Cutting circular table tops with the BT3/21829

[cwithboat]

This note is for novices such as me.

SWMBO came to me yesterday and asked if I could cut a circular table top for a piece of lawn furniture that I had broken the glass top on some time ago. (I have conveniently forgotten this episode, but She remembers these things far better than I.)
I dimly remembered a jig in one of the table saw tips books and looked it up. A quick glance told me that with my 21829 I did not need a jig. Here is the procedure:

• Square up your work piece. I decided on a table top diameter of 26 inches.
• Cut the four corners off to make a regular octagon. I used the SMT with the fence set at 45 degrees.
• Drill a 5/8 hole in the center. If you wish to preserve the finished face use a Forstner bit half way thru the work.
• Cut a 5/8 dowel and fit it in the center hole of the SMT. Fit the hole in the workpiece over the dowel.
• Position the SMT so that the dowel to blade distance is the desired radius and lock it in place.
• Cut all the pointy bits off, stopping the blade and turning the work piece after each cut. The more you cut the more circular the result.

The end result was more than satisfactory. It looks like this technique will work up to at least a 3 foot diameter.

[cabinetman]

Circles on any table saw is an easy procedure. Use a substrate (3/4" thick) and slightly smaller than the desired top that will be cut. First, drill a hole in the center of the substrate to tap in a finishing nail like a #6. Allow it to protrude the substrate at least 75-80% the thickness of the top to be cut. Mount it to the table saw so the nail is in line with the center of the blade, and to a distance of the dimension of the radius wanted.

Drill corresponding hole on the underside of the proposed top to accommodate the nail. The top can be left square. Place top on the nail. With the blade down, gently turn the top to make sure it turns smoothly. With the blade down turn on the saw and raise the blade so it penetrates the underside by about 1/8". Slowly turn the top to make a complete revolution. While the blade is still running, raise it another 1/8" and repeat. Keep doing this until the top is completely cut through.

Tip: To have fall off corners, cut the top as a square very close to the circle diameter desired. That way, the final pass around the blade you have 4 pieces that will fall and not get in the way.

This method also works on a band saw, but you start with a square the size of the diameter, and make one pass around.
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[cwithboat]

[quote=cabinetman;335035]

With the blade down turn on the saw and raise the blade so it penetrates the underside by about 1/8". Slowly turn the top to make a complete revolution. While the blade is still running, raise it another 1/8" and repeat. Keep doing this until the top is completely cut through.

Of course, I should have thought of that.