Review on Bahco 3832 56 Carbide Tipped Hole 32 Inch by Juan Simpson

I bought this because I needed to cut six 56mm (not 2-1/4" or 57mm) holes in a 5mm thick aluminum plate to mount the radial RF to mount switches.advertised as "carbide" but if so then it's not the tungsten carbide I was expecting. Maybe marketing decided that carbon steel is "iron carbide"? The first three holes were good and tight then the edge tolerance and quality gradually decreased until I could see daylight around the edges of the switches. Looking at the hole saw the teeth were worn down and some were almost missing. I used carving oil first and then switched to water based cutting soap to help lubricating the thing and it made no difference.I had to spend money to buy a real 56mm carbide cutter.I got one from Drill America for more than double the price found, but he came with a thorn. I thought it would be economical, but if I have to build another box I'll spend the money anyway.