In the middle along its length, indicator spindle 1 has integral worm a which meshes with worm wheel 2. Rigidly attached to the shaft with wheel 2 are gear 3 and revolution-counter hand (telltale) 4 which indicates the number of whole millimetres. Gear 3 meshes wi th pinion 5 which is rigidly attached to large hand 6. Hand 6 indicates hundredths of a millimetre. Backlash in the mechanism is eliminated by spiral spring 7. Spring 8 provides a constant contact pressure. Spindle 1 is connected by a screw pair to bracket 9 to which one end of spring 8 is attached. When spindle 1 is turned, bracket 9 is traversed axially, adjusting the contact pressure. Guide 10 prevents rotation of bracket 9.
$2834$WG,M$