I cut 3/4″ plywood with a circular saw on a big special knockdown table because I lack the room for a panel saw. I was using a 6.5″ Black & Decker Woodhawk that I have had for 10 or so years. It was clearly underpowered but would labor through the 3/4″ plywood eventually. I bought a Porter-Cable 7.5″ 325MAG saw, installed a brand-new Dewalt plywood blade, and proceeded to try to cut some 3/4″ plywood (some sanded plywood from Lowe’s) with it. From the first few inches, the saw blade smoked and the wood smoked and burned. The saw labored through the cut ( 48″) but left the wood burned on both sides of the cut and the sawblade black. I then switched to another brand-new Dewalt plywood blade and tried the next cut. After about 12″, I gave up because the wood and sawblade were still burning. I took out the old Woodhawk with an old plywood blade and finished my work, slowly but surely without burning either the wood or the sawblade. The plywood was adequately supported for the cutting. The brand repair center said nothing was wrong with the saw itself, but the second blade had warped due to overheating.
Is this result typical of what I can expect from a 7.5″ saw cutting plywood? If so, what size circular saw do I need to cut plywood safely without burning? I have a table saw but I can’t safely cut a 4′ x 8′ sheet on that by myself, which is my usual mode of operation.
Replies
I suspect there are two possibilities here. The first that Dewalt has a beach of blades that do not have proper clearance in the teeth and are heeling out. I would try another brand of blade and see.
The second possibility, if you are using a straight edge to guide the saw, is that the shoe (the base of the saw) is not aligned with the blade perfectly. A service center could overlook this problem. Put a long straight edge on the blade and compare it to the edge of the shoe you are guiding the saw with.
Let me know of any further developments. These are two possibilities but there may be something we have to figure out yet.
With best regards,
Ernie Conover
Thanks for the reply. I will get a new blade of another brand and look into the shoe alignment issue.
Boss/Ernie,
I don't mean to butt in here as I'm no expert but is there any possibility that the blade(s) were put on backwards?
Regards,
Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
Edited 8/8/2007 9:11 am ET by KiddervilleAcres
No, I checked it, my son checked it, and the repair shop checked it and we all agreed the blade was on correctly.
Kudos for thinking of an obvious reason. I was thinking too deeply to think of something that simple. Yes that could be the reason! A blade put in backwards in a hand circular saw is usually pretty untenable, however. One would hope the service center would have spotted that as well. Saying all of this, yes checking the direction of the blade would be good. Regards,
Ernie Conover
Edited 8/8/2007 3:40 pm ET by ErnieConover
Ernie,
I was afraid I might be stepping into unwarranted territory by my post, i.e. Ask the Experts. It's just that I have this somewhat uncontrollable desire to try to help out.
Must be from my Knots upbringing, so to speak.
Best Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
I am a firm believer that two heads are better than one. I appreciate your help.Regards,
Ernie Conover
It ws not the blade direction. That was the first thing I checked. My son and the repair shop both checked that too, and both agreed the blade was on right.
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