Making Wheels

My plan required the crane to move (not motorised) along rails embedded in the yard surface so wheels were going to be pretty important.  As I didn't have anything suitable to hand my only real options were to make some out of either wood or metal.  Ideally I would have turned them out of aluminium rod but as my metal lathe is some distance away I chose to use wood. 

The source material were some little wooden beads that had a 2mm hole through them and were about the right diameter.  I sanded some flat sides on them and then used a 2mm bolt and nut as a mandrel to mount them in a drill chuck.

Each wheel needed a V groove so that it could sit on the rails.  To cut these I used a little skew chisel that I made from a concrete nail.  These are neat they can be ground to any shape you can think of and hold a really good cutting edge (see next picture).   The wood is easy to cut so a soft touch is required to avoid digging the tool in.  While in the chuck the wheels were sanded to a final diameter of 9mm (just under 3/8ths").  This is not precision engineering - just something to keep the crane on the rails.

Peter

A kit of parts

With the wheels made I assembled all the pieces I thought I would need and laid them out on the bench

There are a few items missing from this picture.  I made some electrical pick ups from brass shim.  The crane hook was also scratch built using a product called "Shrinky Dinks" This is a plastic sheet that when heated shrinks to about 45% of its original size. While shrinking in 2 dimensions it thickens in the third. 

Basic process is to find a suitable drawing of what you want. Resize it to about twice the size you need, print it onto the plastic and then cut it out. You then either place the item in the oven or hit it with a heat gun.  Right in front of your eyes it shrinks down.

Peter

Assembling frame sides

Next step was to make up a pair of side frames.  By and large this is just gluing one piece of styrene to another and adding a couple of triangular reinforcing gussets (80 thou styrene).  2mm holes were drilled for the wheel axles and test fitted.  Wheel centers were 1/8" up from the bottom of the frames. Barely visible is a styrene sub floor that carries the brass track wiper. The sub floor was drilled and tapped with a 2-56 thread and the shim screwed to it.  The leads for the lights (38 gauge magnet wire) were soldered to the shim and fed up through tiny holes in the frame.

Peter

Well - this is topical !

Peter - timely post, because I have just started building a gantry (A frame) crane for the Atherton Service track.

1930's version, but principles are similar.

I was just scratching my head about wheels when your blog popped up......

Watching with interest.

Rob
Cornhill & Atherton RR

Tracks

Another straight forward process. Two lengths of Code 100 rail were inset slightly into the yard surface and glued in place with 5 minute epoxy.  Electrical feeds to my 12v lighting buss were soldered to the underside of each rail.

The square section aluminium blocks in the photo are filled with lead. This is one of my invaluable workshop aids. I have a bunch of these 1" square  tubes at 4" long  and another bunch at 8" long. Being lead filled they are  very handy hold downs. Combine that with their exact square section and you can start to imagine their usefulness.

Peter

Hoist

I will be the first to admit that this component is more a representation than true prototype - but it's my railroad right. All I wanted to achieve was something that vaguely looked like a hoist motor and mount that would slide along the truss and support the chain and hook.  So two shaped right angle brackets with a hole for some styrene tube. I actually used two different diameters The larger diameter tube was cut in two pieces to leave a smaller diameter tube in the middle that the chain can wrap around. You can see the filler in the hole of the smaller diameter tube.

Peter

Lights

The Details West HL 133 headlight castings were drilled out to take 0603 size LEDs.  These were wired in two pairs of series arrays.One array of two lights on each side of the frame This allowed the positive feeds to come op one side frame and the negative feeds up the other.  A 220 ohm SMD resistor was wired into the positive feed on each array.  The loose wires in the picture were tidied up later.  The LEDs were set into the headlight castings using Micro Scale Kristal Clear.  

Peter

Assembly

As you can see, my weight blocks came in very handy for the assembly.  They hold each side frame in perfect alignment while the truss is glued onto the top of the frames.   I used another pair of triangular gussets to provide a bit more structural integrity to the truss assembly.  By the way there are prototypical gantry cranes that have a very similar design to this.

Peter

Painting

With the dangly wires tidied up it was time for paint shop.  I used a couple of strips of double sided tape to hold the frame to my painting board.  Nothing fancy in terms of paint.  A rattle can of primer followed by a rattle can of yellow and then some enamel hobby paints hand brushed on to the small details.

Peter

Final Details

Once the paint had dried I fed some brass chain through a pre-drilled hole in the hoist assembly and attached the hook with some 15 thou wire. It was then just  a case of setting it on to the rails and making sure it all worked......  Phew it did.

Thanks for looking

Peter

Kiwi ingenuity

Peter, great looking project. As soon as I saw your method of turning wheels from wood, with a nail, in the drill i thought "that's a very Kiwi solution", then I saw that you're using North Yard chain. What part of NZ are you from? I'm in Masterton modeling a bit of whatever in N. Small world huh!

--Michael

Hi Michael

I'm just over the hill in Wellington.  If you send me a PM we should get in touch at some stage.  Yep the concrete nail turning tool is an oldie but a goodie.

Cheers

Peter

WOW

Thanks Peter. You make it look pretty easy. Now I will have to give more than a passing thought as to where I might put one of those. What are your plans to finish off the track in the area?

Jack

Very nice model. Makes me

Very nice model. Makes me glad I was able to purchase kits for an overhead crane at less than 15.00 American. Two different types one light duty one heavy duty with rails and supports. Nothing wrong with your method and it turns out a great looking model, just commenting on how easy I have it by comparison.

I think it just shows how one can over come a lack of something with creativity and ingenuity. Very clever idea on building the crane and all of it's components with what is at hand. The nail and drill were just great.

Rob in Texas

Thanks for the kind comments.

Jack your question is very pertinent.  It is pretty obvious from the pictures that the overall scene still needs a lot of work. 

My layout consists of a number of small individual dioramas that I attempt to blend into the ones either side. Many of those individual scenes have been relatively easy to plan and execute.  This one however has been through several iterations in my head and I suspect a few more to come. As you can see from the picture below, the spur sits beside one of my staging yards. My main thinking with this area was to create a small industry that would justify a range of different freight cars visiting. The gantry crane adds a few more options but I still need to crystallise my ideas a bit more.

Peter

Bracing

Very nice model, enjoyed your build very much.

I'd like to suggest adding a couple of substantial diagonal braces from the base to the uprights on either side of the crane.  I think if you look at prototype photos of similar cranes you'll find that they mostly have a lot of bracing to ensure the assembly doesn't twist when raising a heavy load.  Get something that weighs a few tons swinging and an unbraced crane like that will fold up like a cheap suit.  

Not to say it doesn't look good, because it does, but it could be made more realistic with a bit of extra work.

Good job!

Craig

Re Bracing

Hi Craig

I certainly hear where you are coming from as the typical perception of a gantry crane would be something like this..

In this case I modelled my example of a much lighter type as shown below..

As you can see, this one (designed to lift 2 tonnes) has even less bracing than mine.  I chose to add 6 x triangular gussets to suggest a slightly beefed up version given the larger span.  Adding more bracing would be possible but not desirable from my perspective.  I'm sure you are correct and no doubt a mechanical engineer will have some views, but I will probably leave it as is.

Peter

Prototype storage tanks.

Im not sure if this sort of thing matters in the modeling world to most people. Just a comment on the storage tank location. In the USA its actually against safety rules and regulations to align the storage tank in such a fashion as to have an end of the tank(s) facing any sort of occupied structure.

I think ...

.... that you have gotten the bracing pretty much correct for the anticipated working loads.  It is easy to 'over engineer' things; but in the real world, that incurs increased cost and in the model world it can play havoc with our perception of the scene.  The proportions of your crane look quite aesthetic in my eye.

@ Chris ... surely that rule does not apply to empties?  I would not think that they would ship tanks such as that full ... or would they?

The Big Ones?

Perhaps Chris is referring to the large tanks over to the right.  They're aimed right at the building.

Correct.

Thats what I meant. I should have been more specific.