# Drill Bit Size For 10mm Dowels



## Gaia (Feb 20, 2010)

Hi,
Never used wood dowels before, what size type drill bit should I use for the holes for 10mm dowels to fit in?
Cheers.


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## Mike (Nov 22, 2004)

Peter, 10 mm dowels are designed to fit in 10 mm holes. There is a lot of variation in dowel size so it is smart to measure your dowel stock to be sure it is actually the size it claims to be.


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## OPG3 (Jan 9, 2011)

Peter, you should use a 10mm diameter drill bit for 10mm wooden dowels. If your dowels are pre-cut and spiral-grooved, make certain to drill just slightly deeper into the mating parts to give a bit of room in the hole below the dowel. Probably over-drill the depth by a total of 4mm. If you're using stick dowel material, cut your dowel(s) shorter than the accumulated hole depths by about the same amount. It is also helpful to slightly taper both ends just enough to facilitate easy entry. A pencil sharpener often is handy for this easy job. Also, if you want to; it is a one-minute job to use common ordinary pliers to grab the dowel with the teeth on the curve and mash a few glue grooves into said dowel.

In most cases, singular dowels do not make great joints due to the tendency toward rotation, but when more than one dowel is used in a joint, and properly sized this can be a great joint. Spaces between dowels often should be limited to 10x the diameter of the dowels, so for your case it would be good to space them 100mm apart, or one centimeter of space for each millimeter of dowel diameter.

Many exceptions to this spacing "rule of thumb" will apply, but the real thing you're trying to avoid is having spacing that can cause the workpiece(s) to split. Use a good glue that does not expand and you should find this an effective connection.

I hope this helps!
Otis Guillebeau from Auburn, Georgia


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## dc_ni (Jul 6, 2013)

Keep your dowels somewhere thats warm and dry. They will expand a bit if damp making them a pain to get in the holes.


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## Quillman (Aug 16, 2010)

"what size type drill bit should I use for................"
*********************************
Third one up, right.


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## Cherryville Chuck (Sep 28, 2010)

Peter, your dowels may be the "expansible" type which means they may fit a bit loosely in a 10mm hole when dry fitted. Expansible Dowel Pins - Lee Valley Tools


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## Gaia (Feb 20, 2010)

OK thanks everyone, feel so dumb asking such a simple question. Couldn't find any info using Google, hence posting on the forum.


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## jw2170 (Jan 24, 2008)

I would use a 10mm brad point drill.


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## rwbaker (Feb 25, 2010)

Let me guess, you hammered a section of 10mm dowel into a 10mm hole and a split occurred - I've seen this happen both at the time off doweling and in green wood with dry dowels. Everything that has been said is good but remember the basics 1 - both pieces are either dry or green, 2 a 10mm hole and 10mm dowel are the same size and will impact at the 10mm diameter point. Most use the dowels in a jar that are already dry, spiral or grooved and tapered as this eliminates a major time loss, you may want to try these or lightly sand the dowel while twisting back and forth so it is several thousandths less than 10mm and groove, taper and cut as stated earlier.

good luck - Baker


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