Thursday, September 19, 2019

Tooth Tips

What is the true definition of “surface finish” — and how can the extremes...

The term “surface texture” is used to describe the deviations from what is considered as a nominally perfectly smooth surface. The term can be...

Despite excellent design and manufacture, if a gear’s hardness doesn’t meet the requirements of...

Critical to a gear’s performance are the flank hardness its depth and the tooth’s core hardness. The tooth flank hardness can be defined as...

Depending on the material being tested, attributes and qualities to be determined, there are...

Material tests should be representative of the complete gear. For example, a test on a separately cast bar of the same material can differ...

Quality gears, other components are the product of many different factors. But it all...

Probably the most critical aspect of inspection is making sure the part has been produced as specified and is flawless. The detail of this...

Any gear manufacturer understands the need to inspect the end product, but there are...

The one essential requirement in the operation of every gear is reliability, and that can only be achieved with systematic inspection methods. Inspections confirm...

We all know lubrication is critical to the operation of any collection of moving...

Today, more than ever, efficiency is on everyone’s mind. It applies everywhere—in production, the transmission of power and, yes, lubrication. Excess lubrication increases churning...

It is critical to understand every aspect of the application for an enclosed gear...

It was once a simple matter to select a gear reducer from a catalog. In order to allow for the application and the inaccuracy...

Many may feel that the rack and pinion is the simplest of all existing...

Of all THE gear systems that exist, the rack and pinion seem to be the simplest… but are they really? In comparison with other...

The more you know about the casting process (including steel strengths and the reasons...

More than 40 ASTM specifications refer to steel castings and they are not easy to comprehend. Standard specifications do exist, and they are the...

While metal casting is a fairly straightforward process on its surface, different methods suit...

Metal casting—pouring molten metal into a mold until it solidifies—is an ancient process. Early civilizations learned that, by using this method, the mold shape...

With large gears in demand for tough applications, the properties imparted by nitriding may...

Nitriding is an alternative to carburizing, but it differs in that the nitrogen is added into ferrite and not austenite. Because it is not...

Material selection can be the difference between whether a gear fails or fulfills its...

The selection of gear material is complex, and must be related to the specific duty and life required by the application. The compatibility with...

The importance of anticipating heat-treatment problems in advance to avoid part failure due to...

Problems, and even failures, occurring from heat treatment are generally created by the stresses that are induced when phase transformations are taking place. During...

Electric erosion can lead to failure in wind-turbine generators, with the expected catastrophic results

My installment of this column in the August 2007 issue of Gear Solutions was devoted to electric erosion and the possible solutions. In the...

Gear-drive inspection reveals the effects of residual stresses on face contact in high-speed gear...

High-speed standards usually require verification of the mating accuracy, and that this record be maintained. This entails recording profile, lead, and pitch deviations. The...

Corrosion alone can lead to gear failure, but when you add fatigue loads and...

How many engineers know that corrosion is generally regarded as the prime cause of failures? In 1986 Batelle Labs estimated the annual cost at...

Determining the reasons for materials-based fatigue failures can be a challenge, but don’t underplay...

In the past 50 years, advances in gear technology have been driven by energy and aerospace, specifically by the gas turbine, jet engine, wind,...

Proper balance is one of the critical keys in designing and manufacturing high-speed gear...

Unbalance is the most common cause of serious vibration in high-speed gear units. When present the vibration results in bearing, tooth, and seal damage....

This conclusion of a two-part series on Hertzian fatigue modes discusses spalling and macropitting,...

Pits form from wear, electric erosion, chemical attack, thermal damage, or porosity that arises during material casting or processing. Grinding burns always lead to...

Part 1 of a discussion on Hertzian fatigue modes begins with a discussion of...

Experience has led us to rate gears by calculating their pitting resistance and bending strength. These calculations do not provide for other types of...
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