Things
That are Usually Wrong
"Things that are usually wrong." In my experience, those are usually the blowhards. They know they're wrong, but they hope bluff will convince others (and themselves I suspect) that they're right.
If
the machinists of a hundred years ago were anything like the machinists I
worked with years ago, I can understand how Professor Sweet was driven to
constantly write in the pages of American Magazine telling the blowhards how
wrong they were. He was constantly contradicting false ideas, goofy assumptions,
and plain rancid ignorance.
Some of the articles he wrote were collected into this small book, reprinted, and no doubt, distributed to know-it-all machinists who hadn't read the articles.
Idiots
and blowhards are convinced they know everything. The rest of us feel more
and more ignorant the more we learn. So this is worth reading for us, but
a blowhard doesn't need it. He won't learn a thing.
Short, sweet, and like he says, you wish it were much longer. Cheap. Get one. 5-1/2 x 8-1/2 booklet 52 pages
No. 23926 ... $5.95
PREFACE.
The following is in the main a reprint of a series of articles published in the American Machinist, and it is thought by the author and publishers that it will be found useful to Mechanical Engineering Students, Machine Designers and Inventors; and should those who buy the book be disappointed they can console themselves with the fact that it did not cost much.
It will not be strange if, among so many statements, some are unjustifiable; but those who hunt them out will profit more by it than those who accept all as fixed facts.
The book is small and it is the hope of the author that the most of the readers will wish there was more of it. JOHN E. SWEET Syracuse, N. Y., May 1, 1906. Equal Length Wearing Surfaces.
Excerpts...
Something over thirty years ago, in a series of articles in Engineering, the writer advocated to a considerable extent the advantage of equal-length wearing surfaces, and being at that time in a position to put his ideas in practice, had built, among other things, a milling machine in which both the knee on the column and the horizontal slide had equal-length wearing surfaces. The machine has been in use ever since and neither slide has worn enough to need taking up, much less refitting. A punching machine was built in which the slide was a mechanical fit without any provision for taking up wear. The last time the writer saw it it was in perfect condition. The cross-slide of the lathe built in 1882, illustrated in the American Machinist in 1889, has never had the slack taken out of it.
The first Straight Line engine, built in 1872, had crosshead and guides of equal length, and when worn out both were as truly straight as when made. Ever since those days the writer has been preaching right and doing both right and wrong-right when he had the courage, and wrong when he was silly or too much of a coward.... Overhung Cranks.
The common form or way of putting on overhung cranks is not the best. Mr. Charles T. Porter in his first engines reduced the overhang to its lowest safe limit and maintained that point ever after. To illustrate the the idea Figs. 9 and 10 show the difference between common practice and Mr. Porter's idea, or just the difference between right and wrong.
In the case of a Corliss or other engine of the side-frame sort, this reduction of the overhang, besides reducing the twisting, reduces the tendency to swing the cylinder from side to side, or... Slide Rests of Lathes.
There has always been diverse practice and, from time to time, much discussion about the guiding of the slide-rests of lathes. The V has the merit of remaining free from lost motion, however much worn, but nothing is much more ridiculous than two V's, as the one at the back does no good and costs money. The common flat way is bad because the guiding surfaces are too far apart. The plan adopted by John Lang & Sons, Fig. 23 A, is much better.... Shaping Machines.
There are certain things about shaping machines that were made in certain ways by the inventor Nasmyth, which ways have been followed by every manufacturer from his day until the present time. One of these things is the location of the guiding slides of the ram, which are, in the main, as shown by Fig. 24. So far as the guiding feature is concerned, that location is as proper as any, but there is another feature and that is the "cocking" or setting over of the tool-holder slide for planing at an angle, when, if turned to a slight angle, the tool-holder slide collides with the guides. If the guiding element were placed... Unfastened False Valve Seats.
Years ago it was not an uncommon thing to put on false seats for the slide valves of locomotives. It was common practice to use screw rivets to secure them, and Henry Watkeys, master mechanic of the New York Central & Hudson River Railroad, proved himself a genius when he abandoned the use of all fastenings. He simply cast horns to fit inside...
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