IRWIN Unibit Step Drill Bits – Review


It is not often that I get excited over drill bits, but the IRWIN Unibits are by far my favorite drill bits ever.  It is like having an entire drill bit set in one bit.  I had to install a dead bolt into a thick steel shell door frame,  I went through a normal bit in no time and hadn’t even drilled the first hole yet.  I went to the local hardware store where I saw the Unibit,  I remembered using one in the past with good results.  When I arrived back the job site and started to drill I was just amazed at the speed and control of the bit.  I drilled all my required holes in no time.

The only downfall to a step bit is that you are limited to the thickness of the material that you drill, so you can’t drill a 5/16 hole though 1″ thick material because the bit tapers.  That being said, for every other application they are time savers.  For custom installers these bits are perfect and they cut through metal like butter.  Every step has a positive stop that you feel when you have hit that diameter hole.  Stay away from the cheap step bits you see online they do not last and dull easy.  The IRWIN Unibit is made from M35 grade Cobalt HSS which gives you 6X the life of other bits.  The laser markings are clearly labeled on the bit and the radial concave flute design cuts fast and removes debris as it cuts.

The Unibit has what IRWIN calls the Speedpoint tip.  It really digs in and gets started fast. The bit stays planted to eliminate wobble, these bits are great for quick knockouts.  The Unibit comes in a variety of sizes and is made right here in the U.S.A.  I am a big fan of the IRWIN Unibit, in fact we are giving away 4 of them in the Ultimate Tool Bag Giveaway.

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  1. I have to put a 1 inch hole through a farm tractor loader bucket.
    compared to using multiple holesaws to get a hole would the step drill bit handle hardened steel without dulling?

    • Hi, Carpenter. I am sure it will put some wear on the bit, but shouldn’t dull it. Make sure to use plenty of lubrication. How thick is the steel?


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