"Lee Michaels" wrote in message news:4bae633d$0$14013$ snipped-for-privacy@news.astraweb.com...
I've posted about this before, but one of the handiest and most accurate cutting guides is made from scrap. In my case, I used
1/2" plywood for a couple of the long guides and 1/4" scrap for the shorter ones. As I recall, they were 8', 7', 4' and 2' long. In all instances, I sized them for BOTH of my circular saws.
To make a guide, rip a piece of plywood to the required length and make the piece about 12" or so wide. Don't worry about the cuts being too straight. Then, get a piece of hardwood that is as long as the plywood and around 3/4" or so thick. Approximation is fine. First, run it through a joiner to get one edge as square and true as possible. Then, rip along the trued edge about 3/8" in, making a straight strip the thickness of the board by 3/8" by the length of the board.
On the plywood, snap a chalk line or use the straightest thing you have in the shop to make a line down the middle. Apply glue to one of the 3/4" sides of the hardwood strip, then place it along the line. Sight along it and use brads to make sure it doesn't move when drying. The strip should be as straight as you can make it and extend the length of the plywood.
Then, put your favorite rip/combo blade in the circular saw, place its base on the straight strip and rip off the excess plywood from the side. Magic Marker an ID for which saw/blade you are using. Then, if you want to use a second saw, do the same thing with it on the other side of the strip. If you will only use one saw, just do that other side with the same saw, or with a different blade. For instance, one side could be with a combo blade and the other with a pure rip or crosscut, depending on what you normally use.
Since a circular saw cuts upward, the edge of the shooting board will act as a break-off for splinters as you rip or crosscut. To use it, clamp the edge on the marks you make for where the cut is to go and just grab your saw. There's no guess work, the cut will be clean and your accuracy will be improved.