. Locomotive engineering : a practical journal of railway motive power and rolling stock . ened is care-fully placed, so as not to touch one an-other or the sides of the box. Over thisanother layer of the mixture is placed;then another layer of the pieces, and soon till the box is filled. The cover is thenput on and the joint luted with clay toexclude the air. The box and its con-tents are then kept at a red heat for fromthree to five hours longer, according to thedepth it is required to harden. It is then un-covered and the contents dumped into a When a good deal of case-hardening isdone, a s
. Locomotive engineering : a practical journal of railway motive power and rolling stock . ened is care-fully placed, so as not to touch one an-other or the sides of the box. Over thisanother layer of the mixture is placed;then another layer of the pieces, and soon till the box is filled. The cover is thenput on and the joint luted with clay toexclude the air. The box and its con-tents are then kept at a red heat for fromthree to five hours longer, according to thedepth it is required to harden. It is then un-covered and the contents dumped into a When a good deal of case-hardening isdone, a special furnace is very commonlyemployed, in which the boxes or pots areplaced for heating. Pneumatic Trestle for Paint Shop. This is a plan proposed for the Man-chester (Va.) paint shop of the SouthernRailway. As will be seen, it consists ofpipe cylinders and plungers, the latter3 15-32 inches in diameter. The pipingis Yz inch and is beneath the floor. Thecylinders are also sunk in the ground, onlyrequiring a S-inch hole a little over 8 feetdeep. Each trestle is 60 feet long, supported. CAR PAINTING PLATFORM MOVED BY AIR PRESSURE. ished and reasonable care is taken, a fairlyfine mottled gray surface is obtained. When the process is employed for smallpieces at frequent intervals the potashmay be kept in any suitable iron piece to be hardened is dipped intothis and stirred about, an old spoon beingused to keep it covered with the the piece cools somewhat it is againheated slowly, the potash adhering to it,and when hot again treated with the pot-ash, then heated as for tempering a pieceof steel and plunged into water. The heating and covering with potashmay be repeated three or four times, ormore, if a little deeper hardening is de-sired. Where case-hardening to a considerabledepth is desired the pieces are packed ina suitable iron box or pot, along withequal parts of charcoal, pulverized boneand leather scrap. Or instead of this, salt- tank of clean, cold w
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroa, bookyear1892
