michael080
Western Thunderer
Driving is very simple, just follow Newtons first law of motion: "A body remains at rest, or in motion at a constant speed in a straight line, unless acted upon by a force."
Ian@StEnochs
Western Thunderer
Working out the likely finished weight, and more important it’s distribution, of a model is quite tricky. That is why I prefer the ease of adjustment of individual coil springs.
Adjustment of the weight on each axle can be done in a number of ways.
1, Use springs of different rate but same dimensions.
2, Use one rate of spring but use shims to pre load them on the axles carrying most weight.
3, Use one rate of spring but with a screw adjustment for very fine tuning.
For most of my builds I use option 2 and adjust the loading by adding plastikard or brass washers between the spring and axlebox until the correct ride height is obtained. All axles can rise and fall above the datum for live springing.
However on a couple of big engines, Scot and WD, I arranged screw adjustment on each axlebox. These are a pair of heavyweights having resin boilers with cast in weights, ex JLTRT kits, so it was relatively easy to equalise the load on each axle. They are a bit over the top weight wise as I normally only load an engine to pull its normal train, no sense wearing a model out carting excess weight around!
I have a short wheelbase dock tank in my build list which looks fairly easy to equalise the weight distribution so I might just try CSBs on that just for comparison.
Ian.
Phil O
Western Thunderer
A whitemetal or pewter loco crew will add weight to the footplate. Another possibility is to add some weight between the frames under the footplate, as long as there's space for the tender coupling.
Ian@StEnochs
Western Thunderer
Yes, I try to get as much weight in there as I can including solid whitemetal boiler back, brake cylinder, rotund crew and even a lead piece bag! In the words of a well known advert ‘every little helps’.
Ian.
simond
Western Thunderer
Not happy. Having got over whatever lurgi I had the week before Christmas, I have now pulled a muscle in my right shoulder and it is b....y agony 
Trying to take my mind off it by doing a bit of CAD work which is uncomfortable, rather than painful. Looked at the list of "things wot need doing" and concluded I should finish the 3D and print the drawbridges for the coal stage, which look reasonably good - difficult to measure but I took key dimensions last time I was there, along with a load of photos.
(Both my copyright)
And that got me thinking about Mervyn and Evan, "see, we've climbed this great big ladder, and there's a nice view an' all, but nothing for us to do"
I know there should be a float and weight connected by a chain over a wheel to tell the coddy how much water is in the tank, and there is presumably a hatchway to gain access to the inside of the tank too - but it seems very difficult to find anything useful in the way of photos or descritpion. The excellent pictures of the restoration of Didcot carefully don't show the corner I want to see, and the Google Earth view shows it before it was restored, so there's bits of roof missing.
www.corrolesseastern.co.uk
www.google.com
So I have drawn up a 3' x 4' hatchway which looks plausible, but if anyone has better information, I'd be delighted!
TIA
Simon
Trying to take my mind off it by doing a bit of CAD work which is uncomfortable, rather than painful. Looked at the list of "things wot need doing" and concluded I should finish the 3D and print the drawbridges for the coal stage, which look reasonably good - difficult to measure but I took key dimensions last time I was there, along with a load of photos.
(Both my copyright)
And that got me thinking about Mervyn and Evan, "see, we've climbed this great big ladder, and there's a nice view an' all, but nothing for us to do"
I know there should be a float and weight connected by a chain over a wheel to tell the coddy how much water is in the tank, and there is presumably a hatchway to gain access to the inside of the tank too - but it seems very difficult to find anything useful in the way of photos or descritpion. The excellent pictures of the restoration of Didcot carefully don't show the corner I want to see, and the Google Earth view shows it before it was restored, so there's bits of roof missing.
Tank Lining and Protective Coating at the Didcot Railway Centre
The water tank at Didcot Railway Centre was exhibiting heavy corrosion, was leaking and required significant refurbishment.
www.corrolesseastern.co.uk
Google Maps
Find local businesses, view maps and get driving directions in Google Maps.
www.google.com
So I have drawn up a 3' x 4' hatchway which looks plausible, but if anyone has better information, I'd be delighted!
TIA
Simon
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simond
Western Thunderer
And one for @Pencarrow
Well, two I guess. Steam brake cylinder and the very obvious riveted angle across the front frame spacer.
Well, two I guess. Steam brake cylinder and the very obvious riveted angle across the front frame spacer.
Pencarrow
Western Thunderer
Lovely stuff. Should I admit to knowing what those bits were and where they go before reading you text? Is there any hope for me??
simond
Western Thunderer
In the last photo, I would like the flashing to look like flashing. It doesn’t, which is disappointing, if predictable.
Might have to readdress that.
Might wait for some evidence of what the real thing looks like.
simond
Western Thunderer
Bit of a milestone in Chris’ pannier today
To get to this point has required the front axle crankpin bush flanges to be turned down to less than 0.2mm thick, and the front crankpin screws to be suitably shortened so they don’t catch on the axle boxes - they’ll need to be replaced with CSK screws to get past the crossheads - but at least the coupling rods don’t catch on the motion bracket.
It really is a bit tight - four layers of paper goes in - that’s 0.33 mm - and a bit of 0.47 NS doesn’t.
Said bracket also acts as a CSB fixed fulcrum, so needed attaching, if I remain happy with this I’ll countersink the frames for these screws.
Given the limited space behind the buffer beams, I used a bit of silicone rubber (glow engine fuel) pipe to secure the hooks, which are Premier steel ones, oil blackened.
Bags of room for the motor
This shot also shows the CSB fulcrum & wire
So, shopping list - I’ve run out of 2mm brass round, 6BA screws & 12BA CSK steel screws
Meanwhile, I can be getting on with the slide bars.
To get to this point has required the front axle crankpin bush flanges to be turned down to less than 0.2mm thick, and the front crankpin screws to be suitably shortened so they don’t catch on the axle boxes - they’ll need to be replaced with CSK screws to get past the crossheads - but at least the coupling rods don’t catch on the motion bracket.
It really is a bit tight - four layers of paper goes in - that’s 0.33 mm - and a bit of 0.47 NS doesn’t.
Said bracket also acts as a CSB fixed fulcrum, so needed attaching, if I remain happy with this I’ll countersink the frames for these screws.
Given the limited space behind the buffer beams, I used a bit of silicone rubber (glow engine fuel) pipe to secure the hooks, which are Premier steel ones, oil blackened.
Bags of room for the motor
This shot also shows the CSB fulcrum & wire
So, shopping list - I’ve run out of 2mm brass round, 6BA screws & 12BA CSK steel screws
Meanwhile, I can be getting on with the slide bars.
Pencarrow
Western Thunderer
The more I see of what you've had to do to get this working satisfactorily, whilst at the same time making it look like the real thing, the more I'm in awe. There's also the realisation that working to proper mechanical tolerances, rather than "that'll do" standards I apply to scenics and buildings, is I skill set that seems to elude me*. Cracking work Simon.
*Edit: But perversely I have the stamina and patience to cut, detail and apply several thousand individual tiles to a model roof... Strange old world.
*Edit: But perversely I have the stamina and patience to cut, detail and apply several thousand individual tiles to a model roof... Strange old world.
Pencarrow
Western Thunderer
...and at the same time I spend stupid hours producing stonework on the face of a building that will be least seen. Perhaps an element of madness
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simond
Western Thunderer
Well, as Albert’s mother said, “I am vexed”
Monday night, set up the printer to do 45 pieces of gutter for the loco shed, and had an inviting gap on the printer bed. “Mmm”, says I, “I’ve already updated that iron coal wagon, let’s have a couple of them on there.
14 hour print…
Back from the office yesterday and fed the cat (not going to get any peace until that’s sorted) and then took the print off and washed it. Looks good, put it in the curing box, and then unpacked.
The gutters are ok, good,
The wagon bodies are looking fine
Though there’s a bit of ripple in the top flanges, I’m thinking, “we’re very nearly there”
But
The end with the supports on is rough.
The ripple in the flange is dreadful, and despite using rivets as the support points, it has left an awful finish.
Back to the print set up. I’ll have another go tonight.
Monday night, set up the printer to do 45 pieces of gutter for the loco shed, and had an inviting gap on the printer bed. “Mmm”, says I, “I’ve already updated that iron coal wagon, let’s have a couple of them on there.
14 hour print…
Back from the office yesterday and fed the cat (not going to get any peace until that’s sorted) and then took the print off and washed it. Looks good, put it in the curing box, and then unpacked.
The gutters are ok, good,
The wagon bodies are looking fine
Though there’s a bit of ripple in the top flanges, I’m thinking, “we’re very nearly there”
But
The end with the supports on is rough.
The ripple in the flange is dreadful, and despite using rivets as the support points, it has left an awful finish.
Back to the print set up. I’ll have another go tonight.
Richard Gawler
Western Thunderer
I don't want to sound like a heretic, but would it be possible to draw and print the wiggly flanges with an L section, and then file off the sacrificial part of the L? On the basis only the sacrificial part will take on a wiggle.
JimG
Western Thunderer
Simon,
I've had your ripple effect on thin flanges.
Wouldn't it be great if that's the effect you wanted and you didn't have to draw it in 3D CAD. When it happened to me, I reckoned I had hit the minimum thickness that my printer/resin combination could print well and I upped the thickness of my flanges by 0.025mm or 0.05mm and all then was well. I also tried tapering the flange, leaving the extremities at the same thickness and increasing the base thickness by about 0.05mm - 0.1mm and that worked in some cases and maintained the apparent thinness of the flanges. I've got a large box full of rejected S scale mineral wagon bodies as a result of fine tuning the top and end flanges on that wagon.
Jim.
I've had your ripple effect on thin flanges.
Wouldn't it be great if that's the effect you wanted and you didn't have to draw it in 3D CAD. When it happened to me, I reckoned I had hit the minimum thickness that my printer/resin combination could print well and I upped the thickness of my flanges by 0.025mm or 0.05mm and all then was well. I also tried tapering the flange, leaving the extremities at the same thickness and increasing the base thickness by about 0.05mm - 0.1mm and that worked in some cases and maintained the apparent thinness of the flanges. I've got a large box full of rejected S scale mineral wagon bodies as a result of fine tuning the top and end flanges on that wagon. Jim.
simond
Western Thunderer
Richard,
thanks, that one is filed away for one of the future trials, it seems like a very good idea
Jim
thanks, yes, done that already, the solebars are convincing, but not really a prototypical cross section! The flange at the "good end" is nearly ok, so it looks like I might be at the limit. Maybe a few hundredths.. But Richard's suggestion is certainly worth a try.
My collection of reject wagon bodies is growing, 4 so far....
thanks both
Simon
thanks, that one is filed away for one of the future trials, it seems like a very good idea
Jim
thanks, yes, done that already, the solebars are convincing, but not really a prototypical cross section! The flange at the "good end" is nearly ok, so it looks like I might be at the limit. Maybe a few hundredths.. But Richard's suggestion is certainly worth a try.
My collection of reject wagon bodies is growing, 4 so far....
thanks both
Simon
JimG
Western Thunderer
My collection of reject wagon bodies is growing, 4 so far....
thanks both
Simon
I just tipped out the basket and counted thirty-six bodies.
Jim.
Rob R
Western Thunderer
I stopped counting a long time ago...I just tipped out the basket and counted thirty-six bodies.
Jim.
