1 Building the jig
With the box-like jig shown at right you can rout flutes in a column while it is mounted in the lathe. Cut the parts of the jig from %-inch plywood, except for the top, which is made from l^-inch clear acrylic. Refer to the illustration for suggested dimensions; the jig should be long and wide enough to support the router and high enough so the top just clears the column when the jig rests on the lathe bed. Once the top, bottom, and sides are assembled, add two braces to make the jig more rigid. Install a double-bearing piloted fluting bit in your router, drill a bit clearance hole through the jig top, and screw the tool’s base plate to the jig. The router should be positioned so the bit will lie alongside the column when the jig is used. Be sure all tools are unplugged during setup.
Preparing the column and the lathe
To ensure that the flutes are spaced equally around the column, mark cutting lines for the flutes on the blank—in this example, 12 in all. Make corresponding reference marks on the lathe faceplate by dividing its circumference, or 360°, into 12 equal segments spaced 30° apart. Mark the lines with a pencil and a protractor (left). Set the jig on the lathe bed, mount the faceplate on the lathe so that one of the reference marks is in the 12 o’clock position, and mount the column so a cutting mark is at the 3 o’clock position. Tighten a handscrew around the lathe drive shaft to prevent it from rotating and clamp stop blocks to the lathe bed to make sure that all flutes will be the same length.
3 Fluting the column
Adjust the router’s cutting depth so the bit is aligned with the 3 o’clock cutting mark. Butt the jig against one stop block, turn on the router and push on the side of the jig to feed the bit into the blank. Once the pilots are flush against the stock, slide the jig along the lathe bed until it contacts the other stop block. Keep the pilots pressed against the stock as it routs each flute (inset). Turn off the router, remove the handscrew, and rotate the blank by hand until the next reference mark is in the 12 o’clock position and the next cutting line is in the 3 o’clock position. Reinstall the handscrew and repeat the operation to cut the remaining flutes (above).