Abstract: An "add-on" vernier adjustment device for retrofitting to machinist dial indicator holders for enhancing measurements. The device is installed upon the articulated, multi-link arm of the dial indicator holder, and by adjusting a single rotatable knob, vernier dial indicator adjustments are facilitated in response to holder arm pivoting. Partial disassembly and then reassembly of the holder's original equipment is necessary to properly fit the device to the holder for subsequent vernier control. A rigid, box-like body is pivotally associated with a first arm link and is secured to the arm by an adjustable screw. A saddle, operationally coupled between the device body and the arm, comprises a rigid, generally rectangular, slotted member which surrounds and slidably receives the second linkage member of the arm, which before and after device mounting is functionally pivoted to the first arm linkage.