Add a Concentric
mate between the scale and pin. Flip the alignment (aligned/anti-aligned)
if necessary to correctly orient the pin.

Because the scale is already constrained to be concentric with the head, the pin and the clamp move within their degrees of freedom to the position shown.
Add a Coincident mate between:
The planar face on the end of the scale
The planar face on the pin

Close the PropertyManager.
