Dovetail DOH!

[Kirk (KC) Constable]

We spent literally HOURS getting a Porter Cable 4112 dovetail jig and router set up properly at the mesquite outfit. We bought a DeWalt 610 router specifically for dovetails, and the bit never comes out. Everybody knows if they screw around with the jig everybody else will be mightily irritated because everybody was there when we set it up and everybody knows it was RIGHT and to LEAVE IT ALONE.

It was a joy last time I used it...and I was the last one to use it. Today I made a couple drawers. Since I KNEW it was spot on, I went right to cutting the 'real' parts. They fit together perfectly, as I expected. Just a little tap with the mallet. But wait....a little more tap and the sides kept going deeper. And deeper! I've still got a very nice, tight fit...but my front and rear pieces are about 3/16 too long on each end. Kinda like I was trying to make a rabbetted/overlay front...but that requires a different set of edge guides and cutting the rabbet BEFORE the dovetails. The sockets are too deep, and it's obvious by looking at them. I am absolutely baffled as to what the hell went wrong. There's simply no way to do it 'wrong' and get that result that I can see, other than having the comb/template out of kilter. Which it wasn't last time I used it.

Anybody smarter than me is welcome to chime in with the answer...and those that are equally befuddled are encouraged to offer sympathy...

KC:mad:

[Jim Becker]

Gee...I don't see how that would happen with a half-blind jig like that unless the back-to-front location of the template changed...as it would for a rabbited setup. Given the pins and tails are tight, your bit height is "spot-on"!

Suspect the jig-fairy on this one! And I hope it wasn't material that was very very unique that got ruined. Of course, you could design a project that uses narrower drawers and carefully trim off that extra 3/16" on the fronts to get your fit...

[Bruce Page]

KC, my 16” Omnijig is bullet proof once it is setup. As long as the thickness from board to board remains consistent, it will churn out beautiful dovetails ‘till the cows come home. I think Jim is right – I’d be looking for that jig-fairy!


Like those little bottles of water? Ever notice that Evian spelled backward is "naïve?"

[Bob Lasley]

KC,

Sounds like those South Texas Shop Gremlins have found you! I have had some of their kin around here a time or two. At least that's who I blame those unexplainable goofs on. Ok, I admit it, sometimes I blame the explainable ones on them too.

You certainly have my sympathy, but don't cry in your beer........it ruins the flavor! ;)

Good luck with the new drawers,
Bob

[Kirk (KC) Constable]

Hmmm...I like the 'jig fairy' idea.

On the 4112 the thickness of parts isn't significant...the side piece butts up against the front/rear piece and the bottom of the template so once the template is set it properly it doesn't make any difference. For rabbetted joints, the edge guide thingies change the offset of the dovetails, but the template doesn't move if you follow the directions and use an 'indexing block' for placement of the front/rear pieces (In 'rabbet mode', the sides are cut separately from the front/rear).

More I think about this the more I wonder if we got it set up with a very tight fit and just never pounded a joint enough to drive it all the way down? I distinctly remember much fiddling around with the depth of cut, and finally deciding that tighter was better than looser. And much fiddling with the template front to rear to get a consistent cut at both the left and right sides.

These are flush-front drawers (Mission). I don't want to reaccomplish them (yet), so what I'm gonna do is go ahead and cut the little rabbet on the the fronts, then lop off the ends of the backs so they're flush with the sides. I've got enough thickness on the front to get away with this...and with any kinda luck it'll end up looking like I did it on purpose. If not, THEN I'll reaccomplish the drawers. After working on the jig, that is. :(

KC

[Mike Schwing]

This might be way too simple an attempt at an answer - the bit isn't creeping out of the collet on its own maybe?

[Jim Becker]

Originally posted by Mike Schwing
This might be way too simple an attempt at an answer - the bit isn't creeping out of the collet on its own maybe?

That would result in a "fit" problem with the pins and tails and would be immediately obvious...they would get real loose if the bit moved farther out of the collet. In KC's quandry, the router traveled too far horizontally into the drawer front resulting in sockets that were really, really deep...with perfectly fitting dovetails. Very strange problem.