If you ever had old limescale and rust like below in the base of your shower and wanted to clean it up without spending a whole day scrubbing it by hand than the powerdrill scrubber head is a tool you should build.
Estimated time: 20 minutes
Step 1: Shopping list and tools
You will need the following tools:
Optional, but nice to have:
Step 2: Drilling
First drill a hole in the center of your brush. The positioning of the hole doesn't need to be perfect, a bit of wobble when the brush will rotate isn't that big of a deal.
The diameter of the hole should be wide enough so that you can easily put the screw through but not too big so that the head of the screw doesn't fall through, obviously.
Step 3: Mounting the screw
Mount the screw through the hole you just drilled.
Step 4: Securing the nuts
Secure the screw on the top side of the brush with both nuts. This is critical because it will prevent the nuts from moving as the brush rotates.
If you want to do this properly it makes sense to read:
this page where the two nut locking method is explained in significant detail.
Step 5: Get rid of the handle
Cut away the handle with a handsaw. You could do it in the beginning but I found that it's easier to handle the brush without removing it. The thing to take care at this point is to leave as little of the handle sticking out as possible.
You can finish up the resulting edge with a bit of sandpaper but that's optional.
Step 6: Enjoy
Enjoy your diy powerscrubber.
Note: As you can see I didn't get rid of most of the parts sticking out of the round brush which made using a bit annoying as it hits stuff when rotating. Do not make the same mistake.
Step 7: Effects
Powerdrill scrubbing is pretty effective. Here you can see that after about 1 minute of scrubbing on high-speed drill setting most of the limescale and rust is removed.
The worse thing is that the fungus is not affected, so that will need to be taken care of separately.