# Dovetail Help



## freedhardwoods (Sep 7, 2008)

I finally got to try to make some dovetail joints for the first time today. I am using a Porter Cable 4216 jig trying to make half blind joints. No matter what I try, the joint always has a gap in the same place. What am I doing wrong?


----------



## Toolman50 (Mar 22, 2015)

Adjust the bit up (less bit) the distance of your gap.


----------



## freedhardwoods (Sep 7, 2008)

I was using plywood for practice, but decided to switch to solid wood, because in actual use, I will only be dovetailing solid wood. I planed a board down to 5/8” (at least I thought I did. More on that below) and cut some lengths to practice (and practice and practice.......) on.

I tried adjusting up and down, in and out, and it still wouldn't work right, so I decided to back up and look at EVERYTHING that went into making a drawer joint.


I first checked my chop saw. It was very slightly out of square, but I'm pretty sure that wasn't causing a joint problem. It would have just made a very slightly out of square drawer. Chop saw is sqare now.


I had bought a Milescraft Base Plate/Bushing Set for my router. Every time I cut a joint, I noticed the router would move very slightly from one side to the other when I would go in and come back out. I just assumed the router bushing was slightly smaller than the jig notch. Then I happened to notice the insert was moving in the base.


Using my ******* engineering degree, I took some 1/32” thick black tape I have and cut 1/8” x 1” strips and stuck them on the outside edge of the insert as shims and got it tight. That made a world of difference. Now the joints were coming out almost right.


On some cuts, the guide would have a hairline gap between it and the right side of the board, and almost every test joint was off on one side and not the other. That's when I checked my board thickness and found on a 4 1/4”board it was 1/32” thicker on one side. That was enough to throw the jig very slightly out of line and make one side of the joint wrong.


By then I had to go on a run. I got some 5/8” drawer stock from the shop I was working for this afternoon and expect the joints should work tomorrow. If everything besides the jig had been right, I probably would have had it set up fairly quickly.


----------



## TomCT2 (May 16, 2014)

I have the same Porter Cable. do you have the manual?

there is a depth stop stop to set the depth of the bit. they say it's factory pre-set but that's not true.

you also have to have a board of the _same thickness_ clamped under the fingers - the depth stop works in conjunction with the thickness of the clamped scrap board.

as to the problem you've shown in the picture, the depth of your router bit is not set correctly on the pins or the tails or both. that's it, that's the whole problem.


----------



## johnep (Apr 12, 2007)

Here's a Utube video:








Johnep


----------



## freedhardwoods (Sep 7, 2008)

Thanks for the replies.

I do have the manual and have watched several videos. These two explain things very well also.









I tried many more joints and still can't get consistent results. The bit depth isn't the problem. Some joints will be tight and then I will get a loose one without changing anything.

In the pic I posted earlier, it isn't a simple loose joint. I've made so many joints I can't remember how I got it to stop doing that.

I am working on a couple changes to try to get consitent results. I'm making a larger guide to make sure the boards stay straight in the jig and stop the slight offset that I *am* consistently getting. It will probably be Saturday before I can get back to it.


----------



## freedhardwoods (Sep 7, 2008)

*SUCCESS!!!!

*I put my new guide on and now I can't make a joint wrong. It works so well I don't even have to do both boards at the same time. :thumbup:


----------

