The Model-H74-A Helios faceting head incorporates in its design an angle dial which is synchronous with the dop arm and having a ratio of 4:1.   The dial will make one full turn when the dop arm is moved 90 degrees. Provided in the design of the Helios faceting head is a micro adjustable positive angle stop.  This stop does not have to be used for all cutting operations since the angle dial moves with the dop arm.  The angle stop can be allowed to float when not in use. The features of the radial upright incorporates a mast height adjustment regulated by a micro height knob.  The facet head pivots on precision ball bearings.  Since the facet head pivots horizontally on the mast or upright column and not on a secondary pivot, maximum rigidity is maintained.  Vertical movement of the facet head is positive up or down without lag.  Upright scale 1/16" increments.   The design also provides a quick release feature (see "H" in picture) which allows the facet head to be moved up or down on the upright without turning the micro height knob. "A" Timken Precision roller bearing arbor which is adjustable for plane with the upright. "B" Precision Four Jawed Collet Chuck: This chuck is a threaded self centering type operated by hand, no set screws to cause misalignment due to uneven adjustment or pressure.  The chuck is hexagonal which allows a wrench to be used for tightening or loosening if needed. Set Screw in Collet End of Dop Arm: This set screw is a dop arm alignment feature which permits removal and replacement of the dop without need to readjust for previous alignment.  The standard transfer block is equipped with the same keying or alignment of system thereby assuring relative alignment of crown facets to pavilion facets. Keyed Dops: Radial self-aligning. "C" Dop Arm 4" long.  (Adjustable for concentricity to .00025 readout.  Patent #4,265,057. "D" Angle Dial with Vernier scale to read 1/4 degree. "E" Micro height knob. "F" PM Motor -- 70" oz. -- 0 to 1800 RPM.      "G" Mast 1: Dia. steel with 1/16" scale.      "H" Quick release knob.     "I" Radial index tooth splitter, on knob self-locking. "J" Index gear easily changed without removing dop arm.   The dop arm pivots on precision double sealed ball bearings. "K" QUADOMETER: For repeat pressure reading.  Registers the pressure that the operator exerts on the dop arm.  The face of the dial can be adjusted or turned so that a light or heavy pressure can be registered.  For a light pressure the indicator at rest should read .001 to .002 minus the zero.  For a heavy pressure .003 to .006 minus zero.  Pressure is then exerted by the operator on the dop arm until the indicator pointer reaches zero.  Note: Lock out screw between quadometer indicator and fine angle adjustment knob: This lock out screw is for the purpose of locking out the quadometer indicator. MODEL B69-A BASE Low profile, 2" Speed 0-1800 RPM Weight of base 28 lbs. Weight of Facet Head 12 lbs. Torque 70 inch ounces Timken Precision roller bearing arbor which is adjustable for perpendicular plane with the upright.  This adjustment is similar to the leveling adjustment found on surveying transits.

HELIOS MODEL H74-A WITH RADIAL UPRIGHT MODEL B-69-A PM BASE