Machine of the Month: Bryant Chucking Grinder Model 10 A

Machine of the Month: Bryant Chucking Grinder Model 10 A

The Machine of the Month is Model Number 10 A, manufactured by Bryant Chucking Grinder of Springfield, VT.

The Number 10 A introduced a unique method of moving the grinding wheels in relation to the workpiece. It was called the “Three Point Suspension” system, and it was used by Bryant at least into the 1970s. Instead of having conventional ways below to slide on, it has an overhead cylindrical bar on which the grinding spindles are moved back and forth (to the operator’s left and right) and swing from side to side (away from and toward the operator).
To change the diameter of the hole in the work, the head would swing away from the operator, controlled by turning the handwheel at about hip level with two handles.

Bryant’s first machine, called the Model 12 x 12, which was rolled out in 1909, had a larger capacity than the 10 A. It could also accomplish three operations in one setup (grinding the ID, the OD, and one face), but it was more than two-and-a-half times as heavy and took up much more floor space. It must have been expensive; apparently, not many were made. (APM owns one of these too.)
This picture is misleading, probably intentionally.
Our 12 x12 machine is bigger and huskier than the one pictured. There are a lot of levers and lubricant circulators on top that have been removed from the picture.
The handwheel connects with the opposite side of the grinding heads. (↓ This is actually a picture of the very similar Number 6 machine. It could grind the inside of a hole, but it couldn’t do facing operations.)
The spindles would move to a greater depth of hole (for the smaller spindle) and to a deeper cut (by the facing wheel) by moving with the overhead bar. The handwheel moved the overhead bar at the right end of the bar.

Our Number 10 A was built in about 1920. It was given to the Museum in 1986. Unfortunately, it was stored in our basement, a very high-humidity environment. In December 2010, APM moved all the machinery in the basement to a local factory building with much better conditions. After being stored on the park’s plaza overnight, the machines were lifted over the office area (!!) and lowered onto a truck. Then they were moved across town to excellent, low-humidity storage.

About 2016, our 10 A was “adopted” by Don Whitney for restoration. Don had previously led the team that restored the Fellows 7-Type Gear Shaper that now works cutting gears in our Innovation Station. He had some significant help working on the 10A, but for the most part, it was his baby. Restoring the grinder wasn’t fast. It had gotten deeply rusted in places, and several parts fiercely resisted removal for cleanup or replacement.

Also, Don Whitney wasn’t as strong as he’d been earlier in his life. For most of his life he had been very active in hiking and skiing. He helped maintain hiking trails for the Appalachian Trail and other local trail systems. He helped collect and organize objects from Fellows Gear Shaper Company for a historical display in Springfield. He’d been a trustee of the American Precision Museum and done other volunteer functions for us. Notably, he did research on all sorts of machine-related topics. But in 2018, when restoration work on this grinder was finished, he was 96 years old. Don lived from October 11, 1922, to March 8, 2022. We are grateful to him, and we are glad that we knew him.

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