Circular pitch gives me the size of the teeth in my mind, but diametral pitch does not. What is the purpose of the diametral pitch concept? Does it merely avoid pi in calculation?

The first thing you see when you walk into Winzeler Gear is a pretty face. No, scratch that — the face is beautiful. Streamlined with chiseled cheek bones, delicate yet bold and strong, a half dozen photos of the feminine face line the building’s entranceway, enclosed tastefully in simple black picture frames, beckoning you to come further in with its pleasant warmth, repelling you to turn and leave with its foreign presence in such a location.

Regarding 3-D printing of gears and machine tools, etc. — does plastic gearing have a future in 3-D printing/additive manufacturing?

Let’s be clear about something up front here: Delta Gear does not make parts for lawnmowers. This is a fairly flippant point that falls under the timeless, clichéd designation of “goes without saying.” Yet, not all that long ago,Tony Werschky had to say it.

Wear is a very important topic for dry running plastic gears. Over the past few years, the authors have worked closely with a number of manufacturers of plastic gears to investigate the problems of gear wear in detail. Together they have developed a calculation method that can be used to predict where and when local wear will occur on a tooth flank. Their findings have also just been published in the final version of VDI 2736.

Happy New Year! I am pleased to announce that I will be your new blog writer for PTE. If we haven’t been introduced, my name is Norm Parke...

EDITORS’ NOTE: “The Applications of Bevel Gears” is the excerpted third chapter of Dr. Hermann Stadtfeld’s latest book — Gleason Bevel Gear Technology (The Gleason Works, Rochester, New York, USA; All rights reserved. 2014; ISBN 978-0-615-96492-8.), which appears here unabridged through the kind graces of Dr. Stadtfeld and Gleason Corp. Future installments will appear exclusively in Power Transmission Engineering and Gear Technology magazine over the next 12 to 18 months.

Four types of gear devices with great transmission ratios (simply called great ratio gears or GRGs) are discussed in this paper. They are strain wave gearing devices (SWGs), trochoidal gear reducers (TGRs), hypocyclic gear reducers (HGRs) and James Ferguson-type planetary drives (JFDs). The structures, advantages and basic performances of these four devices are compared. The latest design and strength analysis methods are also introduced. To conclude, the future tendencies of GRGs are predicted.

For Mark Findlay of UK specialist driveline consultancy Drive System Design, reducing gear noise to suit the low noise levels in an electric vehicle cabin has meant throwing away the rule book.

University lab's motor eliminates pricey rare-earth magnets.