Case depth can be considered the foundation for tooth strength
Specifications for carburized gearing of necessity pay attention to the required surface hardness. Not to be ignored, due to equal importance, is the case...
Evaluating and defining hardness, and the evolution of testing methods
Hardness is not a single, clearly defined, physically changeable value, but a complex combination of diverse concepts. In gears we need to know surface...
Part 2: Epicyclic gearing — when it works, where it doesn’t, and why that...
The application range of epicyclic gearing has now become unlimited. As an example, shuttle astronauts were required to break loose some large bolts on...
Part 1: Epicyclic gearing — when it works, where it doesn’t, and why that...
A dictionary description of epicyclic gearing is as follows: “A system of gears in which one or more gears travel around the inside or...
‘Sounds’ can be good, such as the hum of a well-designed gearbox. It’s ‘noise’...
Many seminars and papers are conducted and written under the title of “gear noise” when the full subject is sound. Sounds can be pleasant,...
Adhesive wear caused by fusing of the parts in contact, and even shearing, is...
The basis for a major part of gear research is the study of the wear phenomena, especially between two metal rubbing surfaces. Wear is...
Abrasive wear is a much more complicated condition than it first seems
A common mistake is to relate surface hardness to wear resistance. Other factors are also involved, such as ductility; the balance of free carbides...
Electrical erosion is a factor to take into account when conducting a failure analysis
With the rapid advance in gear technology, new hitherto unforeseen failures can occur, and typical among them are failures due to electrical discharge. Such...
Tooth cracks are often found to be a culprit when conducting a complete failure...
Cracks originating in the surface of the tooth flank are due to Hertzian stressing at a depth relative to the maximum Hertz shear stress....
When things go wrong, conducting a detailed failure analysis is the best way to...
A gear designer must consider the most economical solution that will avoid failure within the design life. The usual result will be a gear...
Shot peening offers benefits to gears, including added strength, reduced surface fatigue
In the 11th century, every combatant carried a sword. Swords were thick and heavy to prevent breakage, making them unwieldy in battle. Those who...
As progress in the design of globoidal worm drives continues, let’s check out history,...
ISO defines a globoidal worm drive as: “A gear whose flanks are capable of line contact with those of an enveloping worm, when meshed...
The five standardized worm gear tooth forms produced by milling or grinding operations
There is a wide choice in tooth forms, each form with its own share of merits and demerits depending on the application. Several forms...
The more you know about proper lubrication, the smoother your operation will run
It has been said by Ernest Rabinowicz, professor emeritus at M.I.T., that three things terminate the life of a machine: obsolescence, accidents, and surface...
When figuring gear capacities, the load capacity of the lubricant must be considered in...
We consider gear capacities from the effects of loads on strength and wear, but we should not neglect the “third” criteria; the load capacity...
Tooth Tips: John Amendola Sr.
The formulas to which each gear standard is based produce different results in rotor size and tooth geometry. Here are the important points to...
Tooth Tips: William Crosher
Over the past 100 years there has been a remarkable improvement in gear capacities. This increase in the density of a power transmission unit...
Tooth Tips: William Crosher
Bronze Bronze Forgings and Castings
Gear bronzes are designated according to their major alloying element. Only the aluminum and beryllium copper bronzes can improve their...
Tooth Tips: William Crosher
Popular practice is to mill the worm, heat treat, finish grind and, for best results, polish. Material for the worm requires a hard, smooth...
Tooth Tips: William Crosher
The first scale for comparing the hardness of materials was devised by the German mineralogist Friedrich Mohs in 1820. The scale is based on...
