Double Helical Cut Tooth Mill Pinions - These were widely used in steel mills. Double Helical gears feature increased tooth mesh contact area vs straight cut gears, for the ultimate in power transmission, yet without the side thrust common to single helical gears, resulting in a lighter (cheaper) bearing.
Other items in photos shown for size comparison - Not included.
model is for display and operating model railroad load / modelling and
is not a child's toy.
For use by railroad modelers age 14 years minimum.