Q: Motherboard Standoffs

[LjSpike]

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]

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.

 

[jeshikat]

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.

 

[LjSpike]

Removeable standoffs are usually 6.35mm (0.25in).

You happen to know of any places selling 6.35mm ones? Of the ones I've found measurements so far, they always happen to be (listed) in whole millimetres...
https://www.moddiy.com/products/Premium-M3-Motherboard-Hex-Stand%2dOff-(5mm-to-60mm).html

 

[jeshikat]

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

 

[LjSpike]

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...

 

[jeshikat]

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]

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.