Mac pro HDD caddy screws

[mackmack]

Is there any place that sells these screws? After a few HDD swaps the heads of some of my screws have worn down.

 

[gugucom]

They ought to be metric M3 or M4. Just measure the width and replace them with hex headed screws. Beware of fine thread instead of standard.

Edit: They are actually UNC 6-32.
http://www.hitachigst.com/tech/techlib.nsf/techdocs/85256AB8006A31E587256A9300683AB6/$file/dala_spw.pdf page 37
You can get them with Philips head.