This high quality aluminum flexible coupling can be used to connect your NEMA23 stepper motor to your lead screw. The flexibility will help with any misalignment.
Shaft: 6.35mm x 8mm
OD: Outer Diameter: 19mm
6.35mm fits a NEMA23 stepper while the 8mm fits our ACME Lead Screws.
Main dimensions: d1=6.35mm, d2=8mm, D=19mm, L=25mm