Can't figure out where my blot and nut came off

So the other day I was cleaning up the table after a project cut and I discovered one of the black bolts was sitting on the table. I thought, uh oh, and set it aside and kept cleaning. Then I discovered discovered the mating nylon nut was also on the table. Ruh-oh.

I have been all over the dust shoe (which was the last thing I assembled and put on, having just done it the other day), assuming it probably came from there. But the dust shoe appears to be complete. I closely inspected the XZ Gantry and router holder and they all also seem complete. I keep going over the machine but haven’t been able to locate the home for it yet.

Is there a consolidated list of where each piece of hardware goes in the final assembly? Like can I confirm the exact dimensions of the bolt, cross reference it with the list of all assembly parts, and then look at locations where that unique part is used in assembly? It’s got me a bit worried.

I’ll take a photo of it and measure it (I can’t identify an M5 or M3 or whatever by sight yet) and maybe someone can offer a suggestion of where to check.



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Hi Jeff,

I could certainly be of more assistance if you could let us know the size and length of the hardware, but in the meantime if you want to do some of your own investigation I just spent some time updating the LongMill’s BOM with a new column which specifies to location of the parts listed. I think this would help you to narrow down where this bolt and nut could’ve come from:

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Here is a photo of it. Looks to be 15mm.
Thanks for the help, Chris!


Looks to be an M4? I might wager that’s one of the bolts that keeps the drag chain in place if it’s an M4

Aha! I did do something with the drag chain when I was trying to figure out how to hold my vac hose upright, I bet that is it. Will pop out to the shop and check and report back. Thanks for the insight, Chris!


Doh, I’m afraid I’m still in the dark.

No obvious bolts missing in drag chain setup.

2x At the attachement point to the XZ Gantry
1x At the attachment point to the X rail (on left)
2x At the base of the drag chain along the left Y axis

Total of 7 installed, no obvious ones missing. Is there a spot I’m forgetting to check? Any other ideas?


Is it the bolt holding the horizontal metal bracket that the dust shoe aluminum extrusions attach to?

What do I win if I get it right?

Aha! That could be it. Let’s see what’s behind door number 3…

Grant wins fame, fortune and reverence.

It appears to be the bolt and nut from the bottom center of the XZ gantry that is used to hold the dust shoe cross brace to the gantry. I am much happier knowing where it came from and that everything is safe. Thanks, Grant!


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@jwoody18 Lucky guess. :grinning:

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