# Dowels and dowel holes



## Golgatha (Feb 18, 2016)

Dowels shouldn't fit so thight in their holes that force is needed to bring them in place with the risk of breaking or splitting the wood and the risk of pressing the glue out. So my question is: Can I use a 8 mm dowel covered in glue in a 9.5 mm hole half filled with glue ? Does anyone have experience with that ?


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## BZawat (Sep 21, 2012)

No. An 8mm dowel needs an 8mm hole. Use a fluted dowel to allow the glue to spread when you drive the dowel in.


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## Jig_saw (May 17, 2015)

Or you can slightly shave the 10mm dowel with a hand axe or knife until it just fits a little loose, and then apply the glue.


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## woodchux (Jul 6, 2014)

You are correct in stating "dowels should not be forced into a hole" Remember also that most wood (including some dowels) will expand and contract in humid/moist weather. Best to match up dowels with the (nearly) same size hole. Be safe.


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## Tony B (Jul 30, 2008)

When u make the same size hole as the dowel, sometimes the friction will make it a too tight fit. 
Just use standard pliers and squeeze down on the dowel with just moderate pressure and you will have a fluted dowel. If you can purchase the fluted dowels, you will be better off. Most of them or either birch or beech which are very stable woods.


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## pweller (Mar 10, 2014)

I think it depends on what kind of glue you use. If you're using epoxy, then it's probably OK, as epoxy will fill gaps. White glue probably wouldn't work as well in that application.


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## Golgatha (Feb 18, 2016)

I thank you all for your answers. Here are a couple of other dowel questions: Suppose a part of a chairleg or tableleg has to be replaced by a replica. That kind of legs are seldom straight but often curvasious. How do you fasten them in a workbench and how do you drill dowelholes in their exact axises ?


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## Tony B (Jul 30, 2008)

Golgatha said:


> ...... Suppose a part of a chairleg or tableleg has to be replaced by a replica. ......How do you fasten them in a workbench and how do you drill dowelholes in their exact axises ?



Most table legs and chair legs have a straight section at the top end where they join the apron. That end should fit in a vice. 
As for drilling the dowel holes in exact position and angle, that rarely happens. You line up your drill holes as best as you can. Even with a broken leg, you can still get relatively close by sight. Drill the hole in the new leg 1/16" larger so there is some wiggle room. Then dry fit the parts together to make sure they will fit. Since we are assuming that the apron holes are OK, Glue the dowels in the apron and let set over night, The next day dry fit the legs again to make sure everything is still OK. Since the holes in the legs are oversized, you MUST use epoxy. Keep in mind, that you cannot stain epoxy when it sets up. So, you use "touch-up" powders to color the epoxy when mixing it. If Touch-up powders are not available mix in some sawdust - the real fine stuff that you get from your sander, This will darken the epoxy. It is also imperative that when mixing the epoxy, you mix the Part A and Part B together BEFORE you add the powders or dust. 
When clamping the legs in place when gluing, I found the best clamps to be surgical tubing. Surgical tubing is flexible, highly elastic and easy to tie in place. Usually 8' long pieces will work fine. If no surgical tubing, rope is a poor alternative, but still do-able. It will requiring tying and making a touriquet.


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## Steve Neul (Sep 2, 2011)

I'm having computer problems so I'm not going to look up the difference between 8mm and 9.5mm. What you have to understand is with a wooden dowel I'm sure when it left the machine at the factory it was 8mm in diameter but over time sitting in the store or warehouse they swell up a bit. You could cut a v groove in the dowel to releave the pressure and still have to drive the dowel in with a hammer. What I used to do is make the holes 1/64" bigger than the factory dowel were made to allow for the swelling of the dowel. It was still a snug fit but would allow glue to squeeze by. I make my own dowels now and have made the tooling to where it cuts the dowels 1/64" undersized so they will swell up close to the drill bit size.


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## Mort (Jan 4, 2014)

Steve Neul said:


> I'm having computer problems so I'm not going to look up the difference between 8mm and 9.5mm.


It's 1.5mm, I looked it up for you.


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## Jig_saw (May 17, 2015)

I make my own dowels with a small axe. I give them a slight taper for a better fit. Later if the wood expands, there is a small clearance for expansion due to the taper.


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## epicfail48 (Mar 27, 2014)

Mort said:


> It's 1.5mm, I looked it up for you.


Dangit, you beat me to it...


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## Old Skhool (Oct 31, 2009)

BZawat said:


> No. An 8mm dowel needs an 8mm hole. Use a fluted dowel to allow the glue to spread when you drive the dowel in.



Ageed. 


Overfilling the hole will also split the wood even will fluted, or spiral cut dowels. Be sure the sides of the hole are covered with glue and drill the holes a little deeper than 1/2 the length of the dowel to allow for any excess glue.


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## Old Skhool (Oct 31, 2009)

Golgatha said:


> I thank you all for your answers. Here are a couple of other dowel questions: Suppose a part of a chairleg or tableleg has to be replaced by a replica. That kind of legs are seldom straight but often curvasious. How do you fasten them in a workbench and how do you drill dowelholes in their exact axises ?


Use a sliding t bevel square. Use a symmetrical spindle as reference.


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## Steve Neul (Sep 2, 2011)

Mort said:


> It's 1.5mm, I looked it up for you.


What is 1.5mm in inches though.


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## BZawat (Sep 21, 2012)

Steve Neul said:


> Mort said:
> 
> 
> > It's 1.5mm, I looked it up for you.
> ...


1/16" = 1.6 mm

Edit: as a side note, to convert inches to millimeters, multiply by 25.4
Therefore to convert mm to inches divide by 25.4. So 1.5mm = .059"


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## Golgatha (Feb 18, 2016)

Once again, thank you all for your answers. It seems that most of us can agree on tight fitting dowels being risky business. Specially, may I add, in thin chair- and tablelegs. The hammer should stay away !


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## Tony B (Jul 30, 2008)

*Mallet*

A hammer should always stay away in woodworking. Always use a mallet. Here is the one I made on a lathe with scrap 4 X 4's. I like using pine because it is soft and wont damage hardwood furniture parts when they have to be lightly tapped into or out of position.


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## BZawat (Sep 21, 2012)

Golgatha said:


> Once again, thank you all for your answers. It seems that most of us can agree on tight fitting dowels being risky business. Specially, may I add, in thin chair- and tablelegs. The hammer should stay away !


The dowel should not be tight, but it should be precise. That's the whole point of using dowels. They align the joint as well as add structural stability. The allowance for glue is made in the depth of the hole, not the diameter, and in using a fluted or spiral cut dowel. The dowel itself should be a snug fit in the hole in order to work properly.


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## Steve Neul (Sep 2, 2011)

BZawat said:


> 1/16" = 1.6 mm
> 
> Edit: as a side note, to convert inches to millimeters, multiply by 25.4
> Therefore to convert mm to inches divide by 25.4. So 1.5mm = .059"


I usually just google the conversion but my computer is ill with a virus so I'm using my wife's laptop which is working really bad. 

1.5 mm would be too sloppy then. Surely they have drill bits in finer increments than that.


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## BZawat (Sep 21, 2012)

I write CNC programs for European machinery at work, so I'm constantly going back and forth between imperial and metric measurements. 

Consequently though, it's also how I know for a fact that a joinery dowel should be an exact fit for the hole it sits in if it is to be effective.


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## Mort (Jan 4, 2014)

Steve Neul said:


> What is 1.5mm in inches though.


Who cares?

'Murica


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## Golgatha (Feb 18, 2016)

Thanks for the answers.


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## Steve Neul (Sep 2, 2011)

You could use a thick epoxy glue or gorilla glue expands however leaving a 1/32" air space around a dowel would be a week joint. The glue is just suppose to bind the wood together. A plastic such as glue doesn't have enough strength to do the job.


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## Golgatha (Feb 18, 2016)

What we need is a glue that expands as it dries. In that way some wiggle room to start with wouldn't compromise the project. Maybe such glue already exists, but I don't know it.


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## Tony B (Jul 30, 2008)

Golgatha said:


> What we need is a glue that expands as it dries.........


An expanding glue could present new problems of its own.
Epoxy is the main solution to most adhesive problems. Unlike most adhesives that are made to stick 2 things together and dont really have any strength of their own, such as in bridging small gaps, should not be used to fill gaps. 
Epoxy is very strong, not only as an adhesive but also strong on its own and is quite often used to fill small gaps. When I had my woodworking business, I used it a lot in furniture repairs. Even at over $100/gal. it was worth its weight in gold. I used to buy it in 5 gal. kits. Will solve a lot of problems, especially when alignment of dowels are nearly impossible. Also note that most epoxies will not shrink while curing.


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## FrankC (Aug 24, 2012)

Golgatha said:


> What we need is a glue that expands as it dries. In that way some wiggle room to start with wouldn't compromise the project. Maybe such glue already exists, but I don't know it.


Wiggle room will compromise most projects, the dowels are there primarily to align the parts as well as connect them.

If you don't care about precision use Gorilla Glue, it will expand.


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