Well Wagon Suspension

garethashenden
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Well Wagon Suspension

Postby garethashenden » Mon Feb 22, 2016 5:51 pm

I have read repeatedly that wagons over a certain length behave much better with springing/compensation. This is fine for most wagons, but I can't see a good way of fitting it to a well wagon with it's sloping ends. I have a kit for a GWR Loriot which is white metal and come in at a fairly substantial 75g, so maybe it will stay on the track without springing. But I am also working on a backdated version of Dapol's Lowmak, which is much lighter.
Has anyone given any thought to the suspension of this type of vehicle?

dal-t
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Re: Well Wagon Suspension

Postby dal-t » Mon Feb 22, 2016 9:15 pm

I have thought about it at some length (! - I'll explain that in a moment), but I've only reached a tentative conclusion. A couple of years ago I built the (fictitious/freelance) Airfix/Dapol Diesel Crane in EM, purely as a display piece, and decided it needed a suitable match truck. The Lowmac seemed an obvious candidate, both because it was freely available mail-order, and because it also met the rules of the 'group build' I was participating in (being an original Airfix issue). While conversion to EM was simplicity itself, to marry properly with the crane's jib it also needed to be lengthened, and to have the loadbed slightly raised. Looking at the rigid wheelbase I felt it was unlikely to even sit squarely on my averagely imperfect display track, and would certainly struggle to get through any pointwork. But I could not see how to easily spring or compensate it. I pressed on hesitantly with the conversion, but when I reached the point where I could fit the axles and try its running, I found it was surprisingly sure-footed. I spun it, unpowered, through a couple of old EM turnouts and it held the track fine. The explanation lies, I think, in my less than perfect extension of the sides and floor, using soft plastic card, which allows enough twist for all four wheels to sit pretty firmly on the track. To replicate that in a more serious build without the body extension, I think the best way to go would simply be to leave one end rigid, and let the other axle pivot in inside bearings on a compensation beam. The issue is the sloping floor at the point where you need to fix the compensation unit, but I think even undeepened frames give enough coverage to hide an underfloor 'wedge' for a level fixing - providing you don't want the sort of chassis/brake fidelity which seems with some to have become de rigeur in modern wagon building (but if you did, I guess you wouldn't be starting with the Lowmac?).
David L-T

Philip Hall
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Re: Well Wagon Suspension

Postby Philip Hall » Mon Feb 22, 2016 9:29 pm

I have built quite a few Cambrian GW sleeper wagons and (I think, a long time ago now!) a well wagon or two, and fitted them all with at one end with a MJT inside bearing compensation unit. The only problem was excessive height of the rocking unit, so I simply cut off each side member, trimmed a millimetre or two from the base end and soldered it back on. There was just enough room for the wheels to rock a bit after a little adjustment with some thin Plastikard packing. They are very sure footed, I'm told, with a bit of weight, usually a cast metal load.

Philip

billbedford
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Re: Well Wagon Suspension

Postby billbedford » Tue Feb 23, 2016 11:03 am

garethashenden wrote:I have read repeatedly that wagons over a certain length behave much better with springing/compensation. This is fine for most wagons, but I can't see a good way of fitting it to a well wagon with it's sloping ends. I have a kit for a GWR Loriot which is white metal and come in at a fairly substantial 75g, so maybe it will stay on the track without springing. But I am also working on a backdated version of Dapol's Lowmak, which is much lighter.
Has anyone given any thought to the suspension of this type of vehicle?


Short light wire springs will work as well as longer heavier wires.
Bill Bedford
Mousa Models
http://www.mousa.biz

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jim s-w
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Re: Well Wagon Suspension

Postby jim s-w » Tue Feb 23, 2016 12:26 pm

One option is to file the cups in the bearings into a vee. Then use a wire loop mounted centrally so the axle can rock in the bearings.

You might find that building the wagon rigid with a bit of tracing paper between one axle and the bearing gives you enough movement anyway.

HTH

Jim

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Noel
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Re: Well Wagon Suspension

Postby Noel » Tue Feb 23, 2016 1:15 pm

I have a Dapol [ex-Airfix] kit Lowmac EK built 'out of the box', apart from changing the brake rack, which in reality is nothing like the kit one. There is a small amount of side play on the axles, but no compensation. There is also enough lead underneath to bring the weight up to 40 gr. I would not normally leave a chassis this long uncompensated, but it seems to run OK as it is.

jim s-w wrote:One option is to file the cups in the bearings into a vee. Then use a wire loop mounted centrally so the axle can rock in the bearings
I did something like this on a r-t-r Airfix Lowmac EU [actually a Lowmac EP], which is OK but definitely not particularly free running.
Regards
Noel

garethashenden
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Re: Well Wagon Suspension

Postby garethashenden » Tue Feb 23, 2016 7:15 pm

Thanks everyone. I've got some of the MJT suspension units somewhere, I'll try to dig them out and give that a go. Otherwise, lots of weight instead.

Julian Roberts
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Re: Well Wagon Suspension

Postby Julian Roberts » Sun Feb 28, 2016 8:24 am

Hi Gareth

Don't know if this is still useful or relevant to your situation.

Here are a few pictures that show what I did with MJT thingys for ready to run wagons.. The basic idea is, take the wheels off the ready to run vehicle, use the pinpoint axle to adjust the height of the arms to suit the application by bending them inwards if necessary. Broach the holes out to accept a 2mm inside diameter tube, and solder this up when satisfied. This gives a much more solid set up, less easily damaged and put out of adjustment, the wheels also revolve more freely. I cut a slot for oiling.

spring 2011 381 (Large).jpg
Setting it up to correct height before soldering the tube to the arms


spring 2011 380 (Large) (2).jpg
This is my variant of MJT inside bearing



There must be enough room for the wheels to be able to rock enough...filing away plastic from the axlebox are inside is necessary.
Edit - obviously you file off the pinpoints or use plain ended axles

Wagon conversion (4) (Large).jpg


Wagon conversion 2011 003 (Large).jpg



The difficult bit is adjusting the length and washering to have minimal side play with correct B2B without taking the wheels on and off so much that they lose their grip on the axle, and glueing it centrally, checking ride height is correct.

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jim s-w
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Re: Well Wagon Suspension

Postby jim s-w » Sun Feb 28, 2016 9:27 am

Thats interesting but You seem to have gone to a lot of effort to fix a problem that doesn't exist Julian. I can't see how running in a tube produces less resistance than running in 2 thin brass bearings and I'm not sure that there's much to go out of adjustment with the MJT unit if I'm honest. The only real problem I had was that they can be a bit sloppy on thier pivots and as such don't remain parallel to the fixed axle. If you look at one of your pictures and compare the rocking axle with the fixed axle and the ends of the wagon you can see a twist on the rocking axle.

I think we are over complicating things here but most importantly we have lost sight of the original problem. That the wagon in question doesn't have a flat floor to mount off the shelf solutions too.

Cheers

Jim

Julian Roberts
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Re: Well Wagon Suspension

Postby Julian Roberts » Sun Feb 28, 2016 10:17 pm

Hi Jim I skimmed through it all and saw MJT mentioned and thought I should put in my penn'orth in case it helps. Yes I know it is rather more effort than absolutely needed, but I build stuff for our club which is therefore for exhibiting, and in the often stressful exhibiting situation, particularly when unpacking and packing, things can get handled roughly or accidents can happen, even with the best will in the world. So I work on the principle that anything that might go wrong will go wrong. That's why I like things to be robust. And 12 wagons with that style of suspension have never derailed yet during the show.

The tube means the axle runs true. Further than that I can't speculate as to whether one runs more easily than another - though with AJ's totally free running can mean you can't couple up to a wagon standing on its own, it just runs away...

Here are two pix I just took from above the wagon (or below...depending on how you look at it...) - the parallax business means it's difficult to exactly see how truly straight the axle is. I should get one of those Brassmasters jigs. Obviously you are right, that the axles being parallel is critical. That was the best I could do at the time...

20160228_204700.jpg


20160228_204726.jpg


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