362 LIGHTING AND SANITARY EQUIPMENT 



1/2" elbows, two 1/2" tees, one 1/2" union, and two 3/4" 

 x 1/2" tees. The latter is to serve as bearings for axle 

 of roller. The size specified is sufficiently large where a 

 1/2" pipe is used for axle. 

 Preliminary Instruction: 



335. Measuring Materials for Handle. Extreme care 

 must be observed in making measurements to have the handle 

 fit smoothly. The distances A and B (Fig. 349) will depend 

 on the length and diameter of roller. The distance A should 

 be made about 1/2" greater than the length of roller. The 

 distance B between center of fittings should be about 2" 

 greater than the radius of roller. The distance C should be 

 made a length that will make the roller convenient to opera- 

 tor. Measurements are usually taken from the center of one 

 fitting to the center of the next. To make accurate measure- 

 ments, each fitting should be made tight before the next piece 

 of pipe is cut. The 1/2" union can be eliminated if one of the 

 tees in which the cross pipe is threaded has a right-hand 

 thread and the other a left-hand thread. 



Working Instructions: 



336. Threading Pipe. Place a piece of 1/2" pipe in the 

 vise. If not threaded, thread it with a right-hand die as fol- 

 lows: Note that proper die is placed in stock; place guide 

 bushing in place; oil end of pipe with lard oil; place bush- 

 ing end of die-stock on pipe and start die with hands near cen- 

 ter of stock by pressing hard on handles and rotating one- 

 fourth turn at a time. After die has taken hold, move hands 

 out to the ends of handle and continue rotating with less 

 pressure. After each complete turn, rotate backward slightly 

 to allow chips to drop. Continue this process until thread of 



