42 Broadway, N. Y., Oct. 21, 1907.
Chas. T. Porter, Montclair, N. J.
My Dear Mr. Porter: In reply to your request of 14th addressed Cold Springs, I am pleased to give you such account of the crank pin work at B. F. Avery & Sons, at Louisville, in 1883, as my memory will admit of.
When I was instructed to do this work I received a letter from you stating that a new crank pin was to be put in and that it should be “hardened in a furnace,” allowing it to remain in a crucible with the carbon at a lowered heat for ten hours.
This was done and resulted in a fine job of hardening. The pin was then ground true and smooth. Don’t think I ever saw a prettier job.
The old pin had to be taken out and the new one put in. The exact diameter of the old shank was not definitely known. It was thought advisable therefore, to make the new shank about ¹⁄₃₂″ larger than the drawing dimension; so it would surely be large enough to admit of drawing the hole which I proposed to do by hand. Before leaving the works I had a hollow cast iron cylinder or trial plug made, about twice the depth of the crank pin hole in length, about ¹⁄₁₀₀″ smaller than the shank of the new pin and slightly tapered at one end.
We cut the bead off the old pin and tried a hydraulic jack on it, but it would not start. We then drilled five or six 1″ holes in the shank and the pin came out easily. The hole was then calipered and found to require considerable dressing. The crank shaft was then tried for level and found by turning in various positions and by using a very sensitive level, to deflect from the horizontal approximately ¹⁄₂ of 1000th of an inch per foot in length.
The hole was then enlarged by use of file and scraper, its adjustment being proven as the work progressed by frequent trials of level placed within the hole, at various points in the revolution of the shaft. Finally, the trial plug was worked into the hole and used as a surface plate, the “high” spots being scraped down and the plug found to line with the shaft and the hole by caliper, found to be approximately ³⁄₁₀₀₀″ smaller than the shank of the pin. The pin was then forced in and found to stand nearly true. The small untruth was easily corrected in riveting up the back and the pin was thrown approximately ²⁄₁₀₀₀″ away from the center line of shaft rotation to offset the deflection that would be occasioned when running by the impact of the steam admission on centers.
I think it quite likely that the pin during the twenty-four years’ service up to the present date has worn scarcely a measurable amount.
Very truly,
E. F. Williams.