For best results, and to prevent tool breakage, enlarge the hole in small increments of 2-3mm at a time, using the appropriate sized reamer to do this. Fit the reamer to your drive tool. Hole enlargement is often necessary when upgrading or replacing hardware, fixtures, or components that need a larger opening than what currently exists. Typical projects include. 3keego Step Drills are drill bits EASY to DRILL and ENLARGE a wide range of holes on thin sheet metal. If you are planning to enlarge an existing hole in metal, then there are five good methods at your disposal, so let's take a quick look at each of them. When the distribution box is installed on the wall, it should be fixed with split bolt (expansion bolt). The bolt length is generally the sum of the embedded depth (75-150 mm), the thickness of the box bottom plate, the thickness of the nut and. The short answer is yes; it is possible to enlarge an existing hole in metal. For example, softer metals like aluminum or brass are relatively easy to work with and can be enlarged using a variety of. Any suggestions on how to best enlarge a conduit entrance hole in a SS box (without having to buy a KO Set)? I don't want to scratch up the outside of the box and don't have a lot of room inside the box. Does the "Hole Saw Inside a Hole Saw" trick work? Uni-bits have always worked well for me.