I bought the IRWIN #4 Unibit pictured in this article a long time ago and have used it many times over the years. It is the perfect drill bit for easily making clean holes (12 different sizes) in all metals (up to 3/16” thick) and plastics.
The picture below shows a recent use… I needed to drill 3 holes in the back of an electrical panel box for Romex connectors. Back before I had the Unibit I would use a knockout hole punch. The knockout makes a clean hole but it’s a time-consuming hassle to use. The Unibit easily drilled those 7/8” holes in no time flat.
My Unibit is IRWIN #10234CB. The CB designates that it is made with Cobalt Alloy Steel, which is suited for drilling stainless steel. I have not drilled stainless steel with my Unibit but the comments on Amazon indicate that it drills stainless with no problem. That’s impressive!
The IRWIN #102434CB currently sells for $42.97. So, it’s not a cheap bit (lesser quality step drills are, of course, available for less) but if it isn’t abused it should drill beautiful round holes for a good long time. Perhaps a lifetime.
###
In the history of tools, the step drill is a relative newcomer. Patented in 1973, it was called the Unibit by the inventor and manufactured by Unibit Corporation. Patent protection expired in 1990. The Unibit name is now owned by IRWIN Tool Company which, since 2017, is owned by Stanley Black & Decker.
###
The electrical code does not allow Romex box connectors to be put into a box like shown in the photo above but, rest assurred, I have installed them correctly, as this photo shows.
No comments:
Post a Comment