Gears drive the world. Without them, our cars would do naught but idle in the driveway. Bicycles would be stationary, boats stuck in port, and trains forever at the station. Simply put, gears are used everywhere.
Suppose you want to break into the gear-making business. Be warned, this is complex stuff. Plan on some late nights boning up on gear technology. For starters, the sheer variety of gears manufactured today is mind numbing: spur, helical, worm, bevel and hypoid to name a few. Add to that a bewildering dictionary of gear nomenclature—chordal pitch and lines of contact, tooth profiles and root forms, obscure technical jargon describing how gears function. It’s enough to give you a headache.
Once you’ve mastered all that, you’ll need some equipment. Despite their complexity, most gears are machined using one of two basic methods: hobbing and milling. If you want to go the hobbing route, you can pick up a used manual machine off eBay for the price of a decent pickup truck.
The bad news is that you’ll need a gear cutter, or hob, for most every gear shape and size combination ordered by your would-be customers. At a couple hundred bucks a pop times thousands of potential gear configurations, it’s a big investment, one devoted to nothing but making gears.
Before breaking out your checkbook, be aware that the gear-making world is changing. Multi-function mill-turn machines and five axis machining centres are opening the door to low volume gear manufacturing without the need for dedicated cutters and special machines. And cutting tool manufacturers now offer indexable, multi-purpose gear cutters that blow away conventional high speed steel and powdered metal hobs, bringing flexibility to an industry that has historically been one of high volume production and dedicated equipment.
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