The basic idea is to use 4 bolts to mount your circular saw to the bottom of a piece of 1x10, or 1x12, or a wider piece of 3/4 inch plywood. The length of the board can be almost anything you want, but using a long board gives you a long fence and long infeed and outfeed areas to support your wood.

You can use slotted, flat-head machine screws in holes which are reamed out to acdcept them, or you can use carriage bolts. 1/4 inch bolts, or those about 6mm in diameter are fine. Get matching nuts, lock washers and "fender" washers for each bolt. A "fender" washer is a wide flat washer with a hole in the middle. For 1/4 inch holes the normal flat washers are about 5/8ths of an inch in diameter. The washers you want to use should be more like an inch or 1 1/8 inches in diameter, or even a litle more. (25 to 30 mm)

Set your UNPLUGGED circular saw on the bottom of the board you wish to use. Raise the blade so you can get the base to fit flat on the wood and use a square, or use your eye to get the base parallel to the edge of the board. This isn't critical, but it makes it a bit easier to get the fence right in a later step. Use a pencil to trace around the base of the saw. Take one of the fender washers and use it as a guide to find 4 areas around the perimeter of of the base hwere you can fit them so they overlap the base, but don't interfere with the operation of the saw. Mark the center of the washer on the wood. Remove the saw, drill 4 bolt holes where you marked them, flip the board, ream out the holes if using flat head bolts or just drop in the carriage bolts. With carriage bolts you want to tighten then down one time to recess the head before you attach the saw. Use the fender washer and a nut, but not a lockwasher, for this step. After setting the carriage bolts securely in the wood, remove the nut and washer.

Return your UNPLUGGED saw to the area you outlined. It should fit snuggly inside the ring of bolts. Drop a fender washer onto each bolt and check that it does not come near the blade or interfere with any moving part of the saw, add the lockwasher and nut. Gently tighten the nuts to secure the saw to the board.

Set the board on top of some scrap 2x4s, plug in the saw and make a plunge cut. Make this only deep enough to get the blade to protrude an inch from the board. After making this cut, unplug the saw.

Now is a good time to add legs to this, or, you can set the affair on a pair of sawhorses when you need it.

Flip the board so the saw is hanging underneath. Use woodscrews to attach a piece of 1x3 for a fence. Mount this 1/4 inch from the slot you cut, and perfectly parallel to it. The fence goes from the infeed end of the board to the end of the slot you cut. It does not extend past the end of the sawblade.

At this pint you could use this for ripping strips, but for safety you should add a few more things: A kerf splitter, a blade guard, fingerboards, an outfeed fence, and a good switch for remotely starting the saw.

The switch can be made in a metal outlet box from a wall switch and a standard outlet. Mount this in a convenient location. when using this switch you can keep the trigger switch on the circular saw in place with a nylon cable tie.

The blade guard is simply a 10 inch wide board mounted one inch above the slot. One end of the board is supported on the fence (add a 1/4 inch thick spacer) the other end is supported by a scrap of similar thickness which is set far enough away from the fence to allow th boards you are ripping to pass freely between the two supports. Mount this with screws, or bolts, but not nails.

This board should completely cover the blade so you can't get your fingers near it. It should be 1/4 inch above the thickness of the wood you are ripping so that it can't bind. Your saw blade may just barely touch it.

On the outfeed side you would want a fence set in line with the outside edge of your sawblade. this fence would be shaped like a long tapered or wedge, and located about a foot past the slit you cut in the table. The strip which is being ripped will be directed to one side of the wedge, while the freshly cut edge of the board will be supported by the other side of this.

Just some rough suggestions here. I hope to be building something like this soon as a built-in part of a 16-foot-long combination boat construction table/strongback. Hopefully have some pictures in a month. Weather permitting.

Hope this helps

PGJ
PGJ