The Mikrokosmos holes are spot on!
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The mounting holes in the panels of the Performance Filter and the VCO with Tuner (the only two LMNC modules that I have so far) are not the same size nor the same distance from the edge of the board. The filter’s holes are larger and further away from the edges of the board.
The VCO’s holes are perfect for M3 screws but are a bit too close to the edge of the board to my taste. I want to use 1cm wide metal rails with sliding nuts that are 7.9mm squares. With those nuts, I get a small gap between modules, which means that the holes are less than 4mm from the edges. Additionally, because the hole centers are not 5mm from the edge of the board but the screws have to be in the center of the rail, the total height of the board plus the rails ends up being a millimeter or two more than 200mm which ruins the whole metric round numbers thing.
So it seems that there isn’t really a standard yet, the holes in the Filter’s panel seem to give a better fit with 1cm wide metal rails so maybe we can standardize on that, just making sure that the holes are actually centered 5mm from the edges.
What say you @lookmumnocomputer and other Kosmonuts?
We discussed it in another thread and only the filter is different. The rest have 3.5mm holes with the center 3mm from top and side. As far as I can tell, anyway. I would also like them to be further from the sides.
I don’t care much about the horizontal positions of the holes. Whereas with Eurorack the horizontal hole positions are specified to allow compatibility with threaded rail insert spacings, Kosmo’s metric width already eliminates such compatibility; you have to use slide nuts and horizontal position variability isn’t a big issue. Presumably with M2.5 nuts, which are what I’ll be using with the Vector rails (M3 won’t fit in Vectors), there won’t be gaps. Slots instead of round holes could be used to give some leeway although this complicates fabrication.
As for the vertical position, note that some types of rail such as the Zie-Tec rails as used by Doepfer have a lip extending under the bottom of the panel and over the top:
as do the Z-Rails sold by TipTop:
The center of the hole can be no more than 3.8 mm from the edge of the panel to fit on Z-Rails, and no more than 3.3 mm to fit on Zie-Tec rails. The Eurorack standard is to have the hole centers 3 mm from the edge and I would strongly recommend following that in order to allow maximum flexibility in choosing rails. I see no compelling reason why one row needs to be a metric round number from the next, and it definitely won’t be if lipped rails are used.
What I certainly hope there would be is consistency. My understanding is that the VCF is the only one of the LMNC modules whose hole placement differs from the others (I don’t have any of them, so I have to go by what I’ve heard), and it’s not going to be produced any more, so it would not make sense to regard it as the standard setter.
Sam has mentioned before that the Performance filter is going to get a re-design at some point. its even on the shop page. Might be a while, but thats the one thats the most different.
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hey everyone! so yes I went with the standard in eurorack on subsequent panels from the filter, however I I have only been using sliding nuts, Antoine as yeah there is a bit of a gap! maybe I should change to those elongated holes, as they are quite a bit more useful! and can still be mounted with wood panels?
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Elongated holes would exactly be my recommendation 
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Have you tested that? I read somewhere that M2.5 is standard for Vector rails, but M3 will fit at well.
interesting! ill look into the elongated holes then. might just change them all for future. after the delay thats just going up in a week lol, that will be these holes! too late haha.
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So excited for the delay 
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I haven’t. I based that on Euroracks rails DIY guide – SynthRacks
Uses M2.5 square nuts, or threaded rail tapped to M2.5. The threaded rails tapped to M3 we have in stock fit the Vector Rails.
and https://www.etsy.com/listing/239501658/m25-square-rail-nuts?ref=shop_home_active_6
Bag of 100 M2.5 Square Rail Nuts are designed for use in DIY Eurorack cases built with Vector T-Strut Rails.
and this diagram
along with this
Elongated holes are good for threaded inserts. Threaded inserts are only (AFAIK) Imperial units spacing (1HP)… I guess if you have slots that are long enough (more than about 8.5 mm) they’ll be guaranteed to fully expose at least one hole at 1HP spacing without leaving gaps between metric width panels. Less wide than that and I don’t see a reason for them. Well, maybe they’d make sliding nuts easier to use?
Ah, so some threaded rails might fit, but it can’t be expected. Bummer. On the other hand, nuts and bolts are a small expense, I guess.
And 1HP threaded inserts aren’t much good for metric-width panels unless, as I said above, the mounting holes are 8.5 mm wide slots.
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The gap I have is with sliding nuts for M3 bolts, the nuts are 7.9mm square so with less than 4mm distance from the edge of the panel, the nuts touch on the back in the rail. I haven’t tried with M2.5 nuts & bolts because the rail manufacturer doesn’t suggest them for use with this rail .
I’m surprised that with only 3.8mm from the edge, the screws don’t split 1cm wide wooden rails, that’s part of why I was suggesting 5mm spacing, to be centered in 1cm rails, be they wooden or metal.
I hate elongated holes, they are so ugly, but I understand it’s not a simple problem to fix to the satisfaction of all, but it is kinda sad that a brand new standard has to suffer from backward compatibility problems.
I have no plans to make any pcb faceplates as I’m going for more homemade look. it would be on you if you wanted one. But with the kicad files (I promise I’ll upload them soon, my girl is working from home and using PC most of the day) shouldn’t be too hard to make the correct drill alignments.
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I have started my github account and uploaded some things in regards to the pcbs I’ve made so far. I have just been using web browser so far.
Specifically, @d42kn355 @popflier @analogoutput since you have the pcbs.
Next I will make the corrections on the silkscreens to the buffered mult pcb. I kind of intentionally uploaded the erroneous file so I can learn to do the github update.
I included the kicad project archive for each (I will try to keep future projects as clean as possible 
) as well as the Gerber files. Is this all I need? Let me know if I’m doing this wrong
Fair game for anybody do what you will with the files. Fair warning: The clock divider and sequential switch are printed but I haven’t built them yet to test them.
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Thanks!
Mostly, except for a folder of Gerbers in one of them, what you have in your repositories is zip files. That makes it kind of difficult to figure out what’s actually been included… Are the schematics there? The PCB files? In which zip files? And so on.
I prefer to put the unzipped files in my repositories, but if that’s a problem it’d be useful to have a README file that describes what’s in the repository. For that matter it would be useful even if it wasn’t zip files.
Thanks for doing this!
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Oh I see, because it lets you preview each file before opening? Rather than just a zip?
I’ll fix it!
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Yeah, for instance ClockDivider has two zip files. If I just want to peek at the schematic, which one do I need? I can’t tell without downloading.
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