I need those little screws that attach the rotor to the hub so I can hold the rotor still while reattaching the calipers.
What size is are those little screws ?

I think they are M6x12

Thread pitch should be;
6mm x 1.0mm

Thanks…

Is there different pitches for metric machine screws?

No. But it is a M6x1.0 screw. With the tapered head, you will probably only find allen head screws in your local hardware store.

If you want to be picky, go to your P car parts place. They can get an original screw.

Your rightt( Ace Hardware only has 4mm Allen head screws. They will do what I need…

I use the SS screws that hold the mirrors or the door catches.

Exactly the ones I use.

Ace hardware... My local bolt bin. If I don't have it in the garage, Ace is only a mile away. They know me by name there and greet me like an old friend.

And they have an impressive collection of metric bolts and nuts.

Ace is the place.

Clay

Those screws serve no purpose one the lugs are torqued...

Just use a couple lug nuts to hold the rotor snug to the hub while adjusting the calipers, then pull them off and install the wheel.

My father was an automotive engineer. His favorite saying was "Everything costs money, so engineers don't put parts on cars for the fun of it." That 10 cent screw over 100k cars adds up as profit lost for the manufacturer. So it definitely has a purpose, even if you can't see it.

Clay

I was told the screws help prevent torqueing the lug nuts with the brake disc off centered. I would think they would keep crud from getting between the hub and rotor changing a rear flat, potentially putting the wheel off.

I removed mine for reduction in unsprung rotational weight.
Saved almost 0.02 seconds off my fastest time to work.