Head tube reaming and facing question

[Monolith]

I just picked up a restored Masi 3V, and was looking to prep the frame for a build. I noticed that the head tube has a step or 'lip'.

I wanted to ream and face as there's some paint and rough bits inside. Has anyone any experience on how to face this sort of head tube? Should the 'step' remain?

 

[ScillySuffolk]

All supposition, but I'd suggest that's a normal part of the manufacturing process and the excess lug should have been removed by facing before it left the factory.

Ask your local, friendly framebuilder.

Or it could be an extremely rare, one-off model built for an equally rare, one-off headset that you have no hope of finding...

 

[Boscarn]

Re:

The lip you describe is not uncommon, from the first Nervex Pro lugs from 1949 until the 1980s. I have the same lip on my Chesini Precision viewtopic.php?f=12&t=338442 . I would just clean the inside with some fine emery; remember you will be using grease when the headset is inserted.

 

[Monolith]

Re:

That is a nice Chesini! Yes I supposed I could just ream the ID and sand the horizontal surface instead of facing it. Or jury rig an end mill to do the facing.

So the headset sits inside the lip nicely?

 

[Old Ned]

There's a note in here -

http://bikeretrogrouch.blogspot.co.uk/2017/03/

in the Bridgestone Calendar section that mentions some 'Dubois' lugs made by Nervex for Masi. I wonder if it is these that you have on your frame?