. Railway mechanical engineer . - work. It is a five-degree convex clear-ance and shows that with this small Ijut sufficient clearanceangle at the ( utting edge, the back is perfectly cleared. 406 RAILWAY ENGINEER Vol. 94, No. 6 In addition to the correct clearance of taps a uniformangle of taper for all flutes is necessary-. The results of dif-ferent tapers obtained by hand grinding are indicated in r- k Felt tVashers Bronze Bushing g vpm. Fig. 4—General Arrangement of Spindle and Bearings Fig. 2. Even a slight variation from the uniform taperangle means power wasted and taps bro
. Railway mechanical engineer . - work. It is a five-degree convex clear-ance and shows that with this small Ijut sufficient clearanceangle at the ( utting edge, the back is perfectly cleared. 406 RAILWAY ENGINEER Vol. 94, No. 6 In addition to the correct clearance of taps a uniformangle of taper for all flutes is necessary-. The results of dif-ferent tapers obtained by hand grinding are indicated in r- k Felt tVashers Bronze Bushing g vpm. Fig. 4—General Arrangement of Spindle and Bearings Fig. 2. Even a slight variation from the uniform taperangle means power wasted and taps broken. As the bluntangle flute strikes tlie side of a drilled hole, it throws thecutting end of the tap off center and imparts to it a wabblingmotion. This means a tapped hole that is oversized, allow-ing the screw to fit loosely. Tap .4 is correctly ground and will ta]) a hole true to size, properly located and with smooth,accurately shaped threads. Tap B is ground with one fluteat a more blunt angle than the other. This blunt flute ;hown just as it strikes the drilled hole. Tap C shows a-imilar tap after it has been crowded over. The conditiondeveloped is readily seen. In the interest of longer life for taps and more correctwork with less power consumjition and fewer broken taps,the Grand Rapids Grinding Machine Company, Grand Rap-ids, Mich., has developed a line of machines for grindingtaps. These machines are made in four styles for gr
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
