Heljan class 45/0, conversion to S7

[RichardG]

Tyre Profile.

Measure the diameters of all the wheels, and put the smallest one back onto the mandrel.


The deformation of the flange I mentioned earlier becomes more obvious when seen beside the profile tool.


The profile tool ought to remove the plating across the width of the tread in one go. If some plating remains, the tool is not orthogonal to the lathe spindle and needs to be squared up.


As the profile tool reduces the height of the flange, it cuts away the distorted metal.

I use the profile tool to remove all of the plating, and then a further 0.08 mm of metal. Just enough to make sure the wheel is concentric on its mandrel.


Then mark the setting of the hand wheel on the cross slide.

It is then straightforward to leave the mandrel, leadscrew and cross slide untouched, and use the cross slide to form the treads of five more driving wheels.


Put a tiny bevel on the outer edge of the tyre. I make this about 60 degrees, and about 0.015 mm deep front to back.

The bevel removes any tiny pieces of metal pushed over the edge during the profiling operation. The bevel also represents a feature present here on a prototype wheel, though I haven’t checked the detail on a real class 45.

Guess what - do this for the other five driving wheels.

It is now time to finally remove the faithful mandrel, set up the smaller mandrel and complete the two smaller wheels. Maybe it is me but I found the smaller wheels even more difficult to turn. The grade of brass grabs and chips and I was on the verge of stopping to buy four new disc wheels. But I persevered.


The wheels are now ready to be cleaned, blackened and put back into their bogie.

 

[simond]

Metal black?

 

[RichardG]

Metal black?

Added to the final sentence of the last section.

 

[RichardG]

(L-R): Heljan original, profiled to S7, and re-coloured.

I have blackened the wheels for the first bogie. I used antiquing patination fluid (selenious acid) on the bare brass, followed by a coat of clear sealer on the fronts and backs of the wheels.

I suspect this finish is not strong enough and will wear away from the tyres too quickly. I want to find a better process before I do the second set of wheels. The photos of reassembly (to follow) show the bare wheels for second bogie.

 

[simond]

I use metal black and oil on Slater/s wheels, of course they’ve steel tyres, and the combination is conductive, and gives a pleasing finish to my eye.

I’m not sure what you could do to a hard brass wheel to give a steely glint to the treads, I think that’s a challenge. I expect the blacking will wear but hopefully won’t let the brass colour be too obvious, and you do have the advantage of it all hiding in the shadows.

 

[Yorkshire Dave]

I suspect this finish is not strong enough and will wear away from the tyres too quickly.

If the wear is on the wheel tread leaving it cleaner/polished surely it wouldn't be a problem as it's exactly what occurs on the prototype along with brake blocks upon application.

From normal model railway viewing angles (helicopter) I doubt any brass colour would even be noticed as @simond notes - most will be in shadow.

In most lighting conditions and angles as in my photo of a class 45 taken at Quainton Road in the early 1980s (London-Calvert landfill rubbish train) the wheel treads are in shadow albeit against the afternoon sun on a cloudy day. However, you can just make out the right hand leading pony wheel tread on the far is barely glinting with a brass colour probably reflecting the track colour.

 

[RichardG]

From normal model railway viewing angles (helicopter) I doubt any brass colour would even be noticed as @simond notes - most will be in shadow.

I'd like some colouring on the wheels for model photography.

Many RTR wheels I have (00, H0 and 0) seem to be non-ferrous (magnet does not stick) but with a steel-like colour on the tyres. I suspect this is nickel plate. Maybe Heljan's factory plating was nickel. Nickel plating can be done to 100 microns, around 10 or 12 times thicker than the Heljan plating, if this is of interest. This could be hard-wearing and easy to clean.

I really want a process I can do myself at home. I have had a go with some selenium dioxide instead of selenious acid. The selenium dioxide produces a finer finish which does not transfer onto my fingers so easily. It gives a choice of colour too, depending on how long I apply it before rinsing. A reddish-brown colour is possible, which would not be too far from the colour of brake dust on the outside of a tyre.

I imagine, both of these products are effectively producing a controlled tarnish on the brass, akin to the way Birchwood Casey's gun blue produces controlled rusting on steel.

I have looked at several articles on profiling wheels for ScaleSeven and none of them mention a process for blackening brass. I'd like to do more experimentation or find more advice before dipping the second set of wheels.

 

[Brian McKenzie]

Why not turn new wheels, from whatever material you prefer for its colour? You are already doing the trickier part of that !

Something I've noticed with steel (in my surroundings), is that tyres of free-machining grades take on a slight rust-like patina (as do Slaters wagon axles), whereas tyres of EN8 and EN19 stay bright. Another material I've taken a shine to (no pun intended ) is continuous cast iron. It turns very easily, but do protect your lathe from its swarf and dust.

-Brian McK.

 

[simond]

Water cut steel from thick sheet would offer a solution for the tyres.

One could use the existing wheels as centres, and maintain the pickup hub on the rear. I imagine Loctite would be adequate (but might provide rim insulation!)

atb
Simon

 

[Eastsidepilot]

Turning new wheels for Heljans is an easy turning exercise, free cutting steel or cast iron. You could still use the the original axle bushes.

 

[RichardG]

Why not turn new wheels, from whatever material you prefer for its colour?

Well, there is a part of me which wants to call the job finished except for colouring the bare brass. Because I have re-profiled all the wheels, got them all back into the model, and watched it trundle along a bit of track. I don't really want to start all over again.

But it is quite telling, with so many RTR models having plated brass wheels, no-one here has immediately identified a best practice for refinishing brass wheels. Perhaps I am on my own to do something I think is good enough for me.

 

[Bob Essex]

Another material I've taken a shine to (no pun intended ) is continuous cast iron. It turns very easily, but do protect your lathe from its swarf and dust.

As well as being nice to machine I'm of the view that using it plus brass wiper pickups produces perhaps the best and most reliable current collection. One 7mm loco with cast iron wheels which is around 35 years old has only had the treads cleaned once in all that time as it seems not to collect dirt as do other metals. And of course it doesn't tarnish nor rust.

Bob

 

[simond]

I do like turning cast iron.

 

[Ian@StEnochs]

I do like turning cast iron.

Nice stuff to turn but the dust gets everywhere.

 

[Overseer]

Well, there is a part of me which wants to call the job finished except for colouring the bare brass. Because I have re-profiled all the wheels, got them all back into the model, and watched it trundle along a bit of track. I don't really want to start all over again.

But it is quite telling, with so many RTR models having plated brass wheels, no-one here has immediately identified a best practice for refinishing brass wheels. Perhaps I am on my own to do something I think is good enough for me.

I have never had good results with brass tyres on locos. They always get filthy quickly so poor pick up, but nothing nearly as heavy as a Heljan loco so that could be the difference. I bought a nickel plating kit to deal with this (and some non railway things) - Nickel Kit 4 ltrs – Jane Kits - they are in Sydney so probably not much help to you but you could put all you need together fairly easily. I haven’t actually used it yet so can’t show the results.

 

[RichardG]

Perhaps I have done the wrong thing the right way. I mean, maybe Heljan wheels should be discarded and replaced with something else.