Problems with Porter Cable Dove Tail Jig

[Travis]

Take a look at the images below. I was trying to dove the plywood shown for drawer sides. Either you can not dovetail plywood or I am doing something wrong. Any thoughts.

Thanks

 

[Sabre2]

I have never tried to dovetail plywood before, but I understand BB ply can be done. Did you use a backer board? That will definitely eliminate or significantly reduce tear out. By the looks of the last photo, you might not have the correct depth set on your router bits.

I don't know if you used 2 routers, but it makes thing a whole easier. Set one for pins and one for tails, that way you know after your test pieces the dovetails will mate perfectly.

Hope this helps

Gary

 

[Travis]

Yep, i used the backer as the manual suggested. What was the indication that the depth needs to be deeper. Tehse are my first ones so any information would be great.

 

[photog]

I had tear-out when I tried the same thing on 1/2" BB on my 4212. However not as severe as yours. It was enough to make me stop, abandon the idea for the time being and chuck up a drawer lock bit in the router table. I plan to revisit the issue, because dovetails on drawers was my primary reason for buying the jig. I decided to go solid wood on the next project with the plywood tear-out in the back of my mind and re-sawed some Poplar down to 1/2" and made a bunch of drawer sides with half blinds as pretty as you please.

I think there might be a way to back the cuts up by clamping something thin in with the work piece. I'll be anxious to here from some of our problem solvers here.

 

[Ralrick]

Travis -
I don't have much 'right' for posting advice yet as I'm brand new to ww'ing but I just did my first dovetails last weekend with a PC4212 on some scrap plywood. See pics - on my first attempt I did not clamp a scrap board in front of the verticle piece and there was a lot of tearout like you had. On the second attempt, I clamped a piece of thin MDF infront of the board and the difference in the cut was tremendous. I still need a slight adjustment to the bit depth but I got real close to something that would be acceptable . . . . BTW, I did HB DT's just because I thought it would be easier to cut both pieces on one pass.

 

[Nativespec]

That looks like the 4212. I have the same one and you definitly must use backer board on plywood and I would use it on solid wood as well. I replaced the backer board every cut and I still had some tear out using baltic birch plywood. You do not need two routers, but it is nice I guess. My next "quality" project will probably use solid wood drawer sides and the only plywood will be the drawer bottoms, dust panels, and back of carcass.

Thanks,

David

 

[4yanks]

I would not dovetail plywood. I have tried in the past and achieved similiar results. Use the same technique for some solid wood and see what your results are. Good luck.

 

[Joe Scharle]

I can't see a backerboard in the top pic, but you do need one to support the thin bottom layer to prevent that veneer from flapping around and blowing out. Also, you may want to balance the tails by centering the edges between the fingers.
Ply does require a very sharp bit to minimize the 'fuzzing' effect and you might want to slow down the feed rate to see if that helps.
I have DT ply, but my best results have been HB as it hides most of my mistakes!
Good luck, Joe

 

[DavidF]

I would use a back and a front board and sandwich the piece to be cut in the middle. I have found that the back board doesn't need to be replaced each cut if you use a positioning stop to ensure that each piece is in exactly the same place. The front boards are thrown away after each piece. On the tails I routed the left side with a conventional cut going clockwise into the dt guide, but routed the right hand side using a climb cut (anti clockwise) and that seemed to work well. Make sure any clamp you use is as high as possible to make sure that the sandwich is closed up tightly at the top.

 

[dancam]

I have the Leigh DT jig and have not used it on ply but I have seen Norm (New Yankee Workshop) extensively use ply for drawers both with the Leigh and PC DT jigs with what looks like really good results. Who knows how many attempts he's making before the file goes to final.

Besides the backer boards I'd also try a coating of tape (blue painters tape) and see if that helps...just my .02.

Dan C.

 

[Travis]

I am a little confused. Their is already a scrap board laid perpendicular to the piece that is being cut. In addition to this board, I basically clamp another board behind it and move the template out the additional distance of the backer board. Do need some additional clamping other than what is provided by the Porter Cable jig.

Thanks

 

[Nativespec]

You need a board in front of the vertical board as well. There should be two scrap boards in addition to the board being cut.

 

[DavidF]

You need a board in front of the vertical board as well. There should be two scrap boards in addition to the board being cut.

Exactly, leave the existing back board in place and only replace it if it's really beaten up. Use a sacrificial board in front of the piece being cut and replace for each cut.

 

[Travis]

Thanks. I will try the sandwhich method and share the pics.

 

[Travis Porter]

FWIW, I don't think the cutter that comes with the jig does very well with plywood. It seems to be a good cutter, but I had similar issues doing plywood although not near as extreme as yours. Making a scoring pass and light cuts helps. The sandwich will probably be the best route to go overall, but you may still have blowout on the sides.

 

[Nativespec]

Overall, it appears that even the best plywood has voids and weak glue areas. I was not pleased with my results with the plywood and I will probably use poplar or possibly pine on my next project. Plywood seems to be good for carcass and drawer bottom use in my oppinion.

 

[cpowell]

Overall, it appears that even the best plywood has voids and weak glue areas. I was not pleased with my results with the plywood and I will probably use poplar or possibly pine on my next project. Plywood seems to be good for carcass and drawer bottom use in my oppinion.

I agree with your assessment for plywood. Poplar machines well and is reasonably cheap. I use poplar or red oak extensively for drawer stock, depending on the piece.

Chuck

 

[Travis]

Thanks. I will try the sandwich and the poplar. I have never resawn before. Could be an adventure.

 

[Travis]

Re: Problems with Porter Cable Dove Tail Jig (updatew/ new pics)

Thanks for the advice. I was able to get acceptable results dove tailing the Baltic Birch by going to half blind joints and taping the veneer with a 1/4" MDF backer board.

 

[dancam]

Looking good:eusa_clap :eusa_clap :eusa_clap