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M92 Multi front spacer

plasticfactory

plasticfactory

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The M92 Multi (everyone should have one!) uses a spacer + PCB foot to act as a standoff stack on the front of the board. This solution is ~1.4mm taller than the rear board stack-up, causing an equivalent amount of flex on the top board.

While I work on a proper enclosure for this, I did a (very) quick model of a printable spacer to remove the flex. The hole offsets were measured with a digital comparator, so location should be very accurate.

The part was designed for M3 heat set inserts, but you could also use a longer bolt + nut.

I included STEP files so that adjustments can be made in the event that other people are using different length standoffs, or any other number of variations that could exist. I think the model as-is will cover most people.

If anyone who needs one does not have access to a 3D printer, post here -- I can probably help.

printables link

Right:
1744835349746.png


Left:
1744835369729.png


1744835101791.png



Here you can see the difference in height + flex (slightly exaggerated as my board had some flex already) when only swapping one bracket:

1744834720676.png
 
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Thanks a lot for sharing! - On your photo is the upper pcb bend or is it just the camera lens?

Looking forward for that case :)
 
Orakelschaf said:
Thanks a lot for sharing! - On your photo is the upper pcb bend or is it just the camera lens?

Looking forward for that case :)
Click to expand...

You're welcome! If you're talking about the bottom photo, it's two fold: I only installed one mounting bracket (left) to illustrate the height difference and just how much it bends. I edited the post to better clarify. There will be no bend when you install both brackets.
 
Very nice, looking forward to seeing the enclosure you’re putting together as well!
 
Love it man!

I must say, while this multi is very cool, it's SHIT for design! I mean, the ribbon cable comes off at a weird spot, it's multiple boards stacked oddly... great technically designed multi, poor feng shui all around.

A case will be hard, at least a small one, with the oddly placed ribbon cable.
 
@plasticfactory and @Mitsurugi-w please correct me if I'm wrong: original M92 spacers are 17mm and PCB thickness is 1.6mm, so to me we need 17 + 17 + 1.6 = 35.6mm spacers at the front.
I believe the PCB feet that come with the kit are 20mm, giving 37mm total when coupled with the original spacers, or 1.4mm flexing over 20cm, doesn't look to be much to me (I have PCBs with feet sagging 5mm in the middle).
But definitely your solution @plasticfactory is nice.
 
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@Ape Cosplay Yup, that's correct. When I was typing this up I erroneously added the PCB thickness to the front spacer, so the flex is actually only 1.4mm, as you said.

I don't think the setup as-is will cause any real harm, but I'd definitely prefer everything be equal height.
 
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