I find the smaller, 1" driver balls to be perfect for stubborn thermostat screws. Over time the nickel (or whatever) coating on the screws corrodes off, due to poor contact and electrolysis due to poor t-stat construction. (They manufacturers don't clean up the flux after soldering and the residue causes corrosion. I started cleaning contacts and wiring on new stats with 99% ethanol spray just to eliminate this problem)
So many t-stat screwdrivers are so small diameter a normal mans hand's just can't get enough grip. The small EASYDRIVER's give me the grip I need to pop those stuck screws off! And if I break one, I have a pill bottle full of extras I've confiscated off of old stats for just such a use.
The size on these really is very handy.
I picked out the two smoothest ones to send you, but I would recommend drilling a small 1/16 the hole and introducing some oil like i've done to mine and the one I'm giving my dad.
It's made such a huge difference and they're so smooth now.
I'm not sure if it's just these Pratt Read examples or if the small ones were always stiffer than the full sized ones, but it's such a simple fix regardless.
