ħÁ¦É¡ ³¬¼¶Â¼ÆÁ ¼ÆËãÆ÷ÕÒ²»µ½ tpye cºÍ½Ó¿ÚÇø±ð ¼«Æ··É³µ17³µÁ¾

以时时为生

�¥°¤¼¤ñ¥¤¥´Æ¤

The man became quite excited, and took hold of my sleeve. He looked me straight in the face, as if he wanted to find out by the expression of my eyes whether I spoke the truth. I could easily stand the scrutinising look, for I knew too well how utterly false those suspicions were. So I replied with great emphasis:饥¤¤áÑ

�¥¥¹¥ºÇï¥d

�¥¥ß¦¤³¥Ú¬±¤µ¸

�¤¥ç

The use of hand tools should be learned by employing them on every possible occasion. A great many of the modern improvements in engine lathes are only to evade hand tool work, and in many cases effect no saving except in skill. A latheman who is skilful with hand tools will, on many kinds of light work, perform more and do it better on a hand lathe than an engine lathe; there is always more or less that can be performed to advantage with hand tools even on the most elaborate engine lathes.áêÈï¥È§

�¤¥¨¤¥¥¿

�òեϷ¥ß륭¥ì

�䥥椥¤¥ð¥

In casting and forging operations the material is treated while in a heated and expanded condition; the nature of these operations is such that accurate dimensions cannot be attained, so that both forgings and castings require to be made enough larger than their finished dimensions to allow for shrinkage and irregularities. Finishing as a process consists in cutting away this surplus material, and giving accurate dimensions to the parts of machinery when the material is at its natural temperature. Finishing operations being performed as said upon material at its normal temperature permits handling, gauging and fitting together of the parts of machinery, and as nearly all other processes involve heating, finishing may be called the cold processes of metal work. The operations of a fitting shop consist almost entirely of cutting, and grinding or abrading; a proposition that may seem novel, yet these operations comprehend nearly all that is performed in what is called fitting.©¤¥¤Ê¤ÎѤ¤¤

�ÕªÚâö

"A glass of beer, madame."㣤˥¢ã¤¥¨¤Ò¿

�çd䤥¤­¤¡¤

�¥ñà½ëÖ¥¤¥¤

Shaping machines are generally provided with adjustable vices, devices for planing circular forms, and other details which cannot be so conveniently employed with planing machines. Another feature of shaping machines is a positive range of the cutting stroke produced by crank motion, which permits tools to be stopped with precision at any point; this admits of planing [136] slots, keyways, and such work as cannot well be performed upon common planing machines.³ñ¥

It may be noticed that all machines, except milling machines, which act in straight lines and produce plane surfaces have reciprocating movement; the class includes planing, slotting and shaping machines; these, with lathes, constitute nearly the whole equipment of an ordinary fitting shop.¤¤ª

�Ѥ§