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Comment by justinator | Hacker News Reader

Although I can see plastic gears being an alternative choice in some applications, their downsides seem to be many:

* Less load-carrying capacity compared to similarly sized metal gears.

* Molded gears cannot hold the same high tolerances that metal gears can.

* Plastic is less dimensionally stable when compared to metal and this results in dimensional variations due to temperature and humidity conditions.

* Material cost is significantly higher than that of base metals and can vary widely due to fluctuations in the cost of base chemicals.

* Difficulty in attaching plastic gears to metal shafts.

That last point seems especially problematic.

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As somebody who's used a 30 year-old kitchenaid and blown the gears on a brand new kitchenaid on the same recipe... the future sucks

The Professional KitchenAid mixers (i.e. the ones with bowl-holding arms) are all metal gears, with an electric controller to protect the motor from overtorque. The tilt-head models are mostly metal gears, but have a single kevlar gear that's designed to break to protect the motor from overtorque.

Stripping the plastic gear in the mechanics is like blowing a fuse in the electronics. It's possible it was a bad component, but it probably means you've overloaded the circuit. If you need more torque, buy the models with the bigger motors designed to handle it. The main trade-off between the various mixer models is basically price vs max torque.

I agree. Seems a lot of new kitchen devices seems to fail by either some plastic gears stripping or coming loose from the shaft. My mom has 50 or more year old stuff that still works but the newer devices all break. Even very expensive ones.

To be fair the article is talking about new kinds of plastics that might actually be superior to metal gears in the future. The consumer grader plastic gearing of today who's primary advantage (AFAIK) is cost do kind of suck.

When I was a child I can remember my mother deciding the same thing when sewing machines began switching to plastic gears.

It's a little disturbing how cheaply constructed the new Kitchenaids are, especially for their price tag. The ancient one that is a family heirloom weighs about 15-20 pounds more than newer models, and the base is cast steel. The moving parts have proper ball-bearings in them. I think you could set a bomb off next to it, plug it in and whip up a batch of pancake batter.

Wow, you seem to have some very detailed knowledge of plastic gears. It is almost if you copied and pasted text straight from the article.

Yeah, I read the article. I find the the title of the article does not match the content of the article (it's a bit click-bait, eh?) and that's what my own comment really was about.

Did you read the whole thing? Because it was about adding carbon fiber to the plastic to make it as strong as steel

metal gear to metal shaft first, then attach plastic gear for further reduction? Also the article mentions metal-core plastic gears.

I guess then - why not go all-plastic, or all-metal. I fear that if there's large differences in temperature, you're going to start having a really bad time.

You can for that matter pick a glassy self-healing core near the appropriately made metal shaft, continuous rubber as you fill out the radius, and coated harder (UHD) nylon at the outer, but who's to care to make it like that? Ship it with the dough hooks, maybe.

Or as you suggest, printing open-grid metal-inclusion ceramics could go swimmingly for the less green home refactory applications. There goes little Sigfried, recasting his molybdenum iWatch band with the concentrated symmetry-breaking solar from the shed.

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