Page:Practical Treatise on Milling and Milling Machines.djvu/232

226 TABLE OF APPROXIMATE ANGLES FOR CUTTING SPIRALS

TANGENT OF ANGLE OF SPIRAL= C-CIRCUMFERENCE OF CUTTER, DRILL, OR MILL L-LEAD IN INCHES TO ONE TURN T TANGENT OF ANGLE OF SPIRAL

T=

L=

NOS, OF TEETH IN GEARS FURNISHED WITH MACHINE 24(2) 28 32 40 44 48 56 64 72 80 10o

THE LEAD IN INCHES TO ONE TURN=

EXAMPLE ILLUSTRATING USE OF TABLE DIAMETER OF CUTTER, DRILL, OR MILL 1¼ LEAD IN INCHES TO ONE TURN 3.140 REQUIRED ANGLE TO NEAREST QUARTER DEGREE TO SET SADDLE OF UNIVERSAL MILLING MACHINE 54¼

GEAR ON WORM 1ST GEAR ON STUD 2ND GEAR ON STUD GEAR ON SCREW TO ONE TURN LEAD IN INCHES TO ONE TURN DIAMETER Or CUTTER, DRILL, OR MILL

48 44 28 86 3.552 6 12 1823 29 33 3741 4753 44 56 48 100 3.771 72 100 48 86 4.019 5 11 1621 26 301 34 38 44 49 64 48 32 100 4.267 5 10 15 20 24 29 32 36} 42 47 52 56 48 28 72 4.537 5 9 14 19 23 27 3134 41 46 50 56 64 40 72 4.861 4} Fosha, 9 17 25 32 38 44 4852 8 15 23 (29 35 40} 4448 a 7 14 20 26 32 37 4145 51

...........-3.140 6 11 1722 27) 32 36 3946 51 9 1318 22 25 29 32 39 44 48 52!