Super-Thin Bits For Narrow, European-Style Slots
Eighteen incredibly thin bits to fit the extra-narrow screw slots often encountered in the gun shop. Take great care when using these bits. The blade MUST fill the slot from side-to-side and edge-to-edge or it will most certainly break on a firmly seated screw. Freeze spray, heat, penetrating oil, a few taps, regrinding the bit for an even better fit - all these tricks can help give success.
Big Book Catalog, Issue:66, Page:458