BY PERCEVAL GIBBON It was November 10, 1909--a day that will surely have its place in history beside that other day, eighty-five years ago, when George Stephenson drove the first railway locomotive between Stockton and Darlington. In the gre... Read more of THE BRENNAN MONORAIL CAR at Difficult.caInformational Site Network Informational
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Annealing Work
With the exception of several of the higher types of alloy s...

Heat Treatment Of Lathe Planer And Similar Tools
FIRE.--For these tools a good fire is one made of hard foundr...

Quenching The Work
In some operations case-hardened work is quenched from the bo...

The Pyrometer And Its Use
In the heat treatment of steel, it has become absolutely nece...

Carbon Tool Steel
Heat to a bright red, about 1,500 to 1,550 deg.F. Do not ham...

Brown Automatic Signaling Pyrometer
In large heat-treating plants it has been customary to mainta...

Steel Worked In Austenitic State
As a general rule steel should be worked when it is in the a...

Hints For Tool Steel Users
Do not hesitate to ask for information from the maker as to t...

Restoring Overheated Steel
The effect of heat treatment on overheated steel is shown gra...

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...

ANNEALING can be done by heating to temperatures ranging from...

Robert Mushet
Robert (Forester) Mushet (1811-1891), born in the Forest of D...

Shrinking And Enlarging Work
Steel can be shrunk or enlarged by proper heating and cooling...

Instructions For Working High-speed Steel
Owing to the wide variations in the composition of high-speed...

Carburizing Low-carbon Sleeves
Low-carbon sleeves are carburized and pushed on malleable-ir...

The Effect
The heating at 1,600 deg.F. gives the first heat treatment w...

High-carbon Machinery Steel
The carbon content of this steel is above 30 points and is ha...

Surface Carburizing
Carburizing, commonly called case-hardening, is the art of pr...

Protective Screens For Furnaces
Workmen needlessly exposed to the flames, heat and glare from...

Hardening High-speed Steel
In forging use coke for fuel in the forge. Heat steel slowly ...

Testing And Inspection Of Heat Treatment


The hard parts of the
gear must be so hard that a new mill file does not bite in the
least. Having passed this file test at several points, the gears go
to the center-punch test. The inspector is equipped with a wooden
trough secured to the top of the bench to support the gear, a number
of center punches (made of 3/4-in. hex-steel having points sharpened
to an angle of 120 deg.) and a hammer weighing about 4 oz. With
these simple tools, supplemented by his skill, the inspector can
feel the depth and quality of the case and the condition of the
core. The gears are each tested in this way at several points on
the teeth and elsewhere, the scrap gear being also subjected to
the test. Finally, the scrap gear is securely clamped in the
straightening press shown in Fig. 57. With a 3-1/2-lb. hammer and
a suitable hollow-ended drift manipulated by one of Sandow's
understudies, teeth are broken out of the scrap gear at various
points. These give a record confirming the center-punch tests,
which, if the angle of the center punch is kept at 120 deg. and
the weight of the hammer and blow are uniform, is very accurate.

After passing the center-punch test the ends of the teeth are peened
lightly with a hammer. If they are too hard, small particles fly
off. Such gears are drawn in oil at a temperature of from 300 to
350 deg.F., depending on their hardness. Some builders prefer to have
the extreme outer ends of the teeth drawn somewhat lower than the
rest. This drawing is done on gas-heated red-hot plates, as shown
at A in Fig. 58.

Nickel steel, in addition to all the tests given to carbon steel,
is subjected to a Brinell test. For each steel, the temperature
and the period of treatment are specific. For some unknown reason,
apparently like material with like treatment will, in isolated
cases, not produce like results. It then remains for the treatment
to be repeated or modified, but the results obtained during inspection
form a valuable aid to the metallurgist in determining further

Next: Temperature Recording And Regulation

Previous: Affinity Of Nickel Steel For Carbon

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