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

Help and advice for those starting in, or converting to P4 standards. A place to share modelling as a beginner in P4.
CornCrake
Posts: 48
Joined: Sat Dec 05, 2015 2:03 pm

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

Postby CornCrake » Fri Oct 05, 2018 5:58 pm

Hi TIm,
You might find this post interesting as I am sure you will eventually want to add more coaches to your Monsal Dale empire:-
http://www.rmweb.co.uk/community/index.php?/topic/81902-completing-the-4mm-ner-6-wheel-coach/page-1

Steve

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Sat Oct 06, 2018 4:17 pm

RobM wrote:Tim, I've cut glazing bars for windows at .5mm including arched windows so I see no reason why you could not cut at .75mm. If you want me to experiment on my cutter I will do so if you could email me a dxf file. I can PM you my email address if you want to go down that route.
Rob


Thanks Rob ... thats very kind .... yes, please PM me.
Tim Lee

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Sun Oct 07, 2018 2:14 pm

So .... I thought I would load a couple of pics of progress so far on my first scratch build wagon ... I say scratch build but of course there are multiple elements pilfered from other sources - but at least the wagon body is primarily constructed from styrene sheet ;)

The wagon is the ubiquitous MR D299 based upon an original drawing from the Midland Railway Study centre.

D299 trial Scratch build - 1.jpg
D299 trial Scratch build - 2.jpg


Obviously the wagon is not finished yet .... but a steep learning curve so far ... and much to improve on.

Notes/criticisms to self so far :-

1.) Mark and lightly scribe boarding with dividers to keep boards parallel and level ... I drew on the boards and then scribed to the pencil line which has resulted in wonky boarding.

2.) Make sure that the sole bars are the correct width for W irons (to avoid cut and shut of irons and the resultant visible splay). Also slightly over space the wheel centres to allow brakes to fit without having to offset bend the gear (the wrong way as I needed to gain sufficient tolerance) ... which looks a little odd :?

3.) Ensure W irons project far enough below sole bar to avoid filing down axle boxes to fit ... also lock axle boxes over springs correctly (or use spring axle box combo instead).

4.) Place inner 'V' hanger in front of brake gear instead of on the wrong side .... duh!

5.) Ensure that the headstock projects a tad beyond the sole bars instead of stopping flush.

6.) More practice required folding up the brake lever guard/housing/thingy as only approx at the moment.

7.) Bending of the lever itself needs more subtlety as the bends are a little over done.

8.) The brake gear is Bill Bedford's and needs the lower eyes on the shoes removing.

9.) Need to be more sparing with the MEK as it has effected the styrene surface in places.

10.) Hinge to the door strap I think will be fine simply formed around the wire ... no need to include the wire. Perhaps fix some cut off rod once formed ... still need the hinge plate which is missing on this trial.

11.) I have produced the curve to the base of the strapping by stretching and curving as suggested by Guy. I held the end pressed to the mat with a finger and then used the tip of the scalpel to stretch/curve ... it has worked reasonably ... it will be interesting to see what a silhouette cutter can achieve.

12.) Need to brace across the centre of the wagon and form using hot water to avoid sides bowing in ... many wagons over time appear rather to have bowed outwards presumably because of the loads.

Having said all of the above, when viewed with the naked eye it looks remarkably convincing as is and is a very enjoyable project to undertake. The next one will be much better :thumb

Thoughts on things missed from the above list ... or alternative techniques etc etc appreciated. :D
Tim Lee

User avatar
Noel
Posts: 860
Joined: Wed Jun 23, 2010 1:04 pm

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

Postby Noel » Sun Oct 07, 2018 3:26 pm

You don't state what you use for scribing; I use a scraperboard nib in a wooden handle meant for calligraphy pen nibs, plus a steel rule. You still have to be careful that the lines are parallel and spaced correctly, but at least they are straight :). Yours don't actually look that bad to me anyway.

For a an 8T or 10T wagon [sorry, I'm not familiar with the prototype] the springs look a bit OTT. They would probably have only been 4-leaf.

In most cases the bolts went through external ironmongery, the planks, and then internal ironmongery, leaving the heads and nuts standing proud. In a few cases the internal ironmongery was not present, in which case the nuts might be recessed into the wood, but even then they still showed. Unless the wagon is to be permanently loaded the internal detail will be very visible.

Headstocks were the full width of the body normally in that era.

Le Corbusier wrote: many wagons over time appear rather to have bowed outwards presumably because of the loads.

Yes, especially those in mineral traffic.

The classic 'How to do it' in this context is Chris Crofts' article in MRJs 12-15, if you have access to them.
Noel

User avatar
RobM
Posts: 901
Joined: Sun Feb 15, 2009 4:39 pm

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

Postby RobM » Sun Oct 07, 2018 3:51 pm

Apart from your notes/self criticism a good first effort. For scribing the planks I would use a scrawker ( https://eileensemporium.com/index.php?option=com_hikashop&ctrl=product&task=show&name=plastic-cutter-scrawker&cid=1622&Itemid=189&category_pathway=1063 ) It cuts a clean 'V' without any burs.
Rob
http://www.robmilliken.co.uk
Updated December 2016

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Sun Oct 07, 2018 6:53 pm

Hi Noel ... as usual thanks for the input.

Answers to questions below.

Noel wrote:You don't state what you use for scribing; I use a scraperboard nib in a wooden handle meant for calligraphy pen nibs, plus a steel rule. You still have to be careful that the lines are parallel and spaced correctly, but at least they are straight :). Yours don't actually look that bad to me anyway.
I am using one of Eileen's Scrawkers .. still getting to grips with it and I over did it a bit this time I think.

For a an 8T or 10T wagon [sorry, I'm not familiar with the prototype] the springs look a bit OTT. They would probably have only been 4-leaf.

It is an 8T wagon ...This is the drawing for the springs ...Drawing dated 1882
D299 Springs.jpg


In most cases the bolts went through external ironmongery, the planks, and then internal ironmongery, leaving the heads and nuts standing proud. In a few cases the internal ironmongery was not present, in which case the nuts might be recessed into the wood, but even then they still showed. Unless the wagon is to be permanently loaded the internal detail will be very visible.

I have read it that the nuts are prominent on the outside of the wagon ... I haven't fitted the internal strapping yet, but there is a note on the drawing stating that they were to have countersunk heads, so I was not intending expressing them unless anyone has a suggestion as to how?

Headstocks were the full width of the body normally in that era.
Drawing of headstock I am working from..
D299 Headstock.jpg


Le Corbusier wrote: many wagons over time appear rather to have bowed outwards presumably because of the loads.

Yes, especially those in mineral traffic.

The classic 'How to do it' in this context is Chris Crofts' article in MRJs 12-15, if you have access to them.

I will look out for it ... thanks
Tim Lee

User avatar
Noel
Posts: 860
Joined: Wed Jun 23, 2010 1:04 pm

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

Postby Noel » Mon Oct 08, 2018 10:41 am

I got comment about the spring wrong - the 8T spring had more leaves than the 10T or 12/13T because the individual leaves of the 8T are thinner than those of springs with higher ratings.

Countersinking into wooden planks is quite possible, and after the bolt is tight the hole can then be filled, so nothing shows, but, so far as I know, it is not possible to countersink where there is ironwork on the inside.

I notice from the drawings that the brake lever guide is to the right of the axlebox, whereas your model shows it to the left. There are several possible reasons for the discrepancy; as I commented earlier, I don't know enough to comment further.
Noel

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Mon Oct 08, 2018 11:17 am

Noel wrote:Countersinking into wooden planks is quite possible, and after the bolt is tight the hole can then be filled, so nothing shows, but, so far as I know, it is not possible to countersink where there is ironwork on the inside.

It was this note I was referring to - I assume that because we are talking about the bolt head it could be configured with a countersunk head ... the section portion to the right hand side clearly indicates the metal strapping and no protruding bolt head, where as the nuts are highly visible. ?
D299 wagon interior.jpg


I notice from the drawings that the brake lever guide is to the right of the axlebox, whereas your model shows it to the left. There are several possible reasons for the discrepancy; as I commented earlier, I don't know enough to comment further.

I have fitted mine with the earlier Midland short brake lever as most of the prototype pictures I have show this config. - Ignore the notes which have already been answered
044_1903.jpg

Last edited by Le Corbusier on Mon Oct 08, 2018 1:06 pm, edited 1 time in total.
Tim Lee

User avatar
Guy Rixon
Posts: 525
Joined: Sun Mar 27, 2011 6:40 pm

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

Postby Guy Rixon » Mon Oct 08, 2018 12:40 pm

That's a nice-looking wagon and rather finer around the solebars than the Slaters' equivalent. Well done! Some notes follow in reference to your numbered points.

1. The 2FS people have a cunning device for scribing planks. It's a board with a guide fixed at a slope of (IIRC) 1 in 15 to the axis of the planking, against which slides a right-angled triangular piece that also has a 1 in 15 slope. Moving the triangle a known distance along the planking moves it 1/15 as far in the other axis, so distances between grooves can be set rather accurately. There's probably a picture over on the 2mm-Association site.

2. Also make sure that the solebars are to scale width. Most in kits are too thick, and the BB axleguards are already about a scale inch (shocking! :D ) over-width.

If using the BB brakes, I prefer to grind a little off the shoes to get clearance rather than tuning the wheelbase. I have a grindstone with a built-in arbour that is just the right diameter for this.

Having won clearance between wheels and shoes, I still find it difficult to fix the brake assembly in the right position to avoid binding. Hence those baseplate's I've been blathering about: they are an anti-cock-up device. I note that any end-play in the wheel bearings makes this much worse as the axle ends can move sideways in their cones.

3. If using BB "1907" axleguards, and if the bottom of your floor is level with the top of the headstocks, then you should be right for buffer height with 0.5mm packing under the axleguard units. I've done this on most of my Slaters' kits and it always works. Note that "floor level with top of headstock" probably isn't how the MR built the wagons, but nobody will be able to tell without measuring.

4. I used regularly to mess up the vertical position of the V hangers so that they didn't line up with the tumbler in the push-rod assembly. I now make up the hangers and brake shaft as a soldered sub-assembly by clamping the hangers to a scrap of wood that is as wide as the solebar (1.5 or 1.6mm depending on how I've thinned the solebars). I can then clip the hangers over the solebar and secure them with the solebar in place on the wagon.

Check your GA for the shape of the inner hanger. Earlier wagons of the MR had a vertical strap there instead of a V-hanger. D299 is probably late enough to have a V-hanger.

5. You means downwards? I thought that the full-sized headstock was 12" deep, the solebars were 10" x 5" and the bottom of the solebar aligned with the bottom of the headstock, leaving the stop of the floor about level with the top of the headstocks. But I don't have the GA, so don't treat that as gospel.

6. 51L lever-guards are easier to fold than the BB ones (sorry Bill...).

7. Folding the joggle in the lever is hard. I always end up making it too deep because my smallest pliers are a bit too wide and my tweezers don't have the grip to do the bend. There is probably a need for a bending jig ... or possibly grinding down a special set of pliers. In 2FS, there is a freehand technique using two pairs of pliers pushed towards one another; I don't know if it would work with twice the thickness of brass.

Concerning paint, I have a warning (you and others probably know this, but just in case). The colour sold as MR wagon grey in the Precision range may be the wrong colour for 1902. It's a rather blue-green shade of grey and an associate on RMweb suggests that it may represent some ex-Admiralty paint that the MR bought cheaply ... after WW1.

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Mon Oct 08, 2018 1:31 pm

Guy Rixon wrote:That's a nice-looking wagon and rather finer around the solebars than the Slaters' equivalent. Well done! Some notes follow in reference to your numbered points.

1. The 2FS people have a cunning device for scribing planks. It's a board with a guide fixed at a slope of (IIRC) 1 in 15 to the axis of the planking, against which slides a right-angled triangular piece that also has a 1 in 15 slope. Moving the triangle a known distance along the planking moves it 1/15 as far in the other axis, so distances between grooves can be set rather accurately. There's probably a picture over on the 2mm-Association site. Sounds interesting ... I will see how I go with the dividers and practice and if not happy will investigate.

2. Also make sure that the solebars are to scale width. Most in kits are too thick, and the BB axleguards are already about a scale inch (shocking! :D ) over-width. I made them from 1.5mm strip so they should be spot on for the 41/2" original. However I think reducing to 1mm (3") might be the way to go to accommodate the BB W irons. I'm loath to widen the wagon

If using the BB brakes, I prefer to grind a little off the shoes to get clearance rather than tuning the wheelbase. I have a grindstone with a built-in arbour that is just the right diameter for this. 'Just the right diam' is the critical point here... my efforts with the needle file were somewhat dodgy - It will be interesting to see how much the wheel centres will need to move and whether it is noticeable.

Having won clearance between wheels and shoes, I still find it difficult to fix the brake assembly in the right position to avoid binding. Hence those baseplate's I've been blathering about: they are an anti-cock-up device. I note that any end-play in the wheel bearings makes this much worse as the axle ends can move sideways in their cones. well worth consideration me thinks. Using the BB sprung units I also have to chop out the base of the brake etch to miss the spring wire supports.

3. If using BB "1907" axleguards, and if the bottom of your floor is level with the top of the headstocks, then you should be right for buffer height with 0.5mm packing under the axleguard units. I've done this on most of my Slaters' kits and it always works. Note that "floor level with top of headstock" probably isn't how the MR built the wagons, but nobody will be able to tell without measuring. Actually the D299 drawing I have suggests that the bottom of the floor is level with the top of both headstock and solebar

4. I used regularly to mess up the vertical position of the V hangers so that they didn't line up with the tumbler in the push-rod assembly. I now make up the hangers and brake shaft as a soldered sub-assembly by clamping the hangers to a scrap of wood that is as wide as the solebar (1.5 or 1.6mm depending on how I've thinned the solebars). I can then clip the hangers over the solebar and secure them with the solebar in place on the wagon.

Check your GA for the shape of the inner hanger. Earlier wagons of the MR had a vertical strap there instead of a V-hanger. D299 is probably late enough to have a V-hanger.

5. You means downwards? I thought that the full-sized headstock was 12" deep, the solebars were 10" x 5" and the bottom of the solebar aligned with the bottom of the headstock, leaving the stop of the floor about level with the top of the headstocks. But I don't have the GA, so don't treat that as gospel. Again the drawing I have is slightly different ... see below. What I was meaning was on both the drawing and photos I have seen they appear to project slightly outwards beyond the edge framing to the floor which is notched over them. On my model it all looks a bit carved from cream cheese at the moment.
8 TON HIGH SIDED GOODS (5 PLANK) WAGON Diagram No.299 Drawing No.550 Dated 1882-.jpg

6. 51L lever-guards are easier to fold than the BB ones (sorry Bill...). Glad you say this ... I couldn't for the life of me work out how they were meant to fold up :?

7. Folding the joggle in the lever is hard. I always end up making it too deep because my smallest pliers are a bit too wide and my tweezers don't have the grip to do the bend. There is probably a need for a bending jig ... or possibly grinding down a special set of pliers. In 2FS, there is a freehand technique using two pairs of pliers pushed towards one another; I don't know if it would work with twice the thickness of brass. I have ground down my pliers so here's hoping ;)

Concerning paint, I have a warning (you and others probably know this, but just in case). The colour sold as MR wagon grey in the Precision range may be the wrong colour for 1902. It's a rather blue-green shade of grey and an associate on RMweb suggests that it may represent some ex-Admiralty paint that the MR bought cheaply ... after WW1. I suspect i shall be using a range of shades to simulate different lengths of time in service .. but not given much thought to this at the moment.
Tim Lee

User avatar
Noel
Posts: 860
Joined: Wed Jun 23, 2010 1:04 pm

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

Postby Noel » Mon Oct 08, 2018 2:03 pm

Le Corbusier wrote:Noel wrote: Countersinking into wooden planks is quite possible, and after the bolt is tight the hole can then be filled, so nothing shows, but, so far as I know, it is not possible to countersink where there is ironwork on the inside. It was this note I was referring to - I assume that because we are talking about the bolt head it could be configured with a countersunk head ... the section portion to the right hand side clearly indicates the metal strapping and no protruding bolt head, where as the nuts are highly visible. ?


The note on the drawing in your latest post is quite clear, so I've learned something :). The probable answer is shown on the left of the drawing, a shaped head like a modern countersunk screw, which must have been matched by a similar shaped hole in the strapping.

The drawing also shows the V-hangers either side of the solebar, between the lever and the push rods. The vertical strap mounting Guy refers to was, at least on the GWR, a vertical rod inside the brake gear, however, with the top of the rod mounted to a [-shaped bracket between the solebar and the next longitudinal. In either case there would have been no V-hanger on the opposite side. Later the either-side brake was produced by duplicating the arrangement on the other side, using 4 V-hangers but no cross-shaft, but converted existing wagons often had non-standard variations, including single brake shoes. The brake lever would have been bent to clear the axlebox; the arrow actually appears to be pointing at one of the bends.

I can't help on the axleboxes; the photo shows grease boxes, the drawing specifies oil boxes. When the Midland changed I don't know.
Noel

User avatar
Noel
Posts: 860
Joined: Wed Jun 23, 2010 1:04 pm

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

Postby Noel » Mon Oct 08, 2018 2:26 pm

5. You means downwards? I thought that the full-sized headstock was 12" deep, the solebars were 10" x 5" and the bottom of the solebar aligned with the bottom of the headstock, leaving the stop of the floor about level with the top of the headstocks. But I don't have the GA, so don't treat that as gospel. Again the drawing I have is slightly different ... see below. What I was meaning was on both the drawing and photos I have seen they appear to project slightly outwards beyond the edge framing to the floor which is notched over them. On my model it all looks a bit carved from cream cheese at the moment.


According to the drawing both headstocks and solebars are 4.5" x 11". The apparent difference is because the top of the solebars is hidden by the [roughly inverted L-shaped] curb rail.

Le Corbusier wrote:Actually the D299 drawing I have suggests that the bottom of the floor is level with the top of both headstock and solebar


Agreed, the floor is laid across the top of the longitudinals, with the gaps at the end filled by a plain section of curb rail the same depth as the floor.
Noel

User avatar
Colin Parks
Posts: 575
Joined: Sun Oct 27, 2013 4:44 pm

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

Postby Colin Parks » Mon Oct 08, 2018 2:30 pm

Hello Tim,

One thing re. point 9 of your observations on the effect of MEK on styrene: use Humbrol Liquid Poly instead. (It has to be the Humbrol-branded solvent, there is another similarly named product.)

All the best,

Colin

User avatar
Guy Rixon
Posts: 525
Joined: Sun Mar 27, 2011 6:40 pm

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

Postby Guy Rixon » Mon Oct 08, 2018 5:51 pm

IMG_5901.jpg

Tool for grinding brake shoes. The greatest diameter is 10mm. Mine came from Minicraft IIRC, but there are many suppliers.

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Mon Oct 08, 2018 6:38 pm

Guy Rixon wrote:IMG_5901.jpg
Tool for grinding brake shoes. The greatest diameter is 10mm. Mine came from Minicraft IIRC, but there are many suppliers.


Aha! ..... another goody to buy :thumb
Tim Lee

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Wed Oct 10, 2018 9:36 pm

I think I have taken this trial D299 MR wagon build as far as I can for now ... having completed the strapping and any other details I can think of - though I am still pondering how to achieve the ring and chain for the door lock pins which I would like to represent.

So the next stage is the paint shop.

D299 trial ready for paint - 3.jpg
D299 trial ready for paint - 4.jpg
D299 trial ready for paint - 7.jpg
D299 trial ready for paint - 8.jpg


I have found this a very rewarding process, though how the end product compares to the Slaters or Mousa offerings of the same I can't say. Given the relatively modest scale of Monsaldale, I think I shall persevere with scratch building for the moment - as I think I can improve on this a fair bit yet ;) .

The wonky scoring of the boards gets worse every time I look at it, as it makes the whole thing look out of square in the photos :? ... particularly on the ends :shock:
Tim Lee

CornCrake
Posts: 48
Joined: Sat Dec 05, 2015 2:03 pm

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

Postby CornCrake » Thu Oct 11, 2018 3:07 pm

I see what you mean about the planking, now that you have brought it to our attention, it is hard to overcome the feeling of some weird sort of negative perspective a la Martin Escher!

Are the planks scribed both sides of one sheet, or are there two single sided sheets laminated?

As far as the underframe is concerned I noticed that http://www.brassmasters.co.uk/wagon_sub-frames.htm have just brought out some underframe etches based on a Martin Finney design, and in their instructions they refer to the John Hayes "The 4mm Coal Wagon" book, so they might be of use for your next coal wagon.

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Thu Oct 11, 2018 3:45 pm

CornCrake wrote:I see what you mean about the planking, now that you have brought it to our attention, it is hard to overcome the feeling of some weird sort of negative perspective a la Martin Escher!

Are the planks scribed both sides of one sheet, or are there two single sided sheets laminated?

Handscribed both sides ... the photo is extremely unforgiving - you don't notice so much in real life. I am going to make damn certain I get it right next time as the wagon is pretty spot on true and square.
Tim Lee

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Sun Oct 14, 2018 9:16 am

I have two completely unrelated questions which i hope someone will be able to help me with.

The first is to do with the Bill Bedford sprung W irons. The guitar wire threads through the base of the waisted bearing carrier and then is located on either side in a pilot hole in the etch. The wire is not equally straight ... some sections having a slight curvature. This means that when all the bearings are mounted the wheels are actually set at different levels. Getting all the wires to be identical seems a bit of a hopeless task. To date I have put a gentle positive camber into the wire which keeps the bearings at the top of the slot in the W irons ... this seems to work, but my reasoning tells me that this prevents the wheels from dropping should there be a local fall in the track level. Has anyone else encountered this issue?

Second completely unrelated question ... for scenic modelling, what is the best glue to use to bond together dense insulation board ( the blue building board type).

Thanks
Tim Lee

User avatar
John Donnelly
Posts: 577
Joined: Fri Mar 16, 2012 7:03 pm

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

Postby John Donnelly » Sun Oct 14, 2018 9:54 am

For the insulation boards, I use no more nails type adhesive.

John

User avatar
grovenor-2685
Posts: 2974
Joined: Sun Jun 29, 2008 8:02 pm

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

Postby grovenor-2685 » Sun Oct 14, 2018 3:02 pm

The first is to do with the Bill Bedford sprung W irons. The guitar wire threads through the base of the waisted bearing carrier and then is located on either side in a pilot hole in the etch. The wire is not equally straight ... some sections having a slight curvature. This means that when all the bearings are mounted the wheels are actually set at different levels. Getting all the wires to be identical seems a bit of a hopeless task. To date I have put a gentle positive camber into the wire which keeps the bearings at the top of the slot in the W irons ... this seems to work, but my reasoning tells me that this prevents the wheels from dropping should there be a local fall in the track level. Has anyone else encountered this issue?

Yes, to the extent that I don't use the supplied curved wire, instead I use guitar strings which usually are near as dammit straight when removed from the packed and uncoiled. you need the bearings to sit centrally in the slot when the wagon is weighted and on the track, if they are at the top or bottom the springs won't work as intended.
(The original Exactoscale cocept of weak springs that did not support the weight so sat up on the stops when on the track could keep the wheels in contact through dips but otherwise give a hard ride like an unsprung vehicle. It is an option but you need to set the W-irons lower to get the ride height correct).
Regards

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Sun Oct 14, 2018 3:39 pm

grovenor-2685 wrote: instead I use guitar strings which usually are near as dammit straight when removed from the packed and uncoiled. you need the bearings to sit centrally in the slot when the wagon is weighted and on the track, if they are at the top or bottom the springs won't work as intended.


Thanks Keith,

What Thickness of guitar string do you use?
Tim Lee

User avatar
Will L
Posts: 1544
Joined: Sun Jul 20, 2008 3:54 pm

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

Postby Will L » Sun Oct 14, 2018 4:15 pm

Le Corbusier wrote:... The first is to do with the Bill Bedford sprung W irons. The guitar wire threads through the base of the waisted bearing carrier and then is located on either side in a pilot hole in the etch. The wire is not equally straight ... some sections having a slight curvature. This means that when all the bearings are mounted the wheels are actually set at different levels. Getting all the wires to be identical seems a bit of a hopeless task.

I suspect you may be over thinking this. The variation cause by the wires being slightly curved is just noise in an overall robust system which is not significantly effected by the various sources of variation.

If you fit the springs loose in the fingers of the bearing carriers they will all turn so the curvature is the same way (downwards), and as all bits of wire cut from the same length of wire are going to have very similar curvature, all they springs are going to be very similar and the wheel will not be at different levels.

To date I have put a gentle positive camber into the wire which keeps the bearings at the top of the slot in the W irons ... this seems to work, but my reasoning tells me that this prevents the wheels from dropping should there be a local fall in the track level. Has anyone else encountered this issue?


For springing to be fully effective, you need it to set so that in the static, at rest, position the spring is depressed but not fully depressed (the latter is the undesirable position you describe).

The wagon spring units are designed so that the springs will be depressed about 50% for an average weight wagon. Clearly buffer height will vary a little bit for different weight wagons, but as the amount of varation in depression needed to deal with any reasonable track variation is small, wagons settling at slightly different buffer will neither be visible or significant for running performance. Remember that most people do try for fairly consistent wagon weights, although the possibility exists of substituting thicker or thinners wires exist to adjust any wagon visible out of line with the rest.

If the wire curvature realy worries you, or makes the buffer height to lower than you want, you can make use the fact that it will be curved in only one plane. (Caused by rhe wire bing stored in a coil.) If you mount them in the bearing carrier with the plane of the curvature at right angles to the plane of the carrier, and solder them in so they can’t turn, the wire will be effectively strait.

User avatar
Le Corbusier
Posts: 1070
Joined: Wed Feb 11, 2015 3:39 pm

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

Postby Le Corbusier » Sun Oct 14, 2018 5:45 pm

Will L wrote: If you mount them in the bearing carrier with the plane of the curvature at right angles to the plane of the carrier, and solder them in so they can’t turn, the wire will be effectively strait.


Thanks Will,

I have soldered the wire in as I find the carriers very flimsy and was worried about fatigue over time.

I will straighten the wires as much as possible and put it down to experience. :thumb
Tim Lee

User avatar
grovenor-2685
Posts: 2974
Joined: Sun Jun 29, 2008 8:02 pm

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

Postby grovenor-2685 » Sun Oct 14, 2018 9:40 pm

Le Corbusier wrote:
Thanks Keith,

What Thickness of guitar string do you use?

I have a collection from 8 thou to 12 thou, most wagons I think are using 10 with wagon weights around 50g.


Return to “Starting in P4”

Who is online

Users browsing this forum: No registered users and 1 guest