NOD A Tee eee ee ee bE died eee ee er eee Shs nee) te ee see A ro iy a a i 7) pug od i aie a 7 A uy at oS Fr, Pt coe ei. oS cr iy er ra | : ree ere ei Ree eet bad il ed ad Lele etatha el daha eet a, deep cad chs haha acme oe PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. DATE DUE DATEDUE DATE DUE MSU Is An Affirmative ActiorVE qual Opportunity Institution A Design of a 500 lb. Board Drop Hammer for the MeA.C. Shops. A Thesis Submitted to The Faculty of WICHIGAN AGRICULTURAL COLLEGE BY F.B.Love R.J.Clyne Qn Candidates for the Degree of Bachelor of Science June, 1917. THESIS PREFACE. The object of this thesis was to provide a design ofa power hammer that could be made in the M.A.C. shops at some future time and be used for general forge work and the il- lustration of methods of doing drop forge work by the use ‘of the drop or steam hamper. The object of this choice of subject was to give tne designers an insight into some of the methods of common practice in machine design and the making of complete detail drawings. qa. YS ty i Are wd rk a? os won we | BIBLIOGRAPHY. incyclopedia Zrittanica-Vol.XXVII Idition ll. Machinery-Aug.1916. 38000 word article by Dixie, on the design of important details of drop hammers built by well known manufacturers. Catalogs by tne following manufacturers: The Toledo Machine and Tool Co. Toledo Ohio. Chambersburg Fngineering Co. Chambersburg Pa. The Billings and Spencer Co. Hartford Conn. E.W.Sliss Co. Brooklyn N.Y. ty HISTORY The original drop hammers, wiich were believed to have originated with the locksmiths of England in the Birz- ingham district, consisted of a hammer head attached to a rope or a belt, the other enc of which was thrown over a loose pulley suspended from the roof of the shop. The hammer was lifted by hand by pulling on the other end of the rope or belt. This form of hammer is still in use for lisht pressed work on sheet metal in the manufacture of steel ceilings and cornices. In some cases this nammer has been modified to the extent of having the pulley, over which the lifting belt runs, connected to a source of power. With this device,the men pulling the belt do not have to lift the hammer, but only tighten the belt so that the friction between the lifting wheel and the belt will lift the hammer to the required height. At the desired point of release the men let go of the belt. This form of hermer is still being manufactured and sold. Its main advantaces are its simplic- ity, cheapness of construction, and ease of controll. Its greatest disadvantase is in the fact that the manual labor required to run it is very great for steady use. This objection led to the bringing out of the present type of hammer having the board and roll lifting mechanism. It is this type of power hammer that we have endeavored to design for the following reasons: For the 1!..A.C. forge shop the board hammer is to be preferred to the steam hammer because a dead end high pressure steam line would have to te ine stallec in the forge shop and this would be a constant source of waste. uhe u.A.C. forge shop is already equipped with a line maft which is driven by a 7.5 H.P. motor. Sufficient power can be easily obtained to drive a board hammer. The board han- mer is more simple to manufacture than the steam or the pneumatic hammer because there are ro cylinders to be fin- ished. All of the parts on the board type of hammer requir- ing accurate machine work are within the limits of the 1..A.C. machine shop. An Cc. COMPUTATIONS FOR “EIGHT. Base:- Liethod: According to the principles of cormnon practice as followed by the leading manufacturers of board hammers, the base block is designed to weigh from fifteen to twenty times the weight of the hammer. In this design tne least of the two limits in weight was chosen. A preliminary layout was made and the spacing of the upright pieces set at 14". Other parts were proportioned liberally in size so as to give rigidity, strength,and weight. The thickness of the top of the base was set at 173" and a taper to the sides of the base was provided.for. Knowing the width of the base, the mean depth, and the required weight, the height was computed. This was found to be 3'-3". Computations: Wt.of base = 15 x 500 = 7500# Add to this weight the weight of all metal not included in a resular geometrical solid. This will give an approximate weight of base which is near enough to the required weight for this use, Amount of metal cut out to provide die space: Width 5a"total; Length 14"; Height 5"; Wt. cast iron= 267 per cu.in. Total weight to add for clearance space = 5a x 5 x 14 x .26= 100# approx. 100# + 7500 = 7600;7 Assigned length of base-35" Assigned mean depth-21" 7990 = 29200 cu.in. cast iron required in base. 29200 ~ 39.7" height of base. The addition of bottom Seay bosses for bolt holes, brings the height of the base to 39". COMPUTATIONS FOR WEIGHT (Cont). Hammer: - Kethcd: The size of hammer chosen for the dcesicn was to be 500# in weight. This size is convenient for general drop forge work on small parts, and for blacksmith work. The hammer is to be made of .35% carbon steel which has a weight of .282# per cu.in. The width of the hammer was chosen when the base was designed, and this was set at 14". The height of the hammer was set at 18". A slope to the sides was decided upon so as to give the hammer a regular geomet- rical shape to facilitate in the computation of weight. Tne weight of the metal that comprise the slant of the sides was computed, and after allowances were made for the metal taken out for the guides, the depth of the hammer at the top Or the narrowest point)was computed. Allowances for irregularities of form: GCuldes; Triangular section guides having a height of 14" and depth of 1.73" or 1-3/4" approximately. Weight cut out: 1-1/2" x 103/4" x 18" x .262 = 12; Hole for board: 6" x 5" x 13" x .282 = 10; approx. Trip slide: 32/4" x 12" x 14" x .282"= 3.2, Total weight to subtract = 25#. Weight enclosed between the sides:— Slope of sides 2" to 18", 14" x 18" x 2" x .282 => 142; 500 — 25 — 142 = 333# weight of the inner rectangular sec- tion of the hammer. ~.} CCLPUTATIONS FOR WEIGHT (Cont). ah == 1150 cu.in. 4" x 18" x X #21180 cu.in. ene Xa 4.68" depth of the top of hammer. After investigation on actual drop hammers we find that some manufacturers make a liberal allowance for an excess over the rated weight, and do not adhere absolutely to the rated weisht of the hammer. Also for convenience in design of other parts and to provide for a more adequate die hold- ing space, the hammer depth at the top was changed to 54" Actual weight of the hammer as changed 570;. Dies: Dies were not designed for this hammer because of the difference in dies for different classes of work. SIZE OF ROLLER SHAFTS. Test for bending: Let P equal the pressure on the snaft. "8 " " length of the vearing between centers. xu * " pending moment. "ss " " allowable bending stress. " vy 4% " distance from the neutral axis to the outer-most fiber. "oI " " moment of inertia. Then s —~ liv or i sl “L FV Then since li _ PL sl — PL For @ round solid shaft I — 3.14 a4 v «64 - Simplifying, and substituting, a4+_ 16 PLy s taken at 5000 #/sq.in. 4 3.14 8 d*_. 16 x 1920 x 18 x 1.5 ie 53 ~14 x 5000 1920 is the pressure in lbs. against the rolls. ad wy 53 =m 2.7" diameter of shaft. However on account of the sudden and repeated bending stresses that the shaft is subjected to, it was deemed advisable to use a shaft 3" in diameter. WD ROLLER HEAD BEARING PRESSURIS. Diameter of the roller shnaft— 3" Length of one bearing-— 6" Area of one bearing surface = 6 x 3 = 18" Number of bearings on each shaft Qe Total bearing surface = 2x 15= 36 sq.in. Allowable bearing pressures on cast iron bearings for intermittant use= 700 - 800 lbs. per sq.in. Total pressure on bearings 1920 lbs. Bearing pressure — 1370 — 53.37 /sq.in. This bearing is adequate for any stwess it can be put to. CHECK ON THE LIFTING CAPACITY OF THE ROLLER i2tCHANISh. Weight of a steel rod 14" in dia.— 4.177 per ft. " “ow 4 "2H 8 4 10.687 " " Length of the roller releasing rod— 6 ft. " " " lifting arm shaft including sleeves—2.5 ft. Weight of releasing rod~ 6 x 4.17 = 25# . " " lifting arm shaft including sleeves — 2.5 x 10.68 = 26.87 Weight of tripping blocks — 5#. " " " tee — 1.2# Total weight = 607. Length of tripping arm— 12" (Long lever arm) Eccentricity — 3/8" (short lever arm) Mechanical advantage—-12 — 32. 378 60 x 32 = 1920 # pressure exerted against the board by the rollers. Coefficient of friction of steel against wood (maple)- .37 Lifting capacity 1920 x .37= 710 #. Hence if necessary this roller mechanism would be cap- able of lifting a hammer weighing 710 lbs. 2 CHECK FOR STRENGTH OF THE GRIPPING MECHANISM SHAFTS. Total pressure against shafts: From the above diagram- 500 2% 29 2.625 + 4.78 X = 1472 lbs. Assume that the vertical distance is shortened to the extent of $" which would occur if the grips were not ad- justed properly. This would raise the bearing pressure to the following extent: 500 2X te oY 4.53 X= 4530 lbs. Total bearing surface 8x 13" = 12" Resulting bearing pressure- 4530 — 378 lbs per sq.in. area. This is found to be allovable ree cast iron bearings when subjected to intermittant service. The nature of the device is such that the dogs cannot slip when adjusted properly, so checking is unnecessary for this as was done for the roller head. Care must be taken to have the gripping dogs adjusted properly as experience has found that this must be set carefully or the result will STRENGTH OF SHAFTS (Con). be to let the board slip or that the board will be crushed at the point where the dogs grip the board. Strength of the shafts: Suppose that the hammer should drop from its extreme height of 3'-2"and be gripped by the dogs at the bottom just before striking the die. From the table of forces of blows for different heights of fall it will be seen that the pressure of 4530; is increased to 15400# in the ratio of 500 to 1700. Area of the shafts in shear (2-1¢"shafts) }3.52sq.in. 15400 4375 #/sq.in. stress in shafts. This as allowable. SPHED AND POWER, Consider hammer shaft to run 150 R.P.M. 8"dia.roller. Circumference of roller. 8 x 3.14 = 2.1ft. 2.1 ft. x 180 R.P.M. x 500 y=. 189000 ft.lbs./min. 189000 =, 5.73 H.P. required to drive the hammer,when no allowance is made for the time of drop of the hammer Since the forge shop is equipped with a 7.5 H.P.motor and a line shaft this hammer can be easily set up. Size of pulleys on line shaft: Line shaft 250 R.P.M. Hammer shafts 180 R.P.N. 24 : X :: 250 : 180 X = 17.25" 18" pulleys on the line shaft will do to drive the hammer. FORCE OF BLOW FOR DIFFERENT HEIGHTS OF FALL. Vv the velocity of fall in feet per second. h the height from which the body falls. w the weight of the body. (500i) K.z. kinetic energy. K.E.= $mv°_ wre? —wh. (v° = 2gh) eg For lift. fall- K.E.= 500 x 1= 500 ft.lbs. For 1$ ft.fall- K.E. = 500 x 142750 ft.lbs. For 2 ft. fall- K.E.—= 500 x 2— 1000 ft.lbs. For 24 ft.fall- K.E. = 500 x 24—1250 ft.lbs. For 3 ft. fall- K.E.= 500 x 3=1500 ft.lbs. For 3.2 ft. fall- K.E.= 500 x 3.2=1600 ft.lbs. La pa INDEX TO DRAWINGS. Drawing No. 1 iain Assembly " 2 Unit Assembly of Roller head " " 3 Unit Assembly of Gripping iiead " " 4A Upper Half Roller Frame " " E Lower half Roller Frame " " 5A Lifting Arm " " 5B Collar, Lifting Arm " " 5C Bushing " i) " 5D Shaft, " ‘ " " 6A Rollers " " 7A Shaft,Roller " " B Key,Roller Shaft " " A Lower Tripping Block " " 9A Bushing,Top Tripping Block " " 9B Top Tripping Block " " 9C Stud Bolt,Top Lifting Block " " 110A #£Pedal,Arm " " 10B Pedal " * 111A Roller Releasing Rod " " 12A Guide,Roller Releasing Rod " " 128 Board Vedge " w 613A Hammer " " 144A Base,Tripping sechani sm " " 148 Shaft, " " “ §14C Plates, " " " W 15A Sub- base Gib " # 153 Sub-base " " 16A Left Support " " 16B Right Support " " 17A Base " ne oy: Roll Adjusting Rod. " " 16B Tripping Rod Inds(1l&2) " " 18¢C Adjusting Rod Cleat " " 18D Tripping Rod " " 119A Lock Washer,Upright Adjusting " * 19B Plain Washer, " " * = €§619C Pedal Connection " " 19D Upright Screw. " " 195 Rod Cleats " *" 20A #£Rod Spring " “ 2038 Spring Plunger " " §©20C Lifting Lever " " 214A Rod Rest Block " " 21B #£=Rod Shoulder Base " " 22A # Tripping Arm " " 22B Rear Gripping Dog " " 23A #£Front Gripping Dog " " 23B Key,Tripping Arm " * §23C Eecentric Sleeve " " 24A # £=x‘Tripping Tee " * 25A Adjusting Plates " " 26A Tripping Arm Sleeve " ": 26B Lever Support Block " " 6278 Head Bolts " " A Bearing Block " " 2 Bill of Materials. 7 eee =——_ == SL owes Se Ad fae fe) ANOT GAB INATIL aT oYVw “TD prey 7 Ls TUT ATF dle Bo fs he Ale LNT Ms Me Aeked Fs e~] e/a A TOD PAV 7 £4 ot a eo | FP a o oF Tol, 7 ane PA Foray 4/64 > ae“ pai eI he Bel Boo YES A OCBLNMWA+H JWOX ee De oe ee 6 ee Nt hk eA oT a Mae) Medd he es ope i + aie z TD ae ei! A Aas ‘ ae. 4 - AAATHANIAT Ain ULDUUUUUULU VUUUUL me q el! 4 COdd IN iefcoS/A1 a “ibstent! 4 TB/ ON LAY 4A DIA M-/ a et _ 7+ ) ‘52> GCILNVM~/ 4 dee nd eA ee hd f ca 3 vd cd we Ts Ps ) dy a i Z Nw 5 =n G/ DAMAAT P =9 F7+OS Pe, oe + a: ‘F6/ -ON Lites Eid Anne ae na es aoe Pee rey r Sy 2/e/ "ae ty ane Pad EAs i, nd) A | | a) pews. a | ater -----> a dhbede ahd r= Neg Ve ee FA soe a ny ef 7 a ee Saar egg Ns na mec ae 2 lo, 7 Ola a ed a ke aoe TS aot A Lee ad 28 ss rs Sion eal a sy | aed By ee 2 AL Add w aD ee ccc | — ag ay -T i ar ek ee a \"s , verro2> Ww. 02 DMAW 437 StIvros ae Lee a A Lhe eo Al tn a a FA A ee a!) dee, ad) yA fe eA Adee 6 ae O8f FBYMNAFLIWVIT SVNOVE Cd Ses a od + 902 -OV Ld vs ie A A Le = el) ee a ed lL ee ee eed % ie (= £-) to ae oe 7 YIIN AES DANA aS a if sf FS 3 IZPQMYA 12: 9 FIV >= ACT Se ireIvA72 py *4/6/~Dvriv a th hd ITN ee A ef SISTSHL i a Sey ee ed a ae eo Pe a ‘asyra YIFIINONS coy 2 hel = ae tk ee Biel ee) ale | B aks Eee bc EP "gies eel me aid + 3) ro Pd ra Tans a el <4 x a ¥ Te a | Cr rs Li eens ” PR 2 Sd me worn Stille Bice rt ele Me Ded ie | 0 2 a ee ee low me - ae) ae aes oe EN A-Etey ae aa af Tye pet es oa N Ga#.nwm-/ DA 1 hah A heh, Ad) f y Poe) Vo a ded a 2-1). aD at 2M a } ee ae) Ad oe. ae SE Par ee = a4 ~ON Live ee eee eae ee Pek ey be Te T= J ie dee ed Be Capt Eee ae ae ee a3 . Pi fe A Mae eA >) SS a oe ie ad ! SZaomyd #7/S SIWHN-FIVOIS Fa —/0* le a — eee fe oP as 7. Yr en ae oe yf sea ae z aa A ere ieee aa : Ay pe [Va poh A a Ld LM AAA Aon ae ae a a ee i o a eke ial tk se A S/S ee, es lola Moth hhh ee ak le A te Py Be A Peal r 7 nek : : | | | | : | ma os S a. | ete PA 2. | i yy ee oI tA oT Me a 6 er) Ad | >| DP ak Sen - a Bd ae wd ea ee ee em r eases : AEHOMYAT ./= FF 7H 9S FINOTEG AH & FINATILY L/4/ ee. aa | AIRE: heh LE Lek A Ae ae 4 a Zz Ht Pa eT” a 4 ’ ——# on wy “eh SF #IMID />FITHIS CUO r ee ed ee a ian a 0 es Ae LA Ed LA S/S FA L ae T9 Ply 2 a ALS F | | ' 3 eaves Wee oe ae “ Fd 5? ‘2 a2 — EAS SE age oe eam at ee 4 ae 4 Te : ae A a Ka ews i os 9 aioe; ae a ea Amerie S02) } ea as] * e/ A oa Z ee a Wid re mi 2 ae | re mee Aa JFAOTEGS#? INATILYG ie A anys Le ee A OL Lah SISTFTHL OVW Be Aehel 24 Lee | fe ois te Aa 4 agent (pay cer Fi bam ie ¥/ oe x ae cy. ean Py - ‘i iA Pad 7 : Ne 4 / sd ea | hed A Se ae 2 te sly I AB ELLY ae UA % spaplpaeersgpneeny veka eae NINE Regi ctt ET de 2 ‘ieee | . | : ’ ; Koes rae 5 ee ee ee { z LEHIMT (=F f= 2779S PAOTAG AF INATISTY ie a Lib/ ce - V4 tomes Me LIL aE A S/S FH L wre arse oI P ae ta 5% a Tr ¥HLIS i ela’ | Wlz# hate a oS Va 21a = A idea Pr Sean cil ar + Sy FRX LY Pros] 7 cs L PART — S/ZF - np De CAP SCREWS re I i ee 8 ee y 7 a. + a 5 HX 1%4 ~ / " Le » od ¥ Vd Ye X 2h 2 ee as yj Yo x 1°2 ) yo x 4 : 4 / Yr 2 ee e 14X22 6 NUTS ae / a rc} £2 Ss ie 4. ya “ oa 7 PT al SET SCREWS (i Siler P ae Pa Conical pont. a x3 3 4 Y me) « rid ot het BE Ys en ae rR Head/ess 7) oa tf eye ee ee PA WASHERS a y 24, DIA. haat 52 NS = hal AEA erah 4 14 XE=X 7 i NOTE - ABOVE SCREW SIZES US.STO. THREAD. “TC