Friday, December 26, 2008

keyways; damaged, worn and mismatched.

Once upon a time.....
I had a job to do on an old lathe of 38" swing.. The handwheel that moved the heavy tailstock was missing from the shaft of the pinion that worked against the rack. Anyway, I had on hand a suitable diameter handwheel from THE SAINT ELIZABETHS' INSANE ASSYLUM water system (thanks JC.). Obviously a special if somewhat eccentric wheel. It fit over the shaft nicely, but the keyway on the shaft was a typical 1/4" for that one inch shaft. The rub was that the hole in the wheel was square, and the recombinant space appeared as the shape of a short, squat arrow. Not even in packrat heaven would you find such a key as that. Hmmm. I thought about the usual paths, but being in a hurry it occured to me to melt a bit of brass and pour it in the abyss and thus let the hotter than gravy, liquid shapeshifting brass assume the perfect form. I dammed the backside of the affair with a bit of whatever was handy, and would stand the heat for one or two seconds. And the rest was Hisssstory. TAda.
Not even this patron saint of old machine tools would expect the mailbox to be stuffed with thanks from the faithful, testifying to the miracle cure for their 3 1/2 ton lathe. I ignored the one letter demanding return of the valve wheel. Get their own damned wheel! However, the problem of damaged, mismatched (different size or configuration) keyways may on occasion be helped in this way. Being that there are countless trillions for keyways, I'm preparing for the mail sacks. I have no stats on how long this type of fix would last under power and running steadily. Any inquiries about the River Road water main break, long response time and missing handwheels should be directed to my lawyer.

Thursday, December 25, 2008

"A poor man will do any damn thing", a quote from Jim the machinist, now gone to his reward. I struck me as funny, and probably because it's more or less true. After buying, trading for, and other wise obtaining various machines and gadgets, I see an archeology of attempts to repair and refurbish and just plain get the last mile out of the poor thing, and don't forget saving the money. Jim came from southern Virginia where money was scarce in his boyhood, time more plentiful, and tinkering in great supply. My background not being very different, I and the great fraternity and sisterhood of Hillybilly Technologists, find ourselves arriving at what Brother Gordon calls Evolutionary Convergence, ie. give us a bit of string, a rock and an Appropriate stick from the ground and all can be set right in a way that naturally gravitates to the conclusion that is suggested by the extent circumstances.

In my 12 years run of full time repair, welding, manufacturing( typically one-off and small runs) and fabrication in my own shop, and 17 more years in U.S. govt. shops, everyday is a new adventure, or struggle, to make it work, or just make it. So, as I recall or divine new tricks and means I'll add one now and then. I would also be glad to review and add contributions from readers who are still smiling about a victory over the forces of rust, twisting, stripping, wear, bad design ( a really tough category!) unsavory previous attempts by the heathens ( perhaps the worse case), and breakage. So grab your string, rock and stick and we'll meet at the point of convergence. Jon