This section is from the "Modern Machine Shop Construction, Equipment, And Management" book, by Oscar E. Perrigo. Also see Amazon: Modern Machine Shop Construction, Equipment, And Management.
Molding machines are also made for molding the teeth of gear wheels of large dimensions, as well as large segments, and by their use much time is saved and the cost of large and expensive patterns for the gear teeth is avoided. There are also molding machines for pulleys, which are valuable as a part of the foundry equipment, and with a proper supply of rims and spiders this work is much simplified and the costs reduced.
These machines must be selected and provided in accordance with the particular class of work to be done, as their utility will depend almost entirely upon this matter.
Sand sifters and sand mixers are now made so as to be mounted upon a tram car and are driven by a small electric motor attached to them, the machine being thus rendered complete in itself, and may be easily moved to any part of the foundry desired and, when not in use, run out of the way. They will be found very convenient on nearly all classes of work, and may supersede the usual hand riddles almost entirely, saving much of the molder's time and producing better castings, as more sifted sand is likely to be used if the molder is not obliged to sift it by hand. Besides, being sifted close at hand, it is not so liable to contain foreign matter as if it is sifted at one point and carried to different parts of the foundry where it may be needed.
The deep molding pits are located as shown by dotted lines in Fig. 115, one 8 × 12 feet, and the other 12 × 18 feet. These may be of any required depth, but more usually the smaller one would be about 5 feet and the larger one about 8 feet. All these dimensions should, of course, be made according to the character, size, and the weight of the larger castings to be made. The walls and floors of the pits should be constructed according to the directions given in the chapter on Shop Floor Construction, in Part First of the work. These pits will be found very useful in molding large pieces wherein a very deep nowel flask would be required, and which would necessarily raise them several feet higher on the floor than would be the case where a pit is made use of. Such pieces, which may not be cast on their side, and weighing, say, over 4 tons, will usually be found fit subjects for pit molding.
It will be noticed that the cupolas have been located within the space of the foundry proper. This, of course, will occupy considerable room on the foundry floor. They are so placed in many foundries, this being a more desirable location in several respects. In this case they come nearer to the cranes, which are supported from the main columns, and afford a convenient means of transferring a ladle of melted iron from the cupola front to the cars, and thence by the track to any point in the foundry, or from the cranes over to the traveling crane and thence to any part of the central space of the floor. The cupolas may be located in the cleaning room and the blower room space, and thereby save about 140 square feet of molding floor space. In this case the cranes will be placed closer to the wall, but yet with sufficient reach to pass ladles of melted iron to the car track, or to the traveling crane.
If this disposition is made the location of the tumbling barrels will need to be changed, placing one at the front of the room. If it is found necessary, the motors and the air compressor may be placed on the charging floor, where there is ample room for them. Even the blower may be located there, for the purpose of affording more space on the first floor, a partition dividing them from the charging floor proper. The stairs also may be placed at right angles to their position as shown, for the purpose of affording any specially desired location for the first-floor equipment. In case the cupolas are placed in the cleaning room and blower room space, it may be advisable to run a car track immediately in front of them, connecting at each end with the transverse tracks by the usual turntables, and by which means ladles of melted iron may be transferred to the central space under the traveling crane by taking the route either to the right or left, as may be the shorter distance. However, many will prefer the jib crane for this service, as being quick, efficient, and safe.
In the back corner of the main part of the foundry proper is the foreman's office, and adjoining it is a storeroom for the various small articles, tools, etc., necessary for almost daily issue, and which the foreman of a foundry of this size will probably find necessary to have under his personal control, although it will be advisable to have an employee in the office who is conversant with these matters, and to act as a bookkeeper, in order that the foreman's time may not be too much taken up with these matters of routine details.
In the front corner, on the outer side, is located the heating apparatus, which has been previously described in the general chapter on Heating, in Part First on Shop Construction. If preferred, it might as well be located in the corner next to the flask room. This would be convenient if more bench room was required for snap flask work.
The chipping room is provided with the usual benches, having a sufficient number of vises on them to accommodate the work requiring hand chipping. Sprues are cut off in the sprue cutter where this can be done by such a machine. The three emery wheels will do much of the small finishing on the castings, while the pneumatic chipping tools will do very much of the work on the heavy castings.