3/4" Ply

[Bernie Weishapl]

Was wondering if 3/4" plywood could be edge jointed on my jointer? It is a good plywood and is 7 layer. I did some searching and didn't find any info. Thanks.

Bernie

[Dick Parr]

I have tried it in the past and have had good luck with doing it if you go slow. Other times it can tear the edge. A lot depends on if your blades are real sharp.

Test a piece first and good luck.

[Jamie Buxton]

Edge-jointing plywood dulls knives very very quickly.

[Dev Emch]

The glue in ply is murder on steel HSS knives. But I have done this. In fact, about the only ply I use anymore is baltic birch. I actually cut lock mitres in it. But the cutlery I use is german carbide. Even so, it does reduce the milage a bit.

The biggest tip I can give is this. Place masking tape on both sides of the ply to keep the blow out and splintering to a minimum. Another tip is this. As your not cutting profiles but just straight edges, why not use a table saw? A nice sharp forrest duraline sheet goods blade may be just what the doctor ordered. Again, make sure to tape the underside of the ply unless your saw is equiped with a scoring blade.

Good Luck...

[Doug Shepard]

Ditto the comments on the glue being rough on the knives. But I've done it with Baltic Birch ply with good results. The only thing I can add is this: to help minimize tearout on the back edge, first flip the piece around and feed the back edge into the jointer a little bit - an inch is more than enough. Then turn it back around and run it through in it's original orientation. The slight scallop on the bottom of the back edge should stop the knives from grabbing anything to tear out along the back.

[Bernie Weishapl]

I kinda thought the glue may not be good on the blades. I have brand new knives in my jointer. I think probably the best bet is as Dev said is to use the table saw with masking tape. I am new to jointers and planers so wasn't sure. I didn't want to mess up my jointer by doing something that would harm it. Thanks again for the info. It is greatly appreciated.Bernie

[Chris Giles]

Bernie,

I installed carbide blades on my Delta 8" jointer for this very reason. For me, a machine that can only cut solid wood and not mdf or PB is too limited in flexibility. The newest thing is these insert tooling heads with all the little square carbide cutters. Ideal but very expensive, so I found carbide blades for a couple hundred bucks that work fine. Still, I only use the far right hand portion of the blade to cut plywood, because even carbide will dull with repeated exposure to these engineered materials. Two years so far, and I haven't had to sharpen. I hate changing jointer blades.........:mad:

[Phil Phelps]

Ditto the comments on the glue being rough on the knives. But I've done it with Baltic Birch ply with good results. The only thing I can add is this: to help minimize tearout on the back edge, first flip the piece around and feed the back edge into the jointer a little bit - an inch is more than enough. Then turn it back around and run it through in it's original orientation. The slight scallop on the bottom of the back edge should stop the knives from grabbing anything to tear out along the back.

You win the cupie doll and the cigar :cool:

[Jamie Buxton]

I kinda thought the glue may not be good on the blades. ....

It is a common view in the woodworking community that it is the glue which kills the blade. However, I think it is not the glue. I had a set of knives which were nicked enough to need replacement (mine is a replaceable-blade jointer). Out of curiousity, I set the jointer fence at one position, and edge-jointed a piece of plywood a few passes. With a 3X loupe, I could clearly see the dulling on the knives where I'd been running the plywood. The dulling didn't line up with the glue lines. Instead, it lined up with the end-grain.

[Dev Emch]

Jamie...

Hmmmmm, that is an interesting tip. So your saying that its the end grain that causes all the dulling? I often use resourcinol which leaves squeeze out that looks like brown glass. You need to use an old chisel to knock this junk off because it too is hard on the knives. That is why I always assumed it was the glue. But ply does have end grain showing and end grain is always harder on knives than long grain. I can see how this would be the case.

[Gary Herrmann]

As Dev mentioned earlier, you may also want to try a good blade in your saw . I've got a Forrest Duraline A/T for my cs, and it leaves a very smooth edge.