Reprofile of Heljan diesel railbus wheels to finescale profile

[Richard Gawler]

I have sucumbed to a secondhand but tidy AC Cars railbus made by Heljan. This is for 7 mm scale and the wheels have a plain cylindrical profile, no coning.

Please, would a member of WT be prepared to turn these to the usual F/S profile for me?

I am rather hoping I will be able to drop the wheelsets out of the model and send them off complete to someone; and they will return the wheels on their axles and set for usual 0-F and 0-MF track.

Many thanks,
Richard.

 

[Bob Essex]

Forgive me for asking but are the wheels not suitable for FS as they stand? While coning can help in centering a vehicle on the track when running it's not essential and there must have been a reason Heljan produced the wheels in this form - well one would hope so!

Bob

 

[Eastsidepilot]

The early Heljan wheels are rubbish by model railway standards, I do know of owners of some early Heljans that wouldn't go through Peco points properly even with all the slop that O gauge has.

 

[Richard Gawler]

Forgive me for asking but are the wheels not suitable for FS as they stand? While coning can help in centering a vehicle on the track when running it's not essential and there must have been a reason Heljan produced the wheels in this form - well one would hope so!

Well, on my code 100 FB track, the flanges collide with the glued-on cosmetic fishplates. This makes the model "kick" sideways. None of my models with true F/S wheel profiles do this. I reckon, coning would centre the wheels and avoid these impacts.

 

[simond]

Well, on my code 100 FB track, the flanges collide with the glued-on cosmetic fishplates. None of my models with true F/S wheel profiles do this. I reckon, coning would centre the wheels and avoid these impacts.

Well, it might, but if the cone diameter at the large end were not big enough,mthen the flanges would still clobber the chairs on corners.
I reckon the flanges are too big, and it wants coning.

isn't it possible to buy some wheels that might do?

I do have to wonder why they’d be wrong in the first place…?

 

[Richard Gawler]

isn't it possible to buy some wheels that might do?

I have read up on every reference I can find online, and the consistent recommendation is to reprofile the existing wheels. This lets you keep the axle with its gear. Transferring the gear to a different axle is likely to split the gear. Putting different wheels on the axle needs custom bushes. At least, so I am told.

These wheels do not look like a modern wheel. They look a bit like Hornby Dublo ones from the 1950s. The profile is completely wrong, and the model runs like a toy; it has no lateral stability on the track.

Please, would a member of WT be prepared to turn these to the usual F/S profile for me?

I think my question is reasonable.

If someone knows of a different solution (I mean, first-hand knowledge of modification and success) then please do tell me. I don't honestly care why Heljan chose to do this - it won't help me a jot. They have put a more modern profile on their later models, perhaps market pressure came to bear.

 

[Dog Star]

Richard,

Writing from a position of little knowledge of the prototype or model, might there be a different HJ model which could provide, as spares, replacement wheels, axles and gear(s)?

Rgds, Graham

 

[simond]

Sympathies…

this is not reasonable. The G0G standards have been published for many years. I would expected any commercial RTR would be compatible if not totally compliant with them.

I have two lathes and some ability to use them but I would not wish to take on such a job on a model with the potential of wrecking one irreplaceable wheel. I’d happily 3DP or turn up some bushes to make good wheels fit the axles you have.

atb
Simon

 

[Richard Gawler]

I have only one lathe, but an equal reluctance to ruin something irreplaceable!



Here are some Slater's wagon wheels for comparison.

Apart from the lack of coning on the HJ ones, the radius at the foot of the flange is different; the flange thickness looks different; the wheel thickness is different; the B2Bs are 28.5 not 29.2 mm.

I fancy a phone call to Peartree Engineering tomorrow. They do solid disc wheels, too modern for my Heybridge Railway but they look good and maybe something would fit. These are 3 mm axles. Even I could probably turn the ends down to fit a decent wagon wheel.

There is no great rush to sort this out. The model only arrived yesterday.

 

[Bob Essex]

Oh dear, I had read of problems with some Heljan O gauge but didn't appreciate how bad it could be for items that aren't cheap in the first place and concerning parts for which there are no spares. I have a home brew FS profile tool that I have used mainly with cast Iron wheels and I often re-profile wheels in 2/4mm scales for 2FS/P4 using single point tools but I would also be wary of machining wheels where there is no easy alternative path should it all go pear-shaped, which I've encountered a few times........

I'd offer to have a go but it's one thing potentially wrecking something that is yours and quite another when it's somebody elses. I'd certainly agree that the problem seems to be one of multiple aspects coming together, wrong b-t-b plus the oversized root radius and over-deep flange. A real dogs dinner of not quite coarse scale nor fine. Mind, the current FS profile started when Alan Gibson and Slaters started producing their wheels which at the time were finer than the then FS wheel profile. If I remember correctly this was in the mid-80's. Perhaps somehow Heljan 'found' the old profile with their original offerings.

I do hope you find an easy solution Richard.

Bob

 

[Richard Gawler]

The railbus runs through both legs of my 0-MF A6 in both directions, and also the straight leg of my Setrack point. It's probably not worth the effort and indeed the risk of changing anything until the gears split!

 

[richard carr]

Hi Richard

If you have a lathe you have the key tool you need to reprofile the wheels, the tool you are missing is the form tool for the profile.
I happen to have one of those that I bought from Alan Harris probably 20 years ago now, I'd be happy to loan it to you so you can do the work.
You will need to make a couple of mandrels to hold the wheel while you do the reprofiling and stub axle to mount the wheel on.
The Heljan wheel is brass and they machine easily, so even a small lathe should be able to do this set to its slowest speed.
All the ones I do are to reprofile to S7.

Richard

 

[Richard Gawler]

If you have a lathe you have the key tool you need to reprofile the wheels, the tool you are missing is the form tool for the profile.

After I made my last post, I realised I would not let myself be defeated. I had read somewhere the wheels are brass so they will turn easily. So I mounted them up in the 4-jaw chuck with a brass shim around the treads to discourage marking, and skimmed about 0.2 mm off the backs.


Just one wheelset so far. This has taken the B2B up to around 29.2 to 29.4 mm. I skimmed the tips of the flanges too so I don't cut myself on them.

Putting this wheelset at the leading end, the railbus now goes through the Setrack point without hitting the nose of the crossing vee.

The offer of the form tool is very kind. This will need me to take the wheels off their axles and back on again, which is something I could get wrong. I'd better sleep on this.

 

[Eastsidepilot]

After I made my last post, I realised I would not let myself be defeated. I had read somewhere the wheels are brass so they will turn easily. So I mounted them up in the 4-jaw chuck with a brass shim around the treads to discourage marking, and skimmed about 0.2 mm off the backs.

View attachment 235919
Just one wheelset so far. This has taken the B2B up to around 29.2 to 29.4 mm. I skimmed the tips of the flanges too so I don't cut myself on them.

Putting this wheelset at the leading end, the railbus now goes through the Setrack point without hitting the nose of the crossing vee.

The offer of the form tool is very kind. This will need me to take the wheels off their axles and back on again, which is something I could get wrong. I'd better sleep on this.

The wheels will come off the axles easily with a wheel puller or alternatively make a slotted piece of flat bar that will fit the axle behind the bush lay it in the jaws of a vice and use a punch on the axle, you can tap the axle out gently. when reassembling push a wheel back on each end of the axle place them in the vice and close them up with a back to back gauge.

Col.

 

[Richard Gawler]

The HJ wheel has a grooved flange on the back, this resembles a small pulley. The pickup wire goes in here. So it would be wise to keep this and not try a completely different wheel.

But . . . could I turn down the HJ wheels to make them into plain discs, and put on the tyres from a Slater's wagon wheel? This would give me a steel tyre as well as a decent profile. I wonder if anyone has done this.

(I've modified the second wheelset, and the model now passes through the Setrack point with either end leading.)

 

[Eastsidepilot]

The HJ wheel has a grooved flange on the back, this resembles a small pulley. The pickup wire goes in here. So it would be wise to keep this and not try a completely different wheel.

But . . . could I turn down the HJ wheels to make them into plain discs, and put on the tyres from a Slater's wagon wheel? This would give me a steel tyre as well as a decent profile. I wonder if anyone has done this.

(I've modified the second wheelset, and the model now passes through the Setrack point with either end leading.)

It is entirely possible to re tyre any metal wheel, but I would advise not fitting an already profiled tyre as it may not come out concentric, machine a blank tyre that is slightly over size and then re-profile.
I've done this with damaged AGH castings in the past. If you are happy with brass then just re-profile what you've already got but if you want steel a good turning exercise would be to reproduce the Heljan wheels in steel, round bar is cheap enough and as far as turning is concerned it's a simple process as long as you have the right tooling.

Col.

 

[simond]

The HJ wheel has a grooved flange on the back, this resembles a small pulley. The pickup wire goes in here. So it would be wise to keep this and not try a completely different wheel.

But . . . could I turn down the HJ wheels to make them into plain discs, and put on the tyres from a Slater's wagon wheel? This would give me a steel tyre as well as a decent profile. I wonder if anyone has done this.

(I've modified the second wheelset, and the model now passes through the Setrack point with either end leading.)

Whilst you could go the whole hog and profile the wheels, or even make new ones, it seems that you have achieved your key objective of running through the Set track points both ways, which is a win.

Presuming the flanges no longer bump on the chairs, I should call that a wrap (until the gear fails...)

I do like the idea of a separate area for the pickups, not sure it's necessary but I imagine it's reliable.

atb
Simon

 

[Bob Essex]

But . . . could I turn down the HJ wheels to make them into plain discs, and put on the tyres from a Slater's wagon wheel? This would give me a steel tyre as well as a decent profile. I wonder if anyone has done this.

I’m not sure about Slaters tyres, ( I think the centres are injection moulded into the tyres), but I have used Gibson wagon wheel tyres knocked off the centres with replacement brass centres for a freelance diesel shunter. These were hub insulated via tufnol bushes onto the 1/8” axles. It’s the way the 2mm association produce all their loco wheels, machined centres into steel tyres. No issues with concentricity if done with care. But if skimming the wheel backs has worked I’d personally leave well alone.

Bob

 

[Richard Gawler]

Presuming the flanges no longer bump on the chairs, I should call that a wrap (until the gear fails...)

But if skimming the wheel backs has worked I’d personally leave well alone.

Yes I am going to quit this while I am ahead.

I was going to write, you cannot polish a tu*d, but Col (@Eastsidepilot) has posted a detailed explanation of how to reprofile this sort of RTR wheel to the accepted standards. Thanks Col.

For the curious, my railbus wheels have ended up about 3.75 mm thick, close to the F/S standard but with a flange thickness closer to S7. However, they work.

 

[magmouse]

my railbus wheels have ended up about 3.75 mm thick, close to the F/S standard but with a flange thickness closer to S7

Step by step, Richard, you are moving towards S7...

Nick.