How Many Dovetails Make A Joint ?

[Steve Wardley]

Maybe a silly question I know but a friend and I were discussing dovetail joints and he asked me how many DTs do you build into a given size of board and I couldn't tell him other than just how many looks pleasing to the eye.
That then prompted me to ask is there a rule of thumb for how many you would cut into say a 6" deep drawer because let's face it you could go from one or two up to twenty or more if you are brave.

Is it just aesthetics or is there an issue of joint strength that would make you cut X per inch ?

Cheers all, Steve

 

[Jacob]

One is the minimum. I've seen old furniture with drawer sides fixed with just one large DT. More would be better - it's like stitching - a larger number of smaller stitches looks neater, costs more but only up to a point could be stronger.

https://goo.gl/images/Ds2hCy

 

[MikeG.]

........https://goo.gl/images/Ds2hCy

I'm surprised there isn't a nail whacked through that, it looks so crude.

 

[Jacob]

There are better examples in trad furniture. I've got some snaps somewhere of a french example but yes I think it has a nail whacked in. What's wrong with nails?

 

[custard]

how many DTs do you build into a given size of board

Your workshop...your rules. But in my workshop a 3" tall drawer is the maximum height for a single pin, like this,

There's no strict formula because with graduated drawers I also like the number of pins to scale up/down, so I'll start with a single pin for the shallow top drawers and then gain at least one extra pin each row down as the drawer sizes increase.

Incidentally, in first quality work the number of pins is normally the same at both the back and front of the drawer.

 

[Just4Fun]

Paul Sellers has a youtube video that gives some guidance, Personally I just do whatever I think looks OK, and I suspect most people do the same.

 

[Jacob]

how many DTs do you build into a given size of board

Your workshop...your rules. But in my workshop a 3" tall drawer is the maximum height for a single pin, like this,



There's no strict formula because with graduated drawers I also like the number of pins to scale up/down, so I'll start with a single pin for the shallow top drawers and then gain at least one extra pin each row down as the drawer sizes increase.

Incidentally, in first quality work the number of pins is normally the same at both the back and front of the drawer.

Yebbut your pic shows 3 pins and two tails!
There are plenty of examples of two pins and one tail in old furniture; "vernacular", "farmhouse", "rufty tufty peasant", whatever you want to call it. Probably in posh furniture too sometimes e.g. with very shallow drawers etc.

 

[AndyT]

As Jacob often says, it's a good idea to look at old furniture and see what has worked or failed.
An easy way to see a LOT of pictures of the details of old furniture is to read Mark Firley's blog, The Furniture Record. He pokes around auction houses taking photos of lots of construction details.
His blog is here, with this link homing in on the dovetails category

https://thefurniturerecord.wordpress.co ... dovetails/
But also look at his huge photo set on Flickr, devoted just to dovetails - 473 pictures!

www.flickr.com/photos/mark_firley

 

[Tasky]

I'm surprised there isn't a nail whacked through that, it looks so crude.

Better than I can do....

 

[Jacob]

As Jacob often says, it's a good idea to look at old furniture and see what has worked or failed.
An easy way to see a LOT of pictures of the details of old furniture is to read Mark Firley's blog, The Furniture Record. He pokes around auction houses taking photos of lots of construction details.
His blog is here, with this link homing in on the dovetails category

https://thefurniturerecord.wordpress.co ... dovetails/
But also look at his huge photo set on Flickr, devoted just to dovetails - 473 pictures!

http://www.flickr.com/photos/mark_firley

Interesting! American - same but different from UK stuff.
DT angles all over the place - this was before some idiot came up with the 1/6, 1/8 rule which now everybody wrongly thinks is gospel! NB anything goes, from 45º to 90º, do what you like!

 

[custard]

how many DTs do you build into a given size of board

Your workshop...your rules. But in my workshop a 3" tall drawer is the maximum height for a single pin, like this,



There's no strict formula because with graduated drawers I also like the number of pins to scale up/down, so I'll start with a single pin for the shallow top drawers and then gain at least one extra pin each row down as the drawer sizes increase.

Incidentally, in first quality work the number of pins is normally the same at both the back and front of the drawer.

Yebbut your pic shows 3 pins and two tails!

You need to get down to Specsavers Jacob. It shows two half pins and a single full pin.

 

[custard]

before some idiot came up with the 1/6, 1/8 rule which now everybody wrongly thinks is gospel

Except they don't. I see plenty of younger furniture makers using really dramatic dovetail slopes like 1:5 or even 1:4. The fact that these are so popular is why David Baron offers dovetail guides to suit,

https://www.classichandtools.com/acatal ... new-1.html

More power to them for experimenting, but will I be moving to this style of dovetail? No I won't, for one thing there's a lot of vulnerable short grain on the tail boards with angles like 1:4 and 1:5, which are all too easy to snap off.

 

[Jacob]

I call that three pins and two tails.
The term "half" pin is misleading and you see many examples where people have interpreted this literally - resulting in a very thin pin at the edge. Should be a bit more substantial as they are in a vulnerable position. They need more wood than the inner ones

 

[Jacob]

before some idiot came up with the 1/6, 1/8 rule which now everybody wrongly thinks is gospel

Except they don't. I see plenty of younger furniture makers using really dramatic dovetail slopes like 1:5 or even 1:4. The fact that these are so popular is why David Baron offers dovetail guides to suit,

https://www.classichandtools.com/acatal ... new-1.html

More power to them for experimenting, but will I be moving to this style of dovetail? No I won't, for one thing there's a lot of vulnerable short grain on the tail boards with angles like 1:4 and 1:5, which are all too easy to snap off.

It's hardly a bold style experiment!
What are those guides for - do people have a problem with sliding bevels? Traditionally they were set out free hand - often not even marked up just sawn by eye.

PS ferky nell I just looked at the price of those guides! Do people really buy this silly stuff at those unbelievable prices?

 

[DTR]

What are those guides for - do people have a problem with sliding bevels? Traditionally they were set out free hand - often not even marked up just sawn by eye.

PS ferky nell I just looked at the price of those guides! Do people really buy this silly stuff at those unbelievable prices?

I find a normal-sized sliding bevel a bit cumbersome for dovetails. It's far easier to cut an appropriate angle on a small offcut and use that

 

[loftyhermes]

My dovetail marker, one of the first metalwork projects made in the first year at secondary school (1962), this was so we could use it in woodwork class. Angle is 1 in 7, I've not seen it in a while now, looking at the time stamp on the photo I had it 8 years ago, shall have a look for it.

 

[Tasky]

What are those guides for - do people have a problem with sliding bevels? Traditionally they were set out free hand - often not even marked up just sawn by eye.

They take time to set properly and you're talking about hobbyists, I guess... and doing anything by eye is usually after years of practice.

PS ferky nell I just looked at the price of those guides! Do people really buy this silly stuff at those unbelievable prices?

Yup, along with the Rob Cosman™ shooting board!
This is why people like Paul Sellers are so popular, as there's a vid on how to make your own from a bit of wood.

 

[memzey]

My dovetail marker, one of the first metalwork projects made in the first year at secondary school (1962), this was so we could use it in woodwork class. Angle is 1 in 7, I've not seen it in a while now, looking at the time stamp on the photo I had it 8 years ago, shall have a look for it.

Wow! I picked up one just like that at a car boot sale a few years ago!

Always assumed it was a dovetail marker although the angles on this one aren't the same - that is to say the rake on one side of the marker is a bit more than on the other side. Obviously the kid who made this was not a keen metal working student!

 

[custard]

What are those guides for - do people have a problem with sliding bevels?

They're not dovetail layout guides, they're dovetail sawing guides. Magnets hold the saw plate both square and at the chosen angle, so anyone can cut a perfect dovetail without spending hours practising. They could be made pretty simply with a couple of rare earth magnets, but compared to the price of a Leigh jig even the David Baron versions are the bargain of the year.

 

[Sawdust=manglitter]

And they’re easy enough to make, and very useful when first starting out, like stabilisers on a bike. Made this one sometime last year with boxwood