Two heads are better than one when it comes to this drill mounted nibbler.

The Original Biter comes with a 2″ cutting head which is perfect for every-day cutting like trimming flashing, removing rusted sheet metal from a fender, fitting laminate, or cutting sheet plastic. For those cuts that are just out of reach, pop on the Long Dog Head. A full 4″ long, the Long Dog makes access easy to hard-to-reach places such as inside a fender to install marker lights, awkward angles on the dash to install gauges or retrofitting ductwork hidden inside a ceiling. The Long Dog features the same 360° turning radius as the original Bad Dog Biter head.


Power Source: Hand Drill
Speed: 1,200 – 4,500
Width (all materials): 1/8″

Maximum Thickness:
Mild Steel* : 14 gauge
Stainless Steel* : 18 gauge
Brass/Copper/Aluminum : 14 gauge
Plastic & Fiberglass : 3/32″
Laminate & Veneer : 3/32″

*use on flat or corrugated stock/cutting oil is recommended for maximum blade life
Minimum cutting speed 2,000RPM


One or both heads can be set to steerable
Turn the screw 1/4 turn using allen wrench provided
Head should turn freely but still be snug. Lock Tite can be used to secure set screw
Set heads in opposite direction for max versatility
Make sure you:

Bring drill to maximum RPM before cutting material
Keep speed constant while cutting
Don’t force Biter to cut faster



1. Remove metal retaining clip (A).
2. Remove the plastic end cap (B).
3. Loosen lock nut (C) & remove attached set screw (D) with allen wrench.
4. Insert new blade (E) with indentation facing up while gently pushing old blade through and out.
5. Align indentation in center of blade block (F).
6. Replace set screw (D) into indentation in new blade..
7. Re-tighten lock nut (C)
8. Grease
9. Replace end cap (B) & retaining clip (A).