Diagonal ripping plywood?

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  #1  
Old 12-31-18, 01:42 PM
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Diagonal ripping plywood?

I had intended to cut the front edges of planned cabinet on a table saw with the idea of gluing the cut off edge to make a corner concealing the plywood edge. But when I tried to make the cut I found that the going was very tough and decided on a conventional face frame.
I make out with minimal carpentry skills. Is what I intended possible? What would it take to make a smooth diagonal cut?
 
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Old 12-31-18, 01:46 PM
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You might need a new blade. I've made clean cuts with plywood on my table saw numerous times.
I just reread your post - are you trying to cut it at a 45° angle? that can be difficult to get a real clean cut with plywood.
 
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Old 12-31-18, 01:58 PM
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I guess that's why I don't ever see it done.
 
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Old 12-31-18, 02:51 PM
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A fine tooth plywood blade is the proper blade. Since plywood is layers layed perpendicular to the grain from one another you can't get a rip or cross cut to work. Cut with the good side down. You might use a tile knife to score the top layer first. The splintering will stop at the score mark.
Using scrap wood on top and bottom tightly clamped to the surface will help reduce splintering.
 
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Old 12-31-18, 03:16 PM
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Here is some good plywood blades. I have used one for about 3 or 4 years and still makes a clean cut. Built all my kitchen cabinets with it.
https://www.rockler.com/freud-lu79r-...YaArKKEALw_wcB
 
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Old 12-31-18, 04:44 PM
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I don't particularly recall a significant difference cutting plywood diagonally versus straight, so wondering if the difficulty was in the actual cut or in the technique. You might want to revisit that, because contacting the blade at an angle is going to want to push the piece away from the blade, so if everything isn't adequately clamped or otherwise supported it could lead to binding.
 
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Old 12-31-18, 05:07 PM
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How about cutting it with a circular saw? Clamp a guide piece to the plywood and make your cut.
 
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Old 12-31-18, 06:25 PM
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IMO, a 7 1/4" 60 tooth fine finish carbide is the "proper blade".
 
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Old 01-01-19, 07:31 AM
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Holding the stock down firmly against the saw table and keeping the stock in constant contact with the saw fence will give the best results. You may need extra support to keep the plywood level during the cut.
 
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Old 01-01-19, 02:42 PM
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I've had some luck taping over the cut mark before cutting.
Sid
 
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Old 01-02-19, 08:05 AM
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I could never get a chip-free cut with a circular saw no matter how nice the blade. Then I found that ALL of them I owned had lots of arbor end-play.

I never tried doing it on a tablesaw. How do you guide a diagonal cut? Giant sled jig?

My answer was to buy a "track saw". It's designed to cut plywood (not intended for rough carpentry), has no arbor wobble, comes with an excellent blade, rides on a grippy guide plate that doesn't allow the saw to wander.

Perfect cuts every time but they ARE expensive. Well worth it if you do a lot of work with plywood.
 
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Old 01-02-19, 12:04 PM
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I never tried doing it on a tablesaw. How do you guide a diagonal cut? Giant sled jig?
I think we are talking about a straight rip cut with the blade tilted at 45 degrees. Will the OP please correct me if this is a wrong understanding of the situation.
 
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Old 01-02-19, 02:11 PM
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It's my understanding that the cut is 45 degrees across the flat top and no bevel.
 
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Old 01-02-19, 02:52 PM
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I had intended to cut the front edges of planned cabinet on a table saw with the idea of gluing the cut off edge to make a corner concealing the plywood edge. (Snip) Is what I intended possible? What would it take to make a smooth diagonal cut?
Sounds like a straight rip on a 45 degree bevel. Possible on a table saw or with a track saw but certainly not by hand. You wouldn't normally miter plywood in this way... it's too difficult to get 2 perfect surfaces.

A face frame on a square factory edge is best so that was a good call. If you have to cap the edge of a plywood rip, you can use iron on banding... or glue and nail on a strip of solid wood.

But in answer to your question, no... you would not normally try to make a plywood miter return just to cap the end of a piece of 3/4" thick stock.

If you were trying to make a plywood box with mitered corners, thst would be a different story. And even then you would need to use a fine tooth carbide finish blade on a good quality table saw or track saw.
 
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Old 01-02-19, 03:15 PM
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OK, so it seems I got it wrong. a straight cut at a 45 degree bevel.
Many years ago I did in fact do this using birch plywood on a radial arm saw. Made a bed with sliding draws. I had no surface splintering. But alas I can not remember how I did it. It seems I just cut it and it worked!
 
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Old 01-02-19, 04:22 PM
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Okay, after rereading everything, maybe I was in the wrong camp. Was picturing an X straight cut versus a Y bevel, or whatever you want to call it, and didn't see much of an issue, so could only imagine blade binding as the piece pushed against the blade. But, if we're talking a beveled edge, I agree that banding would be the only right way to do it. Mitered joints can be difficult enough sometimes, and plywood can be particularly challenging due to to the inevitable chipping. But we're all still only guessing as Richard hasn't been back since last year.
 
  #17  
Old 01-09-19, 01:07 PM
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Alignment of blade may have been the problem. I have gone to s solid hardwood face frame and much the better for it.
 
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