Getting the objects to the correct size & scale

[YsFLY]

Hello everybody,
I'm having a little difficulty in making my objects exactly to size.

i.e: I want 2 gear wheels spaced 54cm apart, 1 @ 42 teeth 1 @ 20 teeth BUT~ every time I try THE PROGRAM~ shows them in relation to the 1m standard scale, BUT~ not at their correct scale.
Is there a way I can deal with this .... Please?

[electronicboy]

I'm sure someone else may understand what you're asking exactly, but I'm not too sure.

Could you maybe jot up a quick image to show what your trying to do? (making sure to show measurements and such)

[jon_joy_1999]

in order to get gears to be sized correctly, you also need to know the tooth pitch of the gear