Hard Drive internal components

[Jaepheth]

I cannibalized a Hard Drive for it's parts a while ago (not to be used as a HDD, obviously) and now I can't find the screw that threaded into the armature bearing.

I'd like to use said bearing in a little project so I'll need to find a new screw, and was wondering... are the internal components of a HDD imperial or metric?

My General Tools brand caliper is telling me the major diameter is .125" (3.15mm), which would indicate an imperial size.

If I were to tap a hole to attach this bearing to, should I use a 5-40 or 5-44 tap? (I actually will need to buy a tap as well)
Or is my caliper off by ~.01" (which I doubt, but I don't have a standard to test the caliper with) and I should be looking at a metric M3 x .05 tap?

 

[corkyg]

Why not find a dead dupicate drive on E-Bay and cannibalize it for the missing screw?

BTW - what good are such parts?

 

[Jaepheth]

I'm going to use the bearing to provide a stabilizing point on my GSI coffee grinder's conical burr by drilling and tapping the axle. I'll also need to create some custom hardware on my new micro lathe. Hopefully it will vastly improve the consistency of the grounds' size for my french press.

In general though, hard drives are full of useful stuff. Powerful magnets, magnetic shields, and precision bearings to name a few.

I guess I'll just have to find the time to cruise around some hardware stores and try different threads in person to find one that fits.

 

[corkyg]

Yeah - I would say you are in uncharted territory. Great entrepreneurial spirit! Good luck!