On My Virtual Workbench...

[S-Club-7]

The first one out of the blocks:

​

7mm/ft 1:43.5 scale model of GWR-style stop block as seen at Minehead on the West Somerset Railway.

​

Available now from Off The Rails in the Shapeways FUD acrylic. Unfortunately some parts are too small to be produced reliably in the less expensive WSF nylon material so this option will not be available online; however as the designer I'm allowed to order them under the Shapeways "print regardless" scheme which means they may be available from a well-known S7 retailer at Brightwell-cum-Sotwell in April.

 

[3 LINK]

Hi Dave,

They certainly look the biz, I'm just sorry I could not help you with the research. On a flying visit to the ESR last year literally all the stop blocks were in a terrible state and they all had rolling stock buffered up tight on them so I could not get the critical measurements.

Have you any idea of pricing yet?

Cheers,

Martyn.

 

[Dan Randall]

Excellent work Dave, especially the inclusion of the special chairs.

Martyn - I just clicked on Dave's Shapeways link and they're £16.18 each. There are also a couple of CAD renders of what they look like "on the sprue". Additionally, there's a list of parts to be supplied by the purchaser, namely, four ordinary chairs, two lengths of running rail, plus some rail (or timber), for the cross beam and a piece of 0.8mm diameter wire for the tie-bar. With the sides being made of plastic, there are no worries about shorting things out!

I feel an order coming on....


Regards

Dan

 

[3 LINK]

Hi Dan,

Just like buses, we have been waiting ages for these GWR stops and then two come along at once. The fact that it's supplied with the special chairs is a bonus so like your good self I will also be ordering a few.

The timing is great as I am just laying the last sections of track which will lead to the lower level sidings .

Cheers,

Martyn.

 

[BrushType4]

I saw this in the flesh today and the photo's don't do it justice. I great piece of modelling by David.

 

[S-Club-7]

GER 1½ton Crane

I thought I'd revive this thread with my latest design intended in the first instance for the revised goods yard at Love Lane.

The first seven components (3d-printed in "Siraya Tech Fast Navy Grey" resin by Robin @Boyblunder) assembled by yours truly.

​

Really pleased with the level of detail that Robin has managed to print (the sub-1mm text is perfectly legible) although the support structure (think of sprues) does leave some surface damage which requires more careful rectification next time. And yes, the gears do work as should the ratchet and pawl once they're added.

Meanwhile I've been drawing some more bits for it; about two-thirds of the way there now.

​

Some dimensional compromises have been required to ensure printability and sufficient robustness during assembly although actually getting it to work may be pushing the technology a little bit too far...

Dimensions from Great Eastern Railway Society Journals 158 & 159. Originals by The Chatteris Engineering Works, Cambridgeshire, England, 1898.

 

[S-Club-7]

I have just moved the crane into the workshop


If only my real workshop was this empty or spacious

 

[Scale7JB]

I have just moved the crane into the workshop
View attachment 173472

If only my real workshop was this empty or spacious

If only I had a workshop .

JB.

 

[oldravendale]

Oh - I have a workshop. It's full of furniture.

Brian

 

[S-Club-7]

The virtual workshop is running a bit ahead of the the 3d-printing and assembly departments at the moment.

Just noticed that part of the jib assembly has disappeared - must be made of Mickoo's invisible solder

Nearly there, just need to design the hook from scratch. Hopefully this will be of some help:

7th edition revised 1949, reprinted 1958. It cost me considerably more than 2/6

 

[Osgood]

As they say in Ireland (well according to the film Leap Year) -

"Now, if I was starting out on a journey on a Sunday, I wouldn't start from there".

Hopefully the contents will reveal more traditional profiles than the one shown on the cover (I think that might be a sling hook for wrapping the chain around a bundle and hooking back around the chain) such as this oldie that should be good for 2 or 3 Tons - there are a few more knocking abut here but this is the only one accessible in the dark:

 

[Osgood]

Well to my surprise the hook has (barely legible) marking of SWL 1 1/2 Tons, so ideal for the crane!

Here are the dimensions in case of any use:

 

[S-Club-7]

Many thanks Tony, just what was needed.

The book does show this type of hook (Fig 11) on page 11:

​

Subsequent pages deal with calculating the SWL. I think I'll just use @Osgood's measurements

The booklet also contains some hand-drawn sketches by a previous owner. I've attached one below as it shows this type of hook with a pear-shaped ring through the hole. Would the GER crane have had such an arrangement?

​

Of more interest is what's on the reverse side of some of the sketches:

​

 

[S-Club-7]

A couple of views of the second trial assembly using components kindly printed a week ago by Robin @Boyblunder

​

Some parts 3d-printed in "Siraya Tech Fast Navy Grey" resin (some at 50micons and some at 20microns, no visible difference) and some in another more translucent resin (who's name I have forgotten, help please Robin) which is definitely less sharp; but perhaps more appropriate for the cast iron components of a battered 60-year-old crane.

Please see post 170 above for the current CAD model; printing and assembly are usually a week or two behind.

 

[Dog Star]

View attachment 173948
​

I believe that the arrangement shown is referred to as a "pair of brothers". Not sure how many variants there are of this arrangement, a "pair" suggests two hooks. Our Playmobil container crane has similar tackle with four hooks.

 

[Boyblunder]

Some parts 3d-printed in "Siraya Tech Fast Navy Grey" resin (some at 50micons and some at 20microns, no visible difference) and some in another more translucent resin (who's name I have forgotten, help please Robin) which is definitely less sharp; but perhaps more appropriate for the cast iron components of a battered 60-year-old crane.

Please see post 170 above for the current CAD model; printing and assembly are usually a week or two behind.

The translucent resin is Siraya Tech "Build" Smokey Black. The manufacturers description says "High Precision and Resolution - Siraya Tech Build 3D printer resin is an easy-to-use engineering resin with a high resolution and smooth surface. Its high precision allows it to be tapped to create threaded holes, ensuring that the model is printed with the finest details." We tried it because the excellent "Fast" navy-grey as recommended by Mickoo tends to crack if you try to screw self tappers into it and we hoped "Build" would be better. I'm not convinced yet, the detail may not be as good and build-up of surplus resin on the side facing the build plate is worse than "Fast" although it does seem to be more flexible.

 

[Eastsidepilot]

The translucent resin is Siraya Tech "Build" Smokey Black. The manufacturers description says "High Precision and Resolution - Siraya Tech Build 3D printer resin is an easy-to-use engineering resin with a high resolution and smooth surface. Its high precision allows it to be tapped to create threaded holes, ensuring that the model is printed with the finest details." We tried it because the excellent "Fast" navy-grey as recommended by Mickoo tends to crack if you try to screw self tappers into it and we hoped "Build" would be better. I'm not convinced yet, the detail may not be as good and build-up of surplus resin on the side facing the build plate is worse than "Fast" although it does seem to be more flexible.

I know nothing about 3D printing etc. but I'd expect that a self tapping screw thread will be very coarse, with blunt edges to the thread, compared to a machine tap which respectfully I'd suggest would be the correct thig to use if you want to attach fittings with screws.

Col

 

[S-Club-7]

All hooked up now - many thanks to @Osgood for the hook info:

So that's one operative winding each windlass; possibly another operating the brake lever (partly hidden behind the large gear); and one to swing the jib around. Not the most efficient design!
And yes, I know the windlasses should be removed whilst not being used since a rapidly revolving windlass can be lethal, more so when it flies off the end of the tapered square shaft.

 

[OzzyO]

The chances are that a twin acting ratchet would be fitted in the winding gear to stop the load from unwinding the drum and the same on the jib lifting gear.

ATB

OzzyO.

 

[S-Club-7]

The chances are that a twin acting ratchet would be fitted in the winding gear to stop the load from unwinding the drum and the same on the jib lifting gear.

Yes, and No.


Yes, the jib lifting gear (magenta rope) does have a ratchet and pawl (maroon) to keep it in place. The medium gear (green) has to be slid along the keywayed shaft (not shown) to engage it with the large gear (olive green). Rotating the windlasses will then rotate both the load winding gear (cyan rope) and the jib lifting gear at the same time.

No, the load winding gear does not have a similar ratchet arrangement. However, there is a brake drum on this side of the big gear which had a (probably) leather strap tightened around it by the brake lever. I suppose by engaging both the ratchet and the medium gear then a load could be suspended without use of the brake although the other side of the jib has cast upon it the words "No load to be left suspended on this crane"

Great Eastern Society Journal 159 has the details of how these cranes were operated.