Cross Cutting Plywood, Etc.

For many years the Radial Arm saw was a popular shop tool and I used one for many years for crosscutting pieces up to almost 14 inches wide. It’s no longer popular with woodworkers whether novice or professional. I found the photo below on the web when I searched for radial arm saws.

For several years my shop was 12 foot wide and 48-foot long, and I had a setup similar to this along one wall. I used that radial arm saw to crosscut and rip large sheets of plywood for many wood projects until I moved to a wider shop where I could set up a large table saw arrangement.

Some woodworkers still use radial arm saws. They are still available used at many places for as little as $100, a bargain considering the capabilities of a radial arm saw. Crosscutting is this saw’s strong suit but it is capable of many other tasks including ripping and mitering, even though there are many power tools that perform better for those specific tasks.

Many consider the radial arm saw as quite dangerous because of the direction of the blade spin while making cuts, especially when ripping. While there is some truth to that, I think the radial arm saw’s design is just less tolerant of careless use. I used one for over five years for crosscutting and ripping plywood sheets without incident. What all woodworkers need to keep in mind with radial arm saws and every other woodworking power tool is to read the instructions carefully and use them with caution. Safety should be the first consideration to avoid injury.

Sliding Compound Miter Saw

My preference for most crosscutting today is the sliding compound miter saw. It’s the perfect power tool for crosscutting up to 12 inch wide boards. Its strong suit is mitering because of its center swivel. Unlike the radial arm saw where the entire arm must swing to the right or left of center for any miter cut, the sliding compound miter saw cut always remains at the center. My sliding compound miter saw helped me to build every project in the past ten years. The best part is that you can purchase a good compound miter saw for about $200. A photo of a newer model of my Ryobi Sliding Compound Miter saw appears below.

slidingcompoundmitersaw

The Table Saw

Cutting across the entire width of plywood sheets can be handled using the methods described in the section on ripping plywood. Plywood pieces too wide to cut with a sliding compound miter saw can be cross cut using a crosscut jig built to fit on your table saw. The photo below is a simple jig that I built for the table saw in my shop many years ago.

crosscuttingjig

This jig required only three pieces of plywood and two wood strips all from material that I already had in my shop at the time. This jig was capable of cutting pieces as wide as 24 inches and narrow pieces also. The materials list below describes everything you need to build one for your table saw.

crosscutjigmaterialslist

*The size of these parts is based on personal preference. The crosscut fixture will work fine if it’s larger or smaller. You must decide the best size for your shop considering the size of your table saw and the tables on each side of it.

**The size listed in the materials list worked on my table saw and will probably work on many others but you must check the size of the miter guide slots on your table saw to make certain. These guide strips must be cut to fit the miter gauge slot of your table saw snugly. I suggest you make them slightly large and then plane or sand them down to fit the slots on your table saw by testing. If you make them fit too loosely, your fixture will have too much side to side play. If they are too tight, it will take too much force to move the fixture, making it difficult to use. Also, be sure that the depth of the guide strips is slightly less than the depth of the miter gauge slot so that there is no rubbing on the bottom of the slot. Your fixture will work more smoothly with this friction eliminated.

The drawings for the Crosscut Fixture/Jig are shown below. The drawings include details for two miter guides for using with the jig. These two guides are only useful for cutting short parts for small projects because the front and rear fences of the crosscut jig limit their use but they can come in handy for some small projects.

crossscutjig

Note: You can reduce the friction between the table and the bottom of the crosscut fixture by covering the bottom with plastic laminate before fastening it to the guide strips. You can also apply several coats of clear wood finish before applying the guide strips.

Once the pieces are cut to size, you are ready to assemble your fixture. Before proceeding decide on the appearance of your fixture. I view jigs and fixtures as functional shop tools, so I don’t veneer the edges or finish them in any way. You may feel differently. Since this is your project and your shop, you must decide. You can veneer all the exposed plywood edges, or you can round over all the fence edges to prepare for a good finish.

The Order of Things

Step one of the assembly is to place the guide strips in the miter gauge slots. Place thin shims under the guide strips during assembly to facilitate the nailing of the base to them.

If you followed the instructions with your table saw, you would have already checked and made any necessary correction for blade alignment. The blade should be perfectly square with the table and in alignment with the miter saw guides. If you haven’t done this then now is a good time.

The simplest way to do this is to raise the blade almost full height and then measure from the blade to the edge of one of the miter gauge slots. To take this measurement, select one blade tooth and use it as a measuring point for both measurements. Place the tooth in line with the table surface at the front of the saw and take the first measurement. Then swing the blade over until the same tooth is in line with the surface of the table towards the back of the saw and measure again. If the blade is square with the table, these measurements will be identical. If they are, go ahead and assemble your fixture. If the sizes are not the same, you have two options.

The first, and the one that I recommend is to true the blade with the table. In addition to the instructions that came with your table saw, there are many fine books, dealing specifically with table saws, with in-depth instructions for this. A fine article in the Wood Magazine web site at http://bit.ly/1Gz09iW covers how to align the table saw blade with the miter gauge slot.

Safety Note: Always disconnect your table saw before making adjustments or changing blades. Never depend on a switch to protect your hands.

After the guide strips are in, make certain the blade is fully retracted and place the base of the crosscut fixture on the table and slide it into the position you want. Align the front edge of the base with the front edge of the saw table. Now mark the location of the guide strips and lift the base from the front to expose the top of the guide strip. Put a thin bead of glue on the top of the guide strips. Use the glue very sparingly to avoid ooze. Now gently lower the base and use the marks you made to help line up the base with the table saw. Drive some ¾ inch brads through the base and into the guide strip. A pneumatic nailer or stapler is perfect for this task. Drive one nail at the front and one nail at the rear of the base. Now make a line between the nails and drive one nail every 4” along the guide strip. This will hold it in place and ensure a good glue bond. If you don’t have ¾” brads, cut any small finish nails to the proper length and use them.

Take the base off the table saw by lifting it straight up from the front of the saw. Place the base upside down on your work table. Place the rear fence (Part C) under the base (Part A) flush with the base. Measure 3” from either end to center the fence with the base. Now lift the base slightly and apply a strip of glue to the edge of the rear fence. Place the base down on the rear fence and check that it is flush. Nail or screw the base to the rear fence. You can use #6 finish or casing nails for this or a pneumatic nailer. Set the nails or slightly countersink the screws so they will not scratch the table saw surface. You can also assemble this using the biscuit joiner.

Now repeat this process for the front edge of the fixture using the front fence. Finally, drill three small holes into the bottom of the guide strips and countersink them. Drive small 5/8 inch flat head screws through the guide strips into the base for extra strength.

Before starting to set up the tracking, apply a lubricant to the table saw surface and the miter gauge slots. Use silicone or one of the special lubricants sold for this purpose. Next, rub the bottom of the base of the fixture, especially the guide strips, with paraffin wax. These steps will reduce friction and make your fixture easier to use.

Raise the blade of the table saw to approximately 1 ½” depth. Place the fixture behind the blade with the guide strips in the miter gauge slots. Make sure the guide strips seat in the miter gauge slots, and the front fence is directly behind the blade. Hold the fixture steady and start the saw. Slowly push the fixture forward allowing the blade to cut all the way through the rear fence of your fixture. Your crosscut fixture is now ready to use.

You can finish your crosscut fixture using a stain and clear coat, clear coat alone or paint. To keep your fixture working smoothly, lubricate the bottom and the guide strips with paraffin wax after several uses. Even if you covered the bottom of the fixture with plastic laminate before installing the guide strips, a little paraffin reduces friction. Lubricate the guide strips regularly.

For added safety, use bright red to paint the area where the blade cuts through the front and rear fences. For safety, attach a couple of ¾”X¾”X4” wood pieces on each side of the saw blade cut to block your hand from entering the path of the blade. Using this crosscut fixture you can safely and easily crosscut plywood pieces when you are making various projects.