fabricating short wheelbase brakes

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jon price
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fabricating short wheelbase brakes

Postby jon price » Tue Aug 14, 2018 8:46 am

So I'm looking at ten wagons without brakes. They have standard wheels and a 7'6" (30mm) wheelbase. I probably want to make several more. The prototype appears to have had twin brakes on one side, working with the usual v shaped bracket.

My question is how to fabricate/produce this brake gear with the minimum of effort. Cutting down a set of gear from a longer wheelbase wagon isn't so straightforward. The model wagons are plastic. Any brilliant ideas?

garethashenden
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Re: fabricating short wheelbase brakes

Postby garethashenden » Tue Aug 14, 2018 2:58 pm

I'd take a look through Wizard Model's catalouge. They have a good selection of components and you should be able to mix and match to get something that works.

I'd be tempted to use two single shoes, or cut clasp brakes in half, the white metal ones are probably good for this. Then there are levers and Vees, they come both as sets and individually, I'd be inclined to start with this and see if it works: https://www.wizardmodels.ltd/shop/wagon ... way-blgvd/

Finally, the pushrods from the V to the shoes can be made from styrene strip.

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Serjt-Dave
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Re: fabricating short wheelbase brakes

Postby Serjt-Dave » Tue Aug 14, 2018 4:00 pm

Fire and lots of it. LOL.

Personally I would use brass components so that they can be made and soldered up off the wagon which will make mass producing easier.

Let us know how you get on.

Dave

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Guy Rixon
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Re: fabricating short wheelbase brakes

Postby Guy Rixon » Tue Aug 14, 2018 7:23 pm

Ambis sell separate push-rods. But those are difficult to make up into brake assemblies, and the job would not be quick (if I were doing it :-/).

If I wanted a dozen or more brake assemblies in a weird wheelbase, I'd print them, but make the V-hangars on the solebar from etchings. I know that the brakes can be printed in FUD because Coastline Models already sell such. I suspect that a sprue of 4 brake assemblies would come out around £5 without designer's mark-up. Do you have decent drawings or photos?

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jon price
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Re: fabricating short wheelbase brakes

Postby jon price » Tue Aug 14, 2018 7:56 pm

not really any decent drawings or photos. This is the best that there is, courtesy of Flintshire archives. It is clear that the blocks are wood and the V comes in (at least) two forms.
P7100080.JPG

I can't do cad

andrewnummelin
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Re: fabricating short wheelbase brakes

Postby andrewnummelin » Wed Aug 15, 2018 9:54 am

I'd look at using Masokit's early PO wagon brakes - the push rods can be shortened easily.
I believe I used them when converting the Bargoed wagon to P4 a few years ago - unfortunately the plastic in the Blaenavon wagon had degraded over the years and it broke up while I was trying to convert it. Shame as it was one of my earliest attempts at wagon building (the photo is over 50 years old) and the only one where I've made the brakes actually operational! Blocks were from balsa so very easy to fabricate.
I think 3D printing sounds a good idea for batch production; but only if the model is not going to be viewed close up. With wood blocks the hangers are seen edge on, rather than side on, and I suspect this may be too fragile for a 3D print.
model-1967-0001.jpg
Regards,

Andrew Nummelin

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Guy Rixon
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Re: fabricating short wheelbase brakes

Postby Guy Rixon » Wed Aug 15, 2018 12:35 pm

brakes-v1.png

Would this be any good? Printed as 4 of these brake assemblies on a sprue?

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jon price
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Re: fabricating short wheelbase brakes

Postby jon price » Wed Aug 15, 2018 1:22 pm

this is brilliant Guy! So how much does it cost to get the design into Shapeways?

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Guy Rixon
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Re: fabricating short wheelbase brakes

Postby Guy Rixon » Wed Aug 15, 2018 2:11 pm

Shapeways 'bot reckons £3.35 + shipping for for a single assembly as pictured above, so I reckon about £5 for a sprue of 4 assemblies. Thats in FUD; it's a bit more for FXD, but I don't think you'd need the extra resolution.

The 'bot is fretting about the thinness of the tumbler around the hole for the shaft, so I will have to tweak some details. I need to confirm that I've got enough clearance between shoes and wheels, to add the fasteners on the rear of the assembly, and to make up the CAD for the sprue, so it will be later tonight or tomorrow before it is ready.

You can get the prints in either of two ways. Firstly, I can put the thing in my shop and you order normally on Shapeways' web-site; this means that I add $1 margin to the unit price. Secondly, I can send you the STL file so you can upload it and get it printed yourself at cost. Your call. In the latter case, I ask that you don't sell on the prints yourself, and that you accept that this and derived designs will later appear in my shop.

PS: I did the sprue of 4 quickly and uploaded it to get a price. The 'bot reckons only £3.96 + shipping for the sprue.

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jon price
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Re: fabricating short wheelbase brakes

Postby jon price » Wed Aug 15, 2018 4:07 pm

Guy, I would be happier buying from your site than trying to sort this myself. Don't know how many additional sales you would get, but who knows. I probably need enough for 20 wagons.

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Guy Rixon
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Re: fabricating short wheelbase brakes

Postby Guy Rixon » Wed Aug 15, 2018 5:55 pm

This brake assembly is now in the shop at https://www.shapeways.com/shops/guyrixon?li=pb. Price is currently £5.12 in FUD; the lower price I quoted earlier was without VAT.

It should be easy to make other, similar sets of brakes now that I have the basic geometry, so I'm open to suggestions.

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jon price
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Re: fabricating short wheelbase brakes

Postby jon price » Wed Aug 15, 2018 8:31 pm

thanks Guy. I've ordered them. Only issue was proving I wasn't a robot which took a couple of attempts. With regard to further stuff I might come back to you regarding similar brakes, but for a more traditional wheelbase dumb buffered wagon.

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jon price
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Re: fabricating short wheelbase brakes

Postby jon price » Wed Aug 22, 2018 11:29 am

First fitting of the brakes as designed and produced by Guy Rixon, and available from his Shapeways shop. Excellent fit on a new build, inevitably some fettling needed to retrofit on wagons where I have put the lead sheet weighting in the way. The front face of the base has to be slightly sanded to fit behind Bill Bedford springing units, which is now my springing of choice, but fits fine with three point wobbly-wheel compensation which I fitted to some of the earlier versions. The wagons aren't quite as bendy as they look, this is down to wide angle of camera lens.
P8220013.JPG

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John Bateson
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Re: fabricating short wheelbase brakes

Postby John Bateson » Wed Aug 22, 2018 11:55 am

Looking forwards to seeing these in Hancock's Wharf complete with the on-board trucks?
Slaving away still on GCR stuff ...
Avoiding the soaps ...
http://www.greatcentralmodels.co.uk

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jon price
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Re: fabricating short wheelbase brakes

Postby jon price » Wed Aug 22, 2018 12:43 pm

The wharves themselves, maybe not. Connah's Quay: slowly making progress. The trucks: moving at the same pace as the wagons, thanks to the etched lifting loops for which you kindly provided the artwork.
P8220014.JPG


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