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Comment on Standard (SAE)/Metric mixed environments

Sometimes a screw is just a screw. There are reasons beyond what you care about locally for an item on a large assembly. It could be physics related, it could be a miss calculation. It could be political or a payback engineer.

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setsneedtofeed@lemmy.world ⁨6⁩ ⁨hours⁩ ago
I’m not talking about the engineering side, I’m talking about an environment where some systems are metric and some are SAE, usually based on if they are US or European designed. In these environments, technicians who are sometimes not terribly well trained, who are doing daily work, will mix and match the wrong screws into the wrong systems.

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- altphoto@lemmy.today ⁨6⁩ ⁨hours⁩ ago
  Well, you assume we don’t have that problem in engineering. If I want a prototype I can ask my local shop to make it, but I have to use imperial screws. For production we only use metric now. Anyone not using metric is just dumb or have not needed to change. All big machines in US shops have a high probability to be optimized for imperial units while mass production in China is usually metric.
  
  In my line of work, sometimes we keep imperial screws for many reasons. For example, to prevent easy access, or to required a tool that we can provide because we want the acknowledgement that access gas been required. But yeah, the problem is definitely not just user side. You can thread an M6 into a 1/4-20 hole a few rotations before you realized you’re screwed.
  
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  - setsneedtofeed@lemmy.world ⁨6⁩ ⁨hours⁩ ago
    
    Well, you assume we don’t have that problem in engineering.
    
    Huh? What?
    
    I’m working on finished systems designed entirely in metric, only designed with metric hardware. Installed with that metric hardware. The only way SAE hardware finds its way inside is when US technicians, who work for customers and not for my company ram it in there. Engineers are not consulted when they do this.
    
    For example, to prevent easy access, or to required a tool that we can provide because we want the acknowledgement that access gas been required.
    
    We just use metric security screws for most applications. Everything is supposed to be physically accessible by technicians who are theoretically qualified. Sometimes though they just aren’t.
    
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