The Iron Age 1890-07-24: Vol 46

THURSDAY, JULY 24, 1890. ‘THE IRON AGE Turret Screw Machine. The builders of this tool, the Jones & Lamson Machine Company, of Spring- field, Vt., state that it is the largest turret screw machine ever built. It is especially adapted for the heaviest work of station- ary, locomotive and marine — build- ing, also general lathe work and chucking of a heavy character. It will easily do work from the continuous bar up to the limit of its spindle hole, and chucking up to the limit of its swing. It will take in stock up to 3} inches, and is suitable for cutting threads with a die up to 2} inches in diameter. The machine is furnished with a patent roller feed and automatic chuck which handles square, hexagon and round stock equally well up to the limit of its spindle hole. This is operated while the machine is running, and when thus fitted will do from 15 to 25 per cent. Piel be fy ood . oe] AN / . — } d : us , vo Pe ae more work per day than a machine with- out it. The turret revolves automatically ing collars for the accurate adjustment of | a support on both sides and it easily resists the tools. The spindle is provided with back gears, applied by a clutch, operated while the machine is running. The great saving in time accomplished by thus being able to change from high speed used in turning to a slow speed used in cutting a thread, and conversely, will be seen at once. A rotary pump takes the oil from the drip-pot beneath and throws it in a steady stream wherever the operator desires, making the highest cutting speeds practicable. The drainage pan is extra large to hold all the chips accumulated during the day. The principal dimen- sions ure as follows: Diameter of turret, 16$ inches; swing, 24 inches; milling length, 15 inches; bed length, 8 feet 74 inches; bed width, 154 inches; weight, 5500 pounds. The chasing attachment is illustrated by the outline drawing. The chaser is the JONES & LAMSON SPRINGFIELD, VT. U.S.A. TURRET SCREW MACHINE. any strain brought upon it. When not in use this arm can be thrown back in an in- stant, where it is entirely out of the way. The slide block to the threading tool is operated by a screw with ball handle and has a stop that can be quickly set for any depth of thread. The handle at the end of the arm is pivoted and has a lip which bears on the under side of a bar on the front of bed. By this means, together with the correct angle at which the thread- ing tool approaches the stock, the point of the threading tool is easily held down to tue work. This attachment is substan- tially built and fitted throughout with great care, SO The Drawback on Barb Wire.—Under date of June 18, George C. Tichenor, As- sistant Secretary of the Treasury, addressed the following letter to the Collector of Cus- MACHINE CO quickest means of cutting a perfect thread, | toms at New York: ‘On the exportation of as reversing the motion is done away with with the backward travel of the slide, and | and the time lost in running back on an is provided with a patent power feed. | ordinary engine lathe is saved. When the The power is transmitted to the feed rod by a belt running on cones with three grades which give the full range of feed ever required. The curved lever, just back of the pilot wheel, is for throwing the power feed of the turret into and out of gear, and is provided with the new knock off that can be quickly adjusted so that it will mill or drill to any point of its milling length with great accuracy. The carriage, or cut off rest, has a reversible lateral power feed with three changes and may be used for turning like the carnage of a lathe The hand wheel with nut, shown in front at the left, enables the operator to throw this feed out and in and reverse or feed by hand instantly. The carriage is, therefore, operated like that of an engine lathe in all respects, which is eminently convenient. The cross slide is worked by a screw with ball handle, and has a tovl post in front and behind the work. These two tool posts have elevat- desired length of thread has been cut by lifting the arm which carries the tool, the nut or follower is released from the leader and a spring returns the bar to its original position, when the tool is ready to cut anew. Taper and special threads are done more accurately with this tool than in any other way, as it is capable of the finest ad- justment. It is also used for roughin extra heavy threads that are to be sized with a die. The chaser bar is placed just behind the bed, a position giving much greater stiffness than if it were placed above or in front. It is supported by three substantial bearings which give it great strength. The leader runs ona stud at the left end of the head; it is geared from the spindle, so that the threading tool cuts two threads to one on the leader. The arm, which carries the threading tool, is pivoted on the chasing bar between two of the bearings, and it can be set on it at any desired position by a binding screw. Its position between two bearings gives it barb wire fencing, manufactured by the Iowa Barb Wire Company, of Allentown, Pa., wholly from imported steel rods and spelter, a drawback will be allowed equal in amount to the duty paid on the im- ported materials used in the manufacture, less the legal retention of 10 per cent. The quantity of such materials will be ascertained by allowing 4, pounds of spelter, and 102, pounds of rods, for every 100 pounds net of the exported articles. moncnnsinmnsiiigapibiiininiinats Buffalo has no reason to feel disap ointed over the results of the census. hat city’s population of 250,122 is a gain of 95,000 in the last ten years, and leaves Buffalo still close on the heels of Cleve- land. The latest returns indicate that the population of Chicago is almost certain to reach 1,100,000, and that there is no longer room for doubt that the Illinois metropolis has become the second city of the United States, in population as well as in business prominence. Wilmington’s population is 61,275, an increase of 18,797 since 1880. 126 THE IRON AGE, July 24, 1899 The Flow of Metals and Its Relation to Testing. BY P. KREUZPOINTNER, ALTOONA, PA. On Elongation. With few exceptions all metals elongate more or less when subjected to stress, After straining to a certain point and sub- sequent removal of the load, the metal re- turns to its original form or length. The point within which a metal reassumes its original form is called the elastic limit. In other words, metals are elastic in the same sense as we speak of rubber being elastic. The difference consists in the degree only of the elasticity of these sub- stances. Within the elastic limit of a metal its rate of flow, which is indicated by the amount of stretch within a given tional area 0.389 fitted up with microme- ter and electric bells, was ready for test but had to be laid aside to give preference to some other test. Some one, in order to explain to some visitors the manner of making a tensile test, picked up the test piece and pulled with his hands on each end. On letting again of the test piece the electric bell began to ring, show- ing that the test piece could be stretched sufficiently to cause elastic reaction mak- ing electric contact and ringing the bell, Of course the occurrence cau surprise, but since everybody present, and those coming into the room during the day, had to repeat the experiment and pull at that test piece ad nauseam, there remained no doubt that even the few pounds of force exerted with one’s hands by pulling at a bar of spring steel 1 inch wide and 0.389 inches thick caused the molecules of the metal to move and flow. est advantage, and where too much relj. ance on mathematical formule and estab. lished rules may lead to disastrous conge. quences on account of the too prevalent notion that the properties of metals are g fixed quantity and can be solved like a proposition in Euclid. If the load or stress applied exceeds the elastic limit the metal begins to flow visi. bly. It is the rate of this flow, expressed in so many per cent. of elongation per inch of section, which is usually taken as a criterion of the ductility of a metal, The confidence with which the per cent, of elongation as a measure of equality is accepted by the engineer is well founded, provided, first, that care was taken to eliminate as much as possible from the re. sults of tests the retarding and disturbing influences of heads and fillets, and, second, that observations have been made whether the stretch—that is, the flow—was utiform SCREW distance, is extremely small, measurable only by so many tens of thousandths of an inch. As soon as the elastic limit is reached and the stress continues to act in the direc- tion of the length of the metal, then the flow becomes more rapid and percepti- ble, the metal elongating by hundreth and finally by tenth of inches until rupture takes place. Tkose who consider iron and steel as the ideals of strength, rigidity and im- movability, would, no doubt, often be surprised to see what small a force is really required io cause movement of the mole- cules of metals. May not the well-known benomenon of the creeping of rails on ridges or down grade be largely due to that elasticity of steel which, if exerted only to a given degree, may be repeated millions of times without injury to the metal? How small a force may cause movement in the molecules of even hard steel is well exemplified by the follow- ing incident : A test piece cut from a bar of spring steel; section 10 inches between fillet; sec- — MACHINE WITH CHASING ATTACHMENT. This fact, if kept in mind when design- ing and constructing, making stee! for such purposes where with great strength a certain amount of ductility—that is, flow of the metal—is to be combined, or when in- vestigating ‘‘ mysterious” breaks, will often furnish the key to an explanation of what ought to be or ought not to have been done. That superintendent’s head was level, therefore, who refused to make steel of 0.60 carbon for a certain purpose when he knew that a class of steel | | with 0.45 would answer much better, be- cause in the latter, while getting the neces- sary strength, healso got a little flow of the metal, just sufficient to ‘‘ cushion ” the ramlike forces which the steel had to withstand, thus preventing breakage. In the 0.60 carbon steel he would have had a maximum of stiffness coupled with a minimum of that ability to yield at the proper moment which must characterize all metals subject to sudden shocks and vari- able stresses. It is just in such cases where the most intimate knowledge of the nature of materials becomes of the great- or took place in ‘‘starts” and ‘‘fits.” If the flow is uniform, then the measure- ments of the rate of flow expressed in hundredths of an inch and measured from the distance mark to the point of rupture, present a regularly ascending scale, as shown in the table below: Rate of Flow of Soft Steel in Hundredths of an Inch. 1}1/212|8/8/8|8|/814)4/4/515|6/6|719 14]19| ‘otal, 1.04 inches. On the contrary, if the flow proceeds in ‘‘starts” and ‘ fits,” the measurements will be very irregular, as shown in the second table, though the total elongation is considerably more than the first case: Rate of Flow of Soft Steel in Hundredths of an Inch. — 1/21 2/8/2/3/2|1815/217/8/7/ 813) 1) $4 | 64| Total, 1.82 inches. The question will naturally be asked: What reason is there for this striking dif- July 26, Oe 24, 1860 the same classes of metals? To i ad does this difference affect the uality of the material? It must be con- essed that these — are more easily than answere oe nee attention has alread y been id to the restraining influence of heads and fillets on the free flow of metals, and no more need to be said in regard to this point, except that engineers counteract ae "disturbing elements as much as pos- sible by interposing an extra length be- tween the distance mark and beginning of the fillets. Thus, in an 8-inch section, the total length is ordinarily 8} inches between shoulders. By lengthening the straight rt of the test section at eachend } inch Petween mark and fillet, the total length of the straight 4 pry becomes 84 inches, thus getting rid of the disturbing influ- ence of the fillets. In German and Swiss Government specifications this extra por- tion is taken at 10 mm. (§ of an iach). Under the most favorable circumstances, however, the stretch of a metal is found eatest near the point of rupture, dimin- ishing more or less uniformly toward the head in the case of a test ne the eye in the case of an eyebar, the joint in the case of riveted plates, &c. An ideally isotropic material is never met with. The reason for this want of cqual extention of a metal in all its parts is probably found in the want of -—s homogenity. There are blowholes, inations, hard = soft places, effects of unequal cooling, , in the best of them, especially if pro- pa on a large scale in commercial uantities. If the rate of extension or flow is as uni- form as given in the first table, then this is all that can reasonably be expected. An explanation for the irregularity of stretch, as exhibited in the second table, is prob- ably found in the structure of iron and steel. It is well known that these metals con- sist of two essentially different substances. One of these two bodies is softer than the other one, and, generally speaking, in pro- portion as the one or other of these bodies prevails, a metal is harder or softer, r or weaker, brittle or ductile. ing and Martens call these different Dies crystalline and ‘‘ homogene ” iron, considering, in this instance, steel merely as a highly carbonized iron. The greater the proportion of the soft or *‘ homogene ” portion of the iron or steel, the lower its elastic limit and strength and the greater its flow and ductibility, and consequently also its stretch. The observation has been made that whenever the soft portion of the metal prevails there is a tendency to jerky and irregular flow. When closely observing such metal under stress, the impression is made as if the metal wants to brace up to renewed resistance to the pulling force; failing, it is jerked again a greater or less distance; then braces itself again, repeat- ing the ‘performance until rupture takes place. An explanation for this phenom- enon is probably found in the metal be- coming denser at different places, when the flow is momentarily arrested or slowed up until an increase in the pulling force causes a renewed flow. Thus actually several ‘‘heads” may be formed during the progress of a tensile test of soft ma- terial, especially soft, homogeneous steel, such ‘heads ” assuming the function and characteristics of the heads on either end of the test piece. It is well to keep this in mind when seeking for a reason for the well-known fact of an increase of the elastic limit and strength of a metal after having been strained beyond the elastic limit and then allowed to rest. As to the quality of a metal which ex- hibits the irregular flow as described above, it may be excellent metal for all that. Only for certain purposes, however, can it be safely used. For any purpose THE IRON AGE, where a material has to sustain sudden shocks, trusts, twists, or changes in tem- perature, such soft’ metal is not at all ee because, its elastic limit low, the metal, if it should receive a “ den impact which is greater than its elastic limit, will stretch too much before it has reached a point of density which allows it to form a new point of resistance, and subsequently a new elastic limit. In other words, the metal is fatigued beyond the point of recovery and detail fracture is the consequence. Right here it may be in place to call attention to the practice and inclination of some over zealous engineers to take test _— from objects which have already en under strain in one way or another. If the results of such tests serve only to show the changes a metal underwent while rforming ‘‘ work,” then there is no ob- jection. But whenever test pieces are taken from a broken axle, tire, beam, eyebar, &c., and the results of these tests are assumed to represent the natural con- ditions of the metals as it comes from the mill, then such practice is not only unjust to the steel maker, by trying te impose conditions on him which he may not be able to fill to the advantage of the con- sumer and his own reputation, but they are misleading in the the highest degree, and must, if taken as a basis for specifica- tions, sooner or later lead to disastrous and disappointing results. It may safely be said that any part of an object which has been minal until rupture took place, was strained beyond the elastic limit. Consequently the whole structure of the metal has been changed by the metal flow- ing and becoming more dense in places, whereby, of course, its nature has been changed and something entirely different from what it was before has been pro- duced. Even in a bending test the metal on the convex surface of the bent piece flows at such a rate as to’ equal the rate of flow in a tensile test—that is so say, the elongation measured on a previously given distance around the curved surface of a bent test ee generally equals the elon- gation of a similar distance on a tensile test. It is clear that the change of struct- ure which thus takes place in a test piece also takes place in any part of a structure which is similarly strained; only, if it were possible and practicable to strain every sheet, axle, tire, eyebar, beam or bar, before being used, to the same degree as the material was strained by bending or otherwise, then it would be fair, sensi- ble and reasonable to use test pieces from such overstrained material and consider the results of such tests a criterion of equality. This matter being of sufficient importance to warrant a recapitulation of the points made, it is well to remember, whenever the question of equality of ma- terials is under advisement, that the rate of flow of a metal, and consequently its ductility and ability to stretch or elongate, are by no means such a fixed quantity as could be determined like a mathematical proposition. It is also essential to know whether the rate of flow progresses uniformly or in ‘*fits and starts” when the metal is under strain, and to take into consideration that molecular movement takes lace through the whole mass of a metal when under strain (except in such portions which are un- der the influence of artificial restrains as of heads and fillets). The effects, therefore, of sudden impact, shocks, bending, &e., which strain the metal to or near the point of rupture extend through the whole of an axle, bar, beam, eyebar or other structural member, and produce a condi- tion in the metal which makes it something different from what it was be- fore it was strained... The writer, there- fore, takes the liberty to repeat that the taking of results of tensile test of such overstrained material as a basis of equality 127 for other structural material pinata teal chew ¢ mekaael law @ sagned. eaddan ite tic eoutend uae © &.aeiei a serious self-deception and costly error. Years of experience, careful study of the properties of iron and steel, and the experience of the best authorities on the physical equali- ties of metals bear the writer out in his conclusions. From all that has been said in the fore- oing the conclusion is that the degree of ductility and elongation of a metal de- pends on the rate of flow of that metal, and consequently the proper interpretation and economical application of the results of tests not only depends on knowing the percentage of elongation in a given dis- tance of the test piece, but it is also essen- tial to know with what degree of uni- formity the metal flows under a regularly —that is, steadily increasing load; and lastly, what causes, artificial or natural, may influence the rate of flow. To the possible objection to this reasoning, that the engineer cares chiefly for the qualities of the material within the elastic limit, the answer is pertinent that, first, a metal’s qualities within the elastic limit are de- termined with more or less difficulty and uncertainty, and, second, that it is more than reasonable to suppose that the nature of a metal which determines its qualities outside the elastic limit also determines its qualities within the elastic limit. In other words, a metal which flows ‘‘jerky” be- yond this important point is not likely ed of ideal uniformity within the imit of elasticity. The fact is, and every close observer of the properties of iron and steel will agree with the writer, that it is the hardest thing to determine the elastic limit of such metal, requiring extreme care and attention. This is due to the ease with which such metal flows — com- paratively —_ loads. A correspondent at Kokomo, Ind., fur- nishes an interesting item relative to the manufacturing growth of that enterprising city since the development of its natural gas. Some 22 factories have been erected, each employing from 15 to 500 men, mak- ing an aggregate of 2555 hands, and a capitalization invested of $1,715,000. Among these new industries are a plate glass works, a safe and range works, ma- chine works, boiler works, bit and edge tool works, knife and shear works, art glass works, tile works, &c. Street railways are about to be built, a new system of wa- ter works has been put in use, and the streets are lighted by both electricity and gas. The Sims-Edison electric torpedo boat was tested at Willett’s Point, last week, in the presence of many official spectators. The torpedo sent out consisted of two par- allel parts, one above the other, about 6 feet apart and about 30 feet long. The lower portion was a cyliader with conical ends covered with copper. Inside the shell, beginning at the forward end, were three sections, containing 250 pounds of sand, used instead of dynamite, the con- trolling cable over 1 mile long and about + inch in diamer, made of fine twisted cop- per wire, which was paid out as the tor- pedo advanced, and the electric motor and steering device. The upper part consisted of a boat or float with a copper hull. The torpedo when lowered from the pier into the water was almost entirely submerged, only aportion of the upper half showing above the water. The time of the mile run was made under 1000 volts pressure in 2 minutes and 59 seconds, estabiishing the claim that the little destroyer can approach a hostile ship at a speed too great to be se- riously exposed to the fire of secondary batteries. The float was at no time ex- i more than 1 inch above the water. he new boat which the company are building for the Government is larger than the one above described. 128 THE MANNESMANN PROCESS. A Revolution in Rolling. THE IRON AGE. |be rotated in the same direction with | equal pressures, and must be placed at the /same angle to the axis of c. Let the shaft @ be provided with collars, through which it has a tendency to take along the bear. ing. Let this bearing be pressed between About two years since German news- | two guides, so that there is some friction papers announced the discovery of a/| when it tends to move from right to left. method of rolling solid pipe, which claimed The consequence will be that the rotation a good deal of notice on account of its of ¢ is still possible, but that the axial novelty. The principles underlying the | movement is obstructed. This creates, on method were alluded to,* but no very | the sucface of c, a driving tendency as a satisfactory descriptions reached the pub- | result of the friction of a and band ¢, the lic. Soon after, however, paragraphs | effect of which is to cause the surface par- appeared in some of the German trade | ticles of ¢ to flow in the direction of the apers throwing doubts on the practica-| axial movement. Now if the substance of ility of the method, in spite of the fact | which ¢ is made is yielding, such a flow of that some of Germany’s leading authori-| the particles of the surface does actually ties were known to be sanguine concern-| take place. This is the principle of the ing its future. It is now pretty thor-| Mannesmann ‘‘skew-rolls,” as Frederick oughly understood that the inventors | Siemens has called them in a paper before passed through a series of trials and tribu- | the British Society of Arts. July 24, 1899 of the cup reaches the forward Smooth art of the skew rolls and is polished t is then that the tube dotted in Fig 3 is formed. - The process must be considered ag pro, ceeding very rapidly. Great speed j necessary in order to prevent cooling of the billet during the rolling. Profeggo, Reuleaux ene the moment whey the last end of the billet is converted into a tube a remarkable sight. A point of light appears at the end of the billet, rq idly enlarging to a glowing circle. The solid billet is thus converted into a tube the operation being called by Mannesmany, the ‘* blocking” of the tube. The inner surface of the ‘‘ blocked” tube is near} smooth, much more uniform than would be supposed. It has been pointed out that the billet is held back by the conical end of the rolls through the action of the shoulder formed. Fig. 5. THE MANNESMANN PROCESS OF ROLLING. lations, and that they had to overcome difficulties in practical details which were exceedingly great. Now, at last, we have a good account of the methods em- ployed, the special devices developed and the results achieved, from the able pen of Professor Reuleaux, of Berlin, best known to the majority of Americans as the Ger- man Commissioner at the Philadelphia Exhibition, and the man who pronounced the famous ‘‘ Billig und Schlecht” in con- demnation of much in the German ex- hibits at the Centennial. Professor Reuleaux read a paper before the ‘‘ Verein fiir Eisenbahnkunde ” on the Mannesmann tube rolling process, from which we take the following explanation of the method: If a Fig. 1 is a driving friction wheel, ¢ will be rotated and at the same time driven axially, the speed of the entire movement depending upon the angle a. The same effect can be produced in even a better manner by allowing two friction wheels, a and , Fig. 2, placed opposite to another, to act upon c. The axle of ¢ is then no longer in daoger of being bent by the pressure. The Eiviny wheels a and } must Fig. 3 is a sketch of the application of the principle to rolling. In the place of the disks a and }, in former figures steel rolls a and }, Fig. 3, are employed, the back parts of which are spirally roughened in order to increase the friction. The billet or bloom, heated to facilitate the flow, is brought between them. It is kept from falling out by ides. Bv driving the rolls the billet is rotated and is! axially driven from right to left, on the principle explained in Fig. 1. The brake action of Fig. 2 is still missing. This is| obtained by conically turning off the back end of the rolls and placing them so close together that the billet must first be re- duced in size before entering the rolls. In this manner a shoulder forms on the billet which presses against the conical ends of the rolls, and thus has a tendency to retard the axial movement of the billet. The result is that the surface of the billet is really pushed forward more rapidly than the billet, as a whole, and that therefore a cup shaped cavity must be formed in the billet at the point at which the rolls take hold. As the billet follows up the cup formation goes on. Meanwhile the edge If this braking is not done the cupping ceases. This may be taken advantage of to produce tubes closed at the ends. All that it is necessary to do is to point the end of the billet so that it is not caught by the rolls. The same thing may be done at the forward end. In this manner a tube may be produced closed at both ends. These have been frequently made by Mannesmann. It was interesting to learn what were the contents of this cen- tral hollow space. Prof. Finkener found that a cavity of 123.4 c. cm. contained 9.11 c. cm. of gas, consisting of 99 per cent. of hydrogen and 1 per cent. of nitro- gen, a result which supports Mueller’s well-known yiews. The method described of holding the tube back by conical ends of the rolls is not always convenient, particularly in those cases where the obliquity of the rolls must, for some reason, be made very great. Therefore, another method is occasionally ag br A mandrel is adopted. Fig. 4 shows the application. A rounded mandrel, d, which can be ro- tated on its rod is mnt to the ad- vancing billet at the point where the cup- ns, By means of a hand wheel he mandrel is advanced os i suited to the progress of the ies mandrel, which is loose upon the square end of the rod, drops off as soon as the tube is completed. Then the rod can be withdrawn. The rolls are driven by means of couplings at a b’, which permit of an adjustment of the position of the rolls, as to obliquity of position and their approach. It is clear that the thickness and diameter of the tube, aside from the dimensions of the pillet, depends largely upon the position of the rolls. In fact, with the same set of rolls, very thin and very thick tubes can be made. ing begi and screw t ZA FURNACE Ya ROLLS Fig. 6. THE IRON AGE. material in. The tube emerges widened, and thinner at c.’ ‘‘ Blocking” train and the ‘disk ” train are the two most important, and those principally used by Mannesmann. One of the objections promptly raised against the method was the enormous power required to do the rolling. While this is true, it is due tothe fact that the whole process of shaping with its enorm- ous displacement of material must be done in a very short time. The question arose how to store the necessary power in the fly wheel for the relatively brief period of rolling. That could only be done by in- creasing the capacity of the fly wheel to accumulate power. The ordinary fly wheels Fig. 8. Fig. 10. Fig. 9. THE MANNESMANN PROCESS. Tubes rolled in this way may be widened out by reheating them and again introducing them between the rolls atter correspondingly changing the position of the latter. Greater enlargement is pre- ferably carried out by Mannesmann by a set of disk rolls, shown in Fig. 5. The rolls are disks a and } spirally roughened. They revolve at equal speed in opposite directions, so that the tube introduced between them js rotated, and at the same time is pushed forward through the friction of the roughened faces of the disks. The mandrel d aids the operation, its shape being so chosen that between it and the disks there is room for a conical body of material decreasing in thickness. Rolling takes place between «@ and d and between band d. The tubec is rolled do not admit of going above a certain limit for circumferential speed. At Komotau, Austria, a wheel of the ordinary design was destroyed, having been run at a little more than 120 feet a second. The result was a special design of a fly wheel, which is very interesting. As described by J. G. Gordon before the Society of Arts, this wheel consists of a cast iron hub, to which are securely bolted two disks of steel plate about 20 feet in dia- meter. Around the periphery of the wheel thus formed about 70 tons of No. 5 wire are wound under a tension of about 50 pounds, thus binding the whole securely together. Mr. Gordon remarks that there can be no comparison between -the resist- ance to centrifugal force of a wheel so constructed and that offered to this force between what may be called three rolls, | by a cast iron one. This fly wheel of 20 the disks and the mandrel, the spiral|feet diameter and weighing 70 tons re- roughening of the disks crowding the ' volves 240 times per minute, therefore the 129 periphery of the wheel has a speed of 2.85 miles per minute or 171 miles per hour. According to Mr. Gordon the power re- quired to produce the tubes is very large, something like from 2000 to 10,000 horse- power, according to the dimensions of the tube. If a steam engine of this power had to be provided for each rolling mill the plant would, of course, become extremely costly, but, luckily, this great power is only required for a short time. Thirty to forty-five seconds suffice to convert a bar 10 to 12 feet long, and 4 inches in diam- eter, into a tube, and then some time elapses while the next bar is brought up, adjusted in the guides and the fiinished tube removed. During this time energy is accumulated in the fly wheel of the de- sign described, and by this means a com- paratively small stcam engine of about 1200 horse-power is quite sufficient to do the work. A second serious obstacle to regular practice, particularly for larger mills, was the defects of the ordinary tooth gearing. Their use was necessary, on account of the arrangement of the plant. In order to convey the heated billets from the furnace to the rolls conveniently, the plan had to be abandoned to place the shaft of the fly wheel in a line with the main shaft of the rolls; nor could it be placed parallel to it, because this was the direction which the billets took. The arrangement is shown in Fig. 6. The ordinary conical gears, even if made of steel castings and most carefully cut, did not resist the wear and the slightest inaccuracy told at the high speed, 300 revolutions per minute and upward, To meet this difficulty Mannesmann Brothers designed a special form of gear- ing, shown in Fig. 7. The form of the teeth is shown at a’ Bb’. They are so shaped that the one seizes the other like a fork. Considering first the two wheels in their position, with their axes parallel to one another, each having the same number of teeth, it will be seen that the forks and the blades must meet accurately, provided the teeth be always kept in a parallel position. In both wheels this parallel position of the teeth throughout their movement 1s maintained by a special appliance not shown. But the position of the axes of the two wheels may be swung at any angle provided the line A A, Fig. 7, remains vertical. In that manner an arrangemert at right angles sketched at the right side in Fig. 7 may be at- tained. Professor Reuleaux states that these gears work remarkably well, when amply lubricated. A third serious difficulty encountered by the Mannesmann Brothers was to couple the rolls with the driving shafts. In the simplest ‘‘ blocking” train four couplings were necessary, two foreach roll, allowing both for an adjustment in the angle of the roll and their approach. At the same time the rolls had to be driven very uni- formly, on account of their high speed. They were again forced to resort to a special design, indicated in Fig. 8. Let it be assumed tha‘ two axles a and 3, are provided at two points, equally distant from the intersection point s, with their arms, indicated in the sketch by lines. These arms inclose equal angles s 6s, and 8@ 8. Where the two axles are uniformly notched the touching arms will constantly remain in contact. After a revolution of 180 degrees the contact point at s, will reach the position of s:. In doing so the contact point moves in the path of an ellipse. In order to carry out the idea of contact lines the edges could be made of steel blades. But this would lead to rapid destruction. Mannesmann employs in the place of blades a link consisting of two half cylinders, sketched in Fig. 8. They lie upon one another with their flat surfaces, while their round backs make the necessary angle movements in cor- 130 THE IRON AGE. July 24, 18¢9 a ee —ee bearings. This ee is said by Professor Reuleaux to be doing ex- cellent service. One matter to which Professor Reuleaux does not refer, but which is touched upon by Mr. Gordon,is the necessity of careful oibuinent of the rolls. In the Mannes- mann mills every part iseas carefully fitted as in a locomotive or marine engine, and the screws and balances are designed to, and do, enable the foreman roller to ad- just the rolls to the 32d of an inch. The pipe as produced by the blocking nent + mga peculiar properties. The fo flow of the metal groups it in spiral fibers, the pitch of the spirals being greater in the inner parts of the walls of the tube than in the outer walls. Professor Wedding has proven this by microscopical investigations. It is claimed that this structure imparts to the solid rolled tubes special strength, in fact, Professor Reuleaux states that they show tive to six times the strength. He claims furthermore that this structure permits of special ease in further working in flanging, widening, &c. He raises another point, that the great stresses in the process of manufacture make the selection of sound stock absolutely necessary. Blowholes, Pp irregularities, &e., in the steel lead to fractures in the rolling. For this reason wrought iron cannot be used, but copper, delta metal, brass and steel make good materials. The Mannesmann Brothers were forced to put up a crucible and an open hearth plant of their own, in order to ensure yetting the right raw material. There are four works in operation, pro- ducing Mannesmann tubes, the small ex- perimental plant at Remscheid, Germany ; one at Komotau, Bohemia; a small works at Bons, near Saarbriicken, Germany, and the large works of the Mannesmann Tube Company, at Landore, Wales. A fifth plant, for making copper tubing is being built by Gebriider Heckmann, at Duis- burg, Germany. At the meeting of the German society referred to Professor Reuleaux showed a large number of specimezs of pipe which are pronounced to uite remarkable pro- ' ductions. He emphasized the value of the tubes for shafting, and showed some samples of subsequent shaping of the tubes. Thus he calls attention to hollow beams possessing a greater thickness of metal at the center, as in Fig. 9, and a rail of the furm shown in Fig. 10. As a new departure in rolling mill methods, the Mannesmann process is cer- tainly deserving of attention. None of the published reports give any data whatever which might furnish a cue to the solution of the question whether it is as yet a com- mercial success, whether it can compete with the improved methods of manufact- uring welded pipe developed in this coun- try during the past decade. Since the policy was adopted of using none but domestic steel in all the new ships in the navy, there has been a great advance in the art of making and working steel in this country. When that policy was first adupted, on an average less than 70 per cent. of the output of the various mills was able to pass the naval inspection. With increased experience has come the ability to do much better work, and Com- modore Sicard, president of the Naval Board of Steel Inspection, said that more than 90 per cent. of the st@el will now pass the most rigid inspection. The capacity of the steel mills of the country has greatly increased in the meantime, and a still further increase is to be made by the Bethlehem Iron Works, where the erection of the most complete plate rolling mill in the country is under way. This mill is to be able to turn out all kinds of shapes and angles, as well as plates of all thicknesses up to 6 inches. The armor plate plant erected by this company is about ready to begin operations. A few experimental plates have been forged already, but none which is intended for use on a vessel, mm Safety Valves and Horse Power. At the Pittsburgh meeting of the American Boiler Manufacturers’ Associa- tion held in April, 1889, a committee was appointed to consider the subjects of safety valves and horse-power. Thiscom- mittee handed in a report at the conven- tion held a few days since in New York. The committee sent circular letters to the members of the association on SAFETY VALVES, which, together with the replies we pre- sent below : 1. What kind of a safety valve do you recommend—i. ¢., spring or weight and lever? There were 13 replies to this question, eight of which were in favor of spring valves, three preferring weight and lever and two non-committal. 2. State any peculiar construction of any arts which you may prefer, or any changes in the valves now in the market that you recommend. To this question we received 13 answers as follows: Nine express them- selves as being satisfied with any of the first-class valves now in the market; one member recommends a flat seat; one sug- gests multiplying lever arrangements, so that the valve may be raised from its seat at any time, even when there is no steam upon the boilers; one recommends ex- ternal adjustment to the valve, and one to use a hollow loose steam. 3. What metal do you consider the best for valve seats ? The replies to this ques- tion were 11 in number, as follows: Seven members prefer brass or best steam metal ; one each preferred nickel, hard composi- tion, phosphor bronze and tempered copper. 4, What, in your opinion, should be the difference between the capacity of the safety valves and the boilers—i. ¢., do you consider a valve large enough to dis- charge 50 per cent. more steam than the nominal horse-power of the boiler to be a sufficient margin, or do you recommend more? To this question we received a number of replies. Seven state that they think a 50 per cent. margin sufficient; one says 62 per cent. and one 60 per cent. Other members gave arbitrary sizes for valves for certain horse-power of boilers, and others still propose rations of valves to heating surfaces and grate surfaces. 5. Would you recommend the use of valves larger than 4 inches, or the use of two smaller valves giving the same capac- ity of release for sizes above 4 inches ? The general — on this point is against using a larger valve than 4 inches; the replies being nine in favor of using two smaller valves and only two favoring the use of valves larger than 4 inches. The committee feel justified in report- ing on this subject as follows: 1. We recommend that the association adopt the spring loaded safety valve, and that all the members use such valves in their business wherever possible. 2. We consider any of the high grade valves now in the market as reliable, but especially recommend those which increase the area for release as soon as the valve leaves its seat. 8. We recommend that all boilers should be supplied with a safety valve or valves giving 50 per cent, greater release than the nominal power of the boiler, and as the speed of steam varies with the pressure, we insert below a list of sizes to be used: For boilers ra’ at from— 10 h.-p. to h.-p.....- one 14-inch valve. 20 h.-p. to 30h.-p...... one 14¢-inch valve. 30 h.-p. to 40 h.-p...... one 2- inch valve. 40 h.-p. to 80h.-p...... one 2}¢-inch valve, 80 h.-p. to 100 h.-p...... one 3- 100 ea to 125 . ae ate an one Si¢-inek ba 125 h.-p. to 150 h.-p...... one 4- inch-valye, 4. We would recommend that no | safety valve than 4 inches be used unde any circumstances, but that when a larger opening for the release of steam become necessary, two or more valves be used, of such size that their angregate area is the area desired. We would further recom. mend when more than one valve is useq that they be adjusted so as to open g different pressures, say 2 pounds differ. ence between each valve, so that the shock on the boiler, caused by the opening and closing of the valves, may be reduced gs much asit is possible. The replies received by the committee to the questions relating to HORSE-POWER were too few and indefinite to enable them to arrive at an intelligent opinion as to the wishes of the members. The report says; There is a very general opinion, as far ag the answers received go, that the ‘‘ heat. ing surface’ method as at present used is very unsatisfactory, and the wish is almost uniformly expressed that some better method of rating boilers might be de. vised. The present method offers too many opportunities for deceit and mis. representation on the part of unscrupu- lous parties and works against the honest boilermaker who tries to put the desired amount of heating surface into such shape and size as will work to the best advan- tage, while his unscrupulous competitor, by using a smaller shell and crowding it full of tubes or by lengthening his boiler out does really give as much heating sur- face, but pus it in such a shape that although cheaper in cost a good share of it becomes actually useless, either from want of circulation or from the fact that the long tubes quickly get stopped up with soot before the boiler has been long under steam. Of course the whole question of the power of any steam boiler is simply how much water it will evaporate in a given time. It is very unfortunate that the term horse-power was ever applied to steam boilers, but it seems like a useless crusade to undertake to override and do away with a term, however inappropriate, which has the sanction of such long usage behind it. The ‘committee would there- fore recommend the adoption by this asso- ciation of one of the three generally recog- nized standards of horse-power, viz. : The eva tion of 30 pounds of water hour rom and at a temperature of 212° F. _ The evaporation of 30 1 pounds of water per hour from 212° F. into steam of 70 pounds pressure. The evaporation of 30 pounds of water per hour from 100° F. into steam of 70 pounds pressure. The second standard above named was selected by Committee of Judges at the Centennial Exhibition as the ‘‘ Unit of Commercial Horse-Power,”’ and the third was subsequently selected by the American Society of Mechanical Engineers, It seems to your committee that both the above named committees erred in their selection and that the first named unit has more and stronger ments in favor of its adoption than either. It is in the hands of the Association, however, to decide which, if either, of the above units it will select. This point decided, the next step seems to be the establishment of some rate of evaporation per square foot of heating sur- face for each of the common types of boilers. Your committee has fortunately had access to a large number of tests, which have been under working condi- tions by disinterested parties, of all the more common t of boilers, From these tests, which have been carefully examined, your committee has acquired the information which justifies them in July 24, 1890 ing the following ‘‘units of roe alan » all calculated from feed at 212° F. and atmospheric pressure: Pounds per sq. ft. per hour. in cylinder boilers..... . 4 to 6 For nena tubular boilers. 1.5 to3 For upright tubular boilers.... 3.0 to 4.5 For upright with submerged The above named units, taken in con- sideration with units of horse-power, gives us the number of square feet of heating surface effective necessary to develop a horse-power on each of the kinds named, viz. : For plain cylinder boilers, 7 sq. ft. H. S., 1 ae For horizontal tubular boilers, 12sq ft. H. 8., ae For upright tubular boilers, 8 sq. ft. H. 8., es ‘Tee upright wap semenegee tubes boilers, _ ft, H.S., 1H. P. for ‘ocomotive boilers, 8 sq. ft. H. S., 1 P 8 H. Now, it is well known that some heat- ing surface is much more effective, i. ¢., does much more work in evaporating water than other surfaces differently lo- cated ir the same boilers. There is no doubt but that a square foot of fire sheet surface in an externally fired boiler does much more work than a square foot of tube surface, and therefore it seems de- sirable and necessary for the association to establish certain arbitrary values for heating surface, varying according to its location in the boiler. If this is done, the next step is for the association to es- tablish the rating or horse powers of all the sizes of the more common types of boilers which are being built, and also the advisable ratios of tube diameter to tube length, grate area to heating surface, and in fact to design and seal with its ap- proval all the more common sizes of the various types built. This seems to your committee to be eminently proper, as we have already definitely specified, the ma- terial which may bear the stamp of the association and have established rules for riveting, staying and for the attachments. As above stated, this committee does not feel at all sure that the remarks above made reflect the opinions of more than possibly a very small number of the mem- bers, it is, however, clearly the fault of the latter that the committee is in this situation; and, such being the case, we offer the above remarks for your considera- tion, discussion and amendment, and most urgently advise the appointment of an- other committee on this same subject of horse-power, with instructions to again make an effort to secure the opinions of the members on this point. The com- mittee further expresses the hope that in case the above recommendation is adopted, that each member of the association will freely give his opinions on the matter at an early date so that the committee may have plenty of time to consider the replies, correspond with each other, and be in a condition to present an intelligent and satisfactory report, and one upon which the association can act, and, if adopted, take a firm stand. (Signed) Cuas. F, Foster, Chairman. ——_—_—_——aEEES _A Big Propeller for the Lakes.—The big steel propeller Maryland, one of the largest boats on the lakes, was launched at Wyandotte, Mich., 12th inst. She was built for the Inter-Ocean Transportation Company, of Milwaukee, and will be the flag ship of their fleet of seven vessels, carrying iron ore from Escanaba to the rolling mills in South Chicago. She is 335 feet over all, 316 feet on the keel, 42 feet beam and 24 feet depth of hold. Her engines are of the triple expansion order, 22, 35 and 56 inches diameters of cylin- THE IRON AGE, ders and 44 inches stroke of piston, with an estimated power of 1200 horses. Steam will be furnished by two steel boilers, sit- uated on the main deck, each 14 feet 2 inches in diameter and 11 feet 6 inches in length, capable of sus