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.
Only a good quality of hard bricks should be used, and the entire work should be laid in strong cement mortar.
The holding-down bolts, when it is necessary to use such fastenings, are made long enough to reach well down in the foundation, if not entirely through it, and are provided with large washers or plates at their lower ends. These are put in place as the foundation is built up and their top ends are held in position by a templet made of boards in the form of a frame, and representing the base of the machine.
In a large foundation of this character, blocks of dressed stone should be worked into the finishing courses of bricks so as to bring them level with the top. These are usually placed crosswise, one at each end; and others at such points as to furnish firm support for the cylinder, crank shaft, pillow block, and guides of an engine; for the headstock of a lathe, and for suitable points along the length of the bed; under the uprights or housings of planers and at each pair of legs, or at proper intervals where the entire bed rests on foundations without the use of legs.
Fig. 34. End Elevation of Engine Foundation.
Fig. 35. Partial Side Elevation of Engine Foundation.
Usually, in the case of a planer, and often of a large lathe, the foundation is composed of a series of piers built up separately at the points to be supported, each pier being capped by a stone of sufficient size to cover it.
In laying out the foundation for a planer of, say, 36 x 36 inches or larger, a pit should be provided under the center; that is, from a point one to two feet back of the face of the uprights to a point three to five feet in front of the uprights, and five to six feet deep. It should be broad enough for the building of narrow steps leading down into it.
This pit will receive a great portion of the chips produced, and in it, resting on large and firmly set stones, should be two cast iron columns, with strong jack screws tapped into their tops, and coming up into contact with the under side of the bed at a point near the face of the uprights. Thus arranged, they are very useful in maintaining the proper alignment of the planer.
A foundation now in use, upon which large lathes are erected and tested, was built as shown in Fig. 36. Solid ground was found about five feet below the floor level, and a course of concrete was first laid, then three courses of stones, and upon these hard bricks, cement being used throughout.
Fig. 36. Special Pier for a Machine Testing Foundation.
Upon the top of each pier a cast iron plate 1« inches thick was placed. This plate had downwardly projecting flanges all around it, deep enough to cover three courses of bricks. In the top of these plates was a hole six inches in diameter.
When the brickwork was finished these plates were put in place and leveled up so as to leave about half an inch space between the plate and the top of the bricks. Around the lower edges of the flanges the space was carefully closed with cement. Then cement was mixed thin enough to flow easily, and was poured into the hole at the top until the entire space at the top and sides was completely filled, and the whole was allowed to "set".
The tops of the plates were about ¬ inch above the top of the floor, which was built up closely around them. Very heavy lathes are moved on and off these piers almost daily for several years without injury, and the piers have not settled to any appreciable extent, or so as to cause any difficulty in leveling up machines to be tested.
In placing high-speed engines or planers, which are liable to lateral shocks, it may be advisable to provide cast iron plates as described above, with the downwardly projecting flanges to cover the upper courses of brickwork, and also with upwardly projecting flanges enclosing sufficient space for the base, cabinets or legs, as the case may be. After leveling up the machine with steel wedges, say a ¬ to a « inch, the space is filled with melted lead or brimstone, which when cool will form a very secure, serviceable, and durable arrangement.
Foundations for machines subject to considerable vertical shocks, such as steam hammers, drop presses, and the like, must be treated in an entirely different manner. From the nature of the work a solid foundation of stone and brick is not usually considered as best adapted to the conditions.
Such a foundation, unless formed of one solid block of stone, would soon be spoiled by cracks and disintegration from the shocks, and serious consequences to the machine might ensue, the parts broken, for instance, or the dies ruined. For such cases many experienced men prefer foundations that may be elastic enough to relieve the machines somewhat of the sudden strains and shocks of heavy and oft-repeated blows. In these cases the foundations are composed of timbers.