Posts Tagged plywood

In response to my post about building a chest, Pauly asked, “I am considering making an investment in more power tools. What tools did you need to make it?” I thought that would be a good topic for a post.

If I had to pick just a few basic power tools, I would probably start with an electric circular saw and a battery-powered drill. In this post, I’ll discuss the circular saw.

The precision and speed of use with a circular saw is not the same as with a table saw and miter saw, but the value for the money is immense. You can get a good circular saw new in the $150-200 range, and used for half that, and be able to do almost any cut you would ever need. By comparison, a miter saw and table saw can easily run $200-300 each, and that’s for bottom-of-the-line models. Table saws especially can run into the thousands.

I would choose an electric saw because I have a little battery-powered one and it dies after, literally just a few cuts through a sheet of plywood. It is clearly under-powered for the job. I think it was intended more for cross-cuts on lumber and trim pieces. Speaking of power, don’t skimp. Cutting through big pieces of 3/4″ plywood takes a bit of “oomph,” and you don’t want the blade binding or the motor struggling.

The value of a circular saw is dramatically increased if you have a cutting guide. The problem with circular saws is that they don’t cut as straight a line as a table or miter saw. When doing long rip cuts, such as down the length of a board or across a sheet of plywood, a little bit of wandering off your line can add up to a lot of inaccuracy. When doing cross-cuts, it can be hard to get the end of the board exactly square.

For cross-cuts, I recommend a Speed Square. That link is to the 7″ version, but they come up to 12″ (and probably larger) if you need to cross-cut pieces of lumber bigger than 7″ wide. You place the lip of the square against the edge of the board and use the perpendicular edge of the square as a guide for the base-plate of your circular saw.  Above, you can see an illustration of this process. It’s really quick and much more accurate than trying to follow a marked line.

For the record, speed squares are actually very versatile and useful tools, that are much more than a straight-edge. Here’s a video describing more.

For rip-cuts, I recommend two different types of guides. If you’re doing a long rip-cut along the length of a board, such as cutting a 2×4 down to a pair of (approximate) 2×2s, or cutting strips of 1/8″ trim off of a piece of 1×4, I suggest a Rip Fence like the one shown below.

This device attaches to the baseplate of your circular saw and runs along the edge of the board, ensuring a straight cut… well, ensuring that the cut is as straight as the edge of the board, anyway. Rip fences like these may be custom-fit to a particular make or model of saw, and not all saws may accept them, so you should look into this before you buy.

For long cuts down sheet stock like plywood, I would choose a clamp-down cutting guide.This is, basically a straightedge between 4′ and 8′ long that you clamp to the sheet of plywood, and then you run your saw against it to make a straight cut. Not too complicated, right?

Now, this is a link to a clamp-down cutting guide that costs about $35, but I don’t recommend it and that’s why I’m not going to put in a picture. I just want you to see what NOT to buy. It’s not that there’s anything wrong with that particular device, it’s just that it costs $35 and you can easily make your own for much, much cheaper. Here are two links (1) (2) to online instructions.

These cutting guides can be as complicated as you want to make them, but I took the simple route. I bought a piece of 4′ long x 1″ square metal stock at the hardware store. This was about $10. The reason I used a metal bar was I wanted to be as sure as possible that my guide was a straight line, and a piece of wood might not accomplish that.

Then I took a left-over piece of 1/4″ thick plywood. I used self-tapping screws to screw the piece of plywood to the piece of metal stock so that one end of the plywood was flush with one edge of the stock. Then I ran the circular saw down the length of the plywood, with the baseplate pressed up against the metal guide bar. This addresses a problem with cutting guides, which is that you have to compensate for the distance between the edge of the baseplate and the blade when you set the guide in place. Putting on a larger piece of plywood and then cutting it off using the metal guide bar itself means that the edge of the plywood is exactly where the saw’s blade is going to cut. Now, when I want to line up a cut, I just place the edge of the plywood where the cut should go, place the saw’s baseplate against the metal guide, and cut. Piece of cake!

With a 4′ guide I can cut across the full width of a sheet of plywood. If I ever needed to cut the length of a sheet, I could easily make an 8′ guide, but I haven’t yet had to do that. For an 8′ guide, I probably would not buy metal bar stock. I probably would just cut off a piece of plywood and use the factory edge as the guide.

Incidentally, if you’re going to use a clamp-down guide, or if you’re going to do much carpentry at all, you’re going to need clamps. I recommend these as a starting point: Irwin Industrial 12-Inch Quick-Grip Bar Clamp with Bonus 6-Inch Mini Bar Clamp. These clamps are easy to tighten and release one-handed (trust me, this is essential) and they have a million and one other uses, whereas if you bought that purpose-built clamp-down guide, you wouldn’t have a set of clamps to use for anything else.

Next post: the power drill.