hydroguy2

Well Known Member
A recent how to use a flycutter post got my wheels turning. I've had good luck with my el' cheapo fly cutter, but I have access to a set of knockout punches. So last night I punched the firewall and 8 holes in my battery box. Total time for all holes including layout was <1hour AND I still have my hearing and fingers.

First unibit a 3/4" hole for positioning the punch

RV7373.jpg


then 15 seconds of ratchet work.

RV7374.jpg


Makes for easy clean holes with minimal clean up. It does leave a slight burr.

RV7377.jpg


Any journeyman electrician will probably have a set for installing conduit in cabinets/panels. The sizes are labeled funky, due to conduit sizing. such as I used the 1 1/2" knockout to punch a 1.960" hole.