I have a porter cable jig and a bosch router.
I am trying to make a dovetail drawer out of Baltic Birch but each time that I route the Baltic Birch it shatters as if glass. Advancing the router slowly didn’t help
I’m thinking that since Baltic Birch is a composite cutting a dovetail in it doesn’t work.
Any thought?
Ron Sanzone
I’m not familiar with that jig, but maybe you could clamp say 1/4" of solid wood as a backer so the plywood doesn’t blow out? Depends on if you could keep the clamps out of the way of the jig, but it might be worth a go.
thanks for your input but it doesn’t appear that the jig would accommodate that. I’m thinking that a ply board cannot hold up to a router dovetail bit
Ron
Ron
Start with slowing the router to it’s slowest speed. Plywood is going to chip easily, so slow everything down, ease up your feed rate, and try a straight bit to get the bulk of the material out of the way, when use the dovetail bit to finish the cut.
I have usually do dovetails by hand but check out the post that Doug put up, he actually knows what he is talking about.
I did find an internet article with several good ideas which is copied below with credit.
In essence it says that there are four or five factors that go into successful plywood dovetails including.
Jig set up, backer board, a very sharp bit, and quite possibly the wood itself.
If you do not need the decorative aspect of a dovetail, you can use a dovetail bit to make an identical angled rabbet on the ends of the boards. This is a very simple joint that has enormous strength and can be made decorative using 1/8" dowels. Let me know if you need more info. Paul.
Dovetail Tearout using Baltic Birch Plywood?
1/2’’ Baltic birch is an ever-popular choice of material for drawer boxes - including the dovetailed variety - and so is the question of how to prevent tearout when you cut the joints. Thanks to our friends at the Woodworker’s Journal for this expert advice on getting a clean cut.
Q. “I need help about correctly dovetailing in Baltic birch plywood. I have seen beautifully clean cut dovetails for drawers and the like in contemporary furniture, so I know it can be done. I am experiencing a lot of tearout when I attempt it. I am using a Porter Cable Omnijig 24” with a 1 1/2 horse Porter Cable Router. I am using a 1/2" 12 degree dovetail bit, brand-new. Do I need a bit with a smaller angle? Do I need to score the plywood before each cut?" A. (Ellis Walentine) “This is puzzling. You ought to be able to get acceptable results if you use a new, carbide-tipped dovetail bit from a reliable manufacturer. The angle of the dovetail shouldn’t be an issue either. I suggest trying again with a newer or better cutter. If the problem persists, it could be the plywood itself. A cutter with a slight rake to the tip might improve your odds with flaky or difficult material.” A. (Rick White) “Whenever I do dovetails on plywood, I use a backer, i.e. a piece of wood attached to the piece you’re dovetailing so the bit can cut through and into the backer. This prevents a lot of tearout. The other option: do the cuts on a piece a bit wider than you need and trim off the torn out edges with a saw.” A. (Ian Kirby) "You don’t need to change the bit angle or score the plywood if everything is correct. Try the bit on solid wood and another type of plywood. If there is no tearout, then the birch plywood has a problem. If there is tear out, then it would appear that the bit has a problem. New or not, look at its edges very carefully; preferably through a hand lens for damage or incorrect machining. " A. (Rob Johnstone) “If your setup is true and the cutters are very sharp, then I would add the scoring step and see what happens. The idea of using plywood, even the voidless type you have selected, cuts against the grain (sorry about the pun) with me. I recommend a light colored but durable hardwood instead. It would support the contemporary look you are working for, while making the machining process much more manageable.” (From the Woodworker’s Journal eZine 2000 archives)
Thanks for the information. I think that the problem is all the above, the router bit is burned and bluish at the cutting edge although it hasn’t been used very often. The router speed is a 2. I thought that I was advancing the router slowly but apparently too fast?.
To solve the dilemma I used a butt joint In the future I may readdress this problem
Thanks
Ron
I’ve not tried dovetails on baltic birch, I usually use a nice secondary wood like poplar for my drawer boxes. However, if you use birch ply, I would not recommend a butt joint; you will be glueing to end grain and I don’t think it would hold well. Consider a box joint cut by backing with a jig or a backer board:
Another great joint is the drawer lock joint:
This is pretty fast and easy, and strong as long as you orient it the right way.
-e
Thanks for your comment. I used the incorrect term it isn’t a butt joint but a lock rabbet joint I simply didn’t know the correct term
Thanks
Ron
I’ve done dozens of drawers with Baltic birch, usually pre-finished (which is fragile). I use the method outlined in that woodworkers journal article. The scoring is necessary, and sometimes it sill separates. Watching it and immediately regluing separations when they did occur meant very few attempts were wasted. I did though just to be safe, cut my drawers long and do the final cut after the dovetail was cut. Note that dry assembly will break them. So get the cuts right thru testing, then only do a single (final with glue) assembly.
When I was taught to make dovetails with a router jig, the instructor said to use a scoring cut but in the opposite direction, i.e., use a climb cut on the scoring cut, not in the “regular” direction. This works for me, but have not used baltic birch.
Box joints are great and help solve the blowout problem as well. I have a special set of dado blades to do these because most come with the outside blades a hair longer for the “glue joint”. Mine cut square dados. If you do these you do them with a jig on a table saw with a sled. Done right (meaning your sled doesn’t have wiggle room) you can constantly remake the sacrificial backstop with the proper spacing on the block for stepping over to the next cut. You automatically have a way to keep the blowout from happening
I have made a lot of drawers using this joint in 1/2 and 3/4 baltic birch. Never had a problem with them. I have also used the refinished drawer material at TH&H and that works well also.
I think dovetails and box joints are for hardwood. Besides the glue in plywood is hard on router bits.
mick
