Source from :http://homeguides.sfgate.com/cut-straight-line-plywood-99520.html
Plywood is a manufactured by gluing layers of wood veneers together to form a 4-by 8-foot sheet of material. Because plywood is resistant to warping, shrinking and cracking, it offers a high degree of strength in such projects as cabinets, sheathing and other projects that require these attributes. Most of these types of projects will require cutting a straight edge on the plywood at some point during the construction process. The most common methods of cutting plywood involve using a power tool.
Set the fence on the table saw for the size of the applicable cut. The fence is a locking adjustable arm that slides to the applicable measurement and locks into place on the table saw.
Place the sheet of plywood on the table saw and against the fence but without making contact with the blade.
Turn on the table saw and feed or push the material into the saw’s blade to cut the plywood.
Handheld Cutting Tools
Place the plywood on a set of sawhorses. Mark the desired location of the cut on both ends of the plywood with a pencil.
Measure from the edge of the shoe or saw base to the face of the saw blade. This measurement will vary depending on the type of cutting tool you use. Transfer this measurement to the outside of the actual cut line you marked in Step 1 on both ends of the plywood.
Align a straightedge with the outside marks made in Step 2 and clamp into place using standard bar clamps.
Place the shoe of the saw against the straightedge and check the blade alignment with the cut line. The blade should match up perfectly with the cut line.
Plug in the saw and cut the plywood.
Things You Will Need
- Table saw
- Bar clamps
- Handheld cutting tool
- 3-inch multipurpose carbide wheel accessory
- Recruit an assistant to help hold the plywood when ripping long cuts.
- Wear protective eye gear and a dust mask or respirator when operating power tools.
“Skil Saw” is actually a trade name for a circular type saw. The electric-powered, hand-held saw is used to cut boards and rip plywood into smaller pieces. A problem with the circular saw is cutting a straight line on long and wide pieces of material, such as plywood or house siding. Although there is a “V” notch to identify the blades path, it can sometimes be difficult to maneuver the saw over long distances. By using two spring clamps and a straight edge board, a straight cut can be achieved every time you use the saw.
Things You’ll Need
Full sheet plywood ( 4-by-8 feet)
Straight edge board (1-by-4 inch, 8 feet long)
2 spring hand clamps
Skil circular saw
- Measure the distance on the bottom of the Skil saw guide table from the outside edge of the table to the inside edge of the saw blade. This measurement will vary from 2 ¾ inches to a full 3 inches, depending on the model of the saw. Use the pencil and make a note of this measurement on the saw itself. This will help you remember the measurement.
- Mark and identify the overall width you want to remove from the work piece. The work piece is a full sheet of plywood that is 4-by-8 feet. Mark the plywood as if you want to rip the piece completely in half lengthways. Make a small pencil mark at 24 inches on either end of the plywood.
- Deduct the measurement you marked on the saw from the overall measurement of 24 inches. In the case of a 3-inch distance, this would be 21 inches. Mark the plywood at 21 inches with a small, two-sided arrow. Make the point of the arrow exactly at 21 inches on the tape measure.
- Lay the straight edge 1-by-4 inch board on the plywood. Move to one end and hold the edge of the board to the arrow mark. The 24-inch small pencil mark you made should be exposed. Attach the spring hand clamp to hold the board in place. Perform the same task at the other end of the plywood.
- Lay the saw to the top of the plywood. The “V” notch should now be perfectly aligned with the small 24-inch pencil mark. Start the saw and use the 1-by-4 inch straight edge board as the guide. Run the saw down the length of the plywood using the straight edge as the guide for the cut.
Making Perfectly Straight Cuts in Plywood
Tips & Warnings
- Follow the manufacturer’s instructions when using the saw for personal safety equipment. Always wear safety glasses and hearing protection.
- Use a circular saw with sharp blades. Dull blades may cause the saw to perform erratically.
Straight Cuts on Plywood
This is a simple trick to help you make straight cuts on plywood or other wide materials. I wish I would have learned it sooner, as I never can cut wood and follow a line.
To cut wood simply, just measure from the edge of the blade guide to the inner edge of the blade. This accounts for the kerf of the blade – or the amount of wood lost to the cut.
Take that measurement and add it to the distance you need to cut and mark it on your plywood.
For example if I need a 2 foot board and the measurement of my guard is one and a quarter inches, I mark the board at 25 1/4.
I then clamp a straight edge on the mark and measure to ensure that it is even all along my cut.
Then all I have to do is tightly follow my guide and I will cut exactly down the line I need.
Simple right – now in the video I was too busy trying to look good on camera and allowed the saw to move away from my guide which resulted in a wavy cut – that was my fault not the systems…