Guide me while I plan my first build!

Hi everyone, bit by bit I’m making my way towards my first frame build and will be posting here as I slowly make progress.

I’m fully aware this is likely going to take a couple years to get to a full frame. So far I’ve read up about the basics on tubing, joining processes and geometry. I’ve decided I want to silver braze with 3D printed stainless steel classic looking lugs.

Why do I want to build my own frame with 3D printed lugs? Well probably like most of you, I want something really specific which I can’t really find anywhere, and I also just really like designing and making things and I want to create a rideable piece of art.
I really like my current neo-retro road bike but there are some things that also really bother me such as the rim brakes and the lack of torsional stiffness. I’m a light 65kg 183cm guy but have topped out at 1100w on a wattbike and the flex in the frame bothers me a bit when I sprint.

Current road bike: 1988 Columbus SLX frame, Ritchey classic Zeta wheelset, Rival 1x11 etc.

I sprayed it myself with rattle cans!

Here’s what I’d like to build to make something that ticks all my boxes, a modern allroad bike with:

Seat tube 495mm c-t (down from 550)
STA 74 degrees
Reach 400mm (edit: 395mm)
Stack 570mm (edit: 580mm due to new integrated headset idea)
HTA 73 degrees
Chainstay length 415mm (up from 405mm)
Ample clearance for 32mm tires, possibly 35 if possible

Downtube Tange 35mm 8/5/8
Top tube Columbus Zona 28.6mm 7/5/7
Seat tube Zona 28.6mm .8/.6
Head tube Columbus 36mm 1.1 (edit: with that integrated headset idea I’ll be using 38mm 0.9)
Chainstays Zona 425 .8/.6
Seatstays Tange 14mm .7

It’s a combination of Tange and Columbus Zona because I want the frame to be reasonably light but I also don’t want to spend a fortune on tubes in case I mess a few up.
I’d like to ovalize a significant part (150mm or so) of the bottom of the seat tube with a 3D printed tool for added torsional stiffness and maybe a tiny bit of added fore-aft flex to aid the seatpost in compliance?
I can ovalize the tube and then design my BB lug to fit around it because I know it won’t be a perfect oval. Can test fit with 3D printed plastic.

For brakes I’d like to go with flat mount. The flat mount bosses can be printed in one big piece with the non driveside dropout.

What I haven’t figured out yet is the fork situation. I’d like to build my own to fit the look and feel of the rest of the bike perfectly but I’ve heard mixed things about difficulty.

What I’ve managed to do so far:

I think I’ll go for a jig which is made from a frame of aluminium extrusions in which I can mount tools to hold the dummy axle, head tube and seat tube.
This way I have full access to heat the lugs from all sides. I can then also work with X/Y coordinates which I can extract from my cad model.

To do:

  • Practice silver brazing with lugs
  • Order tubes and ovalize seat tube
  • Finish 3D model including rear dropouts
  • Finishing touches on jig design
  • Build jig
  • Order prints to be printed
  • Build a damn frame, I guess!
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I’ve made a “little” to do list:

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Looks like a fun project.

You should definitely practice brazing with stainless lugs. Heat control with stainless is a lot trickier. The window in which it goes from an ideal brazing temp to burnt is smaller.

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Thanks!

I’m really jumping in the deep end aren’t I… Oh well guess I better start practicing.
First thing I’m gonna buy is a few stainless test prints to get my tolerances right and practice brazing. Also gonna see if I can have the threads in the BB shell and front dropout in the print because cutting them from a totally blank shell sounds difficult but I’ll ask a bike shop if they can do it.

Looks like a great project. I’d advise practicing the brazing into SS lugs, (though I don’t know how you’ll do that at a reasonable price - maybe cost is no object). For torsional stiffness, you might consider thicker chain stays, and make sure you include a chain stay bridge.

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After breaking my brain on how I want to make the fork, I think I’m better off buying a pre-made fork. Does anyone know a source of nice carbon forks that look kind of skinny, like the fork of the Specialized Aethos? I don’t like how chunky most carbon forks look.

WoundUp Composites make some nice forks that are more like traditional forks in appearance.

WoundUp

(these are obviously all painted)




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Hmm that’s pretty cool!
Unfortunately it would cost me so much to have that imported to Belgium that it would end up almost as expensive as an aethos fork (which is €850), and I’d like to find something with TA to have more options for wheels.

They do have a TA option (those bikes are from a few years ago). And they have dealer/builder pricing available.

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Im not a big lugs guy, but I have built some lugged stuff,

I would suggest for the first time around the block, that you don’t build a jig; you can easily spend way more time and energy on this side project than on building a frame, and you’ll come out the other end with a jig designed and built by someone who’s never built a frame…

if you work through some simple sub-assemblies by doing one joint at a time, , you can simply build the frame up from scratch with no jig, and make some alignment checks or tweaks as you go.

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This is good advice. Just make one (frame, not jig). Go slow, think through the process.

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Good point. Will also cut down on the cost of the project! Any advice? I’ve got some wood scraps and tools, maybe I can make some wooden blocks that hold tubes as far away from the hot joints as possible?

Does anyone know where to get a decent oxy propane setup in Europe? All I can find at first sight is either those little €100 mini kits or €1000+ setups. Is there anything in between that’s worth getting? I already know where I can get a 27L LPG cylinder for a good price.

Also how do you hold a UDH compatible dropout while brazing? Do I need a dummy axle with a dummy UDH piece or does a UDH hanger survive the brazing process without melting?

I have a sacrificial UDH hanger that i found that is fully aluminum. The SRAM UDH is partially plastic. I also kinda Jerry rig almost every part of the frame building process because my jig has no modern standards, so I might not be the one to trust.

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Brazing will damage an aluminum insert. You could use an extra/throwaway one, but a UDH dummy axle would be the best option.

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I’ll be working on one of the hardest parts of the design tomorrow, got a basic idea of the design drawn and will be trying to surface it in Fusion.
I’ve got a plan on how to construct my surfaces but let’s hope it works how I want it to. It’ll be a tricky one, good for sharpening my CAD skills!

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here’s how I did my first few. I upgraded from this to a marble counter top remnant and then once I had a process (and a mill and lathe) I made jigs/fixtures.
375

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Which joining process did you use for these frames? Wouldn’t a flat surface be a problem for getting the torch all around the lug to evenly wick the silver through?

I fillet brazed this but, this would work for lugs as well.

In the picture, I was checking for miter fit. Once I was confident with the miter fit, I started with the BB/Seattube joint with the seattube sticking straight up in the vice and resting the BB shell in the miter. I tacked that then fillet brazed the tube to the shell. Then I checked the alignment of that with some kind of straight edge. I forget exactly what now.

Then, I set up the DT and HT exactly as it’s shown in the picture and tacked and brazed that joint - again tacks inline with the centerline of the frame. I think I put a sheet of metal under the joint so I didn’t burn my bench!

Then I did the same for the DT onto the BB shell and then the top tube. At least that’s how I remember it. The sequence might be off a bit. I really had no idea what I was doing. I think I skimmed Paterak manual.

Once I had the front triangle together, I visited a local builder who had coached me through my brazing learning curve. He gave me some pointers.

I started with very basic standard tubes, track dropouts, no cable stops or braze ons. My process was crude but the bike rode well enough that I added cable stops and a derailleur hanger to the track dropout and road it for a couple years as my primary road bike. I still ride it now as a Porter type bike with a big rack on the front.

I notice in the picture there is a lot of excess head tube. I’m not sure if I cut that off after the picture or if the TT is not in the right position yet.

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