The last time I punched a hard drive platter, I lathe-turned a bushing to center the Greenlee punch:
This will work better:
The OD centers the bushing inside the punch body, the ID captures the screw, and the raised boss captures the platter.
After drilling the platter on the new fixture, it’s ready for punching:
Line everything up, turn the screw, and It Just Works:
The masking tape holds the platter to the bushing, eliminating the need for a third hand. The bushing emerges unscathed, ready for another platter. Overall, I think that’s faster and less messy than milling the platter ID on the Sherline.
Printing out a base to fit the Duodecar socket and assembling all the parts:
The Duodecar pin circle (19.1 BCD + 1.05 pin diameter) will actually fit inside a hard drive platter’s 25 mm unpunched ID. It might look a bit squinched, but the less you see of the socket, the better. I’ll try that on the next one.
The OpenSCAD source code is the same as before; set Layout = Bushings; and a bushing will pop out.
The original bushing doodle with dimensions:
The Smell of Molten Projects in the Morning 
Comments
3 responses to “Hard Drive Platter Punch Bushing”
When I’ve bent recentish HD platters, I’ve heard and felt a crunching inside, as perhaps a glass platter with metal deposited on it. Do you have a good reference on the composition of contemporary HD platters? Do you get lovely crunching noises as you punch the spindle/socket holes?
I’ve dremeled some from 5-10y old disks and it didn’t look like glass.
These are old enough (and cheap enough?) to have aluminum platters that crunch wonderfully as the punch cuts through! The drills produce really nice chips, too, and I’m sure the alloy’s bullet list has “really stiff” right up near the top.
Trying to drill a glass platter should be amusing…