Material - any machinable aluminum.
Description: 5/8" dia. cylinder x 1/2" length, ends faced off or ground flat. 3/16" wide slot milled 1/4" deep on one end (centered), hole d & t for 1/8" NF thread at right angle to slot* (centered) 1/8" from cylinder end drilled from one outside face to inside of slot.
See sketch.
Quantities - about 12 per order after sample approval.
*and cylinder axis