What is reccomended gap in thousandths of inch for dovetails?

[Joe Chritz]

However much a solid smack with a palm is to seat them. I figure if I can pick up four sides of a box without them falling apart (before glue) it is just right.

Interesting phenomenon is that if you have a .500 hole and .500 dowel they won't go together without help. You are about as good as it can get.

Joe

[Steve Schoene]

I think that number is the spread thickness. The clamped glue line would want to be more like 1 or 2 thousandths thick. And it is the fit of dovetail joints that provides the clamping. Snug is right. Tap tight for sure.

[Dan Friedrichs]

If you're trying to get a gap of 0.003", you're trying to get a space of less than a human hair's width. Good luck.

[Steve Schoene]

Gaps of less than that are common for dovetails cut in drawers with poplar drawer sides. The fit is close enough that there is just a bit of compression in the poplar as it is tapped or clamped into place. The gap is essentially zero. I'm not advocating any measurement of dovetail tolerances. They should be snug. I end up making one or two of them snug with a sliver of wood glued in place after they have been glued up. In maple, there has to be more room since it doesn't compress very easily.

[Alan DuBoff]

Much too often we loose perspective on what we're really trying to accomplish. We are working with wood, not tool steel or precision machinery. The sawdust itself is larger than .0015 and the relative humidity will cause the wood to expand and contract more than this.
...
Leave the precision to the machine shop and enjoy woodworking....

Then prey tell, why do so many folks use a tailed router to accomplish what has been done with wood by hand for years?

To me, using a tailed router is like trying to work wood like metal.

Why does it need to be exactly the same? Why do they need to be perfect?

Sure, I'll never get them perfect by hand, but I will always shoot for those results. And I have learned that I will be happy with my results even if there is a gap...nothing a ball pein hammer can't fix. Closes the gap right up...

[Roger Jensen]

OK, I'm not saying this is right or wrong, but I just happened to be looking at the Sommerfeld web site at their Katie jig. On their tool description they have the following quote:

"The perfect glue gap of .006"-010"-between pins & tails"

I have no idea if this is correct, other than I have seen Marc Sommerfeld at a woodworking show and he seems like a pretty sharp guy.

[John Keeton]

...nothing a ball pein hammer can't fix. Closes the gap right up...

Alan, does this mean that if I am using an 8# sledge, I need to work a little harder on my accuracy?? Just curious.

Actually, I am really enjoying this thread as I just finished acquiring the various "implements" with which to embark on this handcut thing - and I shudder to think what my first gaps will be. But, whatever they are, it will be fun and you guys give me hope that I can accomplish this!

Also, rest assured, that if my first one is tight - you will hear about it! If not, it is winter, and we need wood for the fireplace.

[Sean Rainaldi]

...Actually, I am really enjoying this thread as I just finished acquiring the various "implements" with which to embark on this handcut thing.

Speaking of handcut dovetails, can anyone suggest a hand cut "dovetail kit", with a saw, chisels, maybe templates and such? Or do these items need to be purchased separately?

[John Keeton]

Sean, I am sure this will invoke responses from others, but I have really enjoyed the Rob Cosman DVDs and book. They are informative, and provide a good list of needed tools. You can even watch his 3.5 minute dovetail video and get a good idea of what you need. He sells some of the items, although they are probably cheaper elsewhere. Keep in mind that he is sponsored (it appears) by Lie Nielsen. Not that such a sponsorship is a bad thing, but I think there are other quality tools out there.

There are also other sources for the fret saw, etc. PM me if you want my list - and others may offer theirs as well. Keep in mind that I have yet to cut my first dovetail, so my "list" may not be particularly reliable!!

[Marcus Ward]

Ahhh you silly wood machinists. Frank Klausz can cut better looking dovetails than your router in his sleep and he hammers his together. Are you guys all sure the OP isn't just pulling our legs?

[Marcus Ward]

Sean, you don't use a template or a kit. You eyeball it based on scribed lines. Seriously, it's easier than you think. A nice sharp dovetail saw, a chisel, and a mallet are all you need. Maybe a marking gauge, if you're really anal retentive.

Can I say anal on here?

[Clifford Mescher]

OK, I'm not saying this is right or wrong, but I just happened to be looking at the Sommerfeld web site at their Katie jig. On their tool description they have the following quote:

"The perfect glue gap of .006"-010"-between pins & tails"

I have no idea if this is correct, other than I have seen Marc Sommerfeld at a woodworking show and he seems like a pretty sharp guy.

I'm guessing that glue manufacturers recommend about .003-.005 gap between wood for the glue. Two sides for each dovetail. Double the .003-.006 gap and you have the .006-.010 gap.Clifford.

[Sean Rainaldi]

Thanks John I’ll check it out. I could imagine that after investing in top quality hand tools for hand cut dovetails that the price could be pretty close to a good dovetail jig but I’ll sure look into it.

Marcus,

If you mean I am pulling your leg about the .0015 gap between pin-tail I can get with a Route-R-Joint, I swear on my mothers grave that I am able to do that.

I want to do wider than 14 inch boards which is why I am thinking about getting Leigh jig to replace it – I hear it’s possible to index the template over with my current jig for wider boards, but that will introduce error in the joint fit and probably take a lot more time and aggravation for me to set up. Plus I want a new toy!

[Sean Rainaldi]

Sean, you don't use a template or a kit. You eyeball it based on scribed lines. Seriously, it's easier than you think. A nice sharp dovetail saw, a chisel, and a mallet are all you need. Maybe a marking gauge, if you're really anal retentive.

Can I say anal on here?

Cool thanks!

With what instrument do hand dovetail crafters mark the dovetail angle with?

[Frank Drew]

Sean

Machine cut dovetails are perfectly appropriate for wide boards, such as for casework. Especially if you're doing a run of them (more than one box).

I prefer hand cut for drawer sides and other work that shows, for cosmetic rather than structural reasons. As Marcus notes, hand cutting is pretty low tech and is done, and the results are judged, by eye. A bevel gauge and a small square for layout are the only measuring instruments I'd use. I can't imagine checking my fit with a feeler gauge.

[Just saw your last question: The adjustable bevel gauge is for the angles; you set it by eye, by what angle looks good to you, within reason. You can also buy or make dovetail gauges, with preset angles, but IMO they're superfluous if you've already got a bevel gauge, which is a useful tool for lots of other layout needs.]