5 ms·

Metal, vs plastic gears. Bigger vs tiny electric motor. Metal vs plastic moving parts in contact with the fruit. Plug-in vs battery powered. These are the thing

Metal, vs plastic gears. Bigger vs tiny electric motor. Metal vs plastic moving parts in contact with the fruit. Plug-in vs battery powered. These are the things that I would place money on as the reasons the 70 year old one is still functioning, and none sold today will work in 5 years. (I’ve never looked at one of these items. I’m just guessing. But I’d still place money on it.)

yetihehe 4y ago
> Metal, vs plastic gears. Sintered metal gears, last only a little longer than plastic and then fail catastrophically destroying half of the device so that you can't repair it. But at least they are much cheaper than proper machined gears.
- JKCalhoun 4y ago
  My KitchenAid mixer ate a gear many years ago. They would lead you to believe they are a high quality brand, no? After disassembly, it turned out to be perhaps the only plastic gear in the thing. It occurred to me that it was perhaps designed to fail rather than the mixer continuing to break the bones of the person who got their hand caught in the paddle. So, I throw the engineer a bone for that one. I was bummed though to have to order a replacement gear from some obscure place in Florida for like $75 or whatever.
  - yetihehe 4y ago
    Yeah, sometimes there are plastic gears designed in specifically for this, in blenders and kitchen appliances, some lathes even have a set of several copies of one plastic safety gear. But sintered metal gears in planetary gearbox of a cordless screwdriver which fails faster than it's battery (Einhell) - not acceptable.
  - S_A_P 4y ago
    The real crime is that there are only like 5 appliance parts companies that stock parts and they each seem to look at the other companies for what to stock. Meaning, if someone else has it they won’t. But what ever they do stock ends up selling for 500% or more of the wholesale price.
  - blueblob 4y ago
    I had the same gear fail. It's called a worm gear and is, indeed, intended to fail before damaging the other gears. They're much cheaper if you buy a non-oem part. I bought one from amazon for ~10 USD.
    - JKCalhoun 4y ago
      Yeah, this was a time when Amazon was in its infancy. :-(
  - generalpf 4y ago
    A worm gear! It is indeed designed to take the fall so the entire machine doesn't shred itself. I bought an official replacement from KitchenAid for $12 including shipping.
  - mattferderer 4y ago
    > It occurred to me that it was perhaps designed to fail rather than the mixer continuing to break the bones of the person who got their hand caught in the paddle. This is a good call out of potential other reasons an engineer team might make something cheaper & easier to break. It would be awesome to read a summary of the trade-offs the teams discuss in their process.
  - aidos 4y ago
    For those who want to see a teardown, AvE has one on his channel here; https://www.youtube.com/watch?v=0qKp-0h9P18 https://www.youtube.com/watch?v=0qKp-0h9P18
    - JKCalhoun 4y ago
      Interesting — it is the "Professional" version and appears to have different internals than my consumer-grade one.
  - deleted 4y ago
    [deleted]
  - kwhitefoot 4y ago
    My Electrolux Assistent N8, from 1978, also has a worm drive. Not plastic though, instead it has an electromechanical stall detector that shuts down the motor if it stalls. No need for sacrificial parts!
- jerf 4y ago
  Capitalism is successfully optimizing for what I as a consumer can detect. I am not capable of simply looking at a device and knowing whether the metal is the quality metal it needs to be, or if it is merely some cheap metal that will bend if I breath on it too hard. ($YOU may be. I'm not.) Except that nowadays I tend to just guess the latter and I'm statistically correct anyhow. Superman has a quote about living in a world of cardboard, where he must control his every move lest he rip through everything. I'm beginning to feel that way myself with these consumer products. If you take them even 5% out of spec expect them to catastrophically fail. They'll catastrophically fail even if you use them entirely within spec. I'd happily pay a bit extra for something that wouldn't but there's no way for the manufacturer to successfully convey to me that this is such a thing even if they wanted to. The metaphorical water is so metaphorically muddied that it's just dry dust now anyhow, with fake 5 star reviews and decades of refinement on marketing messages about how this vegetable peeler peels vegetables so well that it will even enhance your marriage prospects.
eternityforest 4y ago
Reliability now isn't done with the same methods as it was then. Back then, the good stuff might have been good because the motor was big. The modern good stuff probably has a brushless motor that can prevent stalls. It doesn't matter if it's big or small, the computer won't let it overheat, so they can make it smaller to save money that they can spend on whatever part is the actual failure mode. The trouble is finding manufacturers that actually do that, rather than just using a tiny motor with no computer and plastic gears with no torque sensing. If you design things with old fashioned methods, you need to use old fashioned heavy parts. Nylon gears in contact with ozone, and switches and connectors of all kinds seem to be the problem on everything I've seen. Which is why I always say I would gladly use 10k lines of code to save one moving part or one switch.
- mikepurvis 4y ago
  100% agree, but I think the issue here comes with a typical phased design process: - Mechanical: "Here's the physical specs, no need to account for A, B, or C, as it's been handled in software" - Electrical: "Here are the physical constraints and electrical spec. No need to account for X, Y, or Z, as it's being handled in software." - Firmware: "You need to handle A, B, C, X, Y, and Z, but if you run out of time or don't have the budget to make up a test rig for validating all those cases are handled correctly, no worries we'll just ship it anyway."
  - eternityforest 4y ago
    The other issue I see is when mechanical and electrical don't actually give firmware the data or control they need. You'll see stuff like a lack of battery level monitoring, or relays without current sensing. I'm not sure why we don't do things the other way, have firmware people present at every step. Some things can't be fixed later. If mechanical puts a weak link gear designed to fail before the motor, firmware might not have enough margin to not wear it out with auto-stop.
    - bumby 4y ago
      Completely anecdotal, but my experience was that a large amount is attributable to systems engineers and project managers not having adequate software background. Invariably, this leads to software rigor being deprioritized or with just little oversight. After all "it's just software"

yetihehe 4y ago

> Metal, vs plastic gears. Sintered metal gears, last only a little longer than plastic and then fail catastrophically destroying half of the device so that you can't repair it. But at least they are much cheaper than proper machined gears.

JKCalhoun 4y ago
My KitchenAid mixer ate a gear many years ago. They would lead you to believe they are a high quality brand, no? After disassembly, it turned out to be perhaps the only plastic gear in the thing. It occurred to me that it was perhaps designed to fail rather than the mixer continuing to break the bones of the person who got their hand caught in the paddle. So, I throw the engineer a bone for that one. I was bummed though to have to order a replacement gear from some obscure place in Florida for like $75 or whatever.
- yetihehe 4y ago
  Yeah, sometimes there are plastic gears designed in specifically for this, in blenders and kitchen appliances, some lathes even have a set of several copies of one plastic safety gear. But sintered metal gears in planetary gearbox of a cordless screwdriver which fails faster than it's battery (Einhell) - not acceptable.
- S_A_P 4y ago
  The real crime is that there are only like 5 appliance parts companies that stock parts and they each seem to look at the other companies for what to stock. Meaning, if someone else has it they won’t. But what ever they do stock ends up selling for 500% or more of the wholesale price.
- blueblob 4y ago
  I had the same gear fail. It's called a worm gear and is, indeed, intended to fail before damaging the other gears. They're much cheaper if you buy a non-oem part. I bought one from amazon for ~10 USD.
  - JKCalhoun 4y ago
    Yeah, this was a time when Amazon was in its infancy. :-(
- generalpf 4y ago
  A worm gear! It is indeed designed to take the fall so the entire machine doesn't shred itself. I bought an official replacement from KitchenAid for $12 including shipping.
- mattferderer 4y ago
  > It occurred to me that it was perhaps designed to fail rather than the mixer continuing to break the bones of the person who got their hand caught in the paddle. This is a good call out of potential other reasons an engineer team might make something cheaper & easier to break. It would be awesome to read a summary of the trade-offs the teams discuss in their process.
- aidos 4y ago
  For those who want to see a teardown, AvE has one on his channel here; https://www.youtube.com/watch?v=0qKp-0h9P18 https://www.youtube.com/watch?v=0qKp-0h9P18
  - JKCalhoun 4y ago
    Interesting — it is the "Professional" version and appears to have different internals than my consumer-grade one.
- deleted 4y ago
  [deleted]
- kwhitefoot 4y ago
  My Electrolux Assistent N8, from 1978, also has a worm drive. Not plastic though, instead it has an electromechanical stall detector that shuts down the motor if it stalls. No need for sacrificial parts!
jerf 4y ago
Capitalism is successfully optimizing for what I as a consumer can detect. I am not capable of simply looking at a device and knowing whether the metal is the quality metal it needs to be, or if it is merely some cheap metal that will bend if I breath on it too hard. ($YOU may be. I'm not.) Except that nowadays I tend to just guess the latter and I'm statistically correct anyhow. Superman has a quote about living in a world of cardboard, where he must control his every move lest he rip through everything. I'm beginning to feel that way myself with these consumer products. If you take them even 5% out of spec expect them to catastrophically fail. They'll catastrophically fail even if you use them entirely within spec. I'd happily pay a bit extra for something that wouldn't but there's no way for the manufacturer to successfully convey to me that this is such a thing even if they wanted to. The metaphorical water is so metaphorically muddied that it's just dry dust now anyhow, with fake 5 star reviews and decades of refinement on marketing messages about how this vegetable peeler peels vegetables so well that it will even enhance your marriage prospects.

eternityforest 4y ago

Reliability now isn't done with the same methods as it was then. Back then, the good stuff might have been good because the motor was big. The modern good stuff probably has a brushless motor that can prevent stalls. It doesn't matter if it's big or small, the computer won't let it overheat, so they can make it smaller to save money that they can spend on whatever part is the actual failure mode. The trouble is finding manufacturers that actually do that, rather than just using a tiny motor with no computer and plastic gears with no torque sensing. If you design things with old fashioned methods, you need to use old fashioned heavy parts. Nylon gears in contact with ozone, and switches and connectors of all kinds seem to be the problem on everything I've seen. Which is why I always say I would gladly use 10k lines of code to save one moving part or one switch.

mikepurvis 4y ago
100% agree, but I think the issue here comes with a typical phased design process: - Mechanical: "Here's the physical specs, no need to account for A, B, or C, as it's been handled in software" - Electrical: "Here are the physical constraints and electrical spec. No need to account for X, Y, or Z, as it's being handled in software." - Firmware: "You need to handle A, B, C, X, Y, and Z, but if you run out of time or don't have the budget to make up a test rig for validating all those cases are handled correctly, no worries we'll just ship it anyway."
- eternityforest 4y ago
  The other issue I see is when mechanical and electrical don't actually give firmware the data or control they need. You'll see stuff like a lack of battery level monitoring, or relays without current sensing. I'm not sure why we don't do things the other way, have firmware people present at every step. Some things can't be fixed later. If mechanical puts a weak link gear designed to fail before the motor, firmware might not have enough margin to not wear it out with auto-stop.
  - bumby 4y ago
    Completely anecdotal, but my experience was that a large amount is attributable to systems engineers and project managers not having adequate software background. Invariably, this leads to software rigor being deprioritized or with just little oversight. After all "it's just software"