What's on your S Scale Workbench?

[WayneKennerley]

Sn42 Loco Shed based on the one used by Rhodesia Railways at Mpopoma, Bulawayo. 

 

IMG_20200911_132625 by Wayne, on Flickr

 

119962257_2766761106928518_814357662080437259_n by Wayne, on Flickr

[Timber]

Throughout the past year I have been wrestling with building a Sharp Stewart Albion class.  This locos appeared in many different forms across many companies.  The challenge I have had is trying to find reliable prototype information.  I have four drawings including a works GA but they all conflict.  Even the works GA is different to early photos.

 

That said I now have what I think is a boiler and accessories that is (in my opinion) the best interpretation of the drawings and photos.  A defining feature of the boiler is the brass band that sits across the mid section of the boiler.  I have made this a detachable feature so that it can be printed in brass or painted in metalic paint rather than trying to mask or paint this on after the loco has been painted.

 

Sharing as a couple of members have expressed an interest.  I have to smooth the boiler and then it should be ready for fitting to the footplate.

[ScottW]

21 hours ago, Timber said:

A defining feature of the boiler is the brass band that sits across the mid section of the boiler.  I have made this a detachable feature so that it can be printed in brass or painted in metalic paint rather than trying to mask or paint this on after the loco has been painted.

 

My preference would be to print the boiler band in brass rather than paint it. I think painting plastic to represent metal never looks as good as the real thing.

 

[Regularity]

If you have a lathe, I would recommend turning the firebox front ring to the correct profile, slitting it at the bottom, and then opening it out to the correct reverse curve.

It's what I did for John Coulter when he built his Cambrian 2-4-0T body mostly in styrene.

http://www.s-scale.org.uk/gallery11.htm

[Timber]

help please

 

on the society website there is a wheel profile.....is there a more detailed spec ....something similar to the one below that the Manchester Model railway society produce for EM?

 

 

[flubrush]

The wheel profile used on all the Society wheels (not the Gibson wheels) are based on a prototype drawing that Trevor Nunn sourced.    New Tech Tools made the form tools to match this drawing and one of these form tools has been used to generate the driving wheel tyres,  and my wagon wheel tyres.  Slaters made their own form tool from the same drawing for their wagon wheels.   I'll see if I still have the drawing around,  or it might have gone up to Paul Greene in amongst all the Parts paperwork.

 

I actual;ly did that drawing on the website many years ago and it is a bit basic. :-)  You can also see it on the ScaleOne32 site as well - ask Mr. Dunkley about that. :-)

 

Jim.

Edited December 15, 2020 by flubrush

[Timber]

Jim

 

There is nothing wrong with the drawing.....it seems to have served the society well over the years..very clear and unambiguos.

 

Thanks for the info.....i will take a look for a drawing too......the HMRS may have something.

[Timber]

I fitted a Hornby motor to a loco chassis today.  First time I had tried a Hornby motor.  I think it is a X7218, they are available on ebay for a tenner.   Only been testing it a couple of hours but it is powerful and quiet.....the High Level Gearbox needed a few changes to fit but it did the job.  No flywheel but the motor is big enought to be a flywheel in iteslf.....

 

Anyone any experience with these motors?

[flubrush]

Your wheels look very good on the loco.

 

Jim.

[Timber]

Thank you Jim,  I cannot take the credit on the leading wheel.  This is a 12 spoke Markit wheel (prototype is an 11 spoke), I need to make one. 

 

My coach stock should be 10 spoke but I found the Alan Gibson wheels touched the chairs.  Whereas suprisingly the standard Markit tyre depth is less.  I am going to 3D print some coach wheels, similar to your wagon wheels, just not got round to it yet....so I asked Markit nicely and he set his 17mm 12 spoke wheel on a 30.7mm axle.   I have plenty of spares if anyone is interested.  I was going to send a couple to our Parts officer so he is also aware, 

 

Plus Markit made a load of S Scale 2mm pin point axles that he has in stock.  They came up 30.7mm rather than 30.5 as Alan Gibson are just fine.  Apparently Alan Gibson pin points are 60 degree whereas Markits are 66 degree.  the Markit pin point bearing is slightly slimmer so the difference is made up there.

 

 

[flubrush]

2 hours ago, Timber said:

My coach stock should be 10 spoke but I found the Alan Gibson wheels touched the chairs.  Whereas suprisingly the standard Markit tyre depth is less.  I am going to 3D print some coach wheels, similar to your wagon wheels, just not got round to it yet....so I asked Markit nicely and he set his 17mm 12 spoke wheel on a 30.7mm axle.   I have plenty of spares if anyone is interested.  I was going to send a couple to our Parts officer so he is also aware, 

 

Plus Markit made a load of S Scale 2mm pin point axles that he has in stock.  They came up 30.7mm rather than 30.5 as Alan Gibson are just fine.  Apparently Alan Gibson pin points are 60 degree whereas Markits are 66 degree.  the Markit pin point bearing is slightly slimmer so the difference is made up there.

 

The plain disk coach wheels in Parts have original Alan Gibson tyres,  so to the SSMRS standard and won't hit the chairs.    If you need that size you can punch the centres out.  I have also done some specials for other members using the complete wheels and CNC cutting the disks to produce 3' 7" spoked wheels.

 

Paul Greene might want to know about the axles.  I believe that they are difficult to manufacture and producers tend to quote minimum order quantities which could keep the SSMRS satisfied for the rest of this century. :-)   I specified parallel journals for the axles on my wagon wheels and got minimum order quantities in the hundreds.  It was also a look ahead to sprung W irons where parallel journals are preferred.  Parallel journals have a bit more rolling resistance than well adjusted pin point bearings but I doubt if any UK S scale layouts could run train lengths where the difference in roll resistance might be a problem. :-)

 

Jim.

[ScottW]

The Drewry shunter pictured in a previous post ran on re-profiled Markit wheels. The problem with using 4mm scale wheels is you will inevitably get more spokes than you require.

 

I have also re-profiled S Scale Gibson wheels:

 

 

The wheel on the left is the original Gibson wheel whilst the one on the right has been re-profiled. From the photograph there doesn't appear to be much of a difference but in the flesh you can see a big improvement.

 

Scott

Edited December 21, 2020 by ScottW

[Lacathedrale]

Is there a standard set of dimensional adjustments? My understanding is that there's about 0.3mm off the back but not clear on the flange changes? Obviously not a problem to measure from first princinples but I'm just curious

 

My workbench has sat somewhat forlorn but the gears are whirring again - I need to figure out everything below the solebar for my trio of wagons. Annoyingly, stuck away from all my modelling supplies due to the most recent lockdown!

 

 

[Regularity]

Technically, you either conform to the stated (prototype-derived) standards, or you are not standard.

In practice, some extra depth on the flange is not a big deal, provided that it doesn’t give you any problems with either running, or the looks.

As with all “rules” (which is what standards are), feel free to break them, but only if you fully understand the rules and the reasoning behind them, and the consequences of breaking them, like bumpy running and loss of interchangeability.

[Lacathedrale]

Sorry, to clarify - I meant, a standard set of adjustments you apply to an off-the-shelf Gibson wheel to amend it to the SSMRS/scale standard specifically

[flubrush]

5 hours ago, Lacathedrale said:

Sorry, to clarify - I meant, a standard set of adjustments you apply to an off-the-shelf Gibson wheel to amend it to the SSMRS/scale standard specifically

 

William,

 

When I checked the Alan Gibson Workshop wheels with our form tool,  the flange width was OK and the flange depth was 0.024".  or 0.006" too large.   So taking 0.006" off these wheels' flanges would pretty well get them to SSMRS standards.  If you do the adjustment with a form tool,   that would probably guarantee the standard.   You would have to be careful using the form tool so that you don't loosen the tyre on the plastic centre.   And don't let the form tool start cutting the tyre face since the forces will almost definitely mess up the wheel.

 

A few members actually prefer the AGW wheels since the deeper flange helps to keep things on the rails if you have tight curves on your layout.

 

Jim.

Edited December 23, 2020 by flubrush

[Regularity]

Jim,

 

It also depends if they are AGW wheels intended for S, or their 00/EM wheels. (The P4 wheels aren’t wide enough over the tyre.)  I am not sure if William is talking about the S gauge wheels, which have a different profile to the EM wheels.

[ScottW]

On 21/12/2020 at 19:48, ScottW said:

The Drewry shunter pictured in a previous post ran on re-profiled Markit wheels. The problem with using 4mm scale wheels is you will inevitably get more spokes than you require.

 

I have also re-profiled S Scale Gibson wheels:

 

 

The wheel on the left is the original Gibson wheel whilst the one on the right has been re-profiled. From the photograph there doesn't appear to be much of a difference but in the flesh you can see a big improvement.

 

Scott

 

I measured the width of these two wheels, which are Gibson S Scale EM profile tender wheels, one measures 0.090" and the other 0.088". Both are just a few thou over the recomended standard. When I reprofiled them I set the tool so that it just touched the back of the tyre which ensured that the wheels can be set to the correct B2B and any extra width would be at the front of the wheel, which in this case was fairly negligable.

 

Scott

[Lacathedrale]

Ah, lovely. I guess for me it is simply a case of getting started, so while a parallel conversation on the S-scale list on groups.io is ongoing about carriage construction, I wondered if this might be fertile ground to discuss a brass chassis scratchbuilding. I'm tracing an LCDR A-class 0-4-4T drawing from the SECR society which seems fairly dimensionally accurate. This is what has resulted:

 

As you can see, my plan is to use a 1420 motor with a Roadrunner+ gearbox, and high level hornblocks in the frames. Somewhat experimentally I'm also going with dead rail, RC-control. As it stands I can fit a fair sized set of batteries in the tanks - 50mm x 18mm x 8mm. In this case, I've hedged my bets for a single 300mAh battery in one tank, with a voltage booster in the other tank.  My thoughts are to use 3/8" x 1/16" brass strip for the frames.

 

I have some other questions if that's OK? Bear in mind this is unlikely to be without error and fault, so reliability and ease of construction much more important than elegance

 

• Should both driving wheels be sprung? Or one fixed, and one sprung? I am assuming yes, with a springy  wire to bear on the gearbox/motor to stop it moving around.
• What's the most straightforward arrangement for the trailing bogie? Thread/nuts and a spring? Should the wheels be sprung/pivot?
• I was thinking of using countersunk screws to hold solid frame stretchers at the front, and strip at the rear to help with weight balance. Other than holes for the wheels, gearbox and a support for the bogie, do I need to bear anything else in mind?
• While I get ready to sketch the extra components - generally speaking, how wide should the footplate be? and the distance between the outsides of the frames?

 

I figure if I get the chassis with the driving wheels and gearbox/motor built, I can at least prove the principles

 

[ScottW]

15 hours ago, flubrush said:

 

William,

 

When I checked the Alan Gibson Workshop wheels with our form tool,  the flange width was OK and the flange depth was 0.024".  or 0.006" too large.   So taking 0.006" off these wheels' flanges would pretty well get them to SSMRS standards.  If you do the adjustment with a form tool,   that would probably guarantee the standard.   You would have to be careful using the form tool so that you don't loosen the tyre on the plastic centre.   And don't let the form tool start cutting the tyre face since the forces will almost definitely mess up the wheel.

 

A few members actually prefer the AGW wheels since the deeper flange helps to keep things on the rails if you have tight curves on your layout.

 

Jim.

 

I can confirm everything Jim has said. When you profile a wheel you need to hold the wheel on a mandrel so that it is being secured solely by the steel tyre.

 

Here are pictures of the mandrel I made when re-profiling the Gibson wheels:

 

 

 

 

The wheel is secured by pressing the tyre between the front face of the mandrel and the brass washer. As Jim said, don't let the tool cut into the tyre face as the forces involved will over come those securing the wheel. This will more than likely result in the plastic spokes coming into contact with the brass screws and damaging them. Ask me how I know

 

I would also recommend using a cutting fluid other wise the finish will be rougher than a badgers a**e.

 

Scott

 

[Lacathedrale]

Thank you Scott!  I've used a mandrel to turn down wooden wheel blanks on my unimat, so very similar to that, albeit much more 'serious'

 

Having done a bit more digging I think the A-class needs some further tweaking. The prototype uses 5'6" wheels. Assuming I'm using 10 thou brass for the splashers, the model would only have 40 thou between the outer flange diameter and the underside of the splasher.  The high-level hornblocks by default have 60 thou of upward deflection, so we have a shortfall of 20 thou. The society has 5'7" wheels and rims available off the shelf - which gives only 20 thou clearance and a shortfall of 40 thou.

 

The solution would appear to be, to use 5'7" wheels and fix the front (driven) axle, springing the other driving axle.

 

Thoughts?

[ScottW]

1 hour ago, Lacathedrale said:

Ah, lovely. I guess for me it is simply a case of getting started, so while a parallel conversation on the S-scale list on groups.io is ongoing about carriage construction, I wondered if this might be fertile ground to discuss a brass chassis scratchbuilding. I'm tracing an LCDR A-class 0-4-4T drawing from the SECR society which seems fairly dimensionally accurate. This is what has resulted:

 

As you can see, my plan is to use a 1420 motor with a Roadrunner+ gearbox, and high level hornblocks in the frames. Somewhat experimentally I'm also going with dead rail, RC-control. As it stands I can fit a fair sized set of batteries in the tanks - 50mm x 18mm x 8mm. In this case, I've hedged my bets for a single 300mAh battery in one tank, with a voltage booster in the other tank.  My thoughts are to use 3/8" x 1/16" brass strip for the frames.

 

I have some other questions if that's OK? Bear in mind this is unlikely to be without error and fault, so reliability and ease of construction much more important than elegance

 

• Should both driving wheels be sprung? Or one fixed, and one sprung? I am assuming yes, with a springy  wire to bear on the gearbox/motor to stop it moving around.
• What's the most straightforward arrangement for the trailing bogie? Thread/nuts and a spring? Should the wheels be sprung/pivot?
• I was thinking of using countersunk screws to hold solid frame stretchers at the front, and strip at the rear to help with weight balance. Other than holes for the wheels, gearbox and a support for the bogie, do I need to bear anything else in mind?
• While I get ready to sketch the extra components - generally speaking, how wide should the footplate be? and the distance between the outsides of the frames?

 

I figure if I get the chassis with the driving wheels and gearbox/motor built, I can at least prove the principles

 

 

35 minutes ago, Lacathedrale said:

Thank you Scott!  I've used a mandrel to turn down wooden wheel blanks on my unimat, so very similar to that, albeit much more 'serious'

 

Having done a bit more digging I think the A-class needs some further tweaking. The prototype uses 5'6" wheels. Assuming I'm using 10 thou brass for the splashers, the model would only have 40 thou between the outer flange diameter and the underside of the splasher.  The high-level hornblocks by default have 60 thou of upward deflection, so we have a shortfall of 20 thou. The society has 5'7" wheels and rims available off the shelf - which gives only 20 thou clearance and a shortfall of 40 thou.

 

The solution would appear to be, to use 5'7" wheels and fix the front (driven) axle, springing the other driving axle.

 

Thoughts?

 

Would these questions be better placed in

Sorry if I sound pedantic but it would then leave this thread for you to show us the fruits of your labour.

[ianb3174]

2 hours ago, Lacathedrale said:

Somewhat experimentally I'm also going with dead rail, RC-control

Again you appear to be on the same page as me. Though I know very little so far about RC. I have got a Deltang controller built from a kit and some receivers. Managed to get it working on a spare N gauge chassis but could not get it to work on anything else. 

 

[Regularity]

4 hours ago, Lacathedrale said:

My thoughts are to use 3/8" x 1/16" brass strip for the frames.

Really? 18 thou is about scale, and a lot easier to saw, especially with two pieces soldered back-to-back.

I also prefer nickel silver to brass wherever possible.

[Regularity]

Re wheels, springing, etc...

 

Firstly, the quoted diameter is the maximum with new tyres: reprofiling could bring them down to 3” less. Simply make your wheels about 1” less than nominal in diameter, and problem solved.

Secondly, if you need lots of vertical movement, say more than ½mm either way, then you need to seriously revisit your baseboard and track construction methods.

If you are going to use BPRC, consider getting a lower voltage motor, say 4.5V or 3V, and then you won’t need to mess around with buck converters, etc.

 

Springing or beam compensation is up to you, but I would advise against a fixed axle (except for 0-4-0) as at some point, the whole movement will transmit to the body. Simplest way is “twin beams” over the drivers, with a pivot midway between the bearings on each side, with the bogie pivot providing the third point. The bogie itself would have each side able to pivot freely so that the wheel sets can adapt to the track, with side-play if you need it - you won’t need much - and if you are so inclined, some side control springing.

 

For an 0-6-0, it “twin beam” compensation applied to the axle bearings looks like thus, although a rod resting on the rear of the front axle would work just as well, and be easier for a 2-4-0, etc. (Motor/gearbox omitted from rear axle for clarity.)