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  • RMweb Gold

Hi Ian, great views. It's all coming together now. That shot with the two locos passing immediately brought to mind some of those early lineside photos of the period.

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  • RMweb Gold

Hi Mikkel I've just been looking at your Farthing thread what lovely modelling

John

Thanks John, although from a much easier point of departure than Ian - and you 2mm modellers in general - who have to start from scratch with many things, not least for pregrouping days. 

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A few weeks ago, virginmedia announced that they were no longer going to provide a web hosting service for their customers.  A result was that my personal website documenting and showcasing the methods used to build Modbury was lost.

 

I have now found a new home for my website, and purchased a domain to point to it.  The website can be found here : www.modbury2fs.co.uk

 

Ian

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  • 3 weeks later...

I have just added another entry to my RMweb blog detailing a bit more progress on my 3rd loco.  This will be another saddle tank, this time an outside framed "Buffalo" or 1076 class.  The blog entry details construction of the chassis : http://www.rmweb.co.uk/community/index.php?/blog/1009/entry-18062-gwr-buffalo-1076-class-in-2fs-part-2/

 

Ian

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  • 2 months later...

Not really progress on Modbury itself, but i have finally got around to putting the brake gear on my Metro tank (spurred on by the photo of it on the rear cover of the latest 2mm Magazine - she really does look like she has something missing down below).  Another driver for actually getting her finished is this weekends AGM!

 

So to the model...

 

As well as the brake gear, there were a few other things lacking below the footplate : The front guard irons (the rear ones being pretty well hidden behind the cab steps so I wasn't going to bother with those), and the wheel balance weights are also noticeable by their absence.

 

The front guard irons are simply some thin nickel silver waste from etches, soldered up and bent to shape before super gluing in place on the chassis.  As usual, these were made over size then trimmed back to enable them to be held while the soldering operation was performed.

 

The wheel balance weights are simply arcs of 0.010" plasticard again super glued in place on the wheels.

 

The brakes and hangers were filed up from 0.010" nickel silver (again scrap etch).  The hole for the cross-chassis operating rod was drilled first then the hanger and brake block filed out around it.  Once I was happy with one hanger/brake block, it was sweated onto more scrap and used as a template to file out the next.  This pair were the used as a template for the third and then the three were sweated on again and used to file out the last.  By doing this I was confident that they would all be the same size and all of the holes would be in the same place on the hanger.  Annoyingly I managed to drill the hole for the cross-chassis rod at the wrong end of the hanger and didn't notice until all 4 had been separated and was left with having to drill new holes in very narrow brake hangers to rectify the problem!

 

post-12089-0-42915700-1476386346_thumb.jpg

Filing out the 3rd or 4th hanger from scrap etch

 

Once I had 4 brake hangers (with holes at the right ends!) I then built up a brake sub-assembly that could be attached in the recess I'd milled in the chassis block for it.  The sub-assembly has a back bone of thin PCB onto which the cross shafts were soldered at driving wheel distance apart, for strength these shafts are 0.45mm brass rod.  The hangers were soldered in place on the cross-chassis rods and the sub-assembly trial fitted and adjusted until I was happy.  The operating rods (that run outside the wheels on this loco) were then drilled and fitted to the cross-chassis rods.  These operating rods being flat were from more scrap etch.

 

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Brake sub-assembly. To avoid shorting a Rizla has been super glued where the assembly will marry up to the chassis block.  Both sides of the PCB have been gapped (along with the cross-rods).

 

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Once painted, the sub-assembly has been secured in the recess milled along the underside of the chassis with double-sided tape.  Hopefully it won't fall off, and will be easy to remove if I ever need to get at the screw that holds the gearbox onto the chassis block.

 

Thanks for looking.

 

Ian

 

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  • RMweb Gold

Very nice Ian, looking at the two photos it does make a difference. Does that complete the loco roster for Modbury or do you have others planned?

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Very nice Ian, looking at the two photos it does make a difference. Does that complete the loco roster for Modbury or do you have others planned?

 

Thank you Mikkel.

 

The loco roster for Modbury has really only just begun!  When I did the artwork for the numberplates I also did some for a Buffalo, Armstrong Goods, Dean Goods, Duke (with early straight nameplate).  I think I also did plates for a 517 too although whether I could actually manage to build one with an open cab is debatable as they're a bit smaller than the Metro!

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  • 2 months later...
  • RMweb Gold

Excellent Ian, all that work with the track and point rodding is really paying off now.  The Peco platform edging looks pretty good, better than the 4mm I think.

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Just discovered this thread!  (I thought it was only on Ian's blog.)

 

Wow.

 

I don't put very much on the blog these days, most of my activities are documented both here and when I get time to do the HTML on my website www.modbury2fs.co.uk (the website is fully hand-crafted so takes time to update or add to).

 

Ian

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Although I have elected to use memory wire to activate the points and signals on Modbury, I have decided that it will be virtually impossible to fit the actuators for the 3 arms on the two signals on the embankment at the up end of the station.  The Down Home has been fitted with a memory wire actuator from the start, but the 2 actuators needed for the Up Advanced Starter/Up Shunt Ahead arms on the other post will be almost impossible to fit in the restricted space below the embankment.

 

Therefore I have decided to utilise servos for the arms on both posts on the embankment, simply because I can house the control electronics away from the embankment.

 

Some years ago I experimented with a servo to control a point on my now abandoned P4 layout, this made use of the little control board available from Mindsets Online.  Because I only need to control 3 servos, I've decided to make use of these servo controllers for the signals on Modbury.  They are not particularly clever, so no bounce or anything like that is feasible but the endpoints of the servo throw can be limited with resistors.  They are relatively inexpensive though at a little over £4 each, and are pretty small (about an inch square). 

 

With this in mind, I've soldered up a couple of little circuits on some veroboard to 1) provide a 5 volt supply for the servo (which is fed into the control board), and 2) to set the servo limits using a pair of 10K preset potentiometers which are switched in/out with an SPDT relay (one pot sets one end point and the other sets the other end point).

 

The complete set up can be seen below :

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Left to Right : Towerpro SG90 Servo, Servo Controller mounted on top of relay (relay control wires going upwards to PP3 battery snap, and preset potentiometers can be seen at the bottom of the circuit), 5 volt regulator circuit (because the servos will be fed off the main 13.7 volt DC supply that is used for the electromagnetic uncouplers, etc).

 

Finally, a short video to illustrate the operation.  The 5 volt regulator circuit is connected directly to the 13.7 volt supply that I use for everything on the layout, and the PP3 battery represents the 13.7 volt supply that is switched on/off at the control panel bank of switches for signals/points.

https://youtu.be/fizsGjOFz-0

 

The next phase will be to construct the servo mount and associated connection to replace the existing memory wire actuator that currently operates the Down Home before I complete and fit the Up signals.

 

Ian

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4 quids per channel? Seems a bit pricey to me but if you only plan to use 3 servos then it probably makes sense to stick with what you are used to.

 

Presets will probably be less of a faff than plugging in a PC or other external box to set the limits of travel. Ideally you need to be able to twiddle the presets while you have visual contact with the signal arm... preferably with the whole thing upright so that gravity is working in the way that it will when you are operating.

 

Regards, Andy

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4 quids per channel? Seems a bit pricey to me but if you only plan to use 3 servos then it probably makes sense to stick with what you are used to.

 

Presets will probably be less of a faff than plugging in a PC or other external box to set the limits of travel. Ideally you need to be able to twiddle the presets while you have visual contact with the signal arm... preferably with the whole thing upright so that gravity is working in the way that it will when you are operating.

 

Regards, Andy

 

Andy,

I agree that it would work out pricey if I was going to do the whole layout that way, but for me one of the main drivers is the ease with setting the travel end points - I no longer have a PC and don't know whether MERG for example do their set up software for the MAC, if not then I would have needed to buy their set up board in addition to the servo control board.  I looked at other makes of servo controller but they seem very expensive, and they too tend to need a separate set up plug-in device.  A further driver for me is that I simply need to swap out the existing memory wire circuitry under the baseboard for the SPDT relay, all of the control panel wiring will be untouched (including the circuitry that powers the track sections in rear/in advance of the relevant signals).

 

As for the signal arm movement, my under-board gubbins includes stops to limit the arm travel.  The existing memory wire actuators generate more throw than needed in each direction, and springy wire allows all of that throw to move the arm, then bend to accommodate the excess throw.  I intend to replicate that movement with the servo throw, adjusting so that I have just a little more than is actually needed, and taking up the excess with spring/z bends in the wire.

 

Regards,

Ian

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There is a Python based ServoSet utility for setting up Merg Servo4 modules, but it requires a USB to 9-pin Serial lead. I tried this for a friend who only has a Mac laptop, but we did not know enough about Macs to configure the lead as a device, or whatever the equivalent of a COM Port is is the Mac world.

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  • 3 weeks later...

Over the last few days, as well as trying to progress the Down platform I have also been trying to make progress on the Main Station Building that will be sited on said platform.

 

This building will be based on the one that used to be at Bovey Tracey in Devon.  The building is still in existence as a heritage centre, so while on a holiday to Devon a couple of years ago I took a few photographs, to supplement various historical ones that can be found on the internet and in the various books I have.  Using those various photos I drew up a set of elevation plans in QCAD :

post-12089-0-77763600-1486124826_thumb.jpg

 

Using my plans, I began to cut out the walls for the structure from 0.040" plasticard taking into account that I will be cladding the whole building in 0.020" embossed stone plasticard, so end walls for example are cut out some 0.040" narrower than on the drawing to accommodate the cladding that will be applied to the front and rear walls.  

 

The window and door openings were scribed onto the sheet with a sharp scalpel/dividers, and a dampened (grubby) finger rubbed over the scribed lines to highlight them.  The openings were then carefully cut and filed to size - where more than one window of the same size appears in an elevation, the dividers were set to the size of the largest one and any slightly undersized ones were carefully filed until they matched.

post-12089-0-33040900-1486124820_thumb.jpg

 

I have now cut out all of the main walls, but before I being fitting them together I need to reduce the thickness around the window and door openings to about 0.020" so that when the windows are fitted behind them they will not be set too far back into the wall.  To do this I intend to mill a rebate around each reveal before the cladding begins.

post-12089-0-73441500-1486124824_thumb.jpg

 

Ian

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