Turns out there are three kinds of handrail knob on the 8F (probably different again on the tender). Two short ones on the smokebox door. Eight the same size on boiler and smokebox. Four odd ones on the firebox. None of the remaining cast knobs were long enough for the boiler and smokebox so I looked elsewhere. I ended up buying a few handrail knobs from Slater's and from Eileen's Emporium, both turned from brass. I could get all three sizes from Slater's but only long ones from Eileen's. Dimensions are shown below... It would be useful to have this information on the respective websites. I'll add the missing dimensions for Eileen's' when they turn up. Of the two the Slater's look slightly better. The ball on the end is closer to scale and it does make a difference. Both need easing out with a cutting broach to take a 0.9mm handrail wire. And both look a little chunky in the stem. Slater's long are a close match in length (A) for the boiler and smokebox knobs so they were put in the little Proxxon drill to have the stem and mounting flange (E) slimmed down a bit with a needle file. Easy enough. The firebox handrail knobs are a different proposition. They are mounted to the firebox by a triangular flange and three bolts. There are cut outs in the firebox cladding sheets for these but you can see in photos that the flange and bolt heads are slightly proud of the cladding. Use standard knobs and ignore the difference? Or do it the hard way? Here's the hard way... Face off a short length of brass rod and set it upright in a toolmakers vice on the milling machine. Find the centre and drill the centre 1.2mm diameter and the triangular bolt hole pattern 0.5mm diameter. Drill down the rod far enough to make four and a spare including the width of the parting off tool. 6mm just about covers it, which requires a bit of patience with the 0.5mm drill. Then back to the lathe to part off a number of discs 0.25mm thick. Each disc has the required hole pattern in it. Remove the parting off nib and carefully file them triangular using the small holes as a guide. Insert 0.5mm wire and a Slater's medium handrail knob (modified as before) and silver solder them together. You have to take care to line up the triangle with the handrail orientation, and making everything a push fit helps to keep it straight during soldering. I'm now using a silver solder and flux paste for small parts like this. Just the tiniest blob of paste on the end of a cocktail stick is all it needs and they solder beautifully with just a waft of blowtorch. Snip off the excess wire and clean them up. I have to admit to using my fingernails as a filing guide on this sort of work so my RH index finger nail is interestingly grooved right now! I'm going to fix the handrail knobs to the body and leave the handrail off for painting and weathering. Particularly weathering, where you can't have convincing streaks down the boiler with a handrail in the way. I'm counting on being able to thread the handrail on at the end and paint it in situ. There's a slight kink in the handrail at the junction of boiler and smokebox (curse Churchward's tapered boilers and smokeboxes !) but I reckon it'll wriggle through as I've not made the handrail knobs too tight a fit on the handrail.