preventive is particularly important for the interior surfaces which are not coated subsequently, thus preventing formation of any white oxides in the presence of moisture. This is true also, of course, of coated surfaces from which the enamel is scratched or chipped by handling which is too severe for any organic coating to resist.
Parkerizing has the advantage that the parts are treated merely by immersion in bulk, using a perforated sheet steel cylinder (Fig. 7) which is given a single turn by a ratchet mechanism while the cylinder and parts are immersed. The phosphate solution is used hot and it requires only three minutes to treat a batch of parts that half fills the cylinder.
All organic finishes employed are of the synthetic type and are sprayed on.
An exception is in the case of wiped-in lettering which is done by hand brush
ing after the base coat has been baked in. Yale’s distinctive silver finish is obtained by baking in, at 400 degrees Fahr., a mixture of aluminum power
with synthetic varnish in the ratio of 3.6 pounds of the flake pigment to 5 gal
lons of vamish. This not only affords an attractive finish, it also makes for longer life, retaining its brightness over long periods.
Where masking is not required to protect interior maohined parts, the cast
ings are hung on racks, sprayed at vari
ous angles, and placed on an oven con
veyor for baking. Tlius the castings are not touched until the finish has been baked hard so they cannot be marked by fingers in handling. A procedure has been developed so that a single spray operator and a helper handle several hundred castings an hour. Thus the labor cost per casting is exceedingly low.
Advantage is also taken of the ease with which die castings may be em
bossed with letters, figures or decorative lines on outside surfaces, both to em
bellish and identify the product. Such depressions are later filled or “wiped-in”
with a contrasting color consisting of
enamel fixed with naphtha or other thin
ner to make it flow easily. App.ication is with a brush, as this puts tire color where it is wanted. Work of this kind is done at bench through the center of which a conveyor belt runs. Locks or parts laid on the belt after brushing are carried through a short oven equipped with infra-red heater lamps that help to set the color. Before the color is- completely dry, the parts issue from the oven and are removed from the belt by girls who wipe off any excess color that has flowed onto the high surfaces. See Fig. 8. This is done by passing the part over paper slightly moistened with naphtha. In so doing, only the high surfaces are touched and wiped clean, the color consequently remaining in de
pressions, as desired, giving sharp out
lines.
Parts are then stowed in the tote boxes for transfer to assembly departments after the enamel in the recesses-has been hardened by air drying. The enamel in the recesses is not easily abraded or chipped in subsequent service. And the
“wiping-in” process has no effect upon the base coat since this was baked hard before the contrasting color was applied.
MASKING JIGS: Machinability, dimensional stability and light weight of Plexiglass masking jigs used in copper plating of carbon rings serve to reduce rejects and speed production at Morganite Co., Long Island City, N, Y. Rings to be plated are inserted in grooves 1/64-inch wide on either side of jig rings and mounted gang fashion on a carbon rod. Electrodes then are attached and
entire assembly is suspended in plating solution
Interior moving parts are given a graphite coating by means of tumbling.
This coating acts as a dry lubricant and tends to prevent any tendency of parts to stick or wear away by friction (gall).
Inspection Control: Samples of die castings are regularly taken from the output of the die casting machines and measured with gages and indicators (Fig. 10) to insure that they are being held to tire specified tolerances.
In addition, samples are periodically given a chemical analysis in the Yale laboratory. This includes an acceler-
“aging test” to determine how well the castings will hold dieir dimensions under severe conditions. The principal factor in the test is exposure to water vapor at 203 degrees Fahr. for ten days.
See Fig. 11. In this way, the stability castings from each melt is assured.
To test their strength and ductility, sample die cast bars, shot as a part of a regular gate of castings, are tested in a special testing machine under varying loads. This machine d e t e r m i n e s whether the physical characteristics—
such as tensile strength, per cent of elongation, elastic limit, and reduction of area—are within the limits set by tire American Society for Testing Materials.
Millings taken from these sample castings are also sent to an independent, commercial metallurgical laboratory for a spectrographic : analysis. An un
usually high purity of 5ialloy has been reported in these periodic analyses of Yale’s die castings.
Thus through stringent laboratory and inspection controls, accurate dimensional accuracy, and chemical and physical quality are maintained. These inspec
tion controls, by searching out whatever
“hidden defects” may exist, prevent as
sembly of defective parts in locks and padlocks.
100 / • T E E L
And here’s how you make real savings when you use Master Gearhead Motors. Both the motor and gear reduction are built as an integral construction, so you have only one unit to order and handle. You reduce to one third or one quarter your own time for selecting the right equipment, and the time and expense in your purchasing, receiving, and invoicing departments. You save greatly in handling and mounting time. Today time is more than money . . . it’s manpower!
But one of the most important savings is usually overlooked.
When you buy a gearhead motor, of say 2 horsepower size, both the motor and gear reduction are designed for 2 horsepower load.
However, when other types of speed reduction equipment are used, too often you must purchase oversize speed reducing parts that will transmit possibly as high as 5 horsepower, because intermediate sizes are not made.
Yes a penny saved is better than a penny earned . . . it's bonus money. And speaking of bonuses, you get a real one in the wide flexibility of gearhead motors made by Master. Motors in any size from 100 down to 1/10 horsepower in all cycles, phases, and frequencies . . . in open, splash-proof, fan-cooled, and explosion proof types . . . with Speedrangers and Unibrakes . . . for every type mounting . . . and over a gear reduction range up to 432 to 1. Any combination of these can be built easily into a compact power package that will add greatly to the economy, appear
ance, convenience, and safety of your motor driven equipment.
Investigate what a really remarkable job Master gearhead motors can do for you both in your plant and on your products.
TH E MASTER E L E C T R IC CO M PA N Y • DAYTON 1, O H IO
10 HP 37 RPM ’ 1 explosion-proof gearhead motor on I magnetic separator for removing tramp
iron from coal. S
By CARLTON A . SHEFFIELD
Industrial Research Department Joshua Hendy Iron W orks
S u nn yvale/ C a lif.