What is the Spanish for the English cycle mechanics word 'facing' a bicycle bottom bracket or headtube?

Heck, that's quite technical, methinks. What does it mean exactly. I had myself a frame tailor made before coming here, by Dave Yates, a really good frame maker.
sorry, am no cycle engineer, but love the sport.

Basically it is making the surfaces of each end of a tube absolutely parallel so that the bottom bracket or the headset seat perfectly when installed. In this instance I am looking at doing a conversion on one of my bikes which will involve cutting 12mm off the headtube which will then need facing to make sure it is parallel with the other end. I am looking for a precision engineer to do the cutting but who will also have the expensive facing tool to complete the job. So it will be a very good bike workshop or frame builder.

Have just googled facing and now understand!

I really don't know the Spanish word. the word "to ream" is 'escariar', but it's not really that, is it.
I'd suggest you contact a frame builder/manufacturer and try to explain in your best Spanish.
I'll enquire in our local bike shop. Cycling here in the Basque country is taken pretty seriousy.
And we host the start of the Tour de France in 29 days!

I'm not too sure what facing is, but if it's this then it's kit de refrentado or juego de herramientas de refrentado for the tools and refrentar for the verb.

Edit: Spelled herramientas wrong...

'Refrentado' it is! Thank you.

Famous for its bike factories I believe.

Famous for its bike factories I believe

Yes. Orbea is one that springs to mind.
Most people here have carbon fibre frames. Mine is good old fashioned Reynolds steel.

I was kind of thinking that by now someone would have said "Pasapalabra".

Sobering to think I know all of these terms in English from metalwork classes some 55 years ago at school, but these terms are a complete void in my Spanish vocabulary. How about moleteado for knurled That has to be in the bike mechanics vocabulary somewhere!

Refrentado seems good.
Went to my local bike shop, where there was a competent mechanic. When I described what you had said, he came up with the word 'escariar' which my dictionary says is for to ream.
Horses for courses!

That was very good of you, thanks. Reaming will be necessary to put the threads for the headset back. However that will be after the cutting and facing; so they are different, but both necessary processes. I have noted both words. Much appreciated.

Ditto: refrentar (facing) is to align and make parallel both ends of the tube. Escariar (Ream) is to clean up the inner bore of the tube.