Drill America - DWT57129 1/4-20 High Speed Steel 2 Flute Spiral Point Tap, DWT Series

originally bought the Dewalt package, which is really, really hard steel & it snapped in the hole. Now this is a really small screw in a lawnmower, holding the transformer in place that sparks the spark plug as the magnets float by, so I couldnt go bigger. Used a grinder to make an [X] on top center of hole & titanium impact bits from Harbor Freight to cut the initial hole & break bit. The larger grooves & some PB blaster, allowed the metals to collect as I turned the new tap, so I could screw unscrew, blow out/wipe & repeat, until the hole was clear for a new screw to go in. Dewalts pack, just didnt have deep enough grooves for the metals & snapped when I was unscrewing, which was likely my fault. But this bit allowed me to go deeper, so it was quicker & a better choice for my project.