Build your own Dropouts

Education
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I finally got to the stage, where I can order the parts for my first frame. Right now I’m looking for (track-) dropouts, but I can’t seem to find the right ones (where the inner angle is correct and both my SS and CS fit nicely into).

So, inspired by this thread, I’m planning to build my own.

My questions on this topics are:

  • Which type of steel do you use? Most professional dropouts (as far as I can tell) are made of 4130, however It seems very hard to order small quantities of 4130 in Europe. All I can really find is structural- or tool-steel.
  • What thickness do you use? And how much “meat” do you try to leave to support the axle?

Also, please feel free to post your self-build dropouts as an inspiration :grin: .

Cheers!

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I’ve been getting lasercut parts for years from 247tailorsteel. The 700C steel is high strength and have given me 0 issues over the years: WGW S700MC walsblauw | 247TailorSteel

I have always used 6mm thickness, with brazed on bits for locating the axle and derailleurhanger.

No, sorry, one issues. On the dropouts below a crack formed on the upper inner corner of the bend. But that was because the design was just too fragile.

12004-08
12004-081500×1000 76.1 KB

All dropouts after that seem to be going strong still after 8 years

insta06
insta063000×3000 3.01 MB

Moved to 3D printed stainless dropouts for the next iteration of the UNpaved Victor fully, but after some issues decided to move back to lasercut (and CNCed) dropouts for the production bikes:

20260114_083122
20260114_0831223468×4624 3.16 MB

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I’m also interested in this. I have been looking at Paragon Machine Work designs and their CAD models, along with their listed material. For example, quite a few of the steel UDH versions are around lower grade 1018 steel. In Europe, I believe this is similar to 080a15 / EN3B; however, in general, the grades/versions of steel, the form it comes in, and where you can get it and at what cost - all make my head spin!

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I don’t think it matters what steel you use because they’re so thick. Sometimes people use stainless to resist rust (but it’s not really a problem). I would just use mild steel if that’s the easiest.

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Im a little spoiled, being in the US means I can get laser cut 4130 pretty easily from sendcutsend.

So I use 4130, 5mm thick. I haven’t seen an issue with cracking, but my oldest bike with these dropouts is just two years old.

I am concerned about rust on the clamping faces of the dropouts, so I solder on a stainless or brass washer.

IMG_8551
IMG_85513024×4032 2.89 MB

IMG_3575
IMG_35753024×4032 1.96 MB

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Dropout material- One issue I have read of is when the dropout material is so hard that the axle won’t get a good “bite” and can slip in a track slot. Mild steel should be fine unless one really carves the bulk of the body away, and then the bike isn’t really about riding anyway:)

I have a pair of the Henry James conversion track dropouts, listed for sale along with a bunch of other cool stuff here A Bunch of Stuff and Philly Bike Expo - Bike Forums . They have a huge amount of real-estate to work with WRT stay angles. Andy.

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Thank you for the link, I will check them out. (and those dropouts look very clean!) And thank you @fiddleheadcycles for the picture and inspiration, I love your Idea with the stainless/brass washer/plate. I might give it a shot, this would solve Andrews concern with the “hard” material as well :slight_smile: .