This is a Checkpoint Platinum motor designed and made by famous motorbuilder Big Jim Greenemeyer. The steel can had a much thicker wall and was housing high-strength Hitachi Grade 8 Wet-Press magnets where other motors were using Grade 5 magnets that time. For improved heat-transfer a “Black Wrinkle” powder-coating was used at the can, the same type as used at several Trinity motors later.
Endbell and frontplate of these motors were machined from aircraft grade aluminium. For showing this is an all American design Big Jim decided going with 4-40 motor screw holes instead of the usual M3 thread. For brushes and springs the Platinum was using the same slot-type system as most of Checkpoints modified motors before.
The Platinum motors were manufactured from 1985 – 1990 at Costa Mesa, CA and approved by ROAR and IFMAR.
update on the powder-coating for the can: according to Big Jim the last two batches of Platinum motors received a “Silver-Vane” painting instead of the “Black-Wrinkle”.
So motors like this were the latest versions of the Platinum.
Sometimes you can find vintage motors looking similar to Platinum motors but using standard brushes and springs instead of the typical slot-type setup. These motors are not true Checkpoint motors. Some of the Platinum cans were sold to Fantom and assembled using Fantom’s own armatures and standard-type brushholders and brushes. So in the end these are Fantom motors based on the Checkpoint Platinum can.