Dry fit hand cut dovetails?

[Randy Klein]

I've been watching Rob Cosman's DVDs on dovetails. He's a strong supporter to not dry fit dovetails and just cut them and glue them. He argues that they will never fit as good as they do the first time, so don't dry fit, just trust yourself.

But then I was watching the DVD that Kevin Drake sends out. He mentions that some (although he doesn't name names) say not to dry fit. But Kevin says that if the DTs are cut with the right amount of clearance, that dry fitting does no harm. Of course, this position also supports his method of using his offset gauge and kerf starter system, but it doesn't sound like he says it just to sell his stuff.

So, what do you guys think? Dry fit first or just glue them?

Also, does anyone use the offset method (not necessarily Glen Drake's tools) to cut DTs?

[Pam Niedermayer]

Not being a guy, you may not want to see this response; but here it is anyway.

As you start learning how to cut dovetails, you must run pre-glue fitness tests. As you move along, this may become unnecessary.

I have no idea what the offset method says.

Pam

[Dave Anderson NH]

Mine is not a long or particularly enlightening response, but I agree completely with Pam.

[Zahid Naqvi]

you must run pre-glue fitness tests. As you move along, this may become unnecessary.

So what is a pre-glue fitness test? I presume it is not what we call dry fit

[Jim Becker]

Even if I actually knew what I was doing and had some skill, I'd still dry fit them...

[Dave Mount]

I'm not sure what people consider an "experienced" hand dovetailer -- hundreds of joints? thousands? I'm well into the hundreds, so I would have called myself experienced prior to reading Pam and Dave's posts. I agree that with experience one quickly reaches a place where the overwhelming majority of joints fit correctly without adjustment. Nevertheless, there are a small number of times when something does not fit "well enough." Perhaps that makes me still short of "experienced", though I don't have an expectation that I will ever get to the place that I never make mistakes -- and being in the middle of a glue up is in my mind a bad time to find out something cannot be driven home, at least not without splitting something. Gaps can be covered, but if pieces are oversize. . .

That said, I can see an argument that there may be some extra grip that comes from the first fitting, though I think it is probably trivial. Perhaps more significant in my view, there can be some risk of damage when driving a very tightly fitting joint back apart after dry fitting.

My approach has developed accordingly. What I do is a very limited dry fit -- I just start the pieces together and feel how it's going. If a joint starts to go together without excessive force, it will fit all the way unless the sawcuts are not parallel or the baseline is not cut straight (or undercut). Both of these things are pretty easy to see by eye. If you're not comfortable with that, they can be checked easily with a square. Just starting the joints will give away any egregious miscuts, takes just a moment, and is in my mind cheap insurance if your error rate is much larger than zero.

My $0.02,

Dave

[harry strasil]

use other peoples instructions as a guideline, but you will have to decide for yourself how you want to do it. remember experience is a cruel teacher, she gives you the answer and then the lesson. And remember what works for one person may not necessarily work well for another.

my 2¢

[Dan Racette]

means that I just have to agree with Pam! At least in my book.

I have not seen the Drake DVD, but I have seen the Cosman, and it did not deter me from test fitting. I did think it was a little over the top to say never test fit. I think Pam is much more on the right track, which, I find is the usual fare with her, and learning about woodworking.

For what it's worth. I have a crosscut dozuki, a lie niesen dovetail saw both too. In either method, It all about marking a good line, and cutting/paring to it. If you watch the cosman videos, later on, he'll talk about how you actually do have to do paring when you do some of the other techniques, so his statement sawing without paring or test fitting is contradicted slightly.

It's never black and white, is it? Pam, being a woman, is still "da man" in my book when is comes to common sense. (I guess I should say "da human" or something more gender appropriate, eh Pam, but you are the best)

Danno

[Bob Oehler]

The way I look at it is dry fit but do not drive them all the way home. If you apply glue and then they do not fit you are in for trouble. It can be said that the first fit is the best fit and that's true. If the fit is loose there is very little ware to the joint and the fit will not change the second time with glue. If the fit is tight it will ware only a little bit and when you apply the glue the wood swells a little anyway so if there is a little ware it goes away.

I am not saying that I am Mr. Dovetail and my way is the right way it just works for me.

I think that this is far less of an issue then pins first, tails first :eek:

No I am not asking what you do first just stirring the coals a little. :rolleyes:

Take care and Happy Dove Tailing
Bob Oehler

[Randy Klein]

I posted this same question over at Woodnet. Most of the same responses as here, but Rob Cosman replied and stated his case very well. It's a good read. I can't post a link, but it should be easy enough to find.

[Mark Singer]

I test fit as Pam said. If it is part of a drawer there is the mechanical strength of the joint itself, drawer with the bottom adds strength and the combination of elements. Dry fitting the joint over and over will loosen the fit and it may become visible after a while. Not dry fitting is intimidating for even advanced woodworkers. Keep i mind, we build furniture and perform many tasks besides making dovetails, everybody has their own way. In the end the it is the final piece of furniture that really speaks, not the road you have taken to get there, IMHO, YMMV

[Matt Wilson]

Not being a guy, you may not want to see this response; but here it is anyway.


Hey Pam,
"Guys" has been unisex for a while now...

http://dictionary.reference.com/browse/guy

check #2 for "guys".

[David Weaver]

To beat another dead horse - if you're using water-based glue and non-exotics, they should expand after your dry fit.

I have to be honest, a lot of my dovetails don't probably fit well enough for it to make much of a difference whether I dry fit or not, especially if they have the benefit of water-based glue to "blow them up".

Regardless of fit, even the ugly ones are strong.

[gary Zimmel]

I took Robs course this past summer. Never handcut a dovetail before I went and with the instruction and good tools seem to do not a bad job at doing 1/2 blinds. ( seems these are all I cut) I don't test fit, but I will set the tails over the pins to get a feel on how it will go together.
The way I look at it is if they are sloppy they may be fixable when together, and if they are to tight they will split with or without the glue and I am not to sure how you get something tight back apart before final glueing without damageing it.

Long story short. I make all my cuts as best I can, have a quick smoke, and bang it together. Only one has been too tight that it cracked, but every one that is done I get a little more confident.

Robs way may be unorthidox but it seems to work with me.

[David Weaver]

Speaking of - I just cracked one last night getting greedy - dovetails on the carcass of a medicine cabinet.

After doing it, I'm surprised i haven't done it before.

[Pam Niedermayer]

Matt, you're right, or course, I've gotten too sensitive hanging around woodworker fora.

Zahid, yes, dry fit, sort of. I mean that pre-glueup you want to test the fit, but not necessarily drive the joint home, you simply get a good idea of how the tails and pins will fit if driven home.

Danno, many thanks, but you've given me a lot to live up to, will do my best.

Pam

[Zahid Naqvi]

I mean that pre-glueup you want to test the fit, but not necessarily drive the joint home, you simply get a good idea of how the tails and pins will fit if driven home.


That's what I do, not really drive ti all the way in but get it in partially to see how things fit together. Now I have a name for the process :D

[Dan Barr]

hilarious jim.

v/r

dan

[Gene DiNardo]

I always test fit the first 1/16".
As long as your cuts are square the rest will follow.
Water based glue WILL cause tight fitting joints to bind.
Only experience will teach you how tight is too tight.
As for the "One time home Only" issue, this is because test fitting will burnish
the surfaces of the wood and some people believe this will affect the glue
penetration and therefore the integrity of the glue joint.

[James Mittlefehldt]

If I had as many dovetails done as Rob Cosman has, I doubt I would test fit either. However for now I do test fit and will continue to for the forseeable future.

[Randy Klein]

The way Rob explained, over at Woodnet, was he teaches his students how and what to check after you're done cutting and chopping. And that this inspection tells you everything you need to know that a dry fit would.

And knowing you only have one chance at a successful fit, you more prone to be precise and cognizant in your inspection and will, in time, become better and faster becuase of it.

[Jerry Olexa]

I'd do a test or dry fit first. Be terrible to find they were not cut right after they're smeared with titebond...