Q: Motherboard Standoffs

LjSpike

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Mar 20, 2017
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I know that the 2.1 ATX spec requires standoffs be at least 6.4mm and fit in a 10mm x 10mm area, however I'm curious as to the standard length(s) which standoff manufacturers tend to follow, and what the length measurement measures from (is it from inside surface of case/frame to back of motherboard, or outside surface or to front of motherboard?)


EDIT: Just a little other thing, please put any dimensions in millimetres, I work in metric, not imperial. ;)
 

HansWursT619

Trash Compacter
Feb 22, 2016
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From the surface of the mainboard tray to the underside of the motherboard.
Literally the height of the standoff :-P That is the only measurement that makes sense for a standoff really.

What do you mean by standard height manufacturers follow?
I have only seen the 6.4mm stand offs in cases so far. At least none that were far enough off to be noticed immediately.
 
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jeshikat

Jessica. Wayward SFF.n Founder
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Removeable standoffs are usually 6.35mm (0.25in).

Fixed standoffs are different since their lengths are for the whole standoff, part of which gets pressed into the sheet metal. So a 8mm pressed-in standoff in a 1.5mm thick sheet ends up with 6.5mm of standoff protruding.
 
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jeshikat

Jessica. Wayward SFF.n Founder
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One trick is if they're sold specifically as "motherboard standoffs" and don't have a length listed, they're probably 6.35mm.
 

LjSpike

SFF Lingo Aficionado
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Mar 20, 2017
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One trick is if they're sold specifically as "motherboard standoffs" and don't have a length listed, they're probably 6.35mm.
Alright. Do they put the absolute minimum thread necessary on there? If there is some spare thread on them, I might design it to presume the standoff to be a bit longer then use small washers on the standoff if it's to short...
Either a 0.3, 0.5, 0.8 or 1.2 or 1.6mm washer thickness I'd probably use. Most probably a 0.8, however a 1.6 would take me within 0.05 of a metric length. Alternatively a 0.5+1.2 would take me within 0.05 of a metric length too.


EDIT: Infact, if using washers I could 3D print one to the exact dimensions necessary... It's still just a case if the standoff features spare thread or not...
 
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jeshikat

Jessica. Wayward SFF.n Founder
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Do they put the absolute minimum thread necessary on there?

I'm not quite sure what you're asking, the male thread length can vary quite a bit.

But the listed dimension on standoffs is for the body, it excludes the male thread.
 

LjSpike

SFF Lingo Aficionado
Original poster
Mar 20, 2017
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I'm not quite sure what you're asking, the male thread length can vary quite a bit.

But the listed dimension on standoffs is for the body, it excludes the male thread.

Ahh ok. I might look around the suppliers which do list lengths so I know what the length for each part will be.