Hard Drive Platter Punch Bushing

The last time I punched a hard drive platter, I lathe-turned a bushing to center the Greenlee punch:

Greenlee punched drive platter

Greenlee punched drive platter

This will work better:

Vacuum Tube Lights - Greenlee punch bushing

Vacuum Tube Lights – Greenlee punch bushing

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:

Hard drive platter - Greenlee punch bushing

Hard drive platter – Greenlee punch bushing

Line everything up, turn the screw, and It Just Works:

Hard drive platter - punched

Hard drive platter – punched

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:

21HB5A in socket on platter - detail

21HB5A in socket on platter – detail

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:

Greenlee 1.25 inch punch bushing for hard drive platter - dimension doodle

Greenlee 1.25 inch punch bushing for hard drive platter – dimension doodle

Advertisements

  1. #1 by Keith Neufeld on 2016-09-19 - 11:05

    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?

    • #2 by Vedran on 2016-09-19 - 11:20

      I’ve dremeled some from 5-10y old disks and it didn’t look like glass.

    • #3 by Ed on 2016-09-19 - 11:34

      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…