This thread has veered somewhat off topic so can I briefly answer the questions raised so that we can all let Paul W get back to his 4G.
Yes, the reamer is a quality Taylor & Jones item. Replacement blades can be sourced still at a cost exceeding £150 (from memory). I lightly touched the old ones up with a fine slipstone and they cut whitemetal at least, very well.
No, I am not railway workshop trained. I mis-spent my youth as a volunteer on the North Yorkshire Moors Railway (NYMR). To get there, I needed a motorcycle. One of the retiring signalmen sold off his stock of the Ariels he had used to go to work on. They ended up (around 1973) with two of the young NYMR volunteers - me and one John Nelson - the same person who posted earlier (and he still has his Ariels). But I still volunteer occasionally for NELPG on the NYMR. I also have a photographers pass for the NYMR - hence the photo.
Steam engines are less subtle than Square Fours - but every bit as obstinate and, to my mind, even more rewarding when they work properly. The photo is leaving Goathland on the NYMR.
On a very hot day last summer I was kneeling on top of the Q6 (the second engine in the photo) but nice and cool as I was up to my elbows in the cold water in the boiler as I removed and fitted bolts in the most awkward of positions down through the dome by feel alone with the sure and certain knowledge that if I dropped bolt or nut, we were never, ever, going to retrieve it until the next time the boiler was completely stripped - probably in 2028. So not too hot and I stay overnight in a local pub.
In the interests of confusing Simon.....
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.