Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

402 nolesworth’s pocket-book Pitches of Equivalent Strength tor ttie Teeth of Wheels in Different .Materials. Pitch for cast iron =1'00 „ brass .. = 1'12 „ bard wood = r 2G SHAFTING. STRENGTH OF WBOV.GHT-IRON SHAFTINß. D — Diameter of shaft in indies. JI = Indicated horse-power to be transmitted. N = Number of revolutions per minute, s /qq jt . p — V —— in csank-slSifts and prime movers. o N ' .s/6511 . .. , p,. j) — V ——m ordinary shafting. Relative Poweb of Metals to Resist Tor.sios, Wrought luox being Unity. Wrough t iron .. 1’00 Cast iron .. .. ‘ 90 Cast steel .. .. 1'03 Gun-metal .. ‘27 Brass.......... ‘25 Copper •• "22 Tin .. •• & Lead........... ’10 Relative Power of Different Sections to Resist Torsion, the Sectional ^Akeas being Equal, Solid Cylinder being Unity. Solid Solid Cylinders. Squares 1-0 -87 Hollow Cylinders whose Inner Diameter is to fhe Outer tu 4 to 10 5 to 10 6 to 10 7 to 16 8 to 10. 1 26 1x44 1’7 2-08 2'74