Helston Revisited

[Andy Keane]

3 minutes ago, Neal Ball said:

That would be good Andy, yes please!

 

How many others might be interested I wonder….

A single etch starts at about £120 because of set up costs but after that much less. The prints of the base would be only a few pounds each but many suppliers have a minimum order of £25 or so. To get to £30 per kit we would probably need around eight buyers. Of course the real cost is the time in CAD but I will certainly be doing this if I cannot get access to the models already made. I am generally happy to share my STL files for people on RMweb to use in a non-commercial way.

Andy

Edited June 27, 2023 by Andy Keane

[Neal Ball]

4 hours ago, Andy Keane said:

A single etch starts at about £120 because of set up costs but after that much less. The prints of the base would be only a few pounds each but many suppliers have a minimum order of £25 or so. To get to £30 per kit we would probably need around eight buyers. Of course the real cost is the time in CAD but I will certainly be doing this if I cannot get access to the models already made. I am generally happy to share my STL files for people on RMweb to use in a non-commercial way.

Andy

Thanks Andy, I will DM you in the morning.

Edited June 27, 2023 by Neal Ball
Typo

[Graham T]

I'd probably be interested in one of these for CR Mk II.

 

[Harlequin]

Put me on the list, too, please.

 

Let me know if I can help with the CAD or test prints.

 

[Andy Keane]

If we are to make a crane kit we need to agree on how to model the jib. No doubt the most accurate method would be scratch building from brass angle and strip, soldered up on a jig. But would people want to do that? Next up would be brass etches that fix the main structure and then decorate these, either with soldered brass strip or glued on 3D printed parts. The quickest approach is a full 3D print but this would be fragile.  A half way house would be a 3D print strengthened with strategically placed brass rods. We need to decide this before starting the CAD. If we avoid an etch it will save a fair bit of the cost. Could people let me have their views please?

Andy

[kingmender]

Morning Andy

I'd go for a brass etch for the jib. Angles can be folded from half etch lines and reinforced wwith solder. Makes a robust object that by its very nature tends to get knocked during layout maintenance and track cleaning. Put me down for 2 please.

Rodger

[Neal Ball]

Looks as if that’s 6 straight away @Andy Keane and we’ve not even advertised yet!

[BenL]

A vote from me for the 3D print reinforced as necessary. I have got a few prototype pics from a couple of different books if that would help at all.

[Neal Ball]

45 minutes ago, BenL said:

A vote from me for the 3D print reinforced as necessary. I have got a few prototype pics from a couple of different books if that would help at all.

7 then.

[Andy Keane]

8 hours ago, BenL said:

A vote from me for the 3D print reinforced as necessary. I have got a few prototype pics from a couple of different books if that would help at all.

Please PM me all and any photos. Although I have the drawings photos are invaluable.

thanks

Andy

[Andy Keane]

My current thinking is a printed base with the option of either a printed jib or an etch based one for those who want a more rugged model and have the patience to assemble it. Does that sound like a plan?

[Andy Keane]

8 hours ago, Neal Ball said:

we’ve not even advertised

Neal, not sure how one would advertise or exactly to whom? 

[Andy Keane]

Another thought is a 3D metal print of the jib. I have a friend who works in medicine and they 3D print stents that are tiny and very intricate in titanium for example. I will try and find out what is possible and at what cost.

[Graham T]

An etched jib would also be my preference.  I know I'd break a resin one...

 

[Mike_Walker]

Whilst I don't have a requirement for a crane, is this view of the 6 ton crane at Marlow (installed circa 1940) of any use?

 

[Andy Keane]

On 27/06/2023 at 03:44, St Enodoc said:

Ah, but has it got seven strands?

So this is what MSE signal wire looks like on a 20 foot roller spacing on my platform edge. I think if it were matt not shiny it would be even harder to see!

Edited June 28, 2023 by Andy Keane

[5BarVT]

34 minutes ago, Andy Keane said:

So this is what MSE signal wire looks like on a 20 foot roller spacing on my platform edge. I think if it were matt not shiny it would be even harder to see!

I was about to say “What wire?” when I managed to make it out.

:-)

Paul.

[Andy Keane]

I have made some progress on the crane jib CAD model, though still a fair way to go:

Edited June 28, 2023 by Andy Keane

[Andy Keane]

This is the finished jib model. Whether we can actually make one remains to be seen!

[Andy Keane]

For those of you interested in a 6 ton yard crane model it is not clear if printing a correct scale model in resin will be possible - most people think about 0.75mm is the smallest thickness it is sensible to print. The diagonal straps on the crane are 2" by 0.5" which comes out as 0.67 x 0.17 mm. This is just about feasible in brass strip but clearly not in a resin print. This leaves two options: leave all the thin detail out and just print a base frame to which brass bits can be glued (or go for a brass etch frame and add the details to that) or stick with a 3D print but alter the dimensions to make the features thick enough to be workable - so those diagonal straps would end up a square section for example. This would not look so nice of course. Views?

[MrWolf]

Would it be possible to make those cross braces as a shallow triangular section which would fool the eye but give a greater cross sectional dimension that would make a print more viable? 

It was something that @chuffinghell and I discussed when working out the lower door runner on the GWR CC7 which has to stand off the solebars. 

[chuffinghell]

13 minutes ago, MrWolf said:

Would it be possible to make those cross braces as a shallow triangular section which would fool the eye but give a greater cross sectional dimension that would make a print more viable? 

It was something that @chuffinghell and I discussed when working out the lower door runner on the GWR CC7 which has to stand off the solebars. 

 

I used optical confusion, the rail is only thin where it is visible

 

 

The rail is much thicker where you can't see it

 

 

 

 

Edited June 30, 2023 by chuffinghell

[MrWolf]

Thanks, that's the kind of thing I'm thinking, a flattened isosceles triangle would give strength and thin edges but be difficult to detect once painted and on the layout.

 

 

[chuffinghell]

44 minutes ago, MrWolf said:

Thanks, that's the kind of thing I'm thinking, a flattened isosceles triangle would give strength and thin edges but be difficult to detect once painted and on the layout.

 

 

 

the same 'model' viewed from the front and back....

 

 

 

....shameful trickery! 🤪

 

I've found that you have to over exaggerate the details details. My CC2 for example looks quite 'chunky' on the drawing....

 

 

....but looks okay(ish) on the layout

 

 

 

Edited June 30, 2023 by chuffinghell

[Andy Keane]

These sorts of tricks will help but remember even the front will be only 0.67mm wide. So I think it would need to be thicker in both directions. Also all the L sections will probably end up as square sections. Will that matter? I am no expert on printers, though I can drive CAD.