dovetail jig PC 4200 for plywood drawers

Tim Sherwood

Tim
Corporate Member
I've been trying to set up my 4200 Porter Cable jig to cut half blind dovetails in !/2" plywood. I'm not having any luck. Has anyone done this successfully?
The manual states that !/2" is the bottom end of it's capabilities for this operation. I was hoping that 15/32 would be close enough.....Maybe not?
The joint is too tight to go together. I've adjusted the bit depth until there's only !/16 left on the drawer front. I've adjusted the template backwards and forwards many times. . When it's is back enough to fully cut the pins, the sockets are too deep. When its set forward to cut a good pocket, it won't even round off the back of the pins.
So I added a 1/16" spacer between the pin board and the tail board. That got me real close, but still too tight . If I set the router bit any lower , to loosen the joint,I'll blow through the front.
I feel like I'm missing something simple, as usual. Any ideas or should I go back to box joints for 1/2" plywood drawers?
 

Joe Scharle

Joe
Corporate Member
A couple of possibilities come to mind...
I believe the PC bit is 17/32 and
the plywood is probably 15/32 so...
Box joints sound like a good choice to me!
Besides, blowout and splintering is a strong possibility with plywood anyway.
But, can you use 3/4 hardwood drawer fronts?
 

Tim Sherwood

Tim
Corporate Member
You may have something Joe, about the bit diameter. But, I've just watched two Utube demos of this jig. Both guys used !/2" birch plywood. Of course they got perfect results. I feel like I followed the instruction manual, just as they did. I even checked that I used the proper sized template ring. I've cut a dozen test joints making every adjustment I can. Still the pins are too tight for the sockets.

I'm not too concerned about plywood blowout. It would be on the inside of the joint, and shouldn't show after the assembly. I'm using baltic birch and that has limited that problem. I was going to apply 3/4" cherry drawer fronts to a four sided box drawer, for easier fitting of the inset fronts. I could try dovetailing the fronts directly. But if I can't get a decent trial joint, I don't want to waste the cherry.

I'll try calling Porter Cable, but doubt that I'll get a lot of advice.
 

JimD

Jim
Senior User
Tim,

The normal thing to do when the joint is too tight is to reduce the bit depth, decrease the amount the bit protrudes below the router. Did you try that? You mention 1/16 left which suggests to me that you increased depth, that makes the joint tighter.

I would not worry about whether the back of the pins are rounded. If the joint fits, it doesn't matter. It's been a long time since I used nominally 1/2 baltic birch for drawers but I got it to work with a different jig. But I am pretty sure the pins did not have fully rounded backs. (I use a Harbor Freight jig with a Grizzly template guide).

If you get it to work, I suggest you make a simple setup jig for next time. I cut a U shape in a scrap of plywood and put a screw in it to adjust to just touch the bit. I keep it and a few other aids in a drawer below the dovetail jig.

I also found that it worked better to back cut plywood. It splintered less. But now I think I will use domino joints in plywood.

Hope this helps.

Jim
 

Tim Sherwood

Tim
Corporate Member
Thanks Jim. You are correct that I made A FEW ADJUSTMENTS IN THE OPPOSITE DIRECTION. Once I got that fixed I did make some progress. But it was slow. I finally added a 3/32 spacer between the pin and tail boards. Awkward, but it works.
 

JimD

Jim
Senior User
Tim, the spacer might be your best option. The HF jig has a metal stop bar to limit the depth the guide on the router base can go into the guide fingers of the jig. I have used other jigs that you move the template in and out to accomplish essentially the same thing. But it makes sense that you may not have adjustment for less than 1/2 inch material if that is the way your dovetail jig works. A spacer would be a solution in that case.

Once you get your jig set up, you will, hopefully, find that your efforts are greatly reduced going forward. I can put my jig up onto the workbench and be cutting dovetails in maybe 10 minutes. And they fit. I still like to cut at least one set of material long so I can cut a joint and make sure things are working. If not, the extra material lets me trim that joint off and try again.
 

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