Cutting plywood

harveydunn · Post by **harveydunn** » Fri Jan 31, 2014 11:59 am

How do you all cut plywood to get good results - no chipping?

I'm not concerned about "breaking down" a full sheet - I would buy my Baltic birch in smaller pieces. But then what is the best way to cut it down to the dimensions required by my projects? I was specifically wondering if there is a good jigsaw and blade combo for this operation, as that would be a tool I could buy and put to other uses.

jerm · Post by **jerm** » Fri Jan 31, 2014 12:11 pm

I personally don't trust a jigsaw, even with a fine blade, for cutting plywood smoothly just because of it's up-and-down action.

Wouldn't a bandsaw and a nice, fine blade be smoother?

I'm a complete newbie at wood, though, so just my thoughts

Value = $0.01

harveydunn · Post by **harveydunn** » Fri Jan 31, 2014 12:25 pm

I was thinking jigsaw only because I saw a demo of a Festool jigsaw that left an amazing edge on a piece of BB. But of course it is way too expensive for me.

I guess I figure that no matter what I'm probably always going to want to have a tool for rough cutting sheetgoods and rough lumber before it goes to the SS.

But then again I am a newbie too.

dusty · Post by **dusty** » Fri Jan 31, 2014 12:27 pm

harveydunn wrote:How do you all cut plywood to get good results - no chipping?

I'm not concerned about "breaking down" a full sheet - I would buy my Baltic birch in smaller pieces. But then what is the best way to cut it down to the dimensions required by my projects? I was specifically wondering if there is a good jigsaw and blade combo for this operation, as that would be a tool I could buy and put to other uses.

If you are serious about this, you need to "invest" in a saw blade designed specifically for cutting without chipping.

I would use one so seldom that I have not invested. Instead, when I am concerned about chip out, I first make a very shallow cut and then go back and repeat the cut at the proper depth.

I have heard (never tried) scoring with with a sharp knife on both sides of what would become the kerf lines before cutting with the saw.

I find that chip out is much less likely when you purchase quality materials. To me that means material not purchased at a box store.

terrydowning · Post by **terrydowning** » Fri Jan 31, 2014 12:27 pm

I have good results with a circular saw and high quality (Freud Diablo currently) carbide tipped blade. with a straight edge.

Then the table saw again high quality, sharp, carbide tipped blade with a Zero Clearance Insert.

anmius · Post by **anmius** » Fri Jan 31, 2014 12:33 pm

harveydunn wrote:How do you all cut plywood to get good results - no chipping?

I'm not concerned about "breaking down" a full sheet - I would buy my Baltic birch in smaller pieces. But then what is the best way to cut it down to the dimensions required by my projects? I was specifically wondering if there is a good jigsaw and blade combo for this operation, as that would be a tool I could buy and put to other uses.

There are a number of tricks or techniques that are used to prevent or at least minimize chip out when cutting plywood. Some that I have used (with mixed results) are: shallow cut first, tape along the line, score with knife first, zero clearance insert, blade just for plywood, and sandwich the plywood between two other boards (sort of like "backing up"). For my money, the most effective is using a blade just for plywood cutting. Adding the others does help but I am still in pursuit of perfection.

wa2crk · Post by **wa2crk** » Fri Jan 31, 2014 12:56 pm

Harvey
If the cuts are straight cuts the best bet is the table saw. For controlling chipout I use a zero clearance insert (ZCI) and a blade that has alternate top bevel teeth that is made for minimum chipout on the bottom of the cut. Also a piece of painters tape can be put on the underside of the cut line and help minimize chipout.
I only use a jigsaw for rough cuts. I think that the upward travel of the blade on a jigsaw will have a greater tendency to cause chipout on the top of the workpiece
I have also used a router with a cutting guide (homemade) and a straight cutting bit to clean up some rough edges on plywood. Just my opinions.
Bill V

keakap · Post by **keakap** » Fri Jan 31, 2014 1:31 pm

jerm wrote:I personally don't trust a jigsaw, even with a fine blade, for cutting plywood smoothly just because of it's up-and-down action.

Wouldn't a bandsaw and a nice, fine blade be smoother?

I'm a complete newbie at wood, though, so just my thoughts Value = $0.01

I tend to agree about the band saw. Set up and used well and it could be all you need, and that includes sandpaper (almost).

But the jigsaw can do a fine job too. The way around the up-and-down is to get one with "orbital" action. Add a "zero clearance insert" and a good blade- even a Very good jig saw blade is dirt cheap- and excellent results may be had.
A coincidence (I seem to be bumping into a lot of those recently)- I just used a jig saw to cut out a hole for a router table insert, and without thinking about a smooth cut or tearout, when done I noticed not only a clean cut but zero tearout. I hope this wasn't a fluke. Musta been good plywood.

[I'm assuming "jigsaw" for this porpoise is the hand-held machine that with a certain feature may be called a scroll saw.]

Ed in Tampa · Post by **Ed in Tampa** » Fri Jan 31, 2014 1:52 pm

A zero clearance insert and plywood blade will work for tablesaw cuts.

For jigsaw I would clamp the piece between two back boards and cut through them using a very fine tooth blade.

Most guys that cut jigsaw pieces for resale always stack their pieces and throw the top and bottom piece away.

On bandsaw a zero clearance insert a fine tooth blade and slow feed rate works wonders as does a backer board.

Or go buy festools that are manufactured to cut at a higher quality level.

keakap · Post by **keakap** » Fri Jan 31, 2014 1:57 pm

harveydunn wrote:...
I guess I figure that no matter what I'm probably always going to want to have a tool for rough cutting sheetgoods and rough lumber before it goes to the SS.
...

Almost forgot- how about hand saws? I recently replaced a worn out classic crosscut saw with a "Shark Saw" and it is amazing. I wanted the same thing you mentioned- tool for rough cutting...- and not another 'standard' fine crosscut saw, for general use on ply and boards and two by fours. This thing is 18", 8tpi, and Pull Stroke. Yes, made in Japan.
Blade is about 4" or so, good for straight cuts, and since Pull is quite thin. Agressive Japan-style teeth, meant for rip and cross.
Quite surprising how fast and straight and clean it will go through a piece of 3/4 ply or a 2-by. (And hand tools generally don't have you clad in sawdust the rest o the day.)

Another nifty hand tool, although mainly for small stuff can well be used to cut sheet or large boards, is a "Saw Guide" available (small saw, large $$) from Traditional Woodworker. Main use is as a miter "box" for 90 and 45 cuts.
Info at z-saw.co.jp/uk.

About "pull" stroke hand saws: they are so different and so cheap you almost owe it to yourself to try one out. One problem tho, when using for "rough cuts" especially, the cuts you get can be so good you start forgetting the "rough" and start going for the "finish". A distraction.

Back to power saws: the blade. Better the blade, better the cut in plywood. "Plywood" blades, btw, really are made for plywood. And they really work. Shopsmith's blade, not carbide but steel with a gazillion tiny teeth, has worked very well for me. More than normal, let the machine- the blade that is- do the work, at its own pace.

{One last opinion: plywood and MDF are two completely totally different and separate subjects.}