Why is ammeter binding post are made of heavy and bare metal?

Question

Why is ammeter binding post are made of heavy and bare metal?

Answer 1

The terminals are made of heavy gauge metal in order to reduce any voltage drop to a minimum.

They are not always bare, some of them have a plastic cover.

Answer 2

The whole meter needs to be rated for the current it's carrying, so its connectors need to be sized appropriately. If they're too small these binding points can overheat.

Answer 3

The resistance of a metal post or bar is determined in part by it CROSS-SECTIONAL AREA.  

For example, compare an 16-gauge solid copper wire with a 24-gauge solid copper wire.  The 16-gauge wire will have less resistence than the 24-gauge wire.

The posts in an ammeter need to be as large as possible in order to present as LOW a resistence as possible to the flow of current rhrough the meter.

They are made of BARE metal in order to make better contact into teh circuit, of course.