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Note: This question was closed as a duplicate because plywood and veneer both have similar issues when being cut with a circular saw. Hopefully the answers in both questions can help out.

When using a circular saw, I often find that I rip up the bottom edge of a sheet of plywood after cutting it. Usually my blade is a good 1/2 inch lower than the bottom of the plywood and I use a 24-tooth blade. Should I switch to a blade with finer teeth? Or should I change the blade height?

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marked as duplicate by Doresoom, Joe, bowlturner, Alexander, Community Mar 17 '15 at 21:09

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • 1
    same techniques in this question (dupe?) would help – ratchet freak Mar 17 '15 at 17:22
  • Hmm, yeah, that seems very close to a duplicate... – Joe Mar 17 '15 at 17:26
  • We can close if you want. I thought it would be different enough with different materials, different saw blade, etc. But I also think editing the other question to become more canonical and marking this one as a dupe could be a good idea. – Blue Ice Mar 17 '15 at 17:28
  • 1
    You don't necessarily need to edit the other question (and I would generally say, should not, except I don't know if private betas are done differently that way). The questions don't have to be perfect duplicates; this question will stick around, after all, as a pointer to the other question. – Joe Mar 17 '15 at 17:57
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    As long as the answers in the other question apply, you close this as duplicate, it has a pointer to the other one, and you leave a comment explaining that plywood and veneer are pretty similar and the same techniques apply - bingo. – Joe Mar 17 '15 at 17:58
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Using a blade with finer teeth will help significantly, but you can also use a piece of masking tape over the cut line before you cut. Additionally, if you have a piece of sacrificial wood you can put underneath the cut, that would help prevent tearout as well.

6

There are many ways to eliminate tearout in plywood. Some are simple techniques you can apply in specific situations, and others require additional materials or accessories.

  1. Put the "good" side facing down.
  2. If you are cutting through 2 or more pieces of plywood at the same time, layer them so the "good" sides are not facing the outside on the top or bottom. (Note that you should use a blade with fewer teeth and deeper gullets if you are cutting through a thick stack, otherwise your blade may bind or burn.)
  3. Use a zero-clearance straightedge guide (aka "homemade track saw").
  4. Tape over the cut line before making the cut.
  5. Score the cutline with a utility knife before making a cut with the circular saw.
  6. Make a very shallow scoring cut with the circular saw before making your through cut.
  7. Use a very sharp blade with a high tooth count (e.g., 60 or more teeth for a 7-1/2" circular saw).
  8. Put sacrificial pieces of material on the top or bottom of the piece of plywood along the cut line.
  9. Cut to rough dimensions first, then clean up the cut on a table saw with a zero-clearance throat plate.
  • Would some of these tips also work for performing cross cuts by hand? (taping over, scoring, fine tooth blade, etc). – user2251 May 27 '16 at 12:26
  • Yes, absolutely. Taping over is not as common but you certainly could do it. As with power saw blades, hand saws do come in crosscut and rip cut varieties, and the crosscut saw with have finer teeth with different geometry from a rip saw. When hand sawing, a very common technique is to create a "knife wall" by scoring with a marking knife then making a V-cut with a chisel. popularwoodworking.com/woodworking-blogs/editors-blog/… – rob May 27 '16 at 13:13
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In addition to cathode's excellent suggestions, Wood Magazine has a nice explanation of some techniques.

Particularly:

  • Score the cutline. Make one very shallow cut where you cut through the top layer (where the splintering will occur), which helps control the splintering, then make a second cut through the rest of the wood.
  • Support the cut, either along the side or from underneath (with a piece of sacrificial wood, as cathode also refers to)
  • Attach a piece of wood to your saw's footplate (a "shoe") to reduce the clearance from the plywood.
  • I didn't even think about a shoe! yes, something like the 1/4" melamine-coated MDF sheets sold at home centers is great for making these kinds of temporary or throw-away devices. You'd basically need to plunge the circular saw through the shoe material after fastening it to the existing footplate. This will give you a "zero-clearance" slot that the blade protrudes from. However, circular saws will tear out on both the top and the bottom in my experience so it isn't a perfect solution. – cathode Mar 17 '15 at 17:55

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