The Iron Age 1923-08-16: Vol 112 Iss 7

HE IRON AGE New York, August 16, 1923 ESTABLISHED 1855 VOL. 112, No. 7 Features in Manufacture of Mack Motors Bonus System Effective in Boosting Production Without Sacrificing Accuracy—New Fixtures and Diamond Tools Show Desirable Results BY L. HECKING accuracy in a commercial product to one-tenth of a thousandth and at the same time maintaining a production schedule is noteworthy even in the automotive industry. This result of com- bining accurate, work with an incentive toward high production has been developed at the Plainfield, N. J., plant of the International Motor Co., manufacturer of Mack trucks. At this plant are built all the motors produced by the company for assembly into completed chassis at another plant. Three sizes are made, and flexibility in equipment is thus required. All motors are of four cylinders, with the cylinders cast in pairs, and they are of 4 in., 4%4 in. and 5 in. diameter, re spectively. The time study system has been worked out and provides a bonus for increased activity on the part of the operator and thus for effort to hasten setting up operations or reduced time between cuts. As a new job comes into the shop, it goes first to the engineer- ing department, where it is analyzed and the operations planned with their sequence progressively routed. The operations are then prescribed on cards, different One Operation on Pistons Is Elim- inated by Use of an Equalizing Arbor Which Chucks on the Inside of the Rough Casting, Thereby Requiring no Preliminary Boring Operation (Right) 389 LOVE colors -being used, cards of one color show routing, those of another color show also the time allowed for each operation. A route and time card follows each job through the shop. In figuring the time element for a given job, a high grade operator is timed in producing not less than ten pieces at best feed and speed and from this performance the average time is arrived at. All time studies are figured in the decimal system and set in hundredths of an hour. To the actual time is added 30 per cent to arrive at the allowed time for which the operator is to be paid. Once the time study is made and allowed time is set, there is no change nor cut made in less than a year. Then a change may be made, but only due to a change in design or method of handling. Any saving of time in setting up work or doing better than the allowed time in any other manner gains a bonus for the operator. At the same time, he must maintain the accuracy limits for the job on which he is working or have work rejected and charged against him. A daily product‘on sheet is tabulated, giving each The L's of Three Tools at Once Per- mits Rough Turning of Pistons in a Car- riage Travel of Two Inches Preparatory to Heat Treatment Carriage feed is by push bar on turret and spring return (Left) t 3 3 390 THE IRON AGE Valve Lifter Roller Pin Holes Are Drilled and Reamed Ss -Automatic Horizontal Two-Spindle Drill ir ng, Taking Only Half the Time Formerly) Four-Spindle Machine, Which Requires Another Chucking perator’s percentage of efficiency. This sheet shows whether he is a consistent bonus earner or whether he persistently falls below the production set in the 4 Cam on the Lathe Spindle Serves to Reciprocate the Auxiliary Slide on the Front Carriage Turning Piston Pin Relief on Pistons. The rear carriage turns grooves while the casting is held by a draw bolt and spring center time study. From this daily sheet a monthly efficiency record is compiled and each operator’s percentage is noted on his record sheet in the employment depart ment. Here his value to the company may be care fully checked according to his actual performance. A daily cost sheet is also tabulated. This shows the acutal cost of producing each job, as it includes the operator’s wages for the actual time consumed plus his bonus earned on the job. In this way a record is maintained of average costs over a period of months. In the screw machine department an operator is illowed four machines. He is expected to keep three machines running constantly, thus being allowed one machine idle.for set up. The incentive is to hasten set ups and thus keep the fourth machine running as much of the time as possible, thereby earning a bonus. Overtime beyond the regular 9-hr. day is credited at time and a half in addition to the bonus. Piston castings, in common with various other cast iron parts, such as cylinders, valve guides, etc., are sub- jected to a heat treatment after the first machining operation. The machining operation removes the scale and the heat treatment, which is a baking at low tem- perature for 24 hr. followed by slow cooling, releases strains. One chucking has been eliminated in the re- vised plan of operations on pistons. It had been the custom in the past to bore the piston skirt adapter bearing in a common vertical drill press preparatory to mounting on a draw arbor with a draw pin which regis- tered the bored skirt in a pilot for rough turning. This August 16, 1923 operation has been eliminated in the preliminary ma- chining before heat treatment, saving one chucking. Pistons are now mounted on an air operated equaliz- ing arbor, which grips on the inside rough wall, proper- ly centering the casting for turning. The operation is performed in a semi-automatic turret lathe. The cross slide carries three nickel alloy cutting tools, cut- ting at once, and travels only 2 in. to perform the rough turning operation over the entire surface. Feed to the carriage is effected by a push bar attached to one side of the turret; a spring returns it. When the cut is completed, the machine returns to starting posi- tion and stops, waiting for the attendant to remove the work and insert another casting. After heat treatment, pistons are bored and reamed in a semi-automatic turret lathe which has a four-sided turret. On the turret are mounted four two-jaw, box- body chucks, one on each side. These chucks are pro vided with special slip jaws of a form properly to grip the pistons. The combination boring and reaming tool is special and is carried in the spindle of the ma chine. With the four chucks in use the operation is continuous, the operator unloading a finished piston and loading another while the machine is working, after which the indexing of the turret introduces an- other casting to the tool. Finish turning is accom plished on a pilot with a draw arbor and pin through the wrist pin holes, Wrist pin relief and ring grooves are turned in a turret lathe in which the piston is chucked as in _ finish turning. A spring ten- sion center carried on the turret supports the outer end. On the fix- ture is a cam which ac- tuates the cross slide against spring pres- sure, causing it to clear the piston periphery all over except where the pin relief is desired, at which points the cam permits the springs to push the slide into cut- ting position. Ring grooves are cut by tools in the rear slide at the same time. The completing op- eration in the turning of pistons is one of bur- nishing the ring grooves to assure absolutely uniform size and also to harden them to resist ring wear. This is done in a common lathe with a hardened disk on a Holes in Both Top and Bottom of Cylinder Castings Are Drilled Under One Cluster Head Drill, Using Two Jigs, the Drill Spindles Being Set in Two Groups. This necessitates lifting the castings from the floor only once C4 eaetiee August 16, 1923 Lapping of Wrist Pins Permits Them In. The abrasive shaft mounted in bearings on the lathe carriage. width for the grooves. being rough milled top and treated. disk has a thickness of the proper Cylinder castings, after bottom and rough bored, next succeeding operation is one of drilling holes in top and bottom of the castings. Those in the bottom are taper reamed and are used for location in finish boring the cy]l- are inders and also on an assembly plate when the cylinders, mani- folds, carbureter, etc., are assem- bled before mounting on the crank case. This drilling operation is handled under a cluster head mul- tiple drill using two jigs, one for each side of the casting. The spin- are arranged in two groups and the operator sets up first for one side, then the other, so that the machine is working constantly, with the necessity of raising the castings only once from the floor to secure the holes on both sides. Cylinders are then finish milled dles four pairs at a time before be- Ce ing bored, reamed and burnished. The latter operation is accom- plished under a radial drill with a rol tool. A remunerative change was recently drilling and reaming of valve lifter rol to medium is washed off in heat Be THE IRON Graded in a tank of kKeresene This The AGE 391 formerly drilled and sensitive These were reamed in a four-spindle, drill The present method involves a twospindle semi-auto- machine with spin- dles opposed. The lifters are mounted in a fixture on the machine; one spin- dle advances, drills the through both sides of the jaw or roller recess, and upon which the other spindle advances from the other side | and The machine stops completion of the cycle until another | has been inserted and the | This change has cut the cost operation in half and at the time alinement, as both operations are pe! formed one chucking. While the International believes generally in the use of mercial machines for shop production, special machines or adaptations of standard machines in some cases have the use of matie horizontal hole retires, reams. upon plece start ing lever again is tripped. of this same assures Motor Co. com ‘ g been found desirable. A case of this Variations of 0.0001 : . kind is in the boring of cunnecting rods. It has been the practice to broach the bronze wrist pin bushing in a horizontal broaching machine, for which the company makes its own broaches. This bushing was checked to limits of 0.0003 in. The split bushing, which is babbitt lined ler mé ing Rods urnishing ide in the pin holes. A Converted Internal Spindle Head Is Used with Diamonc 3oth Ends of Connecting Rods Grinder with i in a Special Tools for Boring One ting Set Two- After ried Two at a Time on Elevating Platform Whict Are Truc Ks mded in Special Racks Inspection Are L« Industrial bronze, was hand reamed. These two operations are now combined in and handled a machine devel oped for the purpose. In this operation the center dis tance is assured and the required accuracy maintained The machine used is a converted internal grinds from which the regular work and wheel heads are removed. In place of the work head a two boring head has been mounted. These spindle fixed centers and are mounted in ball bearings, per mitting high speed of operation. The boring bars carried in the heads are provided with diamond too! which have been found when run at high produce a better finish on babbitt than reamers, maintain accuracy longer due to negligible wear. On the wheel head carriage of the grinder is mounted a fixture which carries the work to be bored. one spindl hav speed to and Although the use of elevating platform industrial trucks, shop boxes, etc., is general in this plant, it was found that connecting rods were rather cumbersome to transport in quantities. For this reason racks have been provided which they may be hung as they come off of the inspection bench. The racks when filled transported two at a time to the assembly department, thereby greatly reducing the number of trips necessar: to carry a given number of rods. A number of improvements in the design and manu- facture of wrist pins have recently been instituted Formerly these pins were designed with a straight 39% bore, and were machined, ready for carbonizing, in a four-spindle automatic screw machine and a_ hand turret lathe on the second operation. The present wrist pin has a tapered hole, tapering from the center both ways, giving a thicker wall in the center and consequently less likely to show deflection under strain. The manner of manufacture has been changed to a commodate the taper, but the making of the pin re quires no more time than did the stra‘ght hole pin. It is rough bored in a four spindle screw machine, cen- tered and champfered in a hand turret lathe and then turned on an arbor to 0.010 in. It next goes to a centerless grinder to be: ground before carbonizing, after which it is taper bored in a double end four spindle chucking machine. Next the pin goes to the centerless grinder again, where it is ground to limits of 0.0002 in. A recent addition to the operations is one of lapping which effects even closer accuracy, namely, 0.0001 in., to which they are graded under a Prestwich fluid gage. This lapping machine is one recently placed on the market by Warren F. Fraser, Westboro, Mass. It consists essentially of a base and column, cach support- After Case Harden- ng, Crank Shafts Are Straightened to Within 0.060 In Under Hydraulic Straighteners Be- fore Going to Crank Grinders ing a large cast iron surfaced disk. Through the center of the lower disk is an arbor which delivers an eccentric motion to the work holder. The latter is a disk having arms to receive the wrist pins, perm't- ting them to roll under the effect of the lapping motion. These arms are on lines which would form chords to the disk circle rather than being radial. This angle together with the eccentric motion of the arbor and the rotary motion of the pins themselves is effective in constantly changing the relative contacts between the disks and the work. Flour of emery and oil is used as the grinding medium. This is washed off after the operation is complete by immersion in a tank of kerosene which permits the solid matter to settle. On the inspection bench these pins are graded ac cording to a range covering 0.0007 in. in seven grades. They are then etched with a number in the bore ac cording to size by tenths of thousandths. The grading ef the seven sizes permits 0.0002 in. under size and 0.0005 in. over. These pins in turn are matched with pistons and rods which show corresponding variations in size. As an example, a wrist pin measuring 1.6244 in. would be called a No. 3 it would be assembled with a No. 3 p‘ston and rod bushing which measure 1.6247 in. and 1.6249 in. respectively. Wrist pins when assembled are full floating, being held in place endwise by re tainer springs in grooves in the piston holes. The Mack truck is one of the comparatively few motor vehicles which has a case hardened crank shaft. After turning, the shafts are placed two in a box with a commercial compound and are brought up to 1700 or 1750 deg. F. in about 4 hr., where they are held for 24 hr. before plunging. This is found to give a hard- ened case % in. deep. Naturally they stretch and warp somewhat under this treatment. Experiments have been made with a clamp attached before plunging, but so far this has not worked out satisfactorily. To over- come the warping, the shafts are swung in centers mounted on a surface plate. On one center are gaging disks to which the dial indicator height gage is set. Straightening is done under hydraulic straightening 2 THE TRON AGE August 16, 1923 presses. It has been found that frequently pressure on the central main journal is sufficient to spring the shaft back to line. These shafts must gage on all bearings to within 0.060 in. before going to the crank grinders. Cam shafts in the past have been ground from the rough. An innovation in this plant is rough turning ‘n a cam shaft turning machine in 5 min. for the & cams instead of 15 min. as formerly required for rough grinding, a saving of two-thirds. In the making of the helical timing gears, all blanks are annealed before cutting and the practice has been to test gears for concentricity of the pitch line before the gears go to heat treatment. They are meshed with master gears in a testing bench and must run within 0.003 in. It was found that to secure this accuracy it was necessary to cut only one gear on an arbor, thereby avoiding spring and chatter due to placing more gear blanks on an arbor and applying cutting pressure farther from the hobbing machine face plate. After hardening, the bore and hub face are ground in an internal grinder. The work spindle of this ma- chine carries a ring chuck which fits the outside dia- meter of the gear. Three pins are placed about the gear between teeth at equi-distant points and serve to center the gear on the pitch line and drive it as the chuck revolves. Flat wheels and cup wheels are used on the bore and hub face respectively. (To be concluded) Metal Working Machinery to Be Exhibited at Steel Treaters’ Convention The metal working machinery manufacturers hav come to recognize the international steel exposition, held jointly with the convention and under the auspices of the American Society for Steel Treating, as an ex cellent opportunity to exhibit their product to a large group of interested individuals. Consequently, from year to year there has been noted a gradual increase in the number of machinery dealers who have accepted the opportunity offered by the exposition to show their product to the thousands of manufacturing executives in attendance. The exposition to be held at Motor Square Garden will have a larger number of meta! working manufacturers than ever before. The follow- ing machinery manufacturers will have their exhibi's in operation: National Automatic Tool Co., Richmond, Ind.; Baker Bros., Toledo, Ohio; American Tool Works Co., Cincinnati; Gould & Eberhardt, Newark, N. J.; Cincinnati Milling Machine Co., Cincinnati; V. & O. Press Co., Hudson, N. Y.; Warner & Swasey Co., Cleveland; Keller Mechanical Engineering Corporation, Brooklyn; National Machine Co., Tiffin, Ohio; Giddings & Lewis Machine Tool Co., Fond du Lac, Wis.; Oh‘o Machine Tool Co., Kenton, Ohio; Laughlin & Barney Machine Co., Pittsburgh; Avey Drilling Machine Co., Cincinnati; Oliver Instrument Co., Adrian, Mich.; Mil!- holland Machine Co., Indianapolis; Universal Grind- ing Machine Co., Fitchburg, Mass.; Blanchard Machine Co., Cambridge, Mass., and High Speed Hammer Co., Inc., Rochester, N. Y. New Testing Methods for Castings—l" Transverse and Shearing Tests Recommended and Tension and Shock Tests Condemned—Argument for Testing a Part of the Casting Itself N response to the invitation of the Institution of | British Foundrymen to present a paper at the Con- gress at Birmingham, the French Foundrymen’s Association has chosen as a subject of world-wide in- terest the new methods established by the researches of two French scientists for inspecting the strength of castings. Both men are well known in England. One of them, Mr. Fremont, was awarded the Bessemer medal at the last gathering of the Iron and Steel Institute, in Paris last September. The other, A. Portevin, has presented to the same institute a large number of re- ports and has received from it the Carnegie medal. Great progress in foundry practice can be hoped for by the systematic employment of these methods for testing. They deserve to be taken into consideration ed Fig. 1. Sketch of the Ramus Machine, often Called the Monge Machine—One of the Earliest Known Devices for Testing Materials and carefully tried out. Since the start of the indus- try the transverse test has been employed. In 1790 we find the Ramus machine, now known as the Monge machine, described in the annals of chemistry. (See Fremont: “New Methods of Mechanical Tests on Cast- ings” [in French], page 11.) The great scientist Monge, who described and employed this machine, was considered its inventor. The researches cf Mr. Fre- mont show that the actual inventor is Michael Ramus, manager of the Creusot foundry. The test bars were square and measured 80 mm. (3% in.) on the side and about 50 cm. (20 in.) in length. They were gripped at one end and loaded at the other end. Fig. 1, copied from Mr. Fremont’s paper, shows the Ramus machine, which has been described and illus- trated by Monge in the “Description of the Art of Manufacturing Cannons” (Paris, 1794, page 18). This fact is the cause of the machine having been attributed to Monge, although he refers to it as the “Creusot ma- chine.” Although Mr. Fremont and many others con- sider the transverse test as the ideal one—Monge’s test is still described in the majority of French specifications —this test has been practically abandoned and replaced by two worthless tests, the tension and the shock test. Colonel Prache, in his paper before the Congress of the Belgian and French Foundrymen’s Associations held in Liége in 1921, says: “The progress of semi- steel during the war was retarded by the mechanical tests imposed by the artillery department. Whoever has made any semi-steel shells knows that these tests had only a remote connection with the castings which were run.” Practice in Various Countries In America, transverse tests were taken in the past on square or rectangular test bars of all dimensions *Paper presented by E. Ronceray, to the Institute of British Foundrymen in the name of the Technical Foundry- men’s Association. Translated by E. J. Lowry, Hickman, Williams & Co., Pittsburgh. 393 and all lengths. Great efforts have recently been made in that country to agree on a standard test bar and pre- vail on other countries also to accept it. A round test bar of 1% in. diameter was chosen, to be broken on knife edges with a spread of 12 in. However, the American pipe foundries are using a bar of 2 in. by 1 in. placed flat on knife edges spread 24 in. apart. Wheel manufacturers who use a tem- pered casting process employ the same bar, while other factories retain the old bar, which is 1 in. square and rests on knives with a spread of 12 in. Finally, test bars have been broken on knives with a 3 ft. and even a 5 ft. spread. Keep has experimented on and recom- mended test bars % in. square, resting on knives with 12-in. spread. In England the standard test bar is 2 in. high, 1 in. wide and 3 ft. 6 in. long, and rests on knives with a 3 ft. spread. In Germany the transverse test is employed on round bars of 30 mm. (1.2 in.) diameter by 650 mm. (25% in.) length, poured from the top in oven-dried molds, and broken on supports with 600 mm. (23% in.) spread. In France the Monge test has been practically replaced by the tension and shock test. The shock test is made on a 40 mm. (1.6 in.) square bar, 200 mm. (7% in.) in length, resting on knife edges with 160 mm. (6.3 in.) spread; a weight of 12 kg. (26% lb.) dropping from an increasing height produces the break. The starting height and the increase between successive drops vary according to the specifications. The tension test is made on test bars of either 16 mm. (5% in.) diameter, or of 25 mm, (1 in.). The Case Against Shock and Tension Tests To prove the shock test worthless, Mr. Fremont com- pared the results obtained on bars tested with the drop 22 14 ee 9 + +——_+ + pment 5 + 2 20 os 144 t S 19 4 Lod Rael D> - . 2 1g Se ae a =, D> |7 a = 6 | + dpa 2 16 Yd {5 . +-+— :33 > © : oO - \4 + : Oo. = \3 4 +—+ £ | | 2 \2 +—+—+ a . = +--bL—-+—4 oO tl | 10 +. UJ + T ‘ 422 | vB MB MB MB MB MB H=40cn. 45cm 50cm. 55cm. 60cm 65cm 153" $e gl” = 2 rs 14 Ng Wig cls 233 C28 Fig. 2 Comparison of Shearing Tests with Tests Made with the Drop Hammer hammer with those on shearing tests made on frag- ments of the same test bars. The results are shown in Fig. 2. These shearing tests were made on small test bars of 2 x 10 mm, (0.08 x 0.39 in.), some of them selected from the center and the others from the edge of the thick shock bars, with a square section 40 x 40 mm. (1.6 x 1.6 in.). For each bar broken under shock at a given height, shearing tests were made on bars selected at the center and at the edge. The points relate to the shearing tests, M signifies center (middle) and B, edge (border) of the test bar. It will be seen that some eer ites HITS ti Kin! abba a lh Me renee : ee “ Sextet « olin myo » *~ apy = a we alaerieeients hieeen ines A aetna dail wipe bes Aye . + * em 394 of the test bars taken from the large bars, having broken at a small height, gave excellent results, while the opposite result is found sometimes on tests from the bars which broke only at a great height. The re- sistance of the test bars from the center is always less than that of those taken at the edge. This is to be ex- plained by the difference in cooling speed. These re- sults are sufficient to condemn the shock test itself, even if there were no other reasons. Everybody knows that the tension test has no value for castings, owing to their sensitiveness against lateral strain. In fact, Mr. Portevin has demonstrated by the mirror method that the tension test is without any value when taken under ordinary conditions. The same remark applies to tempered steel, which presents the same characteristics. In America the tension tests are accepted, but not Fig Machine Designed by Mr. I Using Test Bars of Small Size recommended. This test is very little used in England and has been discarded by the specifications in Ger- many. The best French investigators are of the opin- ion that these tests should not be employed under or- dinary conditions. The structure of cast iron varies with the speed of cooling, and consequently with the thickness of the sample and the conditions of the run. It seems almost unbelievable, even during the present times of progress and science, that the qualities of cast iron should be examined by the aid of test bars run separately and whose structure is entirely different from that of the castings. It is surely very difficult to obtain from the same ladle any two specimens giving the same results on tests. What can be expected of test bars run sepa- rately from the castings whose quality they are to con- trol, and of a thickness entirely different from these castings, and generally cast at a different time? Colonel Prache was quite right in saying that “the Service tests of the artillery department have hindered the foundrymen in making better shells,” and so was Mr. Portevin when he said that “from the point of view of the quality of the metal for shells it is difficult to make a worse selection of testing methods.” It is easy to understand that, to obtain results which can be compared for shells of different thicknesses, test bars of different thicknesses should have been chosen. But the best way would surely have been to judge the quality of the castings by test bars taken from their THE IRON AGE August 16, 1923 own mass, rather than on test bars more or less dif- ferent from the castings themselves. The objection to this method is the impossibility to sacrifice a casting from a given lot in order to secure a test bar. The investigations of Mr. Fremont and Mr. Portevin relate to such methods, and in our opinion are capable of giving considerable progress to foundry work. Their methods will permit foundrymen to choose the best Fig. 4 General Character of Dia- gram from the Fremont Machine, the Elastic Limit Being Reached at OC, and the Angle Measuring the Coeffi- cient of Elasticity compositions of metal and the best foundry methods. Mechanical engineers will then have an opportunity to modify their designs and benefit to the fullest extent- from the results given by all the many tests which will be made on different castings. The result will probably be that the confidence in a given casting will grow, be- cause the finished product will be more regular and more reliable. It would be a great advantage if such methods were submitted to a commission made up of members of the various foundry associations, for the purpose not only of choosing tests to be recommended, but also to agree on the dimensions of the test bars, so that the results of all foundries or all investigators could be compared. Fremont’s Bending Test Machine To study in the laboratory the qualities of a cast- ing, Mr. Fremont recommends the static bending test. But as this must be made on test bars taken from the castings themselves, he has constructed a machine which will permit the employment of a test bar of reduced dimensions. He also thought it necessary to tell the conditions of the test. He chose the dimen- sion of 10 mm. (0.39 in.) width by 8 mm. (0.31 in.) thickness and 35 mm, (1.4 in.) length, so that the test bar can be cut from the casting at any desired spot, thus enabling the investigation of all the various parts. His machine, which is provided with a recording appa- ratus, is shown in Fig. 3. To verify the practical values of the results ob- 7 (697 It Fig. 5 Three Typical Diagrams Obtained on the Fremont Machine, Illustrating Different Qualities of Castings and Superposed to Permit Comparison tained by this method, he has made tests on 110 speci- mens of castings, for most of which he was cognizant of their results through practical tests. The dimensions of the test bar chosen were deter- mined by the power of the machine, which is from 1000 to 1500 kilos (2205 to 3307 lb.), but the effort must be brought about gradually, without the least attempt at extreme shock in breaking. The method chosen is the one using a hand wheel drive on a screw, with the in- sertion of a large spring between screw and the punch August 16, 1923 holder. This spring acts gradually and, without shock, transmits the strain of the screw. The weight of the movable part is balanced by a resistance coil spring placed in the slide of the frame. The large spring will bend proportionately to the work applied, which it transmits at the rate of 1 mm. for 13 kgs. of pressure (1 in for 2408 lb.) The breaking of the test bars takes place only when the screw has made from 3 to 8 revolutions, according to the strength of the casting. This permits a simple and easy way of measuring the strain applied. The elastic limit or co- efficient of elasticity is obtained by reading a recording diagram. A suitable device carries the drum along, by means of wire in connection with a large spring, so that 1 mm. on the line of the abscissae corresponds to a strain of 3.4 kg. (190 lb. for 1 in.) As the bending of the test bar is very minute, it is enlarged about 200 times and recorded on the line of ordinates. Fig. 4 shows the diagram obtained. The left side shows a curve which results from the contact of the test bar with the recording knife. The actual starting point is a’, a’y’ being considered as the zero point. When this line is no longer straight, at C, the elastic limit is reached, and the angle E, 2’y gives the meas- ure of the coefficient of elasticity. Breaking of the test bar, owing to the nature of the yrams Q RAC t - Fig. 6. Showing Proportionality Between the Resist- ance of a Casting to Bending and Its Resistance to Shearing casting, is always sharp. To eliminate damage to the recording apparatus, two Belleville washers have been placed under the tool carrier. The run of the punch is thus limited to 2 mm. (0.08 in.) _However, a spe- cial device is provided to prevent the horizontal levers from being injured when the test bar breaks. The machine is weighted, in measuring the bend of the large spring under a given load, or else while acting on a scale which is gradually weighted. A like proceeding is used to get the deflection of the test bar, by pushing the levers through the intermediary of a precision caliper. Fig. 5 shows three typical diagrams, corresponding to the different qualities of castings and arranged to permit comparison. For the first breaking load, 316 kilos, (697 Ib.) angl 24 deg. 30 min For the second breaking load 724 kilos, (1596 Ib.) angle 10 deg. 30 min For the third breaking load 833 kilos, (1837 lb.) angle ) deg. This diagram shows that the deflection has varied from the low to treble this figure. The coefficient of elasticity can be determined by the bending diagram. Numerous experiments made by Mr. Fremont show that, the more resistant the casting is, the smaller the bending will be, while the variation for steel is in- finitely small. He recommends this method for exam- ining metal and establishing the terms of specifications for the laboratory. For the acceptance of the finished castings he recommends the shearing test. Shearing Tests have been investigated for daily ac- ceptance of castings. In a preceding article on steel * “Principles of Iron Founding,” Moldenke, page 163 THE IRON AGE 395 Mr. Fremont demonstrated that the phenomenon of shearing or punching is an action of tension and not of sliding, as had been supposed. The various layers com- pressed by the punch or the shear blade will not sepa- rate at once from the layer from which they come. Fig. 7 Hollow Drill of Milling Form and _ the Holes It Cuts The core is broken out and forms the test piece Every fiber of metal will act as a tension test bar, which will elongate under the strain of the tool. (See Paper on Riveting, in French, “Bulletin of the Society for the Encouragement of National Industries,” 1906). He has been able to demonstrate that for steel there is a direct relation between the resistance to shearing and the resistance to tension. To determine this mat- ter as far as the casting is concerned, he made tests on 110 specimens from castings, of which he knew the results of their static bending tests. He has been able to ascertain that the resistan¢® to shearing for the casting is proportionate to the resistance to bending, as is demonstrated in Fig. 6. This has been confirmed by new experiments of Mr. Portevin, in semi-steel. Other experiments have shown that, for castings, the resistance to tension is equal to the resistance to shearing. Consequently a shearing test is perfectly satisfactory for the acceptance of the castings and, moreover, there is no chance for any errors similar to those of the present tension test. To pass on the qual ity of a casting, it occurred to Mr. Fremont to test a small square prism of 5 mm. x 5 mm, (0.2 in. x 0.2 in.) taken from the piece, or a small cylinder of 5.64 mm. (0.22 in.) diameter; that is, in each case to use a sec- tion of 25 sq. mm. (0.04 sq. in.) from the casting. This method was presented by him to the Interna- tional Congress for Testing Methods, held in New Machine for Cutting or Shearing Fig s Head of Autographically Recording the Effort Overcome the Resistance York in 1912. Dr. Moldenke said:* “These small stems are sheared every 3 mm. (% in.) and the aver- age is taken. The proportion is exquisite in its novelty and ingenuity.” It is often possible to take from finished castings small prisms of metal which can be adjusted to the square section of 5 mm. x 5 mm. But when this is impossible, the same results are obtained by drilling holes in the casting in a special way, which leaves a bar of metal in the center to serve for the test piece. The hole made by this operation may be plugged if necessary. These holes are made with a drill in the shape of a round mill, having a diameter of 10.5 mm. (0.4 in.) Fig. 7. This round mill in cutting leaves in the center of the hole a small cast iron cylinder, 5.64 mm. in diam- eter (25 sq. mm. section), constituting the test bar. This test bar is detached with a special small tool made up of two eccentric tubes which enter the drilled hole, leaving a small clearance within each other. The inside of the small tube has a diameter of 5.64 mm., while the outside of the larger one has a 10.5 mm. diameter. The two tubes are pushed into the circular 396 slot hollowed 6ut by the round mill. By turning the outer tube with the aid of the lever, the inner tube 1s kept immovable and the test bar is thus separated. This test bar, round or square, is then cut 3 mm. x 3 mm. (% x % in.) and at the same time the strain is measured. This gives the resistance of the casting at the periphery and at the different depths of the cast- ing chosen. One of these castings, of about 20 mm. (0.79 in.) length and weighing about 4 grams, (1/7 oz.) permits making five shearing tests, ie., less than 1 gram per test instead of more than 1 kg. (2.2 lb.) The cutting is effected between two blades with parallel cutting surfaces. The machine employed for this method, as shown in Fig. 8, is to be slightly modi- fied, to make its use more convenient in practice. It New Gasoline Dipper Shovel A gasoline driven power shovel operated entire!y with gears and shafts is being marketed by the Orton & Steinbrenner Co., 608 South Dearborn Street, Chicago. In adapting the gasoline motor to a dipper shovel, the principal difficulty has been in the necessity to provide an arrangement to take the place of the inde- pendent source of power for the reversible crowding motion of the dipper stick. With the steam-operated type this is accomplished by means of a small steam engine geared directly to the dipper shaft. With the gasoline or electric type this method is said not to be feasible. Of sprocket and chain arrangements and wire rope drives, the company claims that they will not stand up under severe usage, especially where the cables are bent over a number of small diameter sheaves and drums, and reversing curves are employed. Positive gear drive is an out- standing feature of the machine illustrated. A shaft-at the bottom of the boom connection carries double steel bevel gears and bronze friction clutches. This shaft is concentric with the pivot of the boom and consequently, being in- dependent of its position, the boom can be used at any angle to suit the exigencies of the work. A steel shaft carrying two bevel pinions extends along the boom. One pinion meshes at the bottom with the gears on the horizontal shaft, and the other at the top meshes with gears on a counter- shaft located about half way up the boom. The countershaft car- ries a brake and “slip friction,” and is geared directly to a cast- steel rack on the dipper stick. With this arrangement it is claimed that a minimum number of levers are required and fatigue incident to operating the rope-driven type is eliminated. The ho'sting mechanism is the same as used in the company’s locomotive cranes. The machine may be conveniently converted into a clam-shell outfit, drag line or skimmer rig. Power is supplied by a heavy-duty four-cylinder Climax motor, and the drive is by means of steel shafting and bevel gears. The flexible crawl- ing tread is a feature, and steering is accomplished by one man in the cab. On the main horizontal drive shaft are two brake wheels by means of which each tread may be operated independently or both may act together. The mechanical differential arrangement is similiar to that used on automobiles. Alemite fittings are used exclusively in lubrication. In using as a crane, only the shovel boom need be removed and the crane boom attached. The crowding frictions for operating the dipper being carried by the shovel boom and an integral part of it are removed with it. The shovel when equipped with double drums may be used interchangeably with the crane. With boom may be THE IRON AGE Gasoline Driven Dipper Shovel Operated Entirely by Gears and Shafts. taken off and crane boom substituted. shovel may be used interchangeably with the crane August 16, 1923 consists simply of a lever which has a stationary point, with a device for applying on the blade the strain of a movable weight running along the lever. This weight is shifted by a small handle that is drawn on the weight by a spring, but a device with screw and fly-wheel will be provided on future machines. The strain is multiplied in proportion to the arms of the levers. When the effort corresponds to the strength of the test bar, the breakage takes place. Dur- ing the operation a pencil shifts along a slip of paper, producing a diagram similar to the one shown. The table, arranged according to the constants of the ma- chine, gives the strength of the specimen tested. (To be continued) the crane boom attached various types of buckets o* scoops may be used and pile driver leads may be swung from the tip of the boom. To Take Over Plant of Eastern Ohio Mfg. Co. C. G. Thomas, Warren, Ohio, announces that a new company will shortly be formed to take over the plant of the Eastern Ohio Mfg. Co., Warren, Ohio, which will be equipped for the manufacture of cold-rolled strip steel. The plant will have an initial capacity of 1500 tons per month and will specialize in the manu- facture of the highest grade of strip steel, including various high carbon, alloys, nickel plating steels, etc. The organization will include C. H. Lewis, formerly Shovel With double drums, the secretary of the Western Reserve Steel Co. and later with the Niles Trust Co., Niles, Ohio. “™ E. B. Hite, Lancaster, Pa., will also be associated with the company as general manager in charge of operations. Mr. Hite has had a wide experience in the manufacture of strip steel. He was formerly with the Crucible Steel Co. of America and for the last few years superintendent of the Lancaster Stee! Products Co., which is a subsidiary of the General Motors Corporation and produces strip steel for its various plants. It is expected that the plant will be in operation prior to Jan. 1, 1924. Jones & Laughlin Steel Corporation, Pittsburgh, has adopted a plan for the sale to its employees, under special terms, of its cumulative preferred 7 per cent stock at $107.50 a share. A maximum of 5000 shares will be sold on this, the initial offering. Details of the plan have not been made public. The Role of Chemistry in Semi-Steel Chemical Control of Both Raw Materials and Finished Product Necessary—R6le of Combined Carbon— Effect of the Other Elements BY J. castings which are strong and tough and at the same time are easily machinable. There is no process by which gray iron can be given these desirable properties more readily, at a reasonable cost, than by the addition of steel scrap to the mixtures in the cupola. The product thus obtained is popularly known as semi- steel. Some people, especially in the last year or two, have objected to this name as being misleading, and for other more or less valid reasons. It is not my intention either to defend or to find fault with the name. I merely use it for want of a better one, and because it means to me, as I am sure it means to most of you, a gray iron of exceptionally high quality, made from mix- tures containing trom 10 to 40 per cent of steel, and having a tensile strength of at least 30,000 lb. per sq. in. and transverse strength of at least 3200 lb. These values are for mixtures containing the minimum steel additions and are correspondingly higher as the per- centage used approaches 40 per cent. 1 gray iron foundrymen we all aim to produce Continuous Chemical Control Such a product is uniformly obtainable only when both raw materials and the finished castings are un- der continuous chemical control. Any foundry whose work is of such nature as to require particularly close- grained, tough iron will find it a paying proposition to employ the services of a chemist. I mean a chemist who is on the ground, in constant touch with the foun- dry and its personnel, rather than one or more outside chemists who supply analyses now and again with more or less accuracy and do not take a personal in- terest in the work at hand. In the foundry of the Vilter Mfg. Co., Milwaukee, we are concerned primarily with ammonia fittings, which are subjected to pressures up to 300 Ib. per sq. in. in service, and consequently close- grained iron is absolutely essential to success. In this paper it is my purpose to tell you as briefly as may be the more important aspects of my work. While one naturally thinks of chemistry as applied to semi-steel as a laboratory process, the foundry chemist who does not spend considerable time in the foundry itself cannot hope to be successful. In our case, it is about a fifty-fifty proposition, and I know that, however important the chemical tests are, the work within the foundry is no less essential. The chemist should personally check over the blue prints of all cast- ings to be made so that he can acquaint himself with their intricacies. This is especially important in a jobbing shop. He can then intelligently calculate mix- tures for the different classes to be cast. The weigh- ing off of these mixtures should be done under his per- sonal supervision or that of a competent assistant. The charging of the cupola should be similarly han- dled. When the iron begins to flow he must again be on the job to check each tap as it is made and to see to it that the metal gets to the mold or molds for which it is intended quickly, and in proper condition for pouring. Cupola Practice In this connection one cannot too greatly empha- size the importance of good cupola practice, and conse- quent hot, fluid metal. If semi-steel is not melted hot, the reaction gases cannot escape and the component parts of the mixture cannot mix properly. The re- sulting castings will be dirty, spongy and altogether unsatisfactory. A number of good textbooks are avail- *The author is with the Vilter Mfg. Co., Milwaukee, Wis. The paper was presented before Wisconsin Foundrymen’s Association, Madison. 397 BOCK* able in which good cupola practice is described in de- tail. There are also illuminating articles appearing from time to time in the technical press, so that one would no longer expect to find poorly operated cupolas. However, we hear of many instances to the contrary and if you are obtaining anything but the best results, a little investigation will repay you beyond the shadow of a doubt. The reactions which take place within the cupola form as important a part of the chemistry of semi-steel as the laboratory work itself, and this paper would be most incomplete without at least a brief sum- mary of the outstanding essentials of good cupola prac- tice. The ratio of the tuyere area to the area of the cupola is very important. The height of the charging door often is a deciding factor. The profer amount of coke on the bed is of utmost importance, and it is a good idea to light the bed sufficiently early so that it may be thoroughly burned through before charging is begun. As regards the amount of coke between charges a ratio of approximately 10 to 1 will be found correct. A mild blast of sufficient volume is always to be pre- ferred to high blast with its attendant evils. Use as little daubing as possible and avoid excess sand on the cupola bottom. Analyses Which Are Necessary Let us now consider the work in the laboratory from the practical viewpoint rather than the theoretical. As already brought out the chemist controls semi-steel (or ordinary gray iron for that matter) by analyzing both raw materials and finished product. The physical state of the raw materials frequently has as much influence upon the results obtained as has the chemical analysis. Pig iron constitutes upward of 50 per cent of the or- dinary semi-steel mixture. The machine cast product is, to my mind, much to be preferred not only because it is cleaner, but because it is of more uniform size. The laboratory analyzes all pig iron received for silicon, sulphur, phosphorus and manganese. Carbon determinations are rarely made in this connection. Graphite and combined car- bon in the raw material have no direct relation to the corresponding constituents of the finished castings and are therefore of no value. Total carbon is sometimes determined for use in deciding upon the percentage of steel to be added to a given mixture. The most important factor, however, in deciding upon the percentage of steel to be used in making the mixture is the thickness of the metal in the finished castings. The lightest sections ordinarily require 10 to 20 per cent of steel and the percentage is increased with increase in section, 40 per cent being the highest percentage feasible under ordinary melting conditions. As regards the kind of steel scrap which is suitable, in general any mild, low carbon steel of suitable size will fill the bill. By suitable size we mean pieces weighing approximately the same as the ordinary pig iron and of roughly the same dimensions. Large pieces will not melt so rapidly as the balance of the charge, and abnormally small pieces will be badly oxidized even before reaching the melting zone. Either condition will result in poor quality metal decidedly off analysis. The laboratory analyzes all steel scrap received for carbon, sulphur, phosphorus and manganese, which are rela- tively important in the order given. The remaining raw material, which is usually used to make up the balance of the semi-steel charge, is scrap gray iron. Many foundries use any scrap which may be available and do not hesitate to use as much as : } ° ‘ LEE wy ee ee ed Ui eA et it a 398 THE IRON AGE 50 per cent. It is our practice, adhering closely to analysis, not only to limit the gray iron scrap used to 25 per cent, but to use only our own semi-steel scrap as produced from day to day. The analysis of this mate- rial is checked continuously in checking the finished castings and it is the only safe scrap to use. Use of Ferroalloys Occasionally we make use of alloys to supply de- ficiencies in the pig iron available, but we aim to avoid their use whenever possible. If charged into the cupola we have found invariably that there are large losses and, furthermore, that the product obtained is not uni- form in spite of every precaution. If added to the metal in the ladle the alloy is rarely properly fused, and in any case it chills the metal by the amount of heat re- quired to melt the alloy added. Ferrosilicon and ferro- manganese are the two alloys commonly used and the laboratory checks these for silicon and manganese con- tent respectively when we cannot avoid using them. Quality of the Coke In addition to the raw materials mentioned the laboratory checks numerous other products which are used in semi-steel practice. Among these are fireclay, firebrick, various sands, limestone and coke. Because of its far-reaching effect upon the finished product, both