Review on Sipery Carbide Multiple Tooth Cutting Stainless: Superior Performance for Precision Cuts by Alvaro Delic

I used this to make a peep hole on a steel exterior door. To do this, it is necessary to cut through both the inner and outer steel skin of the door. The only problem with this is that I probably should have removed part of the circular cutting blade first and just exposed the center drill and either pierced it with the bit that is part of the blade assembly if it was long enough to bridge the gap or still better, use the supplied longer drill bit of the same diameter to center the holes on both sides of the door. I tried piercing with a blade and found that the inner and outer holes were slightly offset. I really didn't like the appearance of a small offset at the end. Benefit from my experience and advice.