I’m new to woodworking and find myself building some projects for my shop out of plywood. I have some questions for the group about cutting plywood.
It seems that the panels for the carcass of my cabinets are all made out of fairly large pieces of plywood. I dont feel like cutting each one of them with my circular saw, but Im concerned about safety. With hardwood, you rip against the fence and crosscut with a mitre guage or a sled. I have a sled, but its not big enough to handle large panels, and more often than not, the cut I want to make would be across the wider section of the board (wider than it is long). I cant use my mitre guage because it just doesnt allow a board of this size accurately, so I’d like to use the fence… In hardwood this would seem to be a kickback problem.
I was reading in Jim Tolpin’s book, “Tablesaw Magic” that the kickback issue of cutting plywood boards this way is non-existent due to the fact that plywood sheets are laminates of alternating grain. Is this true? Can I safely cut a large wide plywood board against the fence?
I’d like your opinions here….
I ripped my first full 4×8 sheet of plywood on my tablesaw by myself this weekend. It was exciting, but worked great. the Freud combination blade I have on the saw didnt tear out the plywood at all!
Replies
BigFrank ,
Using the fence for plywood is the normal mode . Kick back can occur say when you set the fence for about 42" and crosscut a 16 "- 24 " X 8' panel .If you drift off the fence the blade CAN send the plywood in your direction . Take your time and don't try and feed too fast you will get much better cuts .
Having a saw table set up that is large enough to support full sheets is helpful , extension tables and roller supports can also be used . A thin coat of paste wax rubbed on the table surface will help you glide the panels better .
Lastly use a blade that is best suited for plywood , I use an 80 tooth negative rake , the combo blades I use are 50 tooth and are awesome , but the finer blade produces a cleaner edge .
regards dusty
I haven't read Tolpins' book but that is very bad advice if he did make that claim.
One form of kickback comes from wood pinching the blade because of wild grain, or improper or incomplete drying, and plywood, because of its construction, rarely has that problem. But there are several other ways to create kickback that will occur just as well with plywood as with ordinary stock.
John White, Shop Manager, Fine Woodworking Magazine
I find it cumbersome to do sheets of ply on a TS. I cut mine to size with a Festool CS and its guide. This is accurate enough not to require refining on the TS, and its pretty fast. You can use a different CS and the EZ Guide, or a CS and your own jig. Most of the time in carcass construction, many of the ply pieces are cut to the same width, so a jig is ideal. If you have tighter tolerances, or you don't feel the CS/guide is accurate enough, you can oversize the pieces by ~1/4-1/2" and do the final cut with the TS. The precut pieces are much easier to handle.
If you have a big open shop with lots of headroom (I don't), you can make a large outfeed table and do it all on the TS with a bit of brawn.
Glaucon
If you don't think too good, then don't think too much...
I'm not so worried about cutting large sheets down - for that I usually use a CS. However I have a cheap circular saw and it doesnt have alot of staying power, so I'd like to make the smaller cuts on the TS, but often the cuts I have to make are in pieces of board that are wider than they are long. (lets say I have to make 2 29"x24" inch pieces out of one 29"x48" piece). I dont have a sled or mitre guage big enough to handle that.
Is cutting this along the table saw fence okay?
It can be done, but if you're new to woodworking as you say, and not real familiar or comfortable with the table saw, you may want to consider other options.If you try it, make sure you have outfeed and left of the saw support. Keep the leading and trailing edges firmly against the fence all the way through the cut and you should be fine. BUT, if you're not comfortable with the operation, there's no shame in breaking the piece down with a circular saw.
No, I'm comfortable with the operation - I just was worried that this might not be a *safe* operation. Since the board is wider than long and I would be using the fence I was under the impression that this was a kickback hazard...
...kickback hazard.
It is, if your fence isn't well-adjusted. If the fence toes in toward the blade at the back end, when you cut your sheet the side against the fence will force itself into the blade.My goal is for my work to outlast me. Expect my joinery to get simpler as time goes by.
"No, I'm comfortable with the operation - I just was worried that this might not be a *safe* operation. Since the board is wider than long and I would be using the fence I was under the impression that this was a kickback hazard..."While your panel IS wider than it is long, at a ratio of roughly 1.5 to 1, it's not like trying to "rip" a piece that's 4" x 6' down to 4" x 3' using your fence instead of miter gauge. And, with almost 30" against the fence, you have plenty of control surface. John D makes a good point about proper adjustment of your fence. It should never toe IN at the back of the blade -- always parallel, or just slightly (thousandths) OUT. So, you will want to verify that it's adjusted correctly before you do ANY ripping. If your saw is adjusted properly, and you understand the correct technique for each operation (it's kind of like a golf swing -- right things and wrong things involved in every step), and most importantly, keep your mind into every cut, you can work very safely and get good results. But again, if something feels wrong to you, it probably is, and you would be wise to find another way. Get though this cut, and you're qualified to run with scissors.
Well, My Biesemier fence is adjusted with a slight toe *outward*, and I have an overhead guard with a splitter on for any through cut like this. Honestly, ripping the 29" x 40" piece in half against the fence didn't *feel* unsafe, I'd just heard that it was unsafe to do so, and wanted others' opinions.
A good way to pre-cut 4 x 8 sheets of plywood is to get a very straight board and nail or screw to the bottom of it a piece of 1/4" masonite. The masonite should cover the entire bottom of the board and extend out from the straight side a little more than the distance from the blade of your CS to the outside of the shoe, normally that means from the blade to the right side edge of the shoe. Then cut the excess masonite with your CS using the same blade that you are going to use to cut the plywood. Then mark the cuts, clamp the jig to the plywood (bad side up), align the edge of the masonite with the marks and cut it.I use several jigs like this for router dados, etc, you just have to label each jig for the same router and same bit each time.John
Frank,
I am not uncomfortable using my table saw as I've had enough years experience to learn techniques that I (hope) think are safe.
But I don't cut sheet goods much, so every time I need to do that, I'm almost back to square one, and I don't like the feeling. My solution is to cut to rough size (within a fraction of an inch) with a circular saw then finish cutting on the TS. The reduction in stress, guiding the almost-finished piece through the blade for that final, accurate trim cut is immeasurable. The sheet is almost always totally supported by the saw table, and the strain of the whole operation is minimal.
Many workers who have a lot of sheet cutting to do work only with panel saws, which is nothing more or less than a circular saw on a dedicated frame for nothing but panel cutting.
One of the most elegant solutions is the EZ Smart saw and guide:
http://www.eurekazone.com/
Go through the Web site carefully and get a feel for the guide system. It is a very well thought-out solution to this kind of problem. I understand that some consider it superior to the Festool saw and guide system which itself is one of the best engineered systems in existence.
The EZ Smart system is a complete solution to panel cutting, resulting in very accurate, very clean cuts with any low-priced blade. Of course, you would need to upgrade your CS. The Porter Cable 324 Mag is great with the system, is about $125 and is the only saw I know that has a dust port - very important to me. (I have absolutely no connection to these products).
Finally, I have recently been looking at "Euro style" cabinet saws (actually combination machines which consist of a cabinet saw, jointer, planer, spindle shaper and mortiser). These table saws are of a design philosophy quite a bit different than the typical saw available in the U.S market. They are refined far beyond our typical table saws and every operation is elegant in its execution.
Cutting sheet goods is a specialty of these machines. The sheet is held in a sliding table that fully supports the sheet, holds it absolutely without chance of twisting or slipping from the desired cut and glides it past the blade almost whisper smooth. The operator pushes it easily with one hand, never working up a sweat or in danger of injury. There is no fence to guide the work or to trap it against the blade if it rotates. In fact, the cut piece simply and safely falls away from the blade as the cut is finished.
Viewing the DVDs that Felder is glad to send out for their Felder and Hammer lines, and watching the videos on the Rojek site are real eye-openers.
While these machines are pricy, they are not that much more expensive than our "high end" equipment. If you handle a lot of sheet goods, they may be something you want to look at. And the price of an injury is a lot more than a saw.
Rich
I do that type of operation all of the time, it should not be a problem as long as you keep the edge of the stock against the fence along it's entire length throughout the duration of the cut...
the problem occurs when the stock shifts in position relative to the fence and gets bound against the blade...as long as the stock is long enough to prevent this there is not a problem...
As others have said, the trick to cutting plywood on the table saw is to keep the edge of the panel firmly against the fence.
The way to do that is to never take your eyes off of the fence, with most of your attention focused on the outfeed end of the fence, which is where the plywood is most likely to start to move away from the fence. The instinctive thing to do is watch the cut and the blade, and the moment you do the plywood will start to drift. So the safe approach is to ignore the cut and keep your eyes on the fence, the cut will take care of itself.
John White
JohnWW & BigFrank ,
Frank , John's advice to watch the fence is key here and right on . On the factory end that goes against the fence after checking for either putty or staples or other obstructions often I rub a little wax it helps in that direction also .
If your saw table will handle the full sheets or not ,may be the more important factor . Even with an adequate set up , like anything else it takes time to really learn by experience and doing . Learning the feed rate that is best for each operation especially cutting plywoods . Your confidence level will rise with your experience and most likely so will the results.
regards dusty
I have to say that I'm already happy with my table saw's results; I've been using a relatively inexpensive Freud combination blade (full kerf) on my 1 3/4 Delta hybrid saw and the plywood cuts I've made with it have shown *no* tearout and a really nice edge. I will probably not cut full sheets very often on the TS (though its nice to have the option), but being able to cut large sub-sheets on it is very nice as my circular saw isnt very good.really my question here was more about safety than results -- so far they've been better than I expected.
I think the place you will see the difference in blades is when you say , crosscut Oak and other grainy veneers . With the grain the combo blade would not create problems .
dusty
I have a 3hp cabinet saw, but I don't like horsing 4x8 ply on it. I use 4 saw horses a strait edge, and a good CS with a good (key is good) Blade. I set up the ply on the 4 horses with the cut line going through the gap between the 4. When I cut through bouth pieces are supported. I then can take those smaller panels to the TS for final dimensioning. It has worked great so far. I have a PC CS with a Forrest WWII blade and the the edges are perfect. My strait edge is the True grip clamp n'guide. It's 50" capacity allows me to use it on a full sheet of ply. I use a factory side and use a pecision square to align both sides and lock it down. I cut and have a smaller panel that I can then manage with the table saw. I would like a panel saw, but could not afford it. This was a cheap alternative. I did get my latest edition of shop-notes and it has a plan for a homemade panel saw that looks really interesting. Anyway thats How I do it.
I would start by removing the toe-out on your fence. Get it parallel to the blade after getting the blade parallel to the miter slots. If you have a splitter and anti kick-back device, this will keep the edges on the waste pieces from being gnawed by the outer edge of the blade.
A 29"x40" piece should be no problem on a tablesaw. Just make sure to push the piece through by slightly pushing it against the fence. The line of force needs to be as close to parallel to the blade as possible and there should never be a situation where the wood is pinched between the rear of the blade and the fence. As long as the fence doesn't deflect when you push into it, keeping pressure against it with the wood shouldn't be an issue. Keep your hands about midway between the blade and fence (unless it's a small piece- then use a push stick) and make sure the blade is sharp and clean.
Bigfrank,
First and foremost, you are to be commended for your desire to practice safety in your shop and to place such a high priority on learning to do things in the safest manner. Kudos to you.
I, like many of those who have addressed this thread, tend to use the trusty old CS to knock sheet goods down to size. There are a number of ways to get a good clean straight edge on sheet goods using a CS - some excellent ones have already been covered. Two, which I have heard of or read about but not yet tried are:
Like I said, I've not tried either of these with sheet goods (yet), but I have used the router/pattern bit to clean up the ends of large glued up panels with good results.
Work safe!
Regard it as just as desirable to build a chicken house as to build a cathedral.
Frank Lloyd Wright
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