It’s easy to cut perfectly round tabletops of almost any size
on your tablesaw. All it takes is a simple jig (Fig. A., below)
and careful setup. With this method, you can safely cut diameters
from 12 in. to within an inch of your saw’s rip-fence
Why use a tablesaw? It’s better than bandsawing or routing,
especially for large-diameter circles. Unlike bandsawing,
when you’re working on the tablesaw, the blank is fully
supported, so it’s easy to control. Unlike routing, you stay in
one place while making the
cut and you don’t have to
deal with a tangle-prone
cord. Tablesawn results
are better, too. The circular
blade leaves a cleaner
edge than a bandsaw
blade does and it won’t
tear out the end grain, the
way a router bit can.
This tablesaw technique is
similar to the approach used for
cutting circles on a bandsaw.
Using a clamped-on jig with a center
pin, you make the cut by
rotating the blank into the blade. Unlike the bandsaw method, however, you must start
with a blank that’s already roughsawn. Cutting the circle to
final size takes several steps. Like turning a rough blank into
a round on a lathe, you gradually cut down the high spots
until the blank is perfectly round. Here’s how to do it:
1. Draw the circle on the bottom of the blank, using a
compass or trammel.
2. Use a jigsaw to rough-saw the blank 1/4 in. to 1/2 in.
larger than the final diameter. Starting on the bottom face,
draw a diameter line that continues all the way around
3. Enlarge the center hole that remains from drawing the
circle to fit the jig’s center pin. Mount the blank (Photo 1).
Then install the retainers.
4. Before you position the jig, unplug your saw and install
an alternate tooth bevel (ATB) blade with at least 40 teeth.
Raise the blade fully. Set the rip fence so there’s just enough
room for the jig and blank to slide past the blade. Align the
blank’s centerline with the reference line you’ve drawn on
the clamp rail (Fig. A).
5. Hold the jig against the fence, slide it forward into position
and clamp it securely (Photo 2).
6. Lower the blade fully to locate the jig for the first cut.
Spin the roughsawn blank to find its widest spot. Then reset
the fence so the blade will remove about 1/16 in. from this point. A more aggressive cut wouldn’t work; it
would cause binding between the blank and the blade.
7. Start the cut by raising the blade (Photo 3). Then rotate
the blank clockwise (Photo 4). Shut off the saw and lower
8. Reset the fence and repeat the cutting process, as needed,
removing about 1/16 in. from the edge of the blank each
time. Removing 1/16 in. reduces the blank’s overall diameter
by 1/8 in. Your last fence adjustment, to dial in the final diameter,
will probably be less than 1/16 in.
9. Remove saw marks on the edge by sanding or by routing
This technique was developed from a tip supplied by Paul Lee.
This story originally appeared in American Woodworker October 2005, issue #117.
October 2005, issue #117
Purchase this back issue.
Click any image to view a larger version.
1. Mount the roughsawn blank on the jig. It rotates on the
center pin. Align the blank’s centerline with the reference
line on the jig’s rail.
2. Clamp the jig to the rip fence at the point where the tip of
the fully raised blade, the top edge of the blank and the
centerline meet. Lower the blade completely. Then position
the blank for the first cut by adjusting the fence.
3. Start the cut by raising the blade into the blank after setting
the fence to remove only 1/16 in. from the edge. Hold
the blank firmly, so it can’t move. Turn on the saw and slowly
raise the blade to full height.
4. Complete the cut by rotating the blank clockwise. After
one full rotation, shut off the saw and lower the blade
completely. Reset the fence about 1/16 in. closer to the blade
for the next pass. Repeat the cutting process until the blank
reaches its final diameter.
The jig’s base is slightly wider than the diameter of the
circle you plan to cut and deep enough to fully support
the blank. The 1/8-in.-dia. steel center pin (A) protrudes at
least 1/4 in. It’s located on a line perpendicular to the
edge and centered front to back. This reference line continues
onto the clamp rail. Position the pin so the blank
slightly overhangs the base. The retainer risers are the
same thickness as the blank. Heavy paper shims provide
clearance under the risers’ tops so the blank can rotate.