# what size hole to drill for dowels....but in metric!



## peps1 (31 Oct 2012)

Having trouble finding what drill sizes to use for different dowel thickness's in metric....anyone got a handy little chart I can pint out?

Imperial units were a dirty word by the time I got to school!


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## RogerP (31 Oct 2012)

Just divide the Imperial dowel size by .03937 

1/4" dowel = 0.25" / .03937 = 6.35mm 
1/2" dowel = 0.5" / .03937 = 12.7mm

You can do the rest yourself


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## bugbear (31 Oct 2012)

peps1":38ehtq90 said:


> Having trouble finding what drill sizes to use for different dowel thickness's in metric....anyone got a handy little chart I can pint out?
> 
> Imperial units were a dirty word by the time I got to school!



Where are you managing to buy imperial dowel ?!

In any case, given the narrow range of dowel sizes, imperial or metric, just buy the "obvious" bit, e.g. 1/4" or 6mm to match the dowel.

BugBear


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## AndyT (31 Oct 2012)

When dowelling there are many factors which affect how snugly a dowel will fit:

- the actual (not nominal) size of the bit
- the grain direction of the hole
- the type of wood
- the diameter of commercially made dowel
- the moisture content of the woods and any consequent swelling when a water based glue is used

so not only do you need to buy a matching size, but you need to do some test joints using your intended set-up.
That's the only way to find the difference between too tight, too loose and just right.

And just to complete the conversion chart, 3/8" is quite close to 9mm.


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## Paul Chapman (31 Oct 2012)

When fitting the dowels, make sure there is room for excess glue to escape. You can do this by using fluted dowels or by cutting a slot lengthwise in the dowel (something like a junior hacksaw is good for this).

Cheers :wink: 

Paul


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## peps1 (31 Oct 2012)

RogerP":2utjf1fq said:


> Just divide the Imperial dowel size by .03937



Thank Roger, but this tells me the only half the problem.....the peg size, but not what size hole I should drill?  



bugbear":2utjf1fq said:


> Where are you managing to buy imperial dowel ?!


Well I googled before asking the question here, and all the information I could find was on US sites.....ergo imperial measurements.


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## AndyT (31 Oct 2012)

If you go to B&Q you will find a selection of handy dowel kits. Each contains a matched set of dowels; glue; a drill and four dowel points to locate the holes on the other workpiece. They come in 6, 8 and 10mm sizes. One of those should get you started.


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## tomatwark (1 Nov 2012)

Plug It sell dowel that is imperial.

But if you are meaning dowels for gluing up I think most people in this country sell metric now.

If you find that you end up using imperial dowel Axminster sell imperial bits.

Tom


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## bugbear (1 Nov 2012)

AndyT":1aaxq2ch said:


> If you go to B&Q you will find a selection of handy dowel kits. Each contains a matched set of dowels; glue; a drill and four dowel points to locate the holes on the other workpiece. They come in 6, 8 and 10mm sizes. One of those should get you started.



That sounds like a splendid way forward.

BugBear


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## Phil Pascoe (1 Nov 2012)

With any "kits" it usually pays to throw the glue away and use something of which you know the provenance - they often contain glue that's the cheapest of the cheap. That goes for flat pack furniture as well.


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## SteveB43 (1 Nov 2012)

...and go buy a good dowel jig, a proper one like one of them Records....
+1 for real wood glue too..


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## peps1 (1 Nov 2012)

SteveB43":11nj814q said:


> +1 for real wood glue too..



Just picked up a pot of Gorilla wood glue......it has a Gorilla on the front so must be good!


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## Racers (1 Nov 2012)

Hi, Peps1

Did you get some latex gloves as well?

Pete


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## peps1 (1 Nov 2012)

Yep, got a huge box of them in the workshop for when I deal with nasty corrosive chemicals.


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## Racers (1 Nov 2012)

Put some on while you use the glue, unless you want black stained fingers, it does come off in a week or so :shock: 

Pete


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