How to Scarf Flues -
John Massey is home again, and Jim Skeevers is only foreman of the shop to shop men, and plain "Skinny" Skeevers to the engineers.
Massey and the Old Man took a walk through the shop the other day, and were clear out in the boiler shop before they ran onto Skeevers; that hearty was testing some flues that had just been safe-ended by pounding the welded end on the floor.
"Skeevers," said the Old Man, as he cut off a mouthful of plug, "are you working up one of your object lessons?"
"Well, yes, sir; sort of a limited one."
"Where have you put that scarfing machine, Mr. Skeevers?" asked Massey, looking up at the holes in a girder and the dirt where a countershaft used to be.
"Outside there by the scrap bin."
"Outside! Why, man, I only got that running a few days before you took hold here - you ain't stopped usin' of it?"
"Yes; I think I have found a better scheme - I'll show you how it works."
As Skeevers moved away toward the flue welder, the general master mechanic dropped back with the general manager and remarked:
"That's a shame. You remember how I showed you the way the scale prevented a good weld when the scarfing was done hot, and that you aproved my home-made tool to cut the scarf - 'cause we always have clean metal to weld. Don't you remember?"
"Yes; 'pears to me I do."
"And now this loonytic has throwed the scarfer away - and it cost three hundred dollars."
"Say, Mr. Skeevers," said the Old Man, "did I understand you to say you had thrown the scarfing machine away?"
"Let me explain after you see the way we weld the tubes now - think I could make it plainer then."
"All right, sir."
Skeevers stopped before several sets of flues standing on end against the wall, and, selecting one, gave the stone floor a smart rap or two with the safe end, breaking it off through the weld.
"That," said Skeevers, picking up the piece, "is one of a set of flues welded before the scarfing machine was made - a set too short, been up at Granger for a year. You see that the welded joint is very thin; half the metal did not join, and looks black. Now, some of these do pretty well, but in time give out, causing trouble. Mr. Massey looked at some of the broken welds, and came to the conclusion that it was scale - it certainly looks like it. Now, he sought to cure the trouble by furnishing clean metal at the welding point, and he got it with the machine toggled up out of an old bolt cutter. Now, this next set was welded up last month, using the cut-scarf ends."
Skeevers broke one as before.
"Pretty fair job, but you see that the weld looks just the same as the old one. The welded joint is not more than half as thick as the tube. Looks as if there was scale in there yet, don't it?"
Massey looked at the safe end; the Old Man put on his specs, and gave it a careful inspection.
"Break another one," ordered Massey. Skeevers took down one, and it required several blows to break it, but it finally broke in the weld.
"Pretty good job that, as welds go, but it broke in the weld, and it looks the same, Mr. Wider."
"So it does, so it does."
Skeevers looked at Massey, but that worthy had fished up a pocket magnifying glass and was looking very wisely at the break.
"Now," said Skeevers, modestly, "I got to thinking about the trouble we have had with safe ends, and the result is that I defy you to break this tube - selecting one from another set - in the weld."
Skeevers slammed the welded end on the floor time and time again without other effect than to batter the end, then he put it in a vise and, with help, bent the tube - but not in the weld.
"Beats the devil, don't it, John?" piously remarked the general manager. "How do you scarf 'em, Skeevers?"
"Don't scarf 'em at all."
"Thunder and - !"
"Watch that weld being made there," said Skeevers.
The workman took a flue out of the furnace, knocked the hot end on the anvil to clear it of the scale, slipped it on to the mandrel under the little trip hammer and the other end in a V-notch, made to receive it, the end itself resting against a post. His helper brought a safe end from the same furnace at the same time, knocked the scale off, slipped the hot end over the mandrel and gave it a smart rap or two with a heavy mallet. The workman put his foot on the belt-tightener, and the little hammer played a tattoo on the flue as the smith turned it over once or twice with his hand.
"That's jumping of 'em on," observed Massey, "and any mechanic knows that a 'jumped' weld ain't no good."
"That all depends on what you've got to 'jump' and the conditions of the heated parts. Now, if you take a 1-inch rod and a 1/2-inch rod and put 'em in the fire until one of 'em is at welding heat, which one will get ready first, Mr. Massey?"
"The smallest will."
"Just so. Now, nine chances to one if you leave 'em both in till the big one is ready to weld, the little one will be burned. If they are both the same heat - dripping hot - a 'jumped' weld, as you call it, is just as strong as any that can be made - stronger, in fact.
"Now, your scarfed tube and safe end has a sharp edge, and that edge gets hot first, and is burned when the body of the tube is hot enough to weld. What's the result? - a bad weld; looks like scale, but it's burned material.
"With a butt weld, the material of the tube and the end are of the same size; we heat them in the same furnace, to the same heat, and make a perfect weld. Cut one of these tubes in two, and you will find the metal clean and solid clear through, and a little thicker than the tube - that is on account of the mandrel, and explains why you can't break the tube in the weld. I'll give a dollar for any tube there that you can break in the weld."
"Then the scarfer is no good?" asked the Old Man, passing a sly wink to Skeevers.
"Just the same as winter before last's overcoat - you don't need it now."
"Well, that's an object lesson, John," said the Old Man; "kinder of a litter of em. Firstly - Old prejudice against hoppin' welds is dead wrong on flues. Secondly - Scarfin' machine no earthly account where you don't want to do any scarfin'. Thirdly - Thinkin' about a thing is important. Fourthly - Thinkin' in the right direction is more important. What's the use of thinkin' up a scarfer, when you can just as well think up a plan to stop scarfin' altogether - say?"
Massey wandered on to a fire where they were making grab irons by the cord.
"Say, Skeevers, darned if that wouldn't be worth a patent; I'll go halves with ye. Lemme see; what do you do? Don't scarf flues for weldin.' Hum -why say, Skeevers, you can't get a patent for not doing something, not if it saved a thousand dollars a minute, could you now?"
"Well, hardly; I did think I was original in that till day before yesterday, when a drummer for a boiler plate company came along and I showed it to him.
"'Why,' said he, 'Skeevers, old boy, that's old - 'way back yonder. Why, man, you couldn't get Bill Tyler to weld a flue any other way, and he's been in the business so long that he's some relation to half the flues you see around the country. The government specifications call for butt welds - where have you been for the last ten years, anyway?'
"Give me a lot of chaff like that, but he owned up that he never heard of a railroad welding tubes that way, but he said, 'What's the use of telling these ducks anything, anyway? They never go around to see other things, and they feel sorry for everybody in the world 'cause they don't do work as they do.'"
"John," said the Old Man, as they caught up to Massey, "if you've got such a thing as a note-book with ye, just put down in large red letters, 'Jumpin' welds is the stuff!"
"Say, Skeevers," he added, "couldn't ye work that scarfer off on Davis for a lathe or a lean-to, or a chimley, or something?"