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Title: |
1892 Article-Bement, Miles & Co., 63 inch Engine Lathe |
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American Machinist 14 Jan 1892 pg 1 |
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Insert Date: |
12/16/2011 12:41:21 PM |
We give on this page an illustration of a lathe which is typical of a class of lathes of similar sizes built by Bement, Miles & Co., of Philadelphia, Pa.
The lathe swings 63" over the shears, and 50" over the carriage, and can, of course, be made with any length of bed desired, and with" two carriages if wanted. The cone pulley is not on the main spindle of the lathe, but is in front of it, and drives the face-plate by means of a pinion which engages with an internal gear which is in the plate and near its outer edge. This pinion may be driven direct by the pulley or through the medium of the gearing seen in front,, which is engaged and disengaged by sliding the shaft by means of the lever. The cone pulley is for a 5" belt, the largest step being 30" diameter, the smallest 11". There are two speeds on the countershaft, which are so arranged that there are twenty different rates of speed for the spindle. The spindle is of cast-iron, running in cast-iron boxes, the main bearing being 10" diameter, 12½" long, and the rear bearing 7"xl0¼".
The lead screw is driven by gearing at the end of the head in the usual manner, but inside the head there are "cone gears" arranged on the stud, so that by sliding a key three different speeds are imparted to the screw with each arrangement of the change gears. The key is moved by means of the small hand wheel seen at the side of the gear-shifting lever, there being a pinion on the other end of the shaft, which engages with a cylindrical rack.
The screw is splined, and there are two bevel pinions upon it, which engage with a larger gear within the apron of the carriage, these pinions being shifted to reverse the feed motion. Screws can be cut from 9 to the inch to 6" pitch, and the feeds can be varied from 1/72 inch to 3/4 inch.
There is an automatic cress-feed, and at the side of the cross-feed screw there is a splined shaft, which, by means of bevel gears and an upright shaft connected with it, gives an automatic feed to the compound rest, which, of course, operates in any direction.
The foot-stock spindle is 7" diameter, and is moved by a hand wheel, which is brought forward into a convenient position. The foot-stock is moved upon the bed by means of the rack and pinion shown.
The centers of this lathe are not vertically over the center of the bed, but are carried back from the center 9", the object of this being to get as good a support for the carriage as would be secured by a bed considerably wider if made in the ordinary way.
This arrangement, of course, brings workman that much further from his work, but this is compensated for by reducing the width of the carriage at the right, which can readily be done, since there is no gearing there, and, in fact, nothing within the apron at that point except the nut for the lead screw, and the device for preventing its being thrown into engagement when the rack feed is in.
The bed is 49" wide, and the carriage has a bearing upon it 64" long. The feed rack is of steel, bolted to the bed.
The general proportions of the lathe are well shown by the engraving, and, as would be expected, the lathe has, in use, proven itself to be exceptionally well adapted to heavy work, and to the heavy duty now being demanded of machine tools. |
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