Making a Start - The Peak District Midland / Monsal Dale pre 1903

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Wed Oct 02, 2019 9:46 am

Thanks for posting Dave .... I will give it some thought.

Sorry for not introducing myself last Sunday ... I had intended to have a chat about gubbins under the footplate and then completely forgot :? ... must be getting old :shock:

Maybe next time :thumb
Tim Lee

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Wed Oct 02, 2019 10:32 am

davebradwell wrote:The axle must be able to rock so the top of the motor will move sideways. The transverse slot is the obvious way of allowing this while taking the torque reaction.
DaveB
Scangen011.jpg
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Diagram pinched from kit instructions - it is appropriate for any motor/gearbox or indeed gearbox only. I might think again where a drive-stretcher gives a long overhang.


I am trying to get my head around the diagram .... maybe being a bit thick :D

What I am trying to understand is how up or down movement is prevented such that nothing is transferred down on to the driven axle? .... am I right in presuming that the tab pretty much pinched by the ptfe tubing such that next to no rotation can occur and so any force generated is all but horizontal?
Tim Lee

davebradwell
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby davebradwell » Wed Oct 02, 2019 2:19 pm

The motor and gearbox go up and down with the axle which passes through the rigid gearbox frame. The tab is a close fit in the slot but can slide (fit on tab can be adjusted with soldering iron) so gearbox goes up and down and can rotate sideways as springs require but cannot rock fore and aft about axle . The torque reaction is horizontal on the tab so spring action is not influenced. Motor and gearbox are suspended by axle and tab on top of gearbox provides support. The yoke is just an inverted U shaped piece of scrap fret soldered inside the frames and obviously, the taller the better. It's very easy to make.

Does this help?

DaveB

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Wed Oct 02, 2019 2:53 pm

Yep .... was almost there - but got it now. Thanks :thumb
Tim Lee

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Will L
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Will L » Wed Oct 02, 2019 5:11 pm

I've never thought of doing it like that, but it looks like it will have all the right characteristics. The tab will need to be directly over the axle which, as you say Dave, may need a little extra thought using a drivestreatcher in some configurations.

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Wed Oct 02, 2019 5:29 pm

Well, I have now fabricated my Crankpin jig 'a la Goodwillie'. A bit of a fiddle but it seems to work alright. I have set it for the first wheel so that the wheel drops freely down over the axle rod and the crankpin seats freely into the crankpin bush all with its own weight. The nickel spring holds the slide in position fine. The second wheel didn't drop freely so I nudged the crankpin with some pliers and then it sat down just like the first. .... so it seems to work as it should :) the proof of course will be when there is no binding on the rods ;)

Crankpin Jig - 2.jpg

Crankpin Jig - 4.jpg

Crankpin Jig - 5.jpg

Crankpin Jig - 6.jpg
Tim Lee

Julian Roberts
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Julian Roberts » Wed Oct 02, 2019 6:27 pm

Tim your photos seem to me to show a really nice looking well and carefully made loco coming along, terrific at any level and especially for a first one!

I very much doubt I can bring any wisdom that Allan Dave and Will haven't already. But here's just a couple of thoughts I have from reading your blog. Please excuse me if they are unnecessary. Regarding how you will fit the motor inside the body, you will probably want to detach the chassis from the body multiple times in the future, after it is completed, for many aspects of maintenance, even if it does work utterly perfectly straight off - which with the best will in the world is quite unlikely! So I suggest, don't condemn yourself to having to disassemble parts of the body from each other to get the chassis off. Second, brass bodies are very light so I expect you'll need to add some weight - which may affect the first thought.

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Wed Oct 02, 2019 7:17 pm

Thanks Julian ... helpful.

I have been musing about this and discussed it with Will at Scaleforum.

I think there is enough wriggle room to mean that I can have the body as a single piece once the cab detailing etc is complete ... which is good.

We also discussed weight ... having the motor in the boiler limits a little the scope for weight at the front end, but there will still be a good 5 - 7mm available at the smoke box door. I can line the tanks with lead so long as I leave room to remove the battery and the battery itself adds weight. The coal bunker provides scope for more and I am planning to use a pewter loco crew from Andrew Stadden. Then their are the various white metal fittings ... sand boxes/dome/chimney etc. Hopefully I will have enough .... as I plan a 1:100 slope for the layout. :?
Tim Lee

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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby allanferguson » Wed Oct 02, 2019 10:58 pm

I think a wire torque reaction link is ideal but it needs to be fairly long so that any movement of the axle is as near as possible straight up and down. This can cause problems fitting it round everything else. I do feel that a very little movement can give the jerk needed to start a slightly sticky mechanism (not that we have any sticky mechanisms, do we?)

Allan F

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Thu Oct 03, 2019 6:47 am

My understanding of the long wire torsion link (may be wrong here :? ) is that if mounted horizontally and fixed loosely through 'working clearance' holes with no slop (like with axle bearings) the up and down movement of the springs will be accommodated but any rotational movement will be resisted in a horizontal direction - the mounting of the link I assume needs to be as near as possible central over the driven axle?. There seems to be no difference here between the performance of the wire link and Dave's tab (though the rigid nature of the tab structure it seems to me designs out any tendency of the long wire to deform under compression allowing a gnats whisker of rotation?). Where the long wire appears less well engineered than the tab is on the rotational side to side movement caused by one wheel rising independently of the other - assuming the mounting to the gearbox passes through both wings of the box. Such movement it seems to me would be resisted by the wires resistance to twisting. However, in reality I suspect that the 'working clearance' of the wire mounting holes will allow all the movement the system requires - ie in practice it works? ;) .
Tim Lee

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Thu Oct 03, 2019 1:31 pm

Does anyone know of a free source of contour maps similar to the NLS Maps ? ... I am starting to think about the landscape profile for Monsal Dale.
Tim Lee

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grovenor-2685
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby grovenor-2685 » Thu Oct 03, 2019 1:53 pm

Why not use the NLS maps?
This one has the contours https://maps.nls.uk/geo/explore/#zoom=16&lat=53.2454&lon=-1.7397&layers=193&b=1
Rgds

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Thu Oct 03, 2019 2:45 pm

grovenor-2685 wrote:Why not use the NLS maps?
This one has the contours https://maps.nls.uk/geo/explore/#zoom=16&lat=53.2454&lon=-1.7397&layers=193&b=1
Rgds

Thanks Kieth,

I suppose I was kind of hoping for slightly more detail. 100ft contour lines leave much to guess work. The OS do 5m lines and I remember maps in the past with with an imperial equivalent.

I could go to the OS but I balk a little at £80 + VAT :shock:
Tim Lee

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grovenor-2685
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby grovenor-2685 » Thu Oct 03, 2019 3:21 pm

This gets down to 25m, I don't see any better on the NLS list.
https://maps.nls.uk/geo/explore/#zoom=16&lat=53.2454&lon=-1.7397&layers=10&b=1

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Thu Oct 03, 2019 3:31 pm

grovenor-2685 wrote:This gets down to 25m, I don't see any better on the NLS list.
https://maps.nls.uk/geo/explore/#zoom=16&lat=53.2454&lon=-1.7397&layers=10&b=1

Hi kieth,

Thanks ... why did I miss that one :? ... 25 ft I think - so 7m contour lines :thumb
Tim Lee

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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby grovenor-2685 » Thu Oct 03, 2019 5:09 pm

Yes, sorry it would be feet :)

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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby davebradwell » Thu Oct 03, 2019 6:06 pm

I have settled on the above tab system for locating gearboxes as it ticks all the boxes and doesn't introduce any compromises. Frame and tab are rigid structures - this is one of the advantages. Yes, ideally the tab should be directly above the axle but I have used the system on many Roadrunner+ gearboxes in L configuration and there has been no sign of trouble with the slightly offset vertical tab. I had said I wouldn't take it any further than this from optimum position as in such cases you can support the end of the motor to take the reaction because it's a long way from the axle - don"t forget to allow for axle rock.

I don't fancy having a wobbly motor mount to help the motor - better to get a smooth running unit and use a controller that controls the speed properly.

DaveB

Surely you've found the old-maps site?

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Thu Oct 03, 2019 6:44 pm

yep .... all good :thumb
Tim Lee

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PeteT
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby PeteT » Thu Oct 03, 2019 6:47 pm

Would a new (well, current) 1:25k OS map not have 10m contours, and be about £10? A few will have altered but presumably the general lie of the land is still the same?

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Thu Oct 03, 2019 8:06 pm

PeteT wrote:Would a new (well, current) 1:25k OS map not have 10m contours, and be about £10? A few will have altered but presumably the general lie of the land is still the same?


Yep ... but 7.6m is better and free and already digital .... I can pull it into cad and overlay onto the 1897 25" map.

The 5m OS map is a digitised download in DWG format and matches exactly the area I am modelling - but £76 + VAT is I'm afraid having a laugh as far as I am concerned :D
Tim Lee

Julian Roberts
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Julian Roberts » Thu Oct 03, 2019 9:31 pm

Just checking Tim whether you know about layout planning functions in Templot? You can download maps and design your layout around them. (If I understand correctly. :| )
http://85a.co.uk/forum/view_topic.php?i ... forum_id=1

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Thu Oct 03, 2019 10:52 pm

Yep ... all good. :thumb
Tim Lee

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Will L
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Will L » Fri Oct 04, 2019 12:15 am

It is rather nice to have a sensible discussion about torque reaction links which accepts the basic logic behind them without somebody suggesting methods which fail to recognise the need for the link to resist the turning motion from the motor horizontally. However the fact that those who suggest such things seem to get away without (reporting) any unexpected performance issues is probably indicative that the true value of a properly located link only becomes really apparent when the chassis or the load its pulling puts up significant resistance.

I have though more about Dave's methods and I'm happy that having the tab and slot not directly above the axle should be perfectly workable so long as you don't take it to far. I think this design fits well in the large loco's/big boilers which are the staple of the Bradwell range. However my own production tends to feature small boiler-ed prototypes where the space above the gearbox/motor can be at a premium, which perhaps explains why I tend to favour wire links lower in the chassis. Given what Tim is trying to do, he is likely to have this problem.

Also as I tend to want full cab detail and to fully hid the drive train in the firebox/boiler, I do tend to find that threading the chassis plus motor into the body can get a bit difficult. When this gets really complicated it can lead to a desire to be able to connect the link up after the chassis is fitted into the body, which is a feature of the the two Buckjumpers that I had at Scaleforum. Both have a link that pass under the cab floor and which can be hooked up from underneath.
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Martin Wynne
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Martin Wynne » Fri Oct 04, 2019 2:26 am

Le Corbusier wrote:The 5m OS map is a digitised download in DWG format and matches exactly the area I am modelling - but £76 + VAT is I'm afraid having a laugh as far as I am concerned :D

Hi Tim,

Contours at 5m spacing (16ft-5in) are available FREE on the modern OS Maps so-called "Standard" base map:

http://osmaps.ordnancesurvey.co.uk/53.24479,-1.73681,18

What's more that map is geo-referenced and available at global zoom level up to 18.

Which means that Templot (also FREE) can make the screenshot for you, and automatically scale the map to the correct size for P4 to act as a background image to your track plan.

And then if you wish it can print it out full size for the model, or at any reduced scale you wish. You can also copy and paste the image to and fro between Templot and any graphics editor to increase the contrast, change the colour saturation, etc., to suit your printer.

Or instead of printing it, create a full-size PDF file which you can take to your local digital copyshop for printing on wide format roll paper.

(At least Templot can do all that if you are on Windows. Sorry, I don't know about on a Mac because I haven't got one to try.)

It's quite easy:

First set P4. Don't forget to do this FIRST.

Then:

Image

1. enter a name for the map, anything you like.

2. copy and paste the URL link from the browser address bar.

3. click the button.

Follow the instructions and the result will be:

Image

Image

Of course being a modern map of Monsal Dale there are no tracks on there. Image

But you can do exactly the same thing to get the historic 25" maps from the NLS (also FREE for non-commercial use):

Image

Templot will also display a map transparent, so you could superimpose the modern contour map over the historic map:

Image

If you use exactly the same global co-ordinates in the URL, the maps should in theory coincide exactly. But because the old County Series 25" map had to be resampled by the NLS from a different projection (even pre-dating the OS grid system of 1936), some distortion is inevitable. In the above case I shifted the modern map a fraction to the east to get a perfect alignment at the railway bridge.

n.b. Displaying a map transparent slows the screen panning and zooming performance significantly. But you can switch the different maps on and off as required while working over them.

Templot now includes functions to convert screenshots to a lower-contrast and/or negative image for easier-to-see track planning over it:

Image

Image

That appears to be a 1:11 turnout, with an 18ft switch.

p.s. This appears to be the 999th post in this topic!

cheers,

Martin.
40 years developing Templot. And counting ...

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Le Corbusier
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Re: Making a Start - The Peak District Midland / Monsal Dale pre 1903

Postby Le Corbusier » Fri Oct 04, 2019 6:18 am

Will L wrote: However my own production tends to feature small boiler-ed prototypes where the space above the gearbox/motor can be at a premium, which perhaps explains why I tend to favour wire links lower in the chassis. Given what Tim is trying to do, he is likely to have this problem.


Will .... interestingly I have now abandoned the idea of threading the motor into the boiler - although I can make it work on its own the battery has proved too large to allow passage - so it is back to positioning it vertical as hard against the back head as I can reasonably manage. This slings the gearbox low between the frames within the ashpan area. So still trying to decide on the torsion link positioning ... because the box is now mounted so low there may be room for the tab method - but I shall use whichever proves easiest to fit in my case as both methods are tried and tested ;)
Tim Lee


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