Converting a threadless headset steerer tube to threaded?

[deliquium]

There's been some discussion going on in the Tea Shop regarding my new Moulton TSR custom build. Considering a conversion from threadless to threaded steerer.

hercule of the parish discovered this:

I came across this on the Surly FAQs page a couple of days ago:

Can I thread a threadless Surly fork?

No! Don't do it. Really, just don't; It's unsafe. The wall thickness of our forks' steer tubes is too thin to thread safely, and as well as the inside diameter won't be right for your quill stem.

(Reference here http://surlybikes.com/info_hole/faqs/ca ... surly_fork)

I would guess that the steerer on a TSR would be fine for a quill stem, but what about tube thickness? I'd suspect that the Reynolds tubing on the TSR might be thinner than Surly's?

Any thoughts on steerer dimensions and tubing? I doubt very much whether the TSR steerer tube is Reynolds 525? - actually my doubt is a guess and I ain't no engineer, so I'm assuming - and we know where that kinda chain of malarky can lead