Step bits can be handy for cutting sheet metal and plastic, but what if you don’t need a standard size hole? These conical “stepless” bits can create holes of any size from 1/8″ to 3/4″. The obvious limitation is if the material is thicker the hole will be tapered, but then again in some situations that might be desirable.
The pictured bits use a two flute design which supposedly cuts faster and smoother. The 1/4″ hex shanked high-speed steel bits are coated with titanium-nitride to keep them cool.
The only place stateside we could find carrying these bits was Harbor Freight, where a set of three bits sized 3/16″ to 1/2″, 1/4″ to 3/4″, and 1/8″ to 1/2″ sells for $8. Several places in the UK carry similar bits sets including Axminster Tool Centre, which sells a set for £25 or about $40.
Stepless Drill Bits [Harbor Freight]
Conical Bit Set [Axminster Tool Centre]