Bearing Dies
Bearing dies are one of the most important of the various classes of casting-dies. The bearings produced by die-casting are so far superior to those made by other casting methods and machining that their use is now very extensive. Dies are made for “half-round” and “whole-round” bearings. There is little out of the ordinary about a whole-round die, but the half-round die involves many interesting methods of die-making, and for that reason is here described.
[Fig. 13] shows a casting-die for half-round bearings. Half-round bearing dies are usually made to cast two bearings at a time, for the reason that it is just as easy to cast two pieces of such a shape as it is to cast one, and, in addition, the die is balanced in a better manner. As with other dies, the first step is to machine up the frame A and the two die-halves B and C. The pieces D and E that are to form the insides of the bearings are then turned up and one side of each shaped and keyed to fit the slots that have previously been milled in die-half C. These parts are held in place by dowels and screws. One of the bearings produced by this die is shown in [Fig. 14], and it will be noticed that there is an oil groove within that covers the length of the bearing. To produce this groove in the die-castings, a shell must be turned up and bored out whose inside diameter is that of the inside of the bearing, and whose thickness equals the depth of the oil groove. This being done, the oil grooves are laid out upon the shell and cut out by drilling and filing. After rounding the outside corners, these little strips are pinned to the cores D and E in their proper places.
Fig. 14. Die-cast Half-round Bearing, Showing the Cast Oil Grooves
Another little kink in this connection is worthy of noting. So many different styles and sizes of bearings are made by a concern doing much die-casting that it is essential that the die-cast bearings should bear some distinguishing number to identify them. As this number is of no consequence to the user it is well to have the number in an inconspicuous place, but it must be where it will not be effaced by scraping, etc. Bearing in mind that it is much easier to produce raised lettering by die-casting than to produce sunken lettering, it will be readily seen that the oil groove affords a good place in which to put the bearing number. This is easily done by stamping the figures upon the narrow strip that forms the oil groove. In this place on the bearing it may be easily found if needed, and of course there is no danger of its being taken out by machining.
The lower die consists of two blocks F and G, each of which contains an impression of a bearing. The best way to make these parts is to lay out the ends of each of the blocks with the proper radius, taking care to have the center come a little below the surface of the face of the block. Then the blocks should be shaped out to get the bulk of the stock out, before setting up in the lathe. After the lathe work is done on each piece, which of course is usually done separately, the faces of the two blocks are faced down just to the exact center of the impression. It will be noticed that two blocks are used for the lower part of the die. The reason is to facilitate the locating of the female parts of the die in proper relation to the male parts. After properly locating, they may be doweled and screwed to baseplate B.
Fig. 15. Interesting Examples of Die-castings
The sprue cutter H, better shown in the plan view, is square in shape and connects with the die-cavities in a thin narrow opening on either side of the sprue cutter. The ejector pins, I, two to each die, are at the ends of the bearings. The ejector-pin plate J is necessarily large, and is operated by lever K.
[Fig. 15] shows a number of interesting examples of die-castings.
[CHAPTER III]
VAN WAGNER MFG. CO.’S DIE-CASTING PRACTICE
In 1907, Mr. E. B. Van Wagner, of Syracuse, N. Y., established the E. B. Van Wagner Mfg. Co. for the production of die-castings. The factory comprises the office section, the machine shop where the dies and casting machines are built, the metallurgical laboratory where the metals are alloyed, the casting department shown in [Fig. 17] where the die-castings are made, and the trimming department.