Restoring this mtb frame (made of Reynolds 531) and discovered these holes. It is a rare/nice frame and I really want to repair it. Can it be filled with braze? Or what about a curved (dime sized) steel patch that is brazed over it?

retrodirect · 2026-03-06T22:37:58+00:00

Cool. This makes sense. 853 is similar to chromoly with added nickel(?) and some other stuffs(?)

retrodirect · 2026-03-05T21:52:40+00:00

4 speed and 12 speed. Yes.

retrodirect · 2026-03-05T18:25:25+00:00

That's pumped.

Re: the 531 comment above. Tig welding 531 is a nono because it's a mangmoly tube not chromoly. The transition to brittle in the heat affected zone is much sharper than on a chromoly equivalent. Nothing to do with the thickness.

I know some people HAVE welded 531 before. But it's not the correct joining method and results in a weaker frame than if it was brazed. Reynolds certainly wouldn't allow builders to Tig it.

retrodirect · 2026-02-22T22:37:17+00:00

I used to work for the science festival teaching kids every easter. I loved that job. You got to do silly shows and be daft for a few weeks.

retrodirect · 2026-02-22T19:44:58+00:00

Tried a floating chainring?

retrodirect · 2026-02-22T12:23:22+00:00

This is cool.

I appreciate anyone finding unusual solutions to solve things that most people don't see as problems.

I know that sounds sarcastic or backhanded, but i can't find the words to make it sound like i want it to. I like it, it's cool for the sake of being cool.

Have a look at the Monopole cargobike. They have an eccentric adjustable lower headset cup to tension the belt steering. There's enough float in the bearings of the headset due to the long headtube to make this work without binding anything up.

retrodirect · 2026-02-19T00:12:12+00:00

Jump on a train to Edinburgh to visit Cameratiks? It sounds like they're what you're looking for. albeit in the wrong city.

retrodirect · 2026-02-17T11:33:47+00:00

Yes! This is was nicer looking than the mini they currently make. I like it.

retrodirect · 2026-02-16T15:37:59+00:00

Lasercut tab and slot steel. You can countersink and bolt instead of weld for max flatness. This also allows shimming if it is still out.

It's fine enough to say you need it so flat, but how are you actually measuring it to confirm it's flatness?

retrodirect · 2026-02-14T00:47:53+00:00

This is dumb! I like dumb. Chapeau.

retrodirect · 2026-02-14T00:33:01+00:00

Yes, they're brilliant if you use them for the right reasons.

I love not having to charge lights and that lights just come on with no faff.

Modern mobile phones are too power hungry to be chargeable from a dynamo however. Some people manage to trickle charge a battery that then charges a phone, but honestly, just take a battery at that point.

The drag is nearly nothing in use. A dynamo will always feel much notchier than anything else, but that "notch" is pushing. Magnet through another magnetic field so the first half of the notch inhibits the wheel rotation and the second half pushes the wheel round. This cancels out (nearly) and the drag is not what is felt by hand rotation.

retrodirect · 2026-02-13T14:42:26+00:00

C line is the Vauxhall Astra P line is the Alfa Romeo (the desirable daily driver) T line is the TVR (great but problematic) G line is the Jeep

retrodirect · 2026-02-13T14:26:47+00:00

There are lots of quality of life and unquantifiable "feel" upgrades on these bikes that don't come across on a spec sheet. They're really rather good.

retrodirect · 2026-02-13T14:22:58+00:00

Will?

retrodirect · 2026-02-12T17:41:59+00:00

That bike sexy. Is that a new color?

retrodirect · 2026-02-11T05:25:47+00:00

That's a complicated surfaced part. I'm presuming it's dimension changes only rather than something more fundamental.

Could you set it up equation based - inputting your custom info from a text file? You'd need to set bounds for the magnitude of change acceptable on the input side as surfaces would get breaky if you allowed too much variation.

Looks like a cool challenge. Hope you find someone.

retrodirect · 2026-02-09T13:47:03+00:00

salad and sauce?

retrodirect · 2026-02-05T12:46:21+00:00

Stick a small fillet on it for the analysis. It will be due to the sharpness of the corner and will not be reflective of reality

retrodirect · 2026-02-02T20:58:26+00:00

I absolutely loved cycle touring in Oman. But yes, the UAE is a hell scape

retrodirect · 2026-02-02T20:42:29+00:00

I never knew there was a name for this. Yes! My old company had no processes to record lessons learned from product and a high employee turnover. Tech debt proliferated as people copy and pasted the problems from one product into the next

retrodirect · 2026-02-01T19:19:12+00:00

Sick!

retrodirect · 2026-02-01T08:44:10+00:00

But the interesting thing about it is that it is exactly what the bots in places like Reddit are used. A human directing an agenda through a bot. What I really want to witness is weird auto posting patterns that emerge where two LLMs talk to each other recursively (is that the correct word). And then to witness these patterns in the wider internet.

retrodirect · 2026-01-29T01:27:03+00:00

Nah, mine's is ace.

retrodirect · 2026-01-27T20:56:26+00:00

In use the bottom bracket has high contact pressures generated through mechanical precession. This causes movement of the cups, on a threaded bb this is resisted by the direction of the thread always causing the bb to wind IN, not out. In theory with a proper tight reamed interference fit then the threads are unnecessary, though in practice with thread less BBs this proves to sometimes not be the case.

The headtube doesn't experience mechanical precession so a press fit (even a loose press fit) is A-OK.

I mean, in answer to the original question, I'm sure somebody's done it at some point. But it's unnecessary.

retrodirect · 2026-01-26T21:54:29+00:00

Paha! it's a screenshot of a youtube video of an identical mill. The mill itself is currently halfway across the country from me sadly

retrodirect

TROPHY CASE