Weird stem sanity check

[Goldi]

Hey, thinking of making a zero length, very tall (like 20-25 cm) stem. It’s for Larry vs Harry Bullitt and meant as a replacement for Velo Orange Cygne stem and a long spacer. Pictured is the current setup and a pencilCAD of the new stem. In other words, I want a Cygne stem that’s straight and taller, so that it doesn’t need the spacer.

A round plate with a hole in the middle is going to be needed for the preload bolt. My idea is to fix it in a threaded rod, position it inside the steering tube sleeve, put a coil or two of silver on top of it and heat it all around the sleeve from the outside. Then stop and check. And make sure I have a tube wrench long enough so that I can remove the nut from the threaded rod, deep in the sleeve, afterwards.

I might fillet braze a smaller tube to the middle of this round plate first, so that there’s a guide for the bolt to fall straight into the hole, like the Cygne stem has.

Does this sound sane to you? Is there any obvious problem? This is my first stem and a weird one as well, so I am a bit unsure.

[Hananas]

You could also put the washer with the hole for the preload bolt higher and use a long bolt to reduce the potential risk of not having a socket wrench that reaches deep enough

[Goldi]

Thanks, that’s a good thing to check. There should be at least 10 cm of steering tube above the top headset, so while it’s not a multitool job, the preload bolt shouldn’t be extremely deep hopefully.

[Aub3]

Do you have access to a lathe? A slightly thicker plug would hold itself and you’d just need to slide it in. Otherwise it would work as long as the silver dosent run into the bolt and lock it in place maybe use a chromed bolt so it dosent stick? Old quill bolt probably? Or stainless bolt and bronze filler. Here’s what the plug looks like for a 0mm quill but i’ve done threadless too. Brazed with a ring of bronze behind, heated till i saw it go thru all around