Just a Coupler of Things

Helical Beam Shaft Couplings

These are the Helical Beam Shaft Couplings I ordered for the HB2 project. The size is 1 inch in diameter and one inch in length. These are the clamp on type and so will not mar the 1/4 inch shafts like a set screw.

These couplings are rated to withstand 42 peak inch/pounds of torque. That’s 672 in/ounces. The holding power of the steppers is a little over 300 oz/inches so there is a 2X safety margin in my selection.

The helical in the name implies a coil and if you look close you can see there are two coils cut into each coupling. The material is anodized aluminum and adds very little weight to the rotating mass.

This may be a bit deluxe, but the motor drive train is a critical operational part in the design of any CNC machine and I want zero binding between the motor and the screws. No steps dropped because of alignment problems.