Chuffer's Workbench

[Michael Edge]

I always try to fit Gibson wheels only once, sometimes the driven axle gets fitted twice if I have to remove the gearbox for painting. I would be wary of using any solvents near plastic wheels. Some types/sizes of Gibson wheels are a bit looser on the axles than others (4844P is one of these) and in this case I usually knurl the axle ends a little by rolling a coarse file on them.

[5050]

It's only a very light wipe and I've never noticed any degredation of the wheels over the several (many!) years I've been doing this.  The lighter fuel evaporates very quickly in any case.  When I'm building chassis I tend to fit and remove wheels/axles quite frequently to check clearances, smoothness of running, painting frames etc.

[Chuffer Davies]

Time for a progress update on the J2 with work having proceeded on the test build of the cab and smokebox.  Another case of one step forward and one step backward.

 

The step backward related to problems with forming the cab.  There were two problem areas:  the cut outs in the front sheet of the cab to clear the splashers and the boxes over the frames was the wrong shape and I have had to add some brass to obtain a closer fit.  The bigger issue was I'd had miscalculated the length of the cab side sheet wrapper by a horrendous 4mm.  Eventually I realised I hadn't added the 2mm each side caused by the curve in the footplate.  I made an attempt to splice in an extra 4mm in the middle of the roof but its less than perfect and so once I have a new set of etches I will build a new replacement cab, but it'll do for now.

  The smokebox has been far more successful and will not require any adjustment.  I have therefore gone ahead and added the piston valve tail rod castings.  The tail rods are a major characteristic of the J2's and it is these along with the main piston tail rods that distinguish the J2 from a J1.

Before soldering the wrapper to the smoke box's frame I filled it with lead.  Whilst this is a relatively small space it has provided a useful 60gms of additional ballast.

The last etched components to fit will be the combined firebox and boiler.  The component parts are now sat on my workbench awaiting rolling and assembly over the next few days.

 

Thanks for reading,

Frank

Edited March 31, 2022 by Chuffer Davies
Re-instating Pictures

[1466]

9 hours ago, Chuffer Davies said:

Time for a progress update on the J2 with work having proceeded on the test build of the cab and smokebox.  Another case of one step forward and one step backward.

The step backward related to problems with forming the cab.  There were two problem areas:  the cut outs in the front sheet of the cab to clear the splashers and the boxes over the frames was the wrong shape and I have had to add some brass to obtain a closer fit.  The bigger issue was I'd had miscalculated the length of the cab side sheet wrapper by a horrendous 4mm.  Eventually I realised I hadn't added the 2mm each side caused by the curve in the footplate.  I made an attempt to splice in an extra 4mm in the middle of the roof but its less than perfect and so once I have a new set of etches I will build a new replacement cab, but it'll do for now.

  The smokebox has been far more successful and will not require any adjustment.  I have therefore gone ahead and added the piston valve tail rod castings.  The tail rods are a major characteristic of the J2's and it is these along with the main piston tail rods that distinguish the J2 from a J1.

Before soldering the wrapper to the smoke box's frame I filled it with lead.  Whilst this is a relatively small space it has provided a useful 60gms of additional ballast.

The last etched components to fit will be the combined firebox and boiler.  The component parts are now sat on my workbench awaiting rolling and assembly over the next few days.

 

Thanks for reading,

Frank

Clever design and workmanship , Frank and it is coming along nicely . Thank you , too , for explaining your “mistake” which I call experience . It is so helpful to us lesser modellers to learn from your craftsmanship and example ; particularly that it is possible to rectify them and move on .
Ken 

[Chuffer Davies]

2 hours ago, 1466 said:

Clever design and workmanship , Frank and it is coming along nicely . Thank you , too , for explaining your “mistake” which I call experience . It is so helpful to us lesser modellers to learn from your craftsmanship and example ; particularly that it is possible to rectify them and move on .
Ken 

Hi Ken, 

for those wondering about venturing into the world of bespoke etching I think it is best to look at this as an aid to scratch building and recognise that if mistakes have been made it is going to be cheaper to fix them on the go rather than order a replacement set of etches.   Each time a new set of etches (brass for the superstructure and n/silver for the chassis) are ordered you are looking at a 3 figure cost.

 

In my case I intend to offer my artwork to John at LRM and so I will have to correct the errors in my artwork and take the financial hit of ordering new photo tools and test etches from the suppliers.  In which case I have the luxury of a new set of etched components from which I can build a replacement cab.  
 

I don’t think I’m alone in saying that modellers who can deliver good results fall into two schools.  The best are able to get things right first time, but modellers like me only achieve good results because we have the patience to keep correcting our mistakes multiple times until we eventually get it right.  
 

Happy modelling,

Frank

[richbrummitt]

6 hours ago, Chuffer Davies said:

I don’t think I’m alone in saying that modellers who can deliver good results fall into two schools.  The best are able to get things right first time, but modellers like me only achieve good results because we have the patience to keep correcting our mistakes multiple times until we eventually get it right.  

 

I believe anyone in the first category is accomplished in particular aspects of their modelling - as you clearly are. It is worth remembering that many people do not share the trials and mistakes to reach anything that does get shared. We can learn from our own mistakes and those of others. Those that fall into your first category have almost certainly been in the second for quite some time. 

[Chuffer Davies]

This week has once again been a mixture of successes and disappointments concerning progress with the test build of the J2.  Last week I built the combined boiler and smokebox assembly.    Unfortunately once this was bolted between the cab and smoke box it revealed a 1mm mis-alignment between the fronts of the valve chest and the sand boxes.  The alignment of these items is very obvious when examining prototype photographs and so I will need to adjust the length of  the boiler's wrapper in the CAD artwork.  This means that there will be a hiatus whilst I rework the CAD design and send it off to obtain the replacement etches.  I can use this time to build the LRM tender for my J2 but its frustrating none the less.

 

 

Another item that is bugging me is the amount of unfilled space under the boiler where the valve gear should be. 

 

The J2 had piston valves rather than slide valves increasing the pitch of the boiler by 3 or so inches.  I am now wrestling with my conscience with regards whether or not to design some cosmetic valve gear with which to fill this void.  There are several issues not the least is the fact that there are no archived reference drawings (as far as I can determine) of the J2's valve gear.  I obtained a frame drawing from the NRM but the only details provided in this were the pitch of the cylinders, the position of the crank arm at the far end of the reach rod, and the brake gear.    I have drawings showing the valve gear arrangement for the Q2 (another Ivatt design around the same time as the J2) but the position of the reach rod's crank arm is very different indicating that there must be material differences in their respective valve gear.  This is how I solutioned it for the Q2:

 

 You will note that the position of the valve gear on the Q2 is such that it slots into a housing at the rear of the smoke box.  I would therefore need to build a new smokebox for my J2 which means given all the other corrections I now need to make the only element of the version 1 test build that will survive will be footplate at this rate. 

 

Such is life, I'll let you know what I decide.

 

Happy modelling.

Frank

Edited March 31, 2022 by Chuffer Davies
Re-instating Pictures

[Michael Edge]

The frustration of etching errors is greatly lessened if you do more test etches, I have a more or less continuous progression of them in various materials and thicknesses. If I find an error I just add the corrected part to the next test, keeping track of what and where all these modifications are. From what you have said you are doing the whole thing again each time you find a mistake.

[Chuffer Davies]

Hi Michael,

I think the difference is that you are developing kits for your own business and you no doubt have several models at various stages of development at any given point in time making your approach the most efficient.    In my case my primary aim is to create etches as a scratch building aid for myself and so I only have one loco under development at any one time.  

[Michael Edge]

I do exactly the same but probably more of it, it's not the same as kit development although sometimes they overlap - I never stick to one job at at a time anyway...

[Rail-Online]

Frank,

It is a very complicated loco so it is not surprising there are little 'tweaks' that artwork-wise mean complete revisions.  I think the void below the boiler just has to be filled with cosmetic valve gear and your derivation of it will be the closest we will ever know to how it really was. You undoubtably know more about what it was likely to look like than anyone else alive today!  John at LRM can always reflect the extra cost of development with a slightly higher kit price - especially as it includes all this wonderful detail

Tony

[Jol Wilkinson]

6 hours ago, Rail-Online said:

Frank,

It is a very complicated loco so it is not surprising there are little 'tweaks' that artwork-wise mean complete revisions.  I think the void below the boiler just has to be filled with cosmetic valve gear and your derivation of it will be the closest we will ever know to how it really was. You undoubtably know more about what it was likely to look like than anyone else alive today!  John at LRM can always reflect the extra cost of development with a slightly higher kit price - especially as it includes all this wonderful detail

Tony

Tony,

 

etched kits sell in small numbers, so even increasing the kit price to realistically reflect higher development costs sometimes means that it takes quite a while to recover the costs.

 

With two exceptions, my designs for LRM were done with only two test etches. The exceptions were one loco where I had similar issues to those experienced by Frank and were exacerbated by the lack of a decent GA drawing. With a fundamental dimensional error (as was the case on that model,) it is sometimes not possible to complete a test build far enough to see what else needs correcting. 

 

Jol

 

 

[Chuffer Davies]

Its been a long time in the doing but at last I have completed the test build of my first J2.  The origins for this model being a set of etches I have designed myself using the Isinglass drawing as my start point.  Those who have been following this saga may recall that my build came to an abrupt stop late last year when, having assembled the boiler and firebox, I determined that this component was nearly 1mm too long and as a result the front of the valve chest did not align with the front of the sandboxes - this alignment being a critical feature of the J2s.  It was therefore back to the drawing board, the CAD artwork was updated/corrected and new metal commissioned from PPD Ltd.  The replacement etches arrived just before Christmas but in the mean time I turned my attention to building its tender from the London Road Models' GN (Horseshoe) tender kit.

 

When the build came to a halt last year I was in two minds whether to start again from scratch or whether to persevere with what I'd already achieved.  The arguments for starting again were that I'd already decided to make some key enhancements to the design (cosmetic valve gear) which could not be retrofitted to the existing model.  In addition the model needed a replacement cab because the original wrapper was too short and my attempts to splice in the missing metal were unsatisfactory.   The arguments for pressing on were that I'd already invested considerable time and effort into the model and other than the cab and the boiler issues the rest of the model was looking quite good (to my way of thinking at least) and both these issues could be resolved by using parts from the new replacement etches.

 

In the end I decided to make the most of what I'd already built and so a new cab and boiler were constructed using components from the new etches and I've scratch built some very basic valve gear components as an attempt to disguise the void that would otherwise exist at the back of the smokebox saddle.  Having recovered from the earlier set backs I have been able to move forward once more and have now reached the point where construction is complete and its ready for painting.

 

        

I need at least one more J2 for Clayton and so I intend to build a 2nd model using the enhanced design incorporating the cosmetic valve gear. 

 

Thanks for reading.

 

Frank    

 

Edited March 31, 2022 by Chuffer Davies
Re-instating Pictures

[grob1234]

Well done Frank, looks delightful.

 

Glad you managed to overcome past setbacks and get this one complete (construction wise at least!)

[Chas Levin]

Lovely looking loco and like Tom, may I offer congratulations on getting past the difficulties?

 

It's tough sometimes when things don't work out as expected to maintain positivity and it can seem very tempting to give up, but like you I always make myself persevere and the satisfaction of having done so is great: hope you felt that on this job.

 

Doubly so when they're your own etches: that's something I haven't got anywhere near trying yet, still working with others' kits!

[Rail-Online]

Looks lovely Frank and certainly captures the details of the J2 well to my eyes.

 

Well done.

 

Will we get a video of running trials of it with 40 wagons behind the tender?

 

Cheers Tony

[Chuffer Davies]

1 hour ago, Rail-Online said:

Looks lovely Frank and certainly captures the details of the J2 well to my eyes.

 

Well done.

 

Will we get a video of running trials of it with 40 wagons behind the tender?

 

Cheers Tony

Thank you for your comments.

I’ll certainly provide a video in due course but it won’t be for several months because of the delay whilst it gets painted.  I’ve not even test run it in the brass this time because I can’t install the drive shaft in the tender until the frames have been painted.  It runs okay as a push-a-long so I can be confident I’ll be able to get it running okay when it is finally assembled.  

You may not have spotted that I haven’t actually performed a haulage test on the J1 as yet. I’m confident that the J1 and J2 will both perform adequately given my success with the J7’s but perhaps I’ll check out the J1 next time I’m at the club.
Regards,

Frank

[DA]

Hi Frank

 

I’m making steady progress with your chassis kit for the Bachmann C1. I’ve got to point of a free running rolling chassis. There’s a surprising amount of space under the body to fit a P4 chassis, certainly no need to thin the inside of the splashers until they are wafer thin, the only adjustment I had to make was a little material of the back of the middle footsteps. 

 

The next step is getting power to the motor and then the brakes, which look entertaining. 

[Chuffer Davies]

Hi,

thank you for posting your progress so far.  I hope you will find the brake gear okay to build, you may regret to discover its an area I particularly enjoy modelling in detail and so there are plenty of components to be soldered up.  You may choose to simplify it but if you go the whole hog I think you will enjoy seeing the end result.

Please keep on posting progress.

Frank

[Chuffer Davies]

Deleted duplicate entry

Edited March 4, 2022 by Chuffer Davies
Duplicate

[Chuffer Davies]

As usual, although I attempt to progress projects one at a time, I have had to interrupt loco building. 

 

We have all but ironed out the last few 'bugs' (a software term) effecting the operation of our Clayton layout.  At the heart of the operation of the layout and its three associated control panels, are around 70 custom designed micro processor boards.  The processor boards have been designed and programmed by Bill Wyatt-Millington (chairman of the EMGS) an electronics engineer by profession.  I helped to specify how these boards would interface with the devices under the layout and the switches and LEDs of the control panel. What all the switches do, and how the devices under the layout and in the panels are triggered (point motors, servos, LEDs etc.) is all controlled by rules encoded in an Excel spreadsheet.

 

There is still one major element missing from the fiddle yard, this being a turntable with 11 locomotive storage roads.  We cannot finally sign off the electronics until we have an operational turntable and so I have interrupted my locomotive construction to build one. Various commercial solutions were considered, but as well as the associated cost of many of these the main problem I kept coming up against was the depth that these structures occupied under the base board.  Our base boards are 4 inches deep and generally the commercial mechanisms would stick out below the board and therefore be very vulnerable to damage.  I kept coming back to an old unmade Airfix turntable kit that I have had in a cupboard for thirty or more years.  The design is remarkably shallow requiring a well depth of only 6.5mm, but even if I could get it to turn freely enough I would still need a mechanism to drive it.  A recent visit to my good friend Karl Crowther turned up a possible solution from the MERG.  Their solution uses a stepper motor and 1/250 gearbox from RS Components having a total depth of only 2 inches below the base board's surface.

 

I have therefore been working on an upgrade to the Airfix turntable in the hope that I could make it operational.  I ordered four small ball races (8mm o/d x 2.5mm width) to replace the carrying wheels on the outriggers, and I also ordered a slightly larger ball race (15mm o/d x 6mm i/d) to be the central bearing to take the majority of the weight of the table plus locomotive.  The turntable was modified to accept these various ball bearings and a new central brass axle was turned up on the lathe and stuck over the original plastic axle on the underside of the table.

 

 

 

Initial experimentation revealed that the turntable turned freely when unloaded but as soon as a locomotive was placed on top the plastic out riggers flexed too much causing the underside of the table to scrape on the walkway forming part of the base ring of the table.  An attempt to remove material from the underside of the table to achieve the required clearances was unsuccessful.  Today I solved the problem by reinforcing the outrigger supports with nickel silver strengtheners, and this appears to have cured the problem.  The table now turns freely even with my heaviest locomotive (currently a Q2) atop it.

 

(Reinforced Outrigger)

 

The last modification required has been to install a split brass ring on the underside of the table within its central pivot to facilitate the transfer of track current to the rails on top.  Two plunger pickups will be installed in the base of the table to rub against this split ring.

 

(Split ring for transfer of track current.  N.B. lower outriggers prior to addition of n/silver strengthening)

 

(Sprung plungers for transfer of track current)

 

Bill will construct the MERG control board (supplied as a kit of parts) and will then code the software changes required to interface his micro processor boards with the table's control board.  In the mean time I will install the turntable on the layout along with its associated storage tracks and will wire it all in in preparation for Bill's changes.

 

I've really enjoyed this  project as its been something a bit different for a change. I've painted the table black as there is no point in going to town on it because its in the fiddle yard.  I've also not bothered adding the finer detail because it will be vulnerable to damage and is not required anyway.  I have to say that I have gained considerable respect for the original designers of this Airfix kit as it is actually mechanically designed to very tight tolerances.  If it were not for the amount of flex in the plastic this would have been a fairly straight forward conversion.  

 

Thanks for reading,

 

Frank

[Chas Levin]

Hello Frank, nice job!

 

Can I ask though, assuming I've understood correctly about those two plunger pickups transferring current to the two semi-circular brass pieces beneath the deck, what happens if the 'table reaches a point in its revolution where each pickup touches both plates, even if on momentarily? Wouldn't that cause a short circuit? Or does it not revolve to that point?

[Chuffer Davies]

1 minute ago, Chas Levin said:

Hello Frank, nice job!

 

Can I ask though, assuming I've understood correctly about those two plunger pickups transferring current to the two semi-circular brass pieces beneath the deck, what happens if the 'table reaches a point in its revolution where each pickup touches both plates, even if on momentarily? Wouldn't that cause a short circuit? Or does it not revolve to that point?

Hi Chas, 

you are absolutely correct in your deductions. Probably not an issue if we were only using analogue control, but Clayton is a hybrid layout which also provides a DCC option for loco control.  Shorting out the track feed whilst DCC is selected would cause the command unit to drop the feed for the entire zone, not a good idea!
 To mitigate against this we will interrupt the track power to the table whilst it is rotating by means of a relay.  This has the added advantage that there is no risk of accidentally moving a locomotive either on the table itself or on one of its storage tracks until it has come to rest in-line with the selected track.  
Frank

[Chas Levin]

On 31/05/2022 at 10:56, Chuffer Davies said:

Hi Chas, 

you are absolutely correct in your deductions. Probably not an issue if we were only using analogue control, but Clayton is a hybrid layout which also provides a DCC option for loco control.  Shorting out the track feed whilst DCC is selected would cause the command unit to drop the feed for the entire zone, not a good idea!
 To mitigate against this we will interrupt the track power to the table whilst it is rotating by means of a relay.  This has the added advantage that there is no risk of accidentally moving a locomotive either on the table itself or on one of its storage tracks until it has come to rest in-line with the selected track.  
Frank

Of course! I'd like to say I did think of simply cutting the current in an automated way... but I didn't!! Maybe next time...🙂

[Chuffer Davies]

A few days ago I visited Karl Crowther in Lancashire to collect three models that had been through Ian Rathbone's paint shop.  Karl had kindly offered to collect them from Ian at Expo EM (Bracknell) and bring them back North so that I could just nip across from Yorkshire to get my hands on them. 

 

Two of the models are for Clayton (EM) and the third is my Bucket List - P4 model based on Bachmann's excellent GNR Atlantic.  These have now all been through final assembly and with the exception of fire irons and lamps are now complete. On a previous visit to Karl's he had demonstrated a couple of DCC models in which he had installed 'Stay Alive' (SA) components.  This is the electronic equivalent to having a flywheel.  Being suitably impressed I have decided that I will install SA as standard in all models from now on and so two of these models now have it, but the third (the J52) does not because I hadn't left enough room in the model for the components to be installed.  Some DCC Decoders already have the SA circuitry included and just require a capacitor to be connected to the common positive and negative 'rails' on the decoder's circuit board.  In my case I have standardised on the small Zimo MX617 decoder and that does not have SA circuitry as standard and therefore requires an additional control unit.  I have started using the Youchoos SACC16 LifeLink which is a tiny controller that sits between the Zimo Decoder and the Capacitor.

 

I have shown these models before but to avoid the need for readers to look back through this blog I will summarise each loco in turn.

 

J52: This is a model I designed in CAD early in 2021.  This is not a model I have designed with the intention of becoming a commercially available kit on the basis that my etch only provides for one specific sub class of J52 of which only a dozen or so were built.  Without significant modification the etches are only suitable for EM and P4 gauges whereas most modellers wish to build OO gauge models.

 

The model has a split frame chassis and is powered by a High Level 13/20 coreless motor and 48/1 Roadrunner Compact+ gear box.  It is virtually silent in operation.  It is loaded with as much lead ballast as I could find room for and will easily pull 30+ wagons up the 1/50 gradient on Clayton.

 

 

J2:  This is another of my own CAD designed models (the tender is an LRM kit).  It is my intention to offer the etches to John Redrupp at London Road Models so that he has the option to add it to his range of kits.

 

The J2 was evolved from Ivatt's J1 class being fitted with piston valves rather than slide valves.  The tail rods associated with the piston valves and main cylinders resulted in the J2's footplate being extended at the front by several inches (compared to that of the J1) and the rear of the footplate was also extended to provide a larger cab offering more protection to the crew.  The wheel centres, wheel diameter, and valve gear were in the main identical to that of the J1 except for the linkage to the piston valves.   The piston valves were (by necessity) located above rather than between the cylinders, this resulted in the boiler's centre line being raised by a couple of inches when compared to the J1.

 

The model follows my now standard motor in tender (m-i-t) design allowing me to pack the entire smokebox, boiler and fire box assembly with lead ballast.  Current collection is by the American system utilising the draw bar to pass current from the loco's chassis through to the motor.  The usual High Level coreless motor and bespoke H/L RRC+ gearbox have been used along with a Zimo MX617 chip and Youchoos SA circuitry.  The H/L spur gears to the drive shaft in the tender generate a slight whirring sound (compared to the J52) but this is drowned out by the sound of the train's wheels in operation.

 

 

Bachmann C1 Atlantic:  I designed the chassis for this a couple of years ago and have sold several sets of etches to other modellers since then.  The etches allow a chassis to be built in either EM or P4 gauge, and any of the three possible tender chassis options are catered for. I have previously built an EM version so that I can run it for my own enjoyment on Clayton, but I fancied attempting building a model in P4 to see if I had the skills to build something that would run successfully on P4.

 

The model uses the American system for current collection.  The motor is a Portescap 16/16 unit (an early quiet one thankfully) installed in the firebox.  It has my standard Zimo Decoder and SA circuitry and runs happily along my 18" (straight) test track.  I have been invited to run it on Geoff Tiffany's Dewsbury layout and so I will arrange a visit once the current Covid peak has subsided.

 

 

Thanks for reading.

 

Frank

Edited July 4, 2022 by Chuffer Davies
Incorrect year.