NOTE: This type discussion, along with the foregoing material, is based on personal examination of numerous Bed Rock specimens since 1973. Frog & bed machined & mated 100%; inclined frog seat. Keen Kutter Bed Rocks had plain lever caps and Winchester Bed Rocks had Winchester marked lever caps.Many specimens have been seen, but there is always the potential for finding a new type or an anomaly.
Start by reading Patrick Leach's comments on Stanley plane dating. If you thirst for heaps of data on plane dating, visit the Plane Type Study or the Plane Feature Timeline. This page leads you down a hypertext flowchart to determine your plane type.
It includes links to Patrick Leach's original Plane Type Study and the Plane Feature Timeline.
This approach doesn't guarantee that you'll date your plane correctly, as the flowchart can be thrown off by some hybrids.
The best approach is to use the flowchart to date your plane, and then visit the Plane Type Study and Plane Feature Timeline to verify the type. (Does anyone want to take pictures of parts that are hard to describe?
This collar, as well as the cutters, are very easy to lose, and these planes are often found minus them.