What's he doing?

[2door]

This is a screen shot from a Danny MacAskill video. I'm not enough of a builder of custom bikes to know what he's doing. The tool is a reamer of some type, if you watch the vid > YouTube - Danny MacAskill interview - "Way Back Home" you can see the metal chips being cut from the BB.

He is a bicycle mechanic by trade but also the world's best Trials Rider. My guess is he's modifying the BB for his riding style.
Anyone know?
Tom

 

[bairdco]

it's a bottom bracket re-facer. mostly it just gets rid of the powdercoat.

here's a detailed explanation: Facing Bottom Bracket Shells on the Catrike | Bicycle Technology and Patents

 

[2door]

Thanks Baird.
I knew about ceramic bearings but didn't know they were ever used on a bike. Learn sumpin every day. I suppose if I did riding like he does I'd have learned.
Tom

 

[corgi1]

That was my guess, paint removal for a positive seat

 

[Venice Motor Bikes]

My guess too!

 

[Goat Herder]

I knew that

 

[camlifter]

i can't get the pic to load, but when your using a 3 piece crank adapter it's often necessary to ream out the BB for the adapters to fit right.