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How tight should Dovetails be?

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Nads

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I am currently making a box from ash, using dovetail joints and was wondering if someone could advice me on how tight the joints should actual be? As I have heard lots of conflicting things about this! Someone told me that I need to be able to put the joints together by hand without the use of a mallet; otherwise I might have trouble when gluing the joint. Or when the glue sets it may expand and wrap the joint and therefore the box, is this true? :? , as I currently need to use a mallet to drive the joint the last little bit (but am pleased with how flush they are and don’t want to amended them unnecessarily! ) :( I was considering using ‘Titebond original’ glue as suggested by other from this forum!

Any advice would be greatly appreciated! :lol:

Cheers

Nads
 

JFC

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Hi nads , no joint in theory should need to be put together with a mallet if the wood expands you could end up with splitting , and wood does expand and contract . A timber joint should slot together with hand pressure only . You could try under cutting your joint a little wich is a trade cheat , you leave the surface of the joint nice and tight but make the unseen part of the joint a little smaller , this will be taken up with glue .
 

Philly

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Nads
As long as the joint will go together fully-don't worry about the glue warping the piece.
Wipe on the glue, get the joints fully fitted and clamp until dry. If you are happy with the fit of the dovetails don't remove any more or you will have gaps.
Cheers
Philly :D
 

devonwoody

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I have just completed around 104 hand made dovetails and they slid together on the whole quite nicely. I left them in situ over the last couple of weeks and with the very damp weather I reckon the joints have tightened slightly because I have had to use the mallet handle to separate the joints so gluing could be done.
I am reasonably confident this will not be troublesome because we can't get weather any damper than we have had lately.
So if its high summer when you make the joints watch out?????
 

Nads

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Thanks guys,

Maybe I’ll just take a little off the unseen part of the joint leaving the surface, just to make it a bit easier when gluing, I’ll let you know how I got on and try and post some pics soon! I just don’t want to wreck all my hard work! :?

This forum is great, lots of excellent advice! :wink:
 

Chris Knight

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PVA glue starts to swell the wood almost immediately and joints will feel a lot tighter than when tested dry. If you have joints that are really too tight, then using polyurethane can help becuse it is very slippery stuff.
 

Nads

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waterhead37,
I was planning on using ‘Titebond original’ what category of glue does that come under? Do you think I’ll have problem putting the joints together if I using the above? :?
Maybe I should try and loosen them off more! When I say the joints are too tight I can put them together about half way by hand and then just knock them down the rest of the way with ease with a mallet?!
 

Chris Knight

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Nads,
Titebond original - the yellow glue is a PVA. From you description of the tightness of joints you should be OK. Do however, look at how you will clamp them up beforehand and depending on whether or not you have left the pins/tails proud for later planing away; make up cogged clamping cauls if need be.
 

Fred Page

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Here's something more to confuse the issue and it’s a perspective I've never considered before.
This is what Ian Kirby says in his "The Complete Dovetail", (Stobbart Davies, 1999), p. 100:
"Close the joint with a hammer. Tap each tail in turn. If the cuts are right, you will feel and hear the tail go into the socket. If the cuts are wrong, at some point you will unable to drive the tail any further and the hammer sound will change to a sharper pitch. The need for touch and sound feedback is why you shouldn't assemble the joint with a mallet or use a protector pad. Don't worry, the hammer won't dent the wood."
Well, you live and learn. From now on we must take sound feedback into account.
Fred
Kington
Herefordshire.
 

Alf

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Fred Page":l8qayatb said:
From now on we must take sound feedback into account.
Yep, sound can tell you an awful lot, be it with hand tools or tailed demons. I heard a whole heap of routers in pain at the show, for instance...

devonwoody":l8qayatb said:
I like too whack them in, pity I have to take them out again and put some glue on.
Now, now, DW, have the courage of your convictions and "do a Cosman" - don't fit them until you're gluing them. There, if you'd gone to the show last year you could have seen for yourself... :wink:

Welcome to the forum, Nads. I've been debating the right answer to this one, and came to the conclusion there are so many variables that there probably isn't one. I tap my DTs home with a cross pein hammer - couldn't do it by hand - and (so far, touch wood of choice) have yet to have a problem. My feeling is to aim to get them a nice snug fit, 'cos sure as eggs is eggs, I'll still have a little leeway in there to deal with any problems. Sounds to me like your joints are lovely-jubbly, so I wouldn't start to tweak them.

Cheers, Alf

Not yet brave enough to put new DT saw to wood. 8-[
 
A

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Nads":1wcpsz5t said:
I am currently making a box from ash, using dovetail joints and was wondering if someone could advice me on how tight the joints should actual be?


Nads
For the Houndstooth DT box on the 'How-to' link at the top of the forum pages https://www.ukworkshop.co.uk/howto/joints/houndstooth_dovetails/index.php

I made the joints tight enough to need a tap with a mallet to engage them. Glue lubricates the wood and allows easy fitting - use a little glue, not loads.

Rob Cosman (expert DT man) states that the joint should not be test-fitted as it only goes together properly the first time. I tend to agree with him on this point as the fibres are compressed slightly during assembly although I'm sure there are many who 'know better'

Good luck
 

Nads

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Thanks everyone for your great advise, and thanks for the great welcome! :lol:

I just took a little off the unseen part of the tightest joint leaving the surface, just to make it a bit easier when gluing. I left all the rest as they were! I’ll be gluing it all together next weekend once I’ve made the base and top.

I’m sorry but I’ve got two more questions for you, hope you don’t mind!
What is the best way to remove the proud pins/tails (about 1or 2mm) once I’ve glued the sides together? Plane, flush cut saw, belt sander? :?

And I want to make my box in a traditional way gluing all 4 sides together and then cut of the lid afterwards, whats the best way to do this - table saw and then hand saw?! :?

Any advice would be great!

Thanks

Andrew
 

Adam

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Nads":12joqluj said:
And I want to make my box in a traditional way gluing all 4 sides together and then cut of the lid afterwards, whats the best way to do this - table saw and then hand saw?! :? Any advice would be great!
Thanks Andrew
When I made this box, I simply marked a line all the way round, (using a marking guage), and used a tenon saw to cut round. Unfortunately I found the braver and more confident you are the better the cut, which is not something you have when you are doing it for the first time!





Afterwards, I taped some sheets of sandpaper to a flat piece of mdf, to create a large "sandpaper topped" table. And then rubbed both the top and bottom of the box upside down to smooth the cuts away. This ensures everything is flat and joins up tightly. Check regularly and concentrate on putting even pressure all the way round, so you don't remove any excess on one particular edge/corner.

Adam
 

Alf

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Nads":362g67p5 said:
I’m sorry but I’ve got two more questions for you, hope you don’t mind!
We can take it :)

Nads":362g67p5 said:
What is the best way to remove the proud pins/tails (about 1or 2mm) once I’ve glued the sides together? Plane, flush cut saw, belt sander? :?
Bet everyone can guess my answer... Plane!

Nads":362g67p5 said:
And I want to make my box in a traditional way gluing all 4 sides together and then cut of the lid afterwards, whats the best way to do this - table saw and then hand saw?! :?
IMO, handsaw. But a handy dodge to make it go a little easier is to groove the insides and outsides of the box sides before you put it together, just leaving enough to keep the thing together. That way you have a guide for the saw and an indicator to help when planing down the sawn part flush and square.

Cheers, Alf
 

devonwoody

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quote
Bet everyone can guess my answer... Plane!
end quote

But I would use a very sharp chisel and chamfer off the far edge first in addition to Alf's advice.

Hope you didn't mind Alf? :wink:
 

Alf

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devonwoody":177ojxgn said:
quote
Bet everyone can guess my answer... Plane!
end quote

But I would use a very sharp chisel and chamfer off the far edge first in addition to Alf's advice.

Hope you didn't mind Alf? :wink:
Feel free. I'd just plane in from both edges. :wink:

Cheers, Alf
 
A

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Alf":mh29fsft said:
But a handy dodge to make it go a little easier is to groove the insides and outsides of the box sides before you put it together, just leaving enough to keep the thing together. That way you have a guide for the saw and an indicator to help when planing down the sawn part flush and square.

Cheers, Alf
Thanks Alf, nice idea. Must do that for the next box :D
 

Nads

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Thanks All,

Alf,

Just a few questions about your comments –

Bet everyone can guess my answer... Plane!
You said I should plane off the proud tail/pins, how do I set up a flat surface so that I can plane from both sides, I’ve got to plane off between 1-2mm, do I use a block or smoothing plane?

IMO, handsaw. But a handy dodge to make it go a little easier is to groove the insides and outsides of the box sides before you put it together, just leaving enough to keep the thing together. That way you have a guide for the saw and an indicator to help when planing down the sawn part flush and square.
By handsaw, that sounds brave, I’ll give it a go then! What do I use to make the grove on the insides and outsides?
 

devonwoody

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Nads

Stand by for the howls :twisted: :twisted: :twisted:

I puchased the Record belt and disk sander the other week and its lovely .


Would admit it feels like cheating though.
 

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