Quill stem for 25.4 mm handlebars

[vitualis]

This is regarding the Colnago I picked up recently...

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The stem that is currently on the bike is about 9 cm and is just a tad too short. I think that a 12 cm stem would be just about right.

However... I measured the handlebar diameter and it seems to be at a size of 1" / 25.4 mm diameter rather than the more contemporary 26 mm diameter road bars. I was thinking of upgrading the stem to something with a bit more bling (e.g., a Cinelli XA) but they only come in sizes for 26 mm. Indeed, it seems that all Italian quill stems are either 26 mm or 25.8 mm.

Is there some way around this size difference problem (apart from a new bar)?

Cheers.