Cutting a Rabbet in 3/4" plywood

[Joe Von Kaenel]

Hello,

I am trying to put a 3/8" deep X 3/4" wide rabbet into the edge of 3/4" plywood. The plywood sheet is 16" X 32", I cam make the 3/8" deep cut on my TS without any problems. Trying to cut that size sheet of plywood and keep it against my table saw fence is the problem. Any suggestions? Thanks


Joe

[Karlan Talkington]

Do you have a dado stack?

A dado stack and a sacrificial fence should take care of that rabbet easy.

[Jim Becker]

On the table saw, unless this is a very narrow piece of plywood that you can safely stand along the fence you should use a stacked dado blade to cut the rabbit using a sacrificial fence to protect the fence from the stack. Otherwise, use a router with an edge guide to run the rabbit down the edge of the sheet stock.

[Carl Fox]

Why are you having trouble keeping a piece of plywood that small squarely against the fence? Do you have an el-cheapie $100 table saw like I used to have?

[Joe Von Kaenel]

Carl,

I was only having a problem keep the plywood against the fence when it was standing up on edge.

Using a stacked dado won't blow out the plywood? Thanks


Joe

[Karlan Talkington]

If you are worried about chip out, I typically use blue tape (or painter's tape) to tape over the cut before cutting. This helps great in preventing chip out.

[Jim Becker]

Using a stacked dado won't blow out the plywood?

No, it will not do that. Depending on the quality of the dado set, you may want to score the cut line with a sharp knife first and/or put some blue painter's tape down that cut line. This isn't needed with a high-end set, but is a good idea for the low to mid-range products due to the way they are ground.

[Lee Schierer]

I was only having a problem keep the plywood against the fence when it was standing up on edge.


Why are you standing it on edge? It will cut easier and cleaner laying face down on the table. A zero clearance insert will prevent tear out along the cut line. You will only have 3/8" of blade exposed. You will still need the sacrificial fence. Use push blocks to hold it down tight to the table if the plywood is bowed slightly. If it is bowed, run it through the cut twice to insure you get an even cut depth all the way across.

[Jim Becker]

Lee, he's cutting in two passes to remove the material from the rabbit...once flat to score the length of the cut and once on the fence to cut away the material. I agree this is not the way to do it with large chunks of plywood, although I've many times I've used this technque on solid stock; typically smaller pieces that need a rabbit to fit together with something.

[Vince Shriver]

Wouldn't it be better (read, safer) to cut the rabbit by taking multiple cuts, moving the fence over a little after each pass, nibbling away at the stock until completed? Kind to time consuming, but better than waving that big chunk of wood up in the air.

[Greg Hines, MD]

Your other option would be a rabbetting bit in your router, either table or hand held. That should give you a nice clean cut, and you can easily adjust the depth to match your needs.

Doc

[Lee Schierer]

Lee, he's cutting in two passes to remove the material from the rabbit...once flat to score the length of the cut and once on the fence to cut away the material. I agree this is not the way to do it with large chunks of plywood, although I've many times I've used this technque on solid stock; typically smaller pieces that need a rabbit to fit together with something.Okay, I guess I missed that, but he can still hold it against the fence if he has a taller fence like this:
http://www.home.earthlink.net/~us71na/raisedpanel4.jpg

The magnetic feather boards work great for this. He can to the face cut in one pass then the rabbeting cut in the second. Placing the feather board just before the blade and above the height of the cut behind the blade will hold the piece securely and safely. This is how I cut raised panels on the TS all the time.

[John Dugo]

Wouldn't it be better (read, safer) to cut the rabbit by taking multiple cuts, moving the fence over a little after each pass, nibbling away at the stock until completed? Kind to time consuming, but better than waving that big chunk of wood up in the air.


Not if your making a raised panel, the blades at an angle.

[Joe Chritz]

Router. straight bit and edge guide.

Fast, cheap and easy. Once of the few times you can actually have all three.

If you want to do the tablesaw, a good idea if you have a lot to do then a sacrificial fence with a dado stack. The tear out will be the same as a regular blade since the full blade is the one making the cut.

Making it in two cuts, while done often isn't really a good idea. Not so bad for small pieces but a big one like that is a dangerous operation.

Joe

[Peter Quinn]

I would use a stacked dado with a sacrificial fence and a ZCI as my first option. If you don't have one, the multi pass method with a good square tooth blade would be my next option. I would raise the blade to less than 1/16", set the distance to THE OUTSIDE OF THE BLADE to your 3/4" width, make a scoring cut. Then raise the blade to your 3/8" depth with out moving the fence, and make your first cut, keep moving the fence in till the dado is done. You will still need a sacrificial fence and its a good idea to do all set up on scraps before pushing your good stock through.

Either method works better if you use a backer where the blade exits the plywood at the end of the cut, or alternatively leave the sheet slightly oversized and rip to final width after cutting the dado.

The router is always my last option as the noise and dust annoy me, and standing 32" sheets of plywood up against a tall auxiliary fence for two step dados is in my shop not an option I would consider.