Dovetail Jig Tear Out

[farmbag72]

I recently purchased a PC 4216 dovetail jig and have had great success cutting with the dovetail bit, straight bit and my spiral upcut bit (for box joints) in solid wood.  I can not for the life of me, get clean cuts in Baltic birch ply (3/4" & 1/2") with any of the jig bits.  I've tried slower bit speed, moving the router quicker & slower, pushing down firmer, trying to "float" the router on the template.  Nothing works.  The tear out is all on the side facing me.  The back sides come out perfect because of the backer boards in the jig.  I've watched tons of vids on using this jig & don't see that I am doing anything differently from the vids.  Anyone else have this issue?  

 

My shop is unheated & I've been working with 10-15*F (I <3 NY) ply.  Could the temp of the wood make a difference?  Yeah, that question does sound silly to me too.

[bgreenb]

You could use c-clamps or spring clamps to get a backer board on both sides of the workpiece (the clamps should be small enough to be out of the path of the router and still allow the board to register in the jig). I do this sometimes (I have a leigh jig but it's the same idea).

Question though, how come you're doing dovetail/box joints in plywood? I've never used plywood in my jig for this exact reason.

[farmbag72]

Question though, how come you're doing dovetail/box joints in plywood? I've never used plywood in my jig for this exact reason.

 

I am trying to make drawer boxes/storage boxes for shop storage.  No one cuts dovetails in plywood for drawer boxes???  If this isn't common, let me know so I can stop pulling my hair out.  A local lumber mill/dealer has MOUNTAINS of 1/2" Baltic Birch cuts offs (14-1/2" x 50") on the cheap-ish side that I thought were perfect for jigs & drawer boxes.

 

Norm does it

 

http://youtu.be/JkhwnTDizj8?t=17m32s

[AceHoleInOne]

Bgreenb has it right.

 

I often will take a small piece of 1/4" plywood (I use the Katie jig for dovetails)  and clamp that to the opposite side of the jigs backer-board or face if you will. 

 

I have never tried this, however, use some blue painters tape. That may help with the chip-out?

 

 

-Ace-

[bgreenb]

I am trying to make drawer boxes/storage boxes for shop storage.  No one cuts dovetails in plywood for drawer boxes???  If this isn't common, let me know so I can stop pulling my hair out.  A local lumber mill/dealer has MOUNTAINS of 1/2" Baltic Birch cuts offs (14-1/2" x 50") on the cheap-ish side that I thought were perfect for jigs & drawer boxes.

 

Norm does it

 

http://youtu.be/JkhwnTDizj8?t=17m32s

I've never heard of it before, but that doesn't mean it shouldn't/can't be done - if Norm does it then it's probably fine

I just took a look at the Leigh manual, it says "plywood is generally unsuitable for routing dovetails because of tearout." If it were me, given that it's shop furniture, I'd rabbet the drawer boxes, save myself a bunch of time and frustration, and have a couple beers. That's just me though

[dwacker]

I am trying to make drawer boxes/storage boxes for shop storage.  No one cuts dovetails in plywood for drawer boxes???  If this isn't common, let me know so I can stop pulling my hair out.  A local lumber mill/dealer has MOUNTAINS of 1/2" Baltic Birch cuts offs (14-1/2" x 50") on the cheap-ish side that I thought were perfect for jigs & drawer boxes.

 

Norm does it

 

http://youtu.be/JkhwnTDizj8?t=17m32s

 

Of course they do most every cabinet shop in america does it every day. The problem is your cutter. If your using the cheap cutters that came with the jig your going to have nothing but problems in plywood. Onsrud makes ok dovetail cutters that work ok. The best dovetail cutter that works flawlessly in plywood is a Vortex but you have to have them milled to 1/2" for use in your router. One will last a hobby guy a lifetime and will cutter dovetails like nothing you have ever seen.

[farmbag72]

The best dovetail cutter that works flawlessly in plywood is a Vortex but you have to have them milled to 1/2" for use in your router. One will last a hobby guy a lifetime and will cutter dovetails like nothing you have ever seen.

Great looking bits but my wife would shoot me if I bought one of those bits for $200+ (and still had to have it machined so I could use it).  I guess this could fall into the conversation Marc started at TWW about what you would buy if you hit a financial windfall.

[Janello]

I've never tried plywood DT's but I'm wondering if a few drops of hot CA glue along the edge would help tear out when using an "inferior" bit. It may wind up dulling the bit faster but i would think it would hold the end grain together better.

[dwacker]

Of course they do most every cabinet shop in america does it every day. The problem is your cutter. If your using the cheap cutters that came with the jig your going to have nothing but problems in plywood. Onsrud makes ok dovetail cutters that work ok. The best dovetail cutter that works flawlessly in plywood is a Vortex but you have to have them milled to 1/2" for use in your router. One will last a hobby guy a lifetime and will cutter dovetails like nothing you have ever seen.

 

Look at the onsrud they are not much more than any other good router bit. The other ones are made for fast machining in a DT machine thus why they are so expensive. The Onsrud you can benefit from a little climb cutting.

[AceHoleInOne]

Look at the onsrud they are not much more than any other good router bit. The other ones are made for fast machining in a DT machine thus why they are so expensive. The Onsrud you can benefit from a little climb cutting.

 

This is interesting to me. How does one go about climb cutting with a dovetail bit?

 

-Ace-

[dwacker]

This is interesting to me. How does one go about climb cutting with a dovetail bit?

 

-Ace-

 

When you use the 4216 to make drawer boxes your usually making half blinds. Just cut right to left instead of left to right.

[bgreenb]

When you use the 4216 to make drawer boxes your usually making half blinds. Just cut right to left instead of left to right.

X2. I climb cut on my half blinds as a matter of course. Helps tremendously with tearout.

[AceHoleInOne]

When you use the 4216 to make drawer boxes your usually making half blinds. Just cut right to left instead of left to right.

 

Thats my answer, thanks. I do applied drawer fronts. Never done half blinds.

 

-Ace- 

[dwacker]

I would suggest that anyone that uses the PC jig download and read the supplemental manual. There is a bunch more to this little inexpensive jig than meets the eye. It can be used like the keller and lots of other functions. I dont have the link but just google supplemental manual for pc jig it will come up somewhere. Hell you can scrap the clamping part and set up just the templates for mass drawer production nearly as fast as a dovetail machine.

[farmbag72]

I would suggest that anyone that uses the PC jig download and read the supplemental manual. There is a bunch more to this little inexpensive jig than meets the eye. It can be used like the keller and lots of other functions. I dont have the link but just google supplemental manual for pc jig it will come up somewhere. Hell you can scrap the clamping part and set up just the templates for mass drawer production nearly as fast as a dovetail machine.

The supplement instructions are awesome!  I inserted the link above.here.

[sjeff70]

Save the templates and reuse them.  Soon you'll have enough to get rid of the jig.  

They should just sell templates instead of those expensive dovetail machines.  

 

 

[dwacker]

Save the templates and reuse them.  Soon you'll have enough to get rid of the jig.  

They should just sell templates instead of those expensive dovetail machines.  

 

Its not a machine. The pc is just a cheap jig but for some reason they dont tell people about all the other uses or the diversity. I think if they did most would never feel the need to spend money on the more expensive models made by other companies. 

[sjeff70]

I see that with lots of products, PB.  I understand what you're saying.

[Coop]

farmbag72, I just finished making 12 drawers from 1/2" Baltic Birch using the small box joint jig that Rockler sells. At first I had major tear out using my straight 3/8 bit. A front backer board helped but was sure time consuming. I finally went back to Rockler and bought the Freud spiral carbide bit and every cut was very smooth. I even started cutting two boards at a time.

[Skunkeye]

As has been suggested, using a climb cut helps a great deal with tear out, as does scoring the work with a cutting gauge.

[BuilderBill]

I am trying to make drawer boxes/storage boxes for shop storage.  No one cuts dovetails in plywood for drawer boxes???  If this isn't common, let me know so I can stop pulling my hair out.  A local lumber mill/dealer has MOUNTAINS of 1/2" Baltic Birch cuts offs (14-1/2" x 50") on the cheap-ish side that I thought were perfect for jigs & drawer boxes.

 

Norm does it

 

http://youtu.be/JkhwnTDizj8?t=17m32s

 

I don't know about Norm or anyone else but I don't cut dovetails in plywood drawer boxes, I have better things to do with my time. Maybe if i had one of those dovetail machines that use the $200 cutters I would but I manage to get by with a simple rabbet and dado joint. Face it, we don't put plywood drawer boxes with applied fronts in fine furniture, these are for cabinet work where you have a ton of drawers to build and want to get it done.

 

Here's how I cut the joint on the table saw:

 

Set up a 7/32 dado stack, set the height to leave 1/4" in the 1/2" nominal stock. Set the fence so the far edge of the dado is 1/64 shy of the actual thickness of the plywood. Cut the sides to exact length(OK, cut them 1/32 short if you're picky), cut the fronts/backs to width minus 1/2"(that's the 1/4" you left in the side stock when setting the dado height).

 

Run the sides inside face down flat on the table, run the fronts inside face towards the fence vertically against the fence. If your plywood is 7/32 you'll have a 13/64 tongue on the fronts to fit into the 7/32 groove in the sides. Easy-peasy for assembly, a little glue on the sides of the dado, stick in the front/back and pin it with a few staples or brad nails. I'm sure Norm would approve....

 

Here's a drawing, I assumed the plywood is 15/32, you might have to tweak a little depending on what you have. But the general idea is the same.

 

Hope this helps,

Bill

[Slick218]

I've never heard of it before, but that doesn't mean it shouldn't/can't be done - if Norm does it then it's probably fine

I just took a look at the Leigh manual, it says "plywood is generally unsuitable for routing dovetails because of tearout." If it were me, given that it's shop furniture, I'd rabbet the drawer boxes, save myself a bunch of time and frustration, and have a couple beers. That's just me though

If it's for the stop, why not use plywood? Don't have to impress anyone and you can work on removing tolerances,errors,etc.

Sent from my SGH-I727R using Tapatalk