When I was about 14 years old, the female spline in the rear hub of our old Allis Chalmers B wore to nothing and that was hay mowing done for that day. I pulled the wheel hub and visited a local machine shop who tried to explain why they couldn't help (especially at the price we could afford...)
Putting new steel in where it was needed seemed simple enough to a guy who had no idea how the spline had been accomplished in the first place. When the broaching process was explained to me, I realized that it was an integral part of manufacturing, though I'm not sure I've ever seen an actual machine. Simply explained, a lathe removes metal by chiseling it away in a rotational motion, broaching chisels linearly. No news to many of the audience, I know, but a broach is effectively a collection of single-point cutting tools arrayed in sequence, cutting one after the other. Broaching was developed during the 1850s as the need for accurate keyways in shafts, pulleys and gears developed. in the mid 1890s, Joseph Napoleon Lapointe, originally from Ste. Hyacinthe, Québec, invented a much improved broaching process and left Pratt and Whitney to start his own company. That company, Lapointe Machine Tool, struggled along for awhile till J N was forced out in 1911. He and his son immediately started the J N Lapointe Company, making broaching machines like the ones in this post in direct competition to his former company. The original Lapointe Machine Tool company is still around. J N died in 1928 and the son Francis shows up later in Ann Arbor at the American Broach Co. which served the automotive companies and munitions industry, especially during WW2. It is also still active today under different ownership.
As for that struggling, sunburnt teenager in the hayfield, he ultimately got a used hub at a wrecking yard, first experience with that world, and the haymowing resumed.
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Cyclopedia of Modern Shop Practice, American Technical Society Vol III, 1919 |
1 comment:
That brings back memories; in my teen years I worked a summer at a 19th-century factory that made automatic floor shifter assemblies for Ford. They used a keyway broach to cut a slot in the lower end of the shift lever, where it connected to the linkage. That was the final machining step before heat treating, which was done outside (!) so the broach was outside too. My job was to measure the slots with a go-no go gage and let the machine operator know when it was getting close to time to call the toolmaker (an elderly Italian man named Rocco who taught me a lot that summer) to change the broach cutter. When the broach wasn't running, I got to man the "repair" station...shifters that felt too tight or too loose would be dumped off there and I would take them apart and fit thin stainless washers on ether side of the pivot linkage until it "felt right." The repair station was a coveted job that typically required union seniority but since I was hired as a "temp" through an agency I could do any job. Guys would literally walk by and give me the finger and call me names but it was good preparation for later on when I worked in auto plants as management.
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