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Cutting sheet goods with circular saw

4K views 39 replies 30 participants last post by  hairy 
#1 · (Edited by Moderator)
HI This is my first post to LJ's. I've been a member for a couple months now and have mostly been enjoying reading others posts, and learning a ton. Anyhow here is my first post/question and it involves cutting down sheet goods with a circular saw.

I have been attempting to make some cabinets for storage in my garage, which also serves as my shop. My goal has been cut down the plywood sheets with a circular saw then trim them to final dimension on my table saw.
The store I bought my plywood from doesn't cut down sheet goods and I have been struggling to do it on my own. I have attempted making several straight edges for my circular saw (Bosch CS10) but for some reason my cuts seem to inevitably turn out wavy!!! All I can say is this has been incredibly frustrating to the point I've been looking into either purchasing a track saw, although I am not sure I am ready to fork over the $500 plus dollars for one, or give up completely on the project.

Does anyone have any suggestions? Do I bite the bullet for a track saw?
 
#3 · (Edited by Moderator)
Don't buy a $500 track saw!!! You won't always be working with sheet goods….trust me, you won't want to. You will always work with them some but not exclussively so a track saw will be over kill unless you plan to build cabinets for a living or something.

What GR8HUNTER said would work fine but then you have to store the roller stands after that. I use a circular saw as well to break down sheet goods because it's difficult to manage them on the table saw anyway. I'm not a small man either.

I use one of these but mine is just the straight edge part. This has a setup to attach your circular saw to it to guide it. I don't see how it will help more or less with the saw guide but my Bora straight edge works great for this.

http://www.homedepot.com/p/BORA-50-in-WTX-Clamp-Edge-and-Saw-Guide-Kit-543056K/205866206?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-BASE-PLA-D25T-PowerTools%7c&gclid=CjwKEAjwqdi7BRCL6Zmjk5-rsTwSJABmrVabtt9uL6FWgRUaLqRp_Ta8BuunQ_-YjgUAP3CvOzJjDxoCkLbw_wcB&gclsrc=aw.ds
 
#6 ·
If you are using a straight edge and still getting 'wavy' cuts, then you are doing something terribly wrong. Anything from a 2×4 to a long level can be used as an edge to get a straight cut. What exactly are you trying?

Cheers,
Brad
 
#9 ·
I used to have a piece of 9' angle aluminum to which I screwed a nice straight 1"X4" maple board to. It was great for just what you are asking. Just clamp it at either end and cut away.

Problem is, it was a casualty when we moved here 3 years ago, (got run over by a pickup truck, ,dont EVEN ask) and I haven't replaced it yet.

You can buy the angle aluminum and the maple boards at most any of the big box lumber stores.
 
#10 ·
No question with a straight edge guide you should be getting straight cuts. I use a clamp on straight edge similar to the one shown by lew. I get cuts that I could use as finish cuts. And at times they will be.

You didn't mention how you were supporting the sheet goods while cutting. Having done the saw horse thing in the past, I now lay down two 2'x8' pieces of construction foam board. I just lay the sheet goods on the foam in my driveway and set the saw to just cut through the sheet goods. The saw will cut into the foam a bit. Or if I happened to be cutting the 4×8 sheet in half lengthwise, I just create a gap between the foam boards and the saw won't hit any foam.

This works really well, the sheet goods are fully supported and flat. Also, you can usually kneel directly on the sheet goods and stay right over the saw giving you great control.

It also makes it really easy to handle heavy sheets. I just lay the foam board behind my pickup truck and pull sheets off one at a time onto the foam board.

You can use the foam board many, many times. Even all sliced up with shallow cuts, it will still support the sheet goods fine.

Also make sure you have a good blade on your saw. With a good blade, usually thin kerf, the saw should cut almost effortlessly. This will help to control it.
 
#11 ·
I don't like the straight edges that clamp to the plywood. Still allows for wavy cuts if the saw goes off away from the guide.

Track saws don't have to be $500+. I've got the Grizzly one and it works great.

http://www.grizzly.com/products/Track-Saw-Master-Pack/T25552

$257 which includes the clamps, track, etc.
 
#16 ·
Don t buy a $500 track saw!!! You won t always be working with sheet goods….trust me, you won t want to. You will always work with them some but not exclussively so a track saw will be over kill unless you plan to build cabinets for a living or something.

What GR8HUNTER said would work fine but then you have to store the roller stands after that. I use a circular saw as well to break down sheet goods because it s difficult to manage them on the table saw anyway. I m not a small man either.

I use one of these but mine is just the straight edge part. This has a setup to attach your circular saw to it to guide it. I don t see how it will help more or less with the saw guide but my Bora straight edge works great for this.

http://www.homedepot.com/p/BORA-50-in-WTX-Clamp-Edge-and-Saw-Guide-Kit-543056K/205866206?cm_mmc=Shopping%7cTHD%7cG%7c0%7cG-BASE-PLA-D25T-PowerTools%7c&gclid=CjwKEAjwqdi7BRCL6Zmjk5-rsTwSJABmrVabtt9uL6FWgRUaLqRp_Ta8BuunQ_-YjgUAP3CvOzJjDxoCkLbw_wcB&gclsrc=aw.ds

- ki7hy
Hey, do you have a link to the extended rail for that? I've been wanting one that I can do rips and crosscuts with. My shop is a bit too crowded for full sheets as well, and the guys at the box stores can't be trusted to cut where you want the cuts…
 
#17 ·
I have a stout aluminum straightedge that I clamp to the plywood. Bought a fine cut blade for the circular saw. If I don't put too much side pressure on the straightedge, it doesn't deflect and I get a straight cut. I do the cuts with the big sheet of plywood on enough sawhorses to give good support to all of the sheet of plywood. And make a note to adjust the blade just enough to cut through the plywood and not the sawhorses. :)
 
#18 ·
Here's what I use. This thing is simple, cheap and works great. I use it with a $35 Craftsman circular saw that I got 20 years ago, along with an inexpensive blade, and I get great results. The zero clearance chip-free cut on one side, and the foolproof setup aligning directly to the cut line are what I like most about this jig.

http://www.wwgoa.com/article/shop-made-circular-saw-guide-cheap-easy-and-awesome/
 
#20 ·
Spitfire1,

Like you, I could never get a straight cut in full sized sheet goods by merely holding the circular saw against a straight edge, although I probably could have gotten better results had I been on my knees over the saw when making cuts. But then my personal preference is to cut plywood on my workbench.

A few years ago I solved this sheet goods cutting problem by purchasing the EurekaZone EZSMART Track Saw System 108". The kit comes with a universal shoe that attaches to your circular saw. The shoe rides on the aluminum straight track(s). The kit includes with two 54" long extruded aluminum tracks which can be attached to each other for cutting sheet goods lengthwise using a pair of mating bars. Zero clearance inserts that fit in the tracks help minimize tear out. It also includes a pair of clamps to hold the track in place.

This system cost about $300, but now I can make consistently straight cuts when breaking down sheet goods with no worries. If interested, I believe Home Depot online is a little less money than on the Erekazone site. I think both offer free shipping.

http://www.eurekazone.com/Circularsawguiderailp/ezts108.htm
 
#21 ·
A lot of good suggestions here. A couple of 2Xs under your plywood for support, good side down, and a good straight 2×4 for a straight edge. Also as others have mentioned, a sharp blade, and let the circular saw blade extend only 1/4 - 3/8 inch below the stock you are cutting. You will find many more ways to spend that $500.00 on than a track saw.
 
#23 ·
Lot of good ideas here. I have the HF clamping straight edge and have had it shift on me a couple of times. I might've screwed up clamping it though. Just to make sure it doesn't do it anymore, I always put a clamp at each end just behind it to keep it from going anywhere.

I've also found that as I'm getting older, kneeling down to cut sheet goods laying on 2x's or whatever isn't a problem, but getting back up is. I got one of these and I've got to say it's pretty dang handy. http://www.lowes.com/pd/Centipede-96-in-W-x-30-5-in-H-XL-Support-System-Work-Bench/50404012

It's a little spendy for what it is, and honestly getting it to collapse and back into the bag can be a bit of a pain. I was lucky enough to get mine last year after Christmas when the Black Friday stuff started getting marked down for $99.
 
#24 · (Edited by Moderator)
I break down my sheet goods on the ground. I keep 4 - 8-ft 2×4s around to assist with this, and of course, a clamp-on aluminum guide.

I lay down the 4 2×4s where one will be under each edge of the sheet and the other two bracketing the cut line, then lay the sheet goods on top of them.

After marking (sometimes I don't mark, but just adjust the guide using the tape measure or measuring stick), I adjust the two 2×4's that are supposed to bracket the cut line so that I will not cut into them. The blade is set just deeper than the thickness of the sheet. The guide is clamped on one side of the cut line with the appropriate offset added - which is different depending on whether the saw is going to be on the left of the guide or on the right. (You have to measure this on your saw.)

If I'm doing repeated cuts of the same width, I make a stick of exactly the right length and use that instead of the tape measure. I add in the saw base offset to the length of the stick so I just have to use the measuring stick to position each end of the guide as I clamp it. (There is a little piece of scrap stapled to the back of the measuring stick to hook over the edge of the sheet. So the length of the stick is from the hook rather than from the end, if you know what I mean.) I check each end twice or more since when I move one end of the guide, the other end might move. I use strong spring clamps and have no problem with the guide wanting to slide sideways.

Then, I can walk on the plywood or OSB as I crouch down and push the saw through the cut, keeping it tight to the guide. I can often cut within 1/32" of a straight line, but if it's 1/16th it's OK since I'm usually making the final cut on the table saw. The 2×4's under the sheet are positioned to support my weight as I do this.

... sometimes on the driveway in front of the shop if there isn't that much clear space inside on the floor…

-Paul
 
#26 ·
Technique I've been using is to lay a couple of 2×4 on the floor then use something similar to what pmayer posted. I have a 40 tooth thin kerf Freud blade in my saw.

The general consensus here seems to be using some sort of aluminum straight edge. I suppose I'll give that a try as they are substantially cheaper then a track saw. I have a sneaking suspicion it maybe my guide that is not perfectly straight, but I've tried several wood guides with the same result (wavy cuts).
 
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