Greg Macdonald on sat 29 sep 01
If you want to cut a large number of perfect batts, a router works
really well. You need to use either a 1/4" straight or plunge cutting
bit and a jig. Mount your router under a table [1/2" plywood with a
hole for the bit is excellent] and install the bit. Measure on the top
of the table from the edge of the bit to a point on the table that will
be the radius of your batt. Drill for a pivot bolt at this point [I used
a 1/2" x 2" flat head stove bolt for the pivot].
Drill two 3/8" holes in a 1/2" plywood blank for your jig [mine are 10"
apart]. Drill your pivot bolt hole E X A C T L Y in the middle between
these two holes. Install the jig blank onto the table with the pivot
bolt and use the router to cut it into a circle.
Glue a 3" piece of 3/8" dowel into each of these holes and let dry.
Cut your batt material into slightly larger than batt diameter squares
and drill the batt pin holes in the blanks. Drop the batt blank onto the
jig with the pin holes over the dowels. Push the blank down until the
router bit cuts through the batt. Rotate the jig using the protruding
dowels until the entire batt is cut.
Once the jig is made you can make about 50 batts an hour, all of them
perfect. if you have questions I'd be glad to help by E-mail.