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:
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Figured out how to model all the front triangle lugs
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Start practicing silver brazing (by modifying a frame)
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Brainstorm on the jig
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!