A Unibit is a step drill: a cone-shaped bit with a series of stepped diameters that bores clean round holes in sheet metal enclosures, boxes and thin panels. Electricians use it to add a conduit entry where no knockout exists, stopping at the step that matches the fitting: 7/8 inch for a 1/2 inch connector, 1-1/8 inch for 3/4. The brand name is used for all step bits.
No KO where we need it on that disconnect, run the Unibit up to the seven-eighths step for a half-inch connector.
Also heard as
- step bit
- step drill
Related terms
Knockout punch
Punch and die set that shears clean round holes in boxes and panels for conduit fittings.
KO
Knockout: a partly punched disc in a box or panel that is removed to make a hole for a conduit or cable fitting.
Slug
Metal disc knocked or punched out of a box or panel, which ends up underfoot and in the bottom of every panel.