Have you ever needed to see the targets at both ends of an Invar stack at the same time?  We have - especially when calibrating a theodolite system using scales or calibration targets such as Brunson's 6000-CE.  That's why Brunson designed the 8665-G3, -G4 scale holders with a knurled lock knob on the base.  Loosen the knob, and you can rotate the upper portion of the scale holder to the axial angle needed to match the orientation of the fixed scale holder on the other end.

The 8665 Series also incorporates our new "squeeze" lock scale holder clamp. This improved scale mounting clamp has a movable jaw which moves laterally from the side to firmly clamp the scale. The scale holder will work with all old and new style scales, as well as all older Cubic Precision (K+E) scales.

 

The 8665 Series comes in both English and metric units - see the table below for the effective lengths of each. 

Model	Effective Length*
8665-G3	1" ±0.0003"
8665-G4	25 mm ±0.008 mm

*Effective Length is the distance from the bottom interface surface of the scale holder, which mates with the end of the Invar Tubing, to the top interface surface, on which rests the bottom of the scale.