[Patrick]

Yeah I think mine go in about 5mm. The holes in the front of the new are big enough that you can pretty much see if the screw is going to hit the windings or if the screw is all the way through the thread.
I put the screw in by hand (just the motor, not on the mount) as far as it thought was safe then measured how far in it had gone. I also measured how far in it needed to go to use all of the thread. Then you know the range of screws you can use.
Put the screw through your mount and measure how far out it sticks (how far it's going to go into your motor).
Find a screw that's in the safe range for the motor.