[Gdeaver]

Grainger and McMaster-Carr. Allot of times they are listed as die cast frame. Bronze bearings are more common but there are die cast ball bearing units. Stamped steel frames and flanges are also light. There are composite units that are extremely strong and light but the price is high.

In 2004 I bought some fiberglass rods in 1/2", 5/8", and 3/4" dia. to evaluate as shafts. Very strong and light. Just a slight deflection under impact. Our team decided against them but, I am certain they would have worked fine and the weight savings is substantial.