This section is from the book "Wrinkles And Recipes, Compiled From The Scientific American", by Park Benjamin. Also available from Amazon: Wrinkles and Recipes, Compiled From The Scientific American.
Save the scales from the forge (oxide of iron) for this purpose.
This can be done by simply heating the anvil and immersing it in a tank of cold water to a depth of two or three inches. Play a stream of water from a hose on the face.
Fill them with resin or lead, which will prevent them from buckling in the bends.
When these are placed in positions liable to corrode them, they should have the standing ends 1/8 in. larger than the end receiving the nut, and the plain part should be square. By this means a wrench may be applied to extract them when necessary. The stud, also, is not so likely to break off in consequence of weakness at the junction of the thread and the plain part, where the groove to relieve the termination of the thread is cut.
Compress in a crucible until it is full, then cover, and lute the top with pipe or fire-clay.
These shrink 1/8 inch to the foot in cooling.
Cast in green sand, and not in dried moulds, using 1 1/2 lbs. zinc as a fine, as pure copper will not run sufficiently freely to prevent honeycombing.
These shrink 1/4 inch to the foot in cooling in the moulds, and also shrink (as do all other castings) most where there is the greatest substance of metal.
In casting iron on iron or steel spindles, the moulds are cast endwise, letting the cast metal covering the spindle bean inch longer on the uppermost side than is necessary when the job is finished; thus the air holes, if any, will form in the extra inch length, and may be cut off in the lathe.
These shrink 1/10 inch to the foot in cooling in the moulds.
A means highly recommended for obtaining very smooth castings, is mixing with the green foundry sand forming the mould about 1/20 part of tar, a mixture which is employed without the addition of any other substance.
Warm the object over a spirit-lamp, and tap lightly with a stiff brush; the wax will adhere to the latter. If in a hurry, a few seconds' boiling in alcohol will remove the remainder of the wax.
If the jaws are too wide at the points, rest the strap upon the two ends, and (with a round pene-hammer) lightly hammer the outside of the crown of the strap all over, taking care to hammer it evenly, so as not to leave any deep hammer-marks.
To open the jaws of a connecting-rod strap, hammer the inside face of the crown of the strap lightly and evenly all over with a round pene-hammer. To bring back to its original shape a strap that has been opened or closed in its width between the jaws, by being pened with a hammer, remove by filing 1/32 inch in depth of the surface that has been hammered, or heat the part hammered to a low red heat.
 
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