Wright writes.....

[Chuffer Davies]

1 hour ago, gr.king said:

Now there's a challenge, when I get round to building the one that lurks in my kit heap.

Hi Graham,

I converted a Bachman C1 to EM recently and documemnted on WW a couple of months ago.  I've fitted 14mm bogie wheels without problem.  I set up the chassis so that the bogie controlled the vertical movement of the front of the chassis to prevent the footplate from grounding on top of the bogie wheels.  The chassis sits on a pin centred directly above the rear bogie wheel.  As well as controlling vertical movement this pin also prevents sideways movement so there is no requirement for a cut out to allow the rear bogie wheel to pass under the frames.  The bogie then rotates around this same pivot so that the front bogie wheels turn into the curves.  There is still a need therefore for a cut out to allow the front (bogie) wheels to pass under the frames.  The chassis is effectively set up more like a Prairie than an Atlantic  but can still negotiate 2' 6" radius curves with ease.

 

In EM there is enough space between the frames to allow the driving wheels be compensated with twin beams but in OO the narrowness of the frames may need a different approach such as fixed rear drivers and sprung front drivers to ensure that the frames sit down on the bogie. 

 

I'm sure this same approach would be very effective as a solution  for the K's C1 as and when you get round to building it. 

 

Regards,   

 

Frank

 

Edited October 3, 2020 by Chuffer Davies

[gr.king]

Thanks Frank, my first thought was also that of making the front of the loco body ride on the bogie, so that save for the small amount of alteration caused by any tilting of the bogie, there is almost no up and down movement of the bogie wheels relative to the body. That means that one way or another, the body has to be free to tilt relative to the four coupled wheels. That can be arranged by means of compensation beams or springs of course, but the way I did it in my D10 was to make the four-coupled section of the chassis entirely separate from the rest of the loco structure, which simply attaches to it by a couple of pivot screws that bottom-out when tightened fully, rather than nipping up the joint between chassis and body. The rear carrying axle of the Atlantic can easily be arranged to have freedom to rise and fall too. I think I'd stick to a previously tried, successful mounting for the bogie though, with the pin in a suitably curved slot, ensuring that the leading wheels stay forward, clear of the cylinder fronts, as the bogie turns, rather than being swung back on an arc. I know that many modellers settle for taking chunks out of the cylinder fronts to gain clearance, but I wouldn't want to do that unless there was absolutely no other way.

[cctransuk]

2 hours ago, Daniel W said:

... I have had issues with the Markits wheels ...... Many of the wheels simply would not fit properly on to the axles, resulting in a serious lack of squareness. Putting them in a vice helps somewhat .....

 

Do NOT force them on with a vice - just remove any machining burr from the square axle ends with a fine file, and any casting flash from the rear face of the cast square holes in the wheels with a square needle file.

 

The wheels should then fit the axles without force, and you will not have affected the inherent quartering.

 

John Isherwood.

[Tony Wright]

1 hour ago, Chuffer Davies said:

Hi Graham,

I converted a Bachman C1 to EM recently and documemnted on WW a couple of months ago.  I've fitted 14mm bogie wheels without problem.  I set up the chassis so that the bogie controlled the vertical movement of the front of the chassis to prevent the footplate from grounding on top of the bogie wheels.  The chassis sits on a pin centred directly above the rear bogie wheel.  As well as controlling vertical movement this pin also prevents sideways movement so there is no requirement for a cut out to allow the rear bogie wheel to pass under the frames.  The bogie then rotates around this same pivot so that the front bogie wheels turn into the curves.  There is still a need therefore for a cut out to allow the front (bogie) wheels to pass under the frames.  The chassis is effectively set up more like a Prairie than an Atlantic  but can still negotiate 2' 6" radius curves with ease.

 

In EM there is enough space between the frames to allow the driving wheels be compensated with twin beams but in OO the narrowness of the frames may need a different approach such as fixed rear drivers and sprung front drivers to ensure that the frames sit down on the bogie. 

 

I'm sure this same approach would be very effective as a solution  for the K's C1 as and when you get round to building it. 

 

Regards,   

 

Frank

 

Wonderful stuff, Frank,

 

Thanks for showing us.

 

Your solution is far more sophisticated and sound in model-engineering than anything about that old K's C1.

 

Regards,

 

Tony. 

[Tony Wright]

2 hours ago, Daniel W said:

On the subject of wheels, I have had issues with the Markits wheels I used for my North British shunter and also for the Hudswell Clarke tank I am building at the moment. Many of the wheels simply would not fit properly on to the axles, resulting in a serious lack of squareness. Putting them in a vice helps somewhat, and thankfully damage has been avoided so far.

Please take John's advice, Daniel,

 

Don't force Markits wheels on to their axles with a vice (or any driving wheel?). You might be one of the folk I've alluded to who've said they've had difficulty fitting Markits wheels on to their axles. 

 

I can only state, I've never found any problems - the wheels just go on first time. 

 

Regards,

 

Tony. 

[Tony Wright]

3 hours ago, t-b-g said:

 

You make a point there Frank that I hadn't really thought about until you mentioned it.

 

If you have a wheel that is less than concentric, in a rigid frame the loco body will indeed all move around.

 

With compensation or springing the axle can move up and down but the movement of the body is minimised or may even by removed altogether.

 

Looking back at the past, one of the leading figures promoting compensation and also a leading supplier of plastic centred wheels for many years was the late great Mike Sharman. A super engineer with great skill.

 

Perhaps his development of both the wheels and compensation went hand in hand and using the wheels in rigid mechanisms was not what he intended.

 

Edit to add that all the Gibson and Maygib kits were designed to be built sprung too. A pattern begins to emerge!

 

 

I think you've just had a 'light-bulb' moment Tony! 

 

A pattern does emerge, which suggests that with compensation/springing, driving wheels need not be concentric! 'Compensation' usually means doing something to alleviate a problem - in this case compensating for 'dodgy' wheels? 

 

Which suggests to me that with Markits wheels and compensation/springing, the riding should be absolutely perfect. Shouldn't it? 

 

Regards,

 

Tony. 

[Chuffer Davies]

1 hour ago, gr.king said:

Thanks Frank, my first thought was also that of making the front of the loco body ride on the bogie, so that save for the small amount of alteration caused by any tilting of the bogie, there is almost no up and down movement of the bogie wheels relative to the body. That means that one way or another, the body has to be free to tilt relative to the four coupled wheels. That can be arranged by means of compensation beams or springs of course, but the way I did it in my D10 was to make the four-coupled section of the chassis entirely separate from the rest of the loco structure, which simply attaches to it by a couple of pivot screws that bottom-out when tightened fully, rather than nipping up the joint between chassis and body. The rear carrying axle of the Atlantic can easily be arranged to have freedom to rise and fall too. I think I'd stick to a previously tried, successful mounting for the bogie though, with the pin in a suitably curved slot, ensuring that the leading wheels stay forward, clear of the cylinder fronts, as the bogie turns, rather than being swung back on an arc. I know that many modellers settle for taking chunks out of the cylinder fronts to gain clearance, but I wouldn't want to do that unless there was absolutely no other way.

Hi,

Don't know what the minimum radius you are aiming for is?  The way I arranged the bogie meant that there was no need to cut away the inside of the cylinders to allow for swing of the front bogie wheel in EM.  It will be even better with OO clearances.  The benefit of the control pin at the rear of the bogie is that it stops the main frames from swinging too far in either direction which is normally the case if  it is only the coupled wheels controlling the swing.  It also stops the rear bogie wheels touching the main frames.  I should add that I still needed the centre bogie pivot inserted  through a curved slot but only as a means of attaching the bogie to the frames, the pin was doing all the control work.

Cheers,

Frank 

 

[Daniel W]

Thanks for the advice chaps. I've not 'viced' the Hudswell Clarke ones yet, so i shall try using the needle files instead. Tony, it may be that only the smaller patterns of Markit wheels are affected by these issues. I'd imagine the diameter of the average wheel you are using is signifcantly greater than the ones used on industrials.

[Chuffer Davies]

1 hour ago, Tony Wright said:

I think you've just had a 'light-bulb' moment Tony  

 

A pattern does emerge, which suggests that with compensation/springing, driving wheels need not be concentric! 'Compensation' usually means doing something to alleviate a problem - in this case compensating for 'dodgy' wheels? 

 

Which suggests to me that with Markits wheels and compensation/springing, the riding should be absolutely perfect. Shouldn't it? 

 

Regards,

 

Tony. 

Not forgetting the need for suitable (finescale) track then yes you would be correct, as would be the case if using Ultrascale wheels.  With Gibson wheels the ride will be acceptable but not quite as even.  In actual operation on a layout I doubt you would be able to tell the difference.  

 

You may be interested in the following videos which I prepared to compare and contrast the look and ride characteristics of Gibson v's Ultrascale wheels.  When I recently built my J7's to test assemble the etches I had designed I fitted one of them with Gibson wheels and the other with Ultrascale. 

 

 

 

Regards,

 

Frank

Edited October 3, 2020 by Chuffer Davies
spelling mistake

[Woodcock29]

4 hours ago, jwealleans said:

 

Not me, I experimented on the two we have on Grantham and like you arrived at 12mm as a working compromise.

 

5 hours ago, Tony Wright said:

Has anyone out there made a K's C1 work with correct-sized bogie wheels? 

 

Nor me either. My Ks C1, built in the mid 70s had to have 12mm Romford bogie wheels. But I got it to go around the 2ft curves I had then. It was dismantled years ago and is likely to form the basis for a future model of 3279.

Andrew

[Bulwell Hall]

44 minutes ago, Chuffer Davies said:

Not forgetting the need for suitable (finescale) track then yes you would be correct, as would be the case if using Ultrascale wheels.  With Gibson wheels the ride will be acceptable but not quite as even.  In actual operation on a layout I doubt you would be able to tell the difference.  

 

You may be interested in the following videos which I prepared to compare and contrast the look and ride characteristics of Gibson v's Ultrascale wheels.  When I recently built my J7's to test assemble the etches I had designed I fitted one of them with Gibson wheels and the other with Ultrascale. 

 

 

 

Regards,

 

Frank

 

Well that tells you everything that you need to know - Ultrascales every time!

 

Gerry

 

[St Enodoc]

7 hours ago, t-b-g said:

 

You make a point there Frank that I hadn't really thought about until you mentioned it.

 

If you have a wheel that is less than concentric, in a rigid frame the loco body will indeed all move around.

 

With compensation or springing the axle can move up and down but the movement of the body is minimised or may even by removed altogether.

 

Looking back at the past, one of the leading figures promoting compensation and also a leading supplier of plastic centred wheels for many years was the late great Mike Sharman. A super engineer with great skill.

 

Perhaps his development of both the wheels and compensation went hand in hand and using the wheels in rigid mechanisms was not what he intended.

 

Edit to add that all the Gibson and Maygib kits were designed to be built sprung too. A pattern begins to emerge!

 

 

In the early days of compensation it was promoted for getting trains to run on less than perfect track (remember the old "matchstick" demo?). Obviously the converse is equally true.

[grob1234]

No contest between Gibson and Ultrascale there Frank! Super smooth on the Ultras!

[Jol Wilkinson]

8 hours ago, Bulwell Hall said:

 

Well that tells you everything that you need to know - Ultrascales every time!

 

Gerry

 

If they are available in a diameter, number of spokes and crankpin location that suits. Diameter and one of the other two is usually okay but for those that model the LNWR (and probably many other  pre-group railways) there is often nothing available from Ultrascale. That's why Sharman Wheels were usually the answer, even if it took some work to make them run acceptably.

 

Compensation (or springing/CSBs) provides other benefits, such as improved pickup and better adhesion, particularly for smaller, lighter locos.

[dibateg]

I used to dislike the appearance of the Romford/Markits wheel nuts, so would fill them to a smooth finish. Once painted, looks a whole lot better. The filler could be dug out of the nut if necessary to get the wheels off. Can't remember what filler though.... soft enough to dig out I guess....

You can just about see on Tony's phot of my O4 - sorry I only have handful of my 4mm stuff digitally recorded.

 

How many locos do you need to do that on Tony?

[t-b-g]

I have seen too much good running with sprung/compensation and rigid mechanisms and also too much poor running to believe anybody who says one is "better" than the other.

 

It is very much down to the workmanship put in, rather than the type of mechanism.

 

When using Markits/Romfords I do the same as Tony Geary (too many Tonys around here!). Covering the axle nut either with plasticine or a small disc of paper that can be easily removed if necessary but makes a big difference in appearance.

 

Not doing it just seems a bit lazy to me but I see it often.

 

[Tony Wright]

15 minutes ago, dibateg said:

I used to dislike the appearance of the Romford/Markits wheel nuts, so would fill them to a smooth finish. Once painted, looks a whole lot better. The filler could be dug out of the nut if necessary to get the wheels off. Can't remember what filler though.... soft enough to dig out I guess....

You can just about see on Tony's phot of my O4 - sorry I only have handful of my 4mm stuff digitally recorded.

 

How many locos do you need to do that on Tony?

Good morning Tony,

 

'How many locos do you need to do that on Tony?'

 

About 175! I'm too lazy to do all those..................

 

Regards,

 

Tony. 

 

 

 

[Tony Wright]

13 minutes ago, t-b-g said:

I have seen too much good running with sprung/compensation and rigid mechanisms and also too much poor running to believe anybody who says one is "better" than the other.

 

It is very much down to the workmanship put in, rather than the type of mechanism.

 

When using Markits/Romfords I do the same as Tony Geary (too many Tonys around here!). Covering the axle nut either with plasticine or a small disc of paper that can be easily removed if necessary but makes a big difference in appearance.

 

Not doing it just seems a bit lazy to me but I see it often.

 

Like you Tony, I've tried compensation (never springing) and come to the conclusion that (given my 'skills') I can get just as good running (if not better) with rigid chassis, and they take less time to erect.

 

Given your light-bulb moment, it does require wheelsets which are true-round and concentric, even if indolence means I don't fill the centre nuts.

 

It also requires very well-made and well-laid trackwork, on top of very-level baseboards. I'm lucky in those respects. 

 

Regards,

 

Tony. 

Edited October 4, 2020 by Tony Wright
to add something

[Tony Wright]

10 hours ago, Daniel W said:

Thanks for the advice chaps. I've not 'viced' the Hudswell Clarke ones yet, so i shall try using the needle files instead. Tony, it may be that only the smaller patterns of Markit wheels are affected by these issues. I'd imagine the diameter of the average wheel you are using is signifcantly greater than the ones used on industrials.

Good morning Daniel,

 

Could be. The smallest diameter drivers I use are 18mm.

 

Regards,

 

Tony. 

[t-b-g]

20 minutes ago, Tony Wright said:

Like you Tony, I've tried compensation (never springing) and come to the conclusion that (given my 'skills') I can get just as good running (if not better) with rigid chassis, and they take less time to erect.

 

Given your light-bulb moment, it does require wheelsets which are true-round and concentric, even if indolence means I don't fill the centre nuts.

 

It also requires very well-made and well-laid trackwork, on top of very-level baseboards. I'm lucky in those respects. 

 

Regards,

 

Tony. 

 

I still don't think that any of the wheels available to modellers tick every box. Each has its good and bad points.

 

A wheel that looks like an Ultrascale but fits like a Markits and has a price like a Gibson would do very nicely. A 4mm version of the O Gauge Slaters wheel would do the trick apart from perhaps on the price and I for one would worry about that least of all.

 

Until that time (very likely never), we all make our choices and work around the problems in our chosen ways.

[dibateg]

We three should go out for a pint or two sometime..

 

'Who's round is it?'

 

'Tony's'

 

'eh?'

[cctransuk]

1 hour ago, t-b-g said:

Covering the axle nut either with plasticine or a small disc of paper that can be easily removed if necessary but makes a big difference in appearance.

 

I have recently taken to using the blackened etched covers that can be purchased; they are held in place by the  screwed in crankpin.

 

The appearance of the axle end is much improved.

 

John Isherwood.

[t-b-g]

2 minutes ago, cctransuk said:

 

I have recently taken to using the blackened etched covers that can be purchased; they are held in place by the  screwed in crankpin.

 

The appearance of the axle end is much improved.

 

John Isherwood.

 

I did look at those but decided that I would have to loosen the crankpin in the wheel each time they needed to come off and that they would have to be installed early in the construction, before the crankpins and rods were fitted. I prefer to cover the nut when all is finished and working.

 

The etched covers, good as they look, also make the coupling rods stand out further from the wheel, reducing clearances.

 

Using the wider Markits wheels in EM already means that some clearances are tricky, so I prefer not to reduce them any more.

 

On "Valour", the coupling rods and connecting rods are parallel (just as they were in real life, a bonus of working in the wider gauges) and I have had to make a recessed front crankpin to give me a few thou clearance (again, as they did in real life!). Even a half etched extra thickness behind the crankpin would have caused a major re-think.

 

In some applications, like an 0-6-0 with no outside cylinders and no clearance issues, I would certainly consider them.

 

 

 

 

[CUTLER2579]

51 minutes ago, dibateg said:

We three should go out for a pint or two sometime..

 

'Who's round is it?'

 

'Tony's'

 

'eh?'

Mr Geary,

It's obviously Tony's round,even I can see that.  

[Michael Edge]

31 minutes ago, t-b-g said:

 

I did look at those but decided that I would have to loosen the crankpin in the wheel each time they needed to come off and that they would have to be installed early in the construction, before the crankpins and rods were fitted. I prefer to cover the nut when all is finished and working.

 

The etched covers, good as they look, also make the coupling rods stand out further from the wheel, reducing clearances.

 

Using the wider Markits wheels in EM already means that some clearances are tricky, so I prefer not to reduce them any more.

 

On "Valour", the coupling rods and connecting rods are parallel (just as they were in real life, a bonus of working in the wider gauges) and I have had to make a recessed front crankpin to give me a few thou clearance (again, as they did in real life!). Even a half etched extra thickness behind the crankpin would have caused a major re-think.

 

In some applications, like an 0-6-0 with no outside cylinders and no clearance issues, I would certainly consider them.

 

 

 

 

I've had to take these etched covers off some EM locos, as you say the Markits wheels are overscale width at 18.2mm gauge.