Someone mentioned in another thread the desire for a type study on block planes.
There are type studies on the #9-1/2 and the #18/#19 standard angle block planes in the John Walter book. If there is a type study on the #60/#65 low angle block planes, it is well hidden.
Always the curios one, my time this morning was spent looking at different images of, yep, low angle block planes.
My main interest was in a way to determine when the area of bedding changed on the #60 from a pretty decent size to its minimalist size.
It comes down to not only having access to a lot of images and or holding the planes, but how does one determine when a plane was made without some kind of conclusive evidence? What should be considered as conclusive evidence?
Finding a progression of changes is not real difficult. The ease of this comes from an understanding that many changes came about to lower the cost of manufacturing.
Then how does one deal with changes that overlap?
Here is just one item that changes throughout the years of production of low angle block planes, the blade depth adjustment mechanism.
In the beginning, the slide and the knob were cast.
Cast slide.jpg
Then came the stamped/folded metal slide, first with a knurled knob that has a recess machined on the side of the threaded rod, then with a flat surface on this side. This is the time period when the blade support at the mouth changes. I have only seen the knobs with the recess on planes with the larger blade support area. I did see one image showing a non-recessed knob on a plane with a large area. Most of the non-recessed knobs were on planes with the minimalist blade bed. No way of knowing if the parts were replaced. Also, the image was not as sharp as would be wanted to make this a definitive marker.
Early Knurled.jpg
This looks like it may be a later production with the slide's metal not doubled at the threads, but stamped through, then treaded.
Stamped Nut.jpg
The final change seems to be another lowering of cost. The slide is now just a stamped piece of metal that is slung over a slot on the adjuster shaft. Less threading, less cost and less plane.
Bend & Hook.jpg
The images quality could be a lot better, but this is just for fun, right?
jim