Abstract: A bore gage for comparing interior dimensions of a bore with a master. The bore gage includes a pivot mechanism containing centralizer contacts, and a pivotally mounted lever containing a sensitive contact, which, in conjunction with a reference contact, compares the interior surface dimension of a bore. Both the lever and the pivot mechanism containing the centralizer contacts are mounted in an exposed position on the bore gage head to allow easy cleaning, maintenance and repair thereof. The pivot mechanism includes a member that extends around the bore gage head. An associated adjustable stop limits movement of the centralizer contacts. The gage unit, an extension housing and the head may all be readily separated from one another for cleaning and maintenance.