Author Topic: Complicated Software  (Read 9145 times)

0 Members and 1 Guest are viewing this topic.

Offline John Candy

How Small Can You Go : 3D printing?
« Reply #105 on: Sep 14 2021 10:44 »

An annoying part of any project is to "almost be there" and find you cannot locate some small item of detail.
In this case it relates to the various control wheels in the loco cab.
In the planning for these locos (pre-3d print capability), I had prepared patterns for umpteen parts (including larger cab controls) and these had been cast in various materials.
In spite of all the custom made castings, I found myself missing the water valve wheels which sit on top of the tanks, just inside the cab entrance of LNWR Coal Tanks and the 5-spoke brake wheel.

I prepared a SCAD file to make both wheels which have 5 spokes but are vastly difference in size.
One advantage of OpenSCAD is that you can rescale entire items (or individual components thereof) with a simple instruction.

The attached photos show the water control valves (just 7mm in diameter) together with the oval baseplates upon which they sit also the hand brake wheel (16mm in diameter).

Apart from the difference in dimensions, the larger wheel has a handle on the rim. Both can be produced from the same file, with just a couple of tweaks which (literally) take seconds. 

You can produce any size of 5-spoke control wheel from the file which I have uploaded to
http://gauge3.info/openscad/generic_control_wheel_5spokes.scad 

(NOTE: Without tweaking, the file will produce a 20mm dia. wheel with handle).
Instructions for varying size of the wheel and including/excluding handle are contained within the file.

No reason in future to search for suppliers of correct parts or order expensive custom castings.

John
My fellow Members, ask not what your Society can do for you, ask what you can do for your Society.

Offline Nick

Re: Complicated Software
« Reply #106 on: Sep 16 2021 18:30 »
The fittings look good, John, and it's another example of how modern manufacturing methods are changing the hobby. I would, however, argue with your final remark:

No reason in future to search for suppliers of correct parts or order expensive custom castings

That makes an assumption about the suitability of the printing material. Many prototype fittings were made in brass and were not painted. I have yet to see a brass paint that actually looks like brass. To me, the only thing that looks like polished brass is, well, polished brass.

But there is a growing number of companies that will produce fittings in brass from solid model files, either by casting or directly by laser sintering, so the whole process is facilitated.

Nick

Offline John Candy

Re: Complicated Software
« Reply #107 on: Sep 16 2021 23:25 »
Nick,

Don't disagree with that ......also if you were building a live steamer, the plastic bits wouldn't be of much use!
As you point out (and in same way as many of my "prints" are being deployed) the prints do make useful patterns for castings, both resin and metal.

Regards,
John.
My fellow Members, ask not what your Society can do for you, ask what you can do for your Society.