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Cutting plywood

Posted: Mon Apr 11, 2016 10:25 am
by randythewoodchuck
I have the Shopsmith blade package that includes the crosscut, rip and combination blades. I have not worked with plywood previously, but am now conceptualizing a project that will include plywood. Which is the best option for cutting plywood, or is there a specific blade for plywood? And if there is a plywood specific blade, does Shopsith sell it?

Re: Cutting plywood

Posted: Mon Apr 11, 2016 11:16 am
by reubenjames
ShopSmith used to sell blades made specifically for plywood, but they no longer do, as far as I can tell.

If you are going to be doing a lot of plywood cutting, you might invest in a quality plywood blade from a third party, if you have a 5/8" ShopSmith arbor to mount it on. If you are only occasionally cutting plywood, a good quality combination blade can be used. Remember that plywood does not have a specific grain direction, because it varies from ply to ply for strength, but because of that, every cut should be treated like a crosscut. That is to say, you should plan on a slower feed rate, even if you are "ripping" the plywood. That is the reason for the plywood blade with many teeth or a combination blade. You would *not* want to use a ripping blade for plywood. I don't usually like to muck up a nice crosscut blade with the glues, etc. in plywood, so I reach for the combo blade.

Also, a few pointers, raising the blade higher than you normally would can help with a cleaner cut because of the angle of attack. Also, remember if you have a "good" side of your plywood, to keep the good side up. You can also use blue masking tape or other techniques to help prevent chipout when cutting plywood, if you need as perfect a surface as possible.

Last, but certainly not least, always be careful! If you are cutting an entire 4' x 8' sheet of plywood, even if it's thin, it's a beast to handle. Make sure you have plenty of table support, as well as infeed and outfeed support, double check your setup, and go s-l-o-w-l-y. A helper is always recommended for a full sheet, if you can find one. Two helpers for 3/4" stock is not out of the question (those panels are quite heavy). Personally, while I have done it, I don't cut full sheet on the SS anymore. I use a track system (TrueTrac) with a circular saw and a reasonably priced Diablo blade and do my initial breakdown that way. If you can get it broken down at the store on their panel saw or at home via some means where you don't have to push the stock through the blade, but rather can move the blade across the stock, I would recommend it. Once you have pieces in a more manageable size, the above tips on plywood cutting with the ShopSmith still apply.

Re: Cutting plywood

Posted: Mon Apr 11, 2016 11:17 am
by ERLover
First on a piece of scrap plywood, I would try the combination blade.
2nd there is specific blades for plywood that are very fine toothed, I dont know if SS sells them.

Re: Cutting plywood

Posted: Mon Apr 11, 2016 12:30 pm
by Steamdragon
One thing to remember about cutting plywood is you will get a lot of fraying/splintering on the cut edge. When cutting with a table saw make sure the good side is up so any fraying/splintering will be on the bottom.bad side. The reverse is true when using a circular saw.

Re: Cutting plywood

Posted: Mon Apr 11, 2016 12:39 pm
by charlese
Steamdragon wrote:One thing to remember about cutting plywood is you will get a lot of fraying/splintering on the cut edge. When cutting with a table saw make sure the good side is up so any fraying/splintering will be on the bottom.bad side. The reverse is true when using a circular saw.
Or - - you can first make a scoring cut on one side.

Some table saws come with a special scoring blade that preceds the main blade.

Re: Cutting plywood

Posted: Mon Apr 11, 2016 12:57 pm
by nuhobby
For plywood, the high adhesive / abrasive content means you need to be talking Carbide teeth.

I just mention this since my 1st Shopsmith project in 2007 involved plywood and a plain-steel Shopsmith plywood blade, which wore out almost instantly!

For exact tooth pitch and geometry, I'll defer to people who use it more often than me.

Chris

Re: Cutting plywood

Posted: Mon Apr 11, 2016 3:37 pm
by ibskot
I use the kreg rip cut jig and a circular saw. Safe. Accurate. Repeatable.

Re: Cutting plywood

Posted: Mon Apr 11, 2016 4:34 pm
by randythewoodchuck
ibskot, thank you for the Kreg jig reference. It looks like something I could use and not have to deal with trying to cut plywood on the table saw. Seems to make life easier, and I am all for that. Really appreciate the input from all of you.

Re: Cutting plywood

Posted: Mon Apr 11, 2016 5:05 pm
by stephen_a._draper
Last year I made new kitchen cabinets out of 3/4" oak plywood. I did all of my cutting on the Shopsmith. I needed to have no splintering or tearout on both sides. I used the Shopsmith carbide crosscut blade with a zero clearance insert and it worked great! For extra insurance put a piece of masking tape on the cut line on the down side of the plywood.

Re: Cutting plywood

Posted: Mon Apr 11, 2016 6:07 pm
by ibskot
;)
randythewoodchuck wrote:ibskot, thank you for the Kreg jig reference. It looks like something I could use and not have to deal with trying to cut plywood on the table saw. Seems to make life easier, and I am all for that. Really appreciate the input from all of you.
I always work alone. That's why I got one. Amazon is about $8 cheaper then Lowe's and we have prime so shipping is free.