Bill Bedford Springing units

allanferguson
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Bill Bedford Springing units

Postby allanferguson » Wed Sep 12, 2012 5:10 pm

I have become convinced of the value of these units for rolling stock, and have fitted a number of wagons with them; they seem generally successful. I have recently essayed to put them under a luggage van (3'7 1/2" wheels). I used BWF 003 NPCS W-Irons, and when assembled with the bits supplied they came out like the one on the left. Note the bearing at the top of the slot with no suspension movement (and the wheels fouling the W-Iron). So I pinched some bearing carriers from BWF 001 RCH 1907 W-Irons and fitted them, with the result on the right. This works admirably with appropriate weighting. Have I missed something stupid, have I done something wrong, or (dare I say it) has Bill made a mistake here? Note the different proportions of the bearing carriers underneath.

Allan F

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jjnewitt
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Re: Bill Bedford Springing units

Postby jjnewitt » Wed Sep 12, 2012 10:10 pm

Hi Allen,

I don't think it's you. I have some Bill Bedford W-Irons around somewhere that came out like the ones on the left. I remember Geoff Kent having the same issue with a Bill Bedford Conflat L kit when he wrote up the build for, I think, one of his wagon books. I think his solution was to solder one end of the springing wire so that spring wire was angled upwards. I think some of the etches were redrawn to correct the height error. Just a thought but you could try resting the spring wire on top of the fold out bearers rather than through the holes. Judging from your photos that should raise the carrier up about the right distance, though they may be a little high. Once the wheels are in the shouldn't fall out as the bearings will prevent this. I might try this solution on one of my wagons with Bill Bedford W-Irons.

allanferguson
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Re: Bill Bedford Springing units

Postby allanferguson » Wed Sep 12, 2012 11:10 pm

Thank you, Justin -- it's reassuring to think it isn't me! I'm happy with the solution I've found, and I'm happy with the performance of these units on the other stock (all wagons) under which I've used them. The other issue I've found with these NPCS units is that the spring wire supplied is the same as in the other wagon units (10 thou), but the longer span means that a heavier gauge wire is necessary to give an adequate load capacity; as they stand each unit will carry 33g at most -- app 100g for a 6 wheeler, which isn't enough, I think. But that's easy enough to sort!

Allan F

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Tony W
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Re: Bill Bedford Springing units

Postby Tony W » Thu Sep 13, 2012 10:30 am

Allan

I've had a similar problem to you but noticed it happening after the model was finished. Closer inspection showed I was distorting the wire as it was retained by the three fingers at the top of the bearing carrier. Not a problem in itself but after a while the wire rotated to find its own level, with interesting results! I now either solder the wire to the bearing unit or solder a bit of hyperdermic needle (as used in scratchbuilt hinged Alex Jackson couplings) to the unit. The latter ensures the bearing unit sits nicely against the back of the w-iron and the wire is dead in line with the retaining holes, removing the need to solder it at one end.

Hope that helps

Tony

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LesGros
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Re: Bill Bedford Springing units

Postby LesGros » Thu Sep 13, 2012 2:31 pm

Since BB has adopted a policy of producing building instructions for download, perhaps he should include advice on how he thinks such issues should be addressed by the builder.
Meeting such a problem as a beginner, I would probably reject the things, and choose kit from different supplier.
LesG

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allanferguson
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Re: Bill Bedford Springing units

Postby allanferguson » Thu Sep 13, 2012 5:03 pm

Tony W wrote:Allan

......The latter ensures the bearing unit sits nicely against the back of the w-iron and the wire is dead in line with the retaining holes, removing the need to solder it at one end........

Tony


I'm not clear about this soldering business; as long as the wire is retained by the fingers, and is long enough to come through the holes at each end, there shouldn't be any need to solder it anywhere. When the wheelset is in place the bearing can't move anywhere except in its slot. To do so seems to negate one of the benefits of the system, the ability to change wires easily, as well as inhibiting the flexibility of the wire.

Allan F

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Russ Elliott
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Re: Bill Bedford Springing units

Postby Russ Elliott » Thu Sep 13, 2012 6:25 pm

I agree with Allan. The spring should not be soldered anywhere. The carrier fingers need to be squeezed sufficiently to hold the spring but without gripping it tightly, which will distort the spring shape and affect its movement. The ideal squeeze is where the carrier can rotate freely about the spring without altering its axis in any way. Not easy, and everyone makes a mess of their first carrier fingers, which is why I pleaded with Bill to put spares on the artworks (there's plenty of room).

I can't explain the seemingly incorrect carrier depth on the NCPS, and I'm not sure an RCH carrier height is quite correct for the NCPS either.

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Tony W
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Re: Bill Bedford Springing units

Postby Tony W » Thu Sep 13, 2012 10:30 pm

I also agree with Allan, but I've found that the success of the carrier fingers gripping the wire whilst keeping it dead straight can be a bit hit and miss. I guess I'm going OTT in making damn sure the carrier and wire don't part company!

Tony

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Jol Wilkinson
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Re: Bill Bedford Springing units

Postby Jol Wilkinson » Fri Sep 14, 2012 7:32 am

There is no longitudinal restrain for the wire, so in the fingers don't grip it sufficiently it could move.

I have also found that the spring wire also has a bit of curve as seen in the photos, that is difficult to remove. So the no load or static loaded positions can be marginally different if the springs are not held in matching alignment. Perhaps the answer is to drill small holes in the underframe and bend the end of the spring to fit into this, thereby retaining the spring longitudinally and to stop it from rotating.

Jol

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John Bateson
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Re: Bill Bedford Springing units

Postby John Bateson » Fri Sep 14, 2012 7:45 am

If soldering the carrier doesn't suit, how about a small dab of paint or varnish - that should stop sideways movement.
John
Slaving away still on GCR stuff ...
Avoiding the soaps ...
http://www.greatcentralmodels.co.uk

allanferguson
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Re: Bill Bedford Springing units

Postby allanferguson » Fri Sep 14, 2012 12:38 pm

Jol Wilkinson wrote:There is no longitudinal restrain for the wire, so in the fingers don't grip it sufficiently it could move.

I have also found that the spring wire also has a bit of curve as seen in the photos, that is difficult to remove. So the no load or static loaded positions can be marginally different if the springs are not held in matching alignment. Perhaps the answer is to drill small holes in the underframe and bend the end of the spring to fit into this, thereby retaining the spring longitudinally and to stop it from rotating.

Jol


I think that it wouldn't be difficult to arrange a restraint for the wire if considered necessary -- we arrange this sort of thing after all for our CSB'd locomotives. I've had no problem in this regard on my own stock, and some of the wagons have been running around on "Burntisland" for about three years. The mileage isn't enormous, but there's a lot of handling.


I find that while the guitar wire I buy for AJ's and CSB's usually uncoils straight, the stuff supplied in Bill's kits seems often to have a wee bit of a residual curve (it also often seems to be a wee bit rusty). However, over the 21mm span of these units (less for some of the wagon units) the curve seems to me to be immeasurably small, and I've managed to ignore it, with no apparent deleterious effects.

Allan F

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Ian Everett
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Re: Bill Bedford Springing units

Postby Ian Everett » Fri Sep 14, 2012 4:45 pm

Have you thought of asking Bill directly? I would think he should welcome customer feed-back.

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jim s-w
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Re: Bill Bedford Springing units

Postby jim s-w » Sat Sep 15, 2012 9:54 am

Read 'the finescale illusion' on his blog and judge for yourself

Jim
Last edited by jim s-w on Sat Sep 15, 2012 11:37 am, edited 1 time in total.

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LesGros
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Re: Bill Bedford Springing units

Postby LesGros » Sat Sep 15, 2012 10:43 am

My thoughts exactly!
LesG

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Paul Townsend
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Re: Bill Bedford Springing units

Postby Paul Townsend » Sun Sep 16, 2012 6:57 am

clecklewyke wrote:Have you thought of asking Bill directly? I would think he should welcome customer feed-back.


He does in my experience AND acts upon it.

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Paul Townsend
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Re: Bill Bedford Springing units

Postby Paul Townsend » Sun Sep 16, 2012 6:58 am

jim s-w wrote:Read 'the finescale illusion' on his blog and judge for yourself

Jim

I re-read it just now and added my own twopennorth

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LesGros
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Re: Bill Bedford Springing units

Postby LesGros » Sun Sep 16, 2012 7:23 am

paultownsend wrote:
clecklewyke wrote:Have you thought of asking Bill directly? I would think he should welcome customer feed-back.


He does in my experience AND acts upon it.

Hi Paul,
Unfortunately, that is not always the case with everybody he deals with; "acting on it" should also incude updating downloadable guidance with remedial advice to deal with problems arising. Ideally, his intent should be to also help less experienced modellers than yourself. :|
LesG

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David Thorpe
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Re: Bill Bedford Springing units

Postby David Thorpe » Sun Sep 16, 2012 7:39 am

It appears that there is a fault with the BWF 003 NPCS W-Irons. Has anyone actually brought this to Bill's attention? If not, it doesn't seem to be fair to snipe on about Bill's customer service - surely we should wait and see what he says about it before launching a barrage of criticism.

DT

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Paul Townsend
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Re: Bill Bedford Springing units

Postby Paul Townsend » Sun Sep 16, 2012 7:57 am

DaveyTee wrote:It appears that there is a fault with the BWF 003 NPCS W-Irons. Has anyone actually brought this to Bill's attention? If not, it doesn't seem to be fair to snipe on about Bill's customer service - surely we should wait and see what he says about it before launching a barrage of criticism.

DT


100% agree.
Bill may take a week or three to respond so patience is an essential ingredient....from one who grew up with Studiolith!!

allanferguson
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Re: Bill Bedford Springing units

Postby allanferguson » Sun Sep 16, 2012 10:39 am

As the original instigator of this thread I feel I should offer an update on progress. I should say that these units are going underneath a Caledonian Railway Luggagge Van by John Boyle (Decent Models), another purveyor of excellent bits, but which often demand that the builder does some thinking for himself(!).
I mounted the units directly under the floor, which gave me a correct ride height, with adequate suspension movement up and down. All well until I tried to fix the cosmetic springs and axleboxes. There just wasn't room -- the springs disappeared behind the solebars. After a good deal of headscratching I realised that the bottom of the W-Irons was 1mm too close to the solebar i.e. the units should be mounted 1mm lower. This of course means the ride height is 1mm too high. OK, so more weight. But then the upward travel available in the axlebox slots is barely sufficient...... :? See para 1 above! (Incidentally I also realised that the cast axleboxes I'm using are a bit over scale compared with the drawing I'm using, which doesn't help).
So I've fudged it, in the best modelling tradition, and I'll see how it all works.
The idea behind all of this was an experiment in 6 wheel suspension less complicated than the otherwise excellent Cleminson arrangement offered by Brassmasters. I'll get back to my experiment in due course!

Allan F

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Russ Elliott
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Re: Bill Bedford Springing units

Postby Russ Elliott » Sun Sep 16, 2012 12:58 pm

allanferguson wrote:Note the bearing at the top of the slot with no suspension movement

On the substance of the OP, seems to me the primary requirement for the design is to ensure x is greater than y + 0.5.

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jjnewitt
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Re: Bill Bedford Springing units

Postby jjnewitt » Sun Sep 16, 2012 2:33 pm

Russ Elliott wrote:
allanferguson wrote:Note the bearing at the top of the slot with no suspension movement

On the substance of the OP, seems to me the primary requirement for the design is to ensure x is greater than y + 0.5.

carrier-movement.png

I seem to remember that the problem I encountered with mine was that x = y. It seemed that no allowance had been made for the deflection of the spring under load. I've used Masokits ever since.

It would also seem to me that a fundamental requirement of the design is that y is such that the vechicle sits at the correct ride height when the springs are under load and has the right relationship to the axleboxes. Also that the carrier is able to move both up and down. I spent a fair amount of time trying to get this right for my sprung bogies so that the axle centres line up with the cosmetic axleboxes. Not always sucessfully it has to be added, well not at first at any rate.

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Russ Elliott
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Re: Bill Bedford Springing units

Postby Russ Elliott » Sun Sep 16, 2012 6:22 pm

jjnewitt wrote:I seem to remember that the problem I encountered with mine was that x = y.

"Dear Eileens/Bill: am returning these units, since x is the same as y. I look forward to receiving corrected versions."

It would also seem to me that a fundamental requirement of the design is that y is such that the vechicle sits at the correct ride height when the springs are under load and has the right relationship to the axleboxes.

Correct ride height under load will be given by the user's packing strategy, which is not controllable by the manufacturer. On the buffer to axlebox relationship, is it reasonable to assume wheels intended for use in those 'NPCS' units would be 14mm to 14.5mm diameter?

In the general case, is this useful?:

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jjnewitt
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Re: Bill Bedford Springing units

Postby jjnewitt » Sun Sep 16, 2012 7:13 pm

Russ Elliott wrote:"Dear Eileens/Bill: am returning these units, since x is the same as y. I look forward to receiving corrected versions."

Yes I suppose I could have done that and perhaps should have done.
Russ Elliott wrote:"Correct ride height under load will be given by the user's packing strategy, which is not controllable by the manufacturer."

Only up to a point. There are specifed figures for this aren't there? Do we not have a specifed range for buffer heights? It doesn't seem unreasonable at all for a manufacturer to make sure their products fall within this. Masokits managed to get it right.
Russ Elliott wrote:"On the buffer to axlebox relationship, is it reasonable to assume wheels intended for use in those 'NPCS' units would be 14mm to 14.5mm diameter?"

Sorry I didn't make myself clear with that I was trying to refer to axle centre relationship with the axleboxes rather than the buffer centres. I shall revisit my grammar. If the carrier is the wrong length then obviously the axle centres aren't going to line up with the axleboxes.

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Russ Elliott
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Re: Bill Bedford Springing units

Postby Russ Elliott » Sun Sep 16, 2012 8:36 pm

jjnewitt wrote:Only up to a point. There are specifed figures for this aren't there? Do we not have a specifed range for buffer heights? It doesn't seem unreasonable at all for a manufacturer to make sure their products fall within this. Masokits managed to get it right.

I'm afraid we don't have a specified range for buffer heights. The "getting it all right" brigade delight in telling us about all sorts of unhelpful prototype values. I try to aim for a consistent 13.8mm.

Sorry I didn't make myself clear with that I was trying to refer to axle centre relationship with the axleboxes rather than the buffer centres. I shall revisit my grammar. If the carrier is the wrong length then obviously the axle centres aren't going to line up with the axleboxes.

Quite so, but the ultimate reference can only be to buffer height. The relationship of axlebox centre to axle centre is not controllable by a W-iron manufacturer. What is controllable is the elevation of the W-iron shape itself to the axle centre.


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