Weird CF base inserts

Hey! does anyone know what these square insert bolt things are called/where i can buy them?


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It looks like a carriage bolt receiver. Most hardware stores should carry them.

I’ve tried to find those too at one point. Couldn’t find them, it doesn’t seem to be a standard part… I ended up gluing in t-nuts instead.

Is that the Exceed Carbon base that sells? I wonder if @JoshBuilt knows…

It’s not, an exceed base, looks like an “Axel base” (or perhaps a UDC carbon base) to me, that someone modified to use these nuts instead of the “standard” carriage bolts.

Looking at it further, I’d guess someone cut off the threaded part of a carriage bolt, and drilled and tapped holes in it.

I agree with finnspin.

That would be a lot of work. I think T nuts would work better, but they wouldn’t have that same clean look.

I was going to suggest a cut down hex rivnut, but then I remembered that the hex part isn’t threaded as that’s what’s intended to be compressed so you couldn’t just cut them short.

Using rivnuts from the underside would possibly work but leave you with large nuts sticking up into your arse.

Edit: Flanged hex nuts are a thing, although their flanges aren’t as large as a carriage bolt, and are generally not flat on the nut side.

If you have a lathe, then drilling and threading carriage bolts would not be terribly difficult. Filing or milling the sides into a square profile would be tougher IMO. You can see that there’s not a lot of metal near the threads. For an experienced machinist I am sure it would be child’s play. For a cut and try hack like me, I’d probably just make twice as many as I would need and throw away the mistakes. For someone without any metal working experience at all, I think this would be an extremely difficult project.

Edit: Never mind. I forgot about the square flange near the top of the carriage bolt. With a lathe it would simply be drilling and tapping a hole then cutting the bolt flush with the square flange. Easy peasy…if you’ve got a lathe.

A saw (plus perhaps a file), a well placed centre punch, and a drill press could get you there too.