Hard Drive Screws

I'm currently building a mech KB and I want to use some screws I have sourced from old hard drive cases.

I have the driver for the screws, however I am running into a problem trying to determine the thread pitch. I need to tap the holes they will be used in.

I also have found that the battery in my calipers is dead and since I live in a one pony town, I have to order a new one online. The finest thread gauge I have is 35, so I know its smaller than that.

I thought it was m2.5 x 45, but that proved to be too big. I think it may be the right pitch though. I can't quite tell, as the screw is too short to reach the threaded area of the tap for a side by side comparison.

When I lay it on a scale the screw looks to be more like 1.5 or 1.25mm.

Can anyone help me out with the tap size and pitch I need? Bonus points for also letting me know what drill bit is needed.

Thanks for reading!

 

this is out of my league, but these people might be able to answer your question:
https://www.metricscrews.us/
my brain was freezing over at the multitude of screws they carry,
and they'll make custom screws if needed,
so, i would think, they would know all about tap size and pitch.
anyway, good luck with it