fit that you require.
Yesterday in class we ran up against a dowel-like problem while we were making marking gauges. We wanted to add a pencil to the gauge that was friction-fit into the wooden beam. The diameter of the pencils was a bit more than 7mm, depending on how much paint was on them. A 7mm hole was too small.
So we drilled a 7mm hole anyway and used the shop’s “drawplate” to accurately size the pencils down to a tenth of a millimeter.
What’s a “drawplate?” It’s like a dowel plate and is used in the jewelry industry to create wire of precise sizes. Using lubricant and a pliers-like tool, you can pull oversized wire through the holes to create a desired diameter.
It works great for dowels. The shop had an old drawplate with holes from 1mm to 10mm in increments of 1/10 of a millimeter. This allowed us to size the pencils down to 7.2 or 7.3mm, which created a perfect friction fit.
Quality drawplates can be expensive, so another option is to use a drill bit gauge, which is fine for sizing short sections of dowels if you don’t abuse it. Purchasing metric and inch versions can cover most of the sizes you might need.
If you are fussy about your dowels or round tenons, these are the perfect tools to scratch that itch.
— Christopher Schwarz