Step 1: Salvage a Brush Handle, a Hard Drive Disk, and Some Steel
Hard drives are fairly easy to recover. I put a star bit on a screwdriver and a dead hard drive in front of my seven year old son and watched him go to work. Don't forget to recover the super powerful magnets!
The paintbrush head removes easily enough with needle nose pliers.
The piece of steel shown is cut to size with a hacksaw from a 3/4" wide and 1/8 " thick rod I bought at a hardware store. I used a 4" length.
Step 2: Measure and Chisel a Seat for the Steel Bridge
Idealy, the width of your steel bridge and your chisel will be the same. Mine are each 3/4". Determine how much room you'll need for two bolts to comfortably secure the steel bridge. If you haven't chiseled a groove before, just mark out your parameters and make numerous parallel grooves from the top to the bottom of the groove. Now you can chisel out the first layer of your groove. Repeat till you get to the desired depth.
Step 3: Bore and Bend the Steel
Mark your drill targets with chalk or a bright wax pencil. I purchased a bit for drilling steel but it's not necessary. The two things that'll help get through are a sharp bit (see other instructables on sharpening bits) and some water applied while drilling. Fit the bored bridge in its seat, mark the holes on the handle and drill holes through the paintbrush.
Bending the steel takes heat and pressure. After measuring where you want your "S bend" to start and stop to give clearance for the disk, you'll want to clamp your steel in a vice to heat with a torch. I can't tell you empirically when to lay off the heat and add pressure. Using the weight of my body, I grabbed a thick file by the ends and pushed perpendicular against the top of the steel. Repeat further down in the opposite direction to get an "S bend".
Temporarily secure to handle with bolts and nuts to check fit.
Step 4: Sharpen Disk and Affix Spindle/platter
I thought that sharpening the disk (technically a platter) would be easily honed with my Dremel and an abrasive disk. No dice. The material doesn't respond well. It did however sharpen with a basic file as I braced it in the vice with wood clamps to protect the mirror finish.
Finally, the most difficult part was drilling into the spindle after drilling the final holes in the bridge. It's not a straightforward process as I ended up securing the bolts with JB Weld apoxy after not getting adequate holes.
Finally I affixed the platter to the spindle with apoxy.
Step 5: Eat Pizza!
First, cut pizza with a data dazzling pizza cutter. Gently lift pizza . . .