154 MA' HIM I'KXWIN'. \NI l'KS!<;\ 



lead. The valve need not be drawn to scale, but may i>< 



sketched and the dimensions maik.-d .-n it. 



57. What is the use of the water-gauge cock Blown m tig. 94, 



where it is placed on the boiler. 



58. With the aid of sketches describe how a steam-tight joint is 



made between the cylinder and cylinder cover 



in-. If the cylinder ci.ver carries a stiiffiiig-l><>\ for the 



piston rod. show how the cover is fitted so that tin- . 



line of tin- rod must exactly oinoide with tin- centre line 



of tin- cylinder. 

 I i :,: I hi. ] I-JJ. explain how the high pressure water used 



in the cylinder is prevented from escaping past the ].i>t..n. 



and between tin- plunger and cylinder cover. I). 



also how \nii would make a tiht joint between the 



cylin.li-r and tin- cover at the end \.. 



Describe the working of the pump .sho\\n in ti-j. 11:'.. \< l:.'<i 

 '.!. With the aid of sketches desc-ril>e how to uiake a st.-am-t i-_'ht 



joint between two flanges. Kxj.lain under what ni.-um 



stances studs are used instead of l.olts. 

 Describe with sketches two methods l.y \\hirh the joints are 



matlt in connecting lengths of cast-iron pipes. 

 ^ketch, partly in nection, a union nut and joint f..i connect- 

 ing two lengths of small piping. 



<< H0H i- the joint sliown in fig. 102, p. ll'J, made water- 

 tight? How are the bolts prevented from tmninu r in the 



lx.lt -holes \\hen screwing up the nuts? 



65. What is the object of usin^ chipping or facing strips in tit 



ting up machine parts ? < Jive one or two examples. 



66. Describe in detail how the mud-hoh- door in tii;. l"-\ p. 1 I I. 



is removed for tin- purpose of deaninir the loiler and how 



it is replaced and the joint made steam-tight. 

 87, Sketch and describe a method of connecting' t.>.jcthi two 



length* of a i '1 of round >,- flat iron. 



68. Kxplain the action of the gov. MI in fijj. IIM;. ],. 1 I.Y 



lixplain the use of the ijiiadnuit for change wheels for a 



screw-cutting lathe shown in fig. !<*>. p. 111. l.y making a 



sketch showiim it in place on a lathe with wheels in gear. 

 7" Make a sketch showing how the adjustment is made in the 



sliding parts of machine tools; AS, for example, in the 



slide rest of a lathe. 



