Klein Tools 25960 3-Step Drill Bit, Double-Fluted, 7/8-Inch to 1-3/8-Inch

Three sizes, spanning 7/8 inch up to 1-3/8 inch (22.2 to 34.9 mm). The sizes are laser etched on the steps so you can read where you are mid-cut. That top end covers the common conduit knockout work an electrician does in a panel or box, and the bit steps up through the range without changing tools.

Either one. The 25960 has a 1/4 inch hex shank and an impact-rated shaft, so it drops straight into an impact driver chuck or a standard drill chuck. No adapter, no keyed chuck required.

Steel up to 16 gauge is the stated limit for the Klein 25960. That covers sheet metal enclosures, panel sides, and junction box walls. Heavier structural steel is past what this bit is meant for, and you want a hole saw or knockout punch there instead. It also cuts wood, plastic, and aluminum.

The 25960 uses a split point tip, which bites and starts the cut instead of skating across the surface when you lean on it. On thin material that is the difference between a clean centered hole and a scarred panel. A center punch still helps on slick painted steel, but the bit is built to start on its own.

Double fluting is the working difference on this bit. The 25960 carries two spiral flutes, and the second one clears chips faster while helping pull the bit down through the material, so the cut goes quicker and you push less. Single-flute step bits clear from one side only and load up sooner in ductile material like aluminum.

The 25960 covers 7/8 inch through 1-3/8 inch in three steps, so it handles the larger end of a conduit job and nothing below 7/8 inch. If your work runs from small pilot holes up through trade sizes, you need a smaller-range step bit alongside it. Buying this one alone is the right call when the holes you cut are consistently in the 7/8 to 1-3/8 inch band.

TiN coating on the 25960 sheds heat rather than letting it build in the cutting edge, which is what kills a bare high speed steel bit on repetitive holes. The bit body underneath is high speed steel. If you are punching a panel full of holes in one session, the coating is what keeps the edges sharp through it.

It measures 3.57 inches on its long dimension with a 1.38 inch body diameter, and weighs 0.43 pounds. Worth knowing before you commit to it inside a crowded enclosure or a shallow box, since the whole bit plus the driver nose has to clear whatever is behind the panel.

Klein Tools 25960. That is the manufacturer part number to order by, and it identifies the double-fluted three-step version covering 7/8 inch to 1-3/8 inch with a 1/4 inch hex shank.