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This question is pretty niche, but maybe someone investigated this topic before me and can give advice.

I want to source voice coils from HDDs (new or second hand ones). The more torque/force the better. What HDD properties do I need to look out for to have higher chance of finding stronger voice coils inside them?

  • the old 1980's mainframe drives with 14 inch platters had huge magnets and voice coils that could accelerate to the velocity of around 300 MPH in the distance of 6 inches ... it is kind of hazy now, but it was something like that – jsotola Jun 14 '19 at 22:13
  • That sounds great. What name/description do they go by? – matthias_buehlmann Jun 14 '19 at 22:50
  • what are you trying to do? – jsotola Jun 14 '19 at 23:05
  • i think that it was IBM 3340 or something similar – jsotola Jun 14 '19 at 23:13
  • If you are going to want coils in any quantity it'll be cheaper to make them, or have them made. – TimWescott Jun 15 '19 at 03:36
  • @TimWescott, what makes you think it would be cheaper? Voice Coil actuators for positioning stages are actually pretty expensive. I want to see if I can make use of HDD voice coils and fun them with my own PID and position encoders – matthias_buehlmann Jun 15 '19 at 09:19

2 Answers2

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Look for high capacity drives,

More capacity means more platters, more platters means a heavier head assembly, and that's going to require a stronger voice-coil.

High capacity is a moving target, so you want to look for drives that were the largest model in their series when they were manufactured.

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Disk drives have not used linear voice coils for at least the last 2-3 decades. The last ones I saw were on the bulky 14" and 8" drives used in workstations in the 1980s.

All modern drives (5.25" and down) move the heads on an arc using very flat but powerful rotary positioners with strong arc-shaped permanent magnets as stators.

Dave Tweed
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