View Full Version : Lathe and paint questions

04-25-2010, 03:30 AM
Hi all!

I just chopped and ground my first bottom bracket using an angle grinder and AZ's bike hacking tutorial as a guide.

I'm a member of a communal hackspace club that has a metal lathe, metal bandsaw, drill press, CNC, welder, and other tools. I showed the bottom bracket off to a machinist, who pointed out that I could have used the metal lathe to do the job in a few minutes.

Is this true? Exciting!

Also, he said that I don't need to remove the paint, because a welder can burn right through the paint, "especially a MIG or a TIG". Is that true? This bike I chopped has an awfully nice colour of paint on it.

Thanks for your comments!


Radical Brad
04-25-2010, 11:04 AM
True on both points, but...

I would challenge any machinist to get a bottom bracket clean in even half the time I could do it with my angle grinder!

And once you inhale your first few puffs of burning cycle paint, you may consider grinding the welded area the next time.


04-25-2010, 09:58 PM
Thanks for the answers, Brad!

Wow, you can clean a bottom bracket faster with an angle grinder than with a metal lathe? Impressive! I may try the lathe too and and see how it goes. It will be fun even just to learn a new tool.

But man, was I stoked when I finished my first bottom bracket!



04-25-2010, 10:29 PM
Ahhhhh, the wonderful aroma of burning paint.
Even burning flesh smells better than that, including the pain.
Yes, the paint does burn off but when you are learning to weld its better to have clean joints so you can see what is happening easier and it makes it easier to strike the arc.

09-23-2010, 06:28 PM
I know this is an old post, but I just came across it. Be sure to remove the paint and any dirt/ oil from anything you are welding. The paint will contaminate the weld and make it weaker.