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I want to create some bike lugs for my specific geometry using 316L and 3D printing. What is the thickness of traditional steel lugs? Are there any other suggestions on this build?

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    With all due respect, in my opinion you should properly do the engineering work to figure out exactly what your bike design needs. I think that's the better approach rather than trying to copy what other designs are using and hoping they're appropriate for your own.
    – MaplePanda
    Dec 19, 2022 at 8:16
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    So you're 3D printing in low-carbon stainless steel, but you don't have access to vernier calipers ? This whole question might be better on engineering.SE or 3dprinting.SE
    – Criggie ♦
    Dec 19, 2022 at 9:28
  • @Criggie I do have calipers, but I don't have lugs to measure, and they're not produced in my area.
    – Zyleyus
    Dec 19, 2022 at 13:24
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    It may be worth pointing out that many lugs on perfectly well-used bikes are extremely thinned down. Many builders see thinning and tapering them once brazed as being a big part of the craft and good for reduction in stress risers (particularly on very thin tubes), and some of these basically go to almost nothing. The not-obvious thing about lugs can be that a lot of strength in the joint comes from precise fitting of the tubes to one another inside the lug.
    – Nathan Knutson
    Dec 19, 2022 at 18:21

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I have handled quite a few lugs of different types. Some are cast and some are made out of pressed sheet steel then curved and jointed shut to make the 3D shape. Other people create a fillet joint in the correct size tube (where the ID fits the OD of the main tubing) and cut the lug to their own design.

Most of these are 1mm thick, or less, though some of the cast ones I have seen are thicker. I don't think they are very expensive, so you could order up some basic examples from a framebuilding supplier to have a play with, or cut up an older frame to see what is going on within.

Have a look at this website, which is well stocked with nicely presentled examples. https://framebuildersupply.com/collections/lugs/products/top-lug-for-standard-1-frame-extended-top-31-8mm-headtube-and-25-4mm-top-tube-73-5

I have used a UK distributor called Ceeway in the past. While they have a great selection, they don't have such pretty pictures on their website.

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  • Lugs aren't manufactured in my country, and they are actually pretty expensive in my currency. And I'd rather not buy something that I can't use and waste them. But thanks for your info tho.
    – Zyleyus
    Dec 19, 2022 at 13:27
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    Well you can still ask one of these suppliers for the dimensions, they are generally happy to help, and depending who you talk to may have more detailed information that can help you. I doubt many people on this forum have built a frame and even fewer using lugs
    – Noise
    Dec 19, 2022 at 14:16
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    The photos look good enough that you could measure the wall thicknesses to at least full significant digit. I too find it odd getting a few example lugs would be prohibitively expensive but carbon fiber tubes and 3D printing stainless steel are affordable. But whatever.
    – ojs
    Dec 19, 2022 at 16:02

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