Tuesday 3 July 2018

26/6 - 2/7/18 - Pansy

For about the last week I have stopped "putting off" researching the overseas (UK) suppliers and their price lists.  Been a big job to get in the headspace, but I think I'm there now.  It all started when looking for some GWR style globe valves for the cab of Pansy, and also looking for the water gauges that are actually available.  I had drawn up the globe valves for the cab and managed to find them in a price list when I was looking up something else!

Some of these price lists are not that easy to decipher, and there's products hidden all over the place.  Particularly difficult sometimes to understand UK prototype locos and what stuff was on what loco, can't go down to the local tourist railway for a squiz!

Quite a good range in what Doug Hewson has, and have managed to find some stuff in the Polly "practical scale" catalogue.  Adam Cro of Cro Fittings is taking it to a new level...check out his website.

All the hashing and rehashing of pice lists has shown me that if I want a nice gauge glass that will look right in the cab I'm probably going to have to make it (unless I come across something I haven't yet seen!).  Not  that others don't sell the fittings, but the Boiler code compliance is one thing, and that you don't know how big these things are until you get them!  I've got a design up my sleeve for a nice gauge glass now...

In the last several years of learning curves I have become aware how difficult it has been to find readily-accessible information to give me a quick solution, or find an equivalent UK design.  I can search for hours and come up with a few things, but there's always that one time when you see someting you weren't looking for which would have been helpful last week!

Fortunately I have some Model Engineer resources which can be easily searched.  One of the typical things is remembering that I saw some technique or product somewhere, but I can't seem to remember exactly where it was!

Long overdue, but I have realised that I need a system to quickly recall and save information...a second "brain" where I can put all the loose ends.  I've had books and paper copies but they aren't easily edited.

I tend to avoid getting a program until I outgrow Excel or other Microsoft systems, as it's easy to be sold a product but the hard thing is customising it to do just what you want, once you know what it is you want!  So Excel with some hotlinks seems to work well for the time being.

I've managed to develop a quick lookup system in Excel to find me things like all the gauge glasses available, common sizes of tubes and fittings and threads, commnly available valves and what they look like (significant variations) and a host of other things like what size hex can you get off the shelf and where from if not in Australia.

I've got a filing system which lists
  • Loco parts (cylinders, wheels, etc) and drawings I have of each
  • Special tools and techniques.  Always handy to take photos and file away for later.
  • Suppliers and who's got what, and what sizes are out there
  • A Master spreadsheet of the commonly available sizes and combinations of things (say 3/16" pipe steam fitting has 5/16" x 32 threads, and the union nut for those will be 3/8" AF).  Makes a real easy job of making your own stuff if you can't get what you want.
  • The Model Engineer designs (Who drew what and when - great resource to have). 
  • Photos of models that I like (good inspiration)


Here are some common themes I've seen on different designs of 5" gauge engines.
  • 3-5mm frames at about 4-1/8 to 4-1/4" apart (inside spacing).
  • 3/4" silver steel or 4140 axle for the drivers, 5/8" for the other bogie wheels
  • Pommy/fine scale wheels are usually 9/16" or 5/8" wide
  • Plain bearing axle boxes are usually 1-1/4" wide and running height is with the axlebox 1/8" off the horn stay, and 3/16" from the top of the horn
  • 16g (1.6mm) running boards with 18g (1.2mm) cab and tender platework
  • Probably 1/16" rivets for platework, in some close spacing the exact number of rivets can look odd. Reduce the rivet size or less rivets for better effect.
  • Mostly 3/16" plumbing for the steam stuff, and thereby having mostly 5/16" x 32 steam fittings
  • Balls in check valves are usually the same diameter as the pipe.
  • Minimum 5mm gauge glass (at least) which will be on 1/4" or 5/16" threads.  The dimension from the bottom nut to the centreline of the bush is a critical one for the 10% cover of the crownseet, I am yet to see a drawing with this dimension, but I believe it to be 1/2"
  • Boiler tubes and flues for an average 5" barrel boiler I'd make is 1" flues, and 1/2" tube.  It is common to see the flues double the tube diameter.
  • 3/8" radiant superheaters fit nicely up the 1" flues, 5/16" up 3/4" flues, and 1/4" in 5/8" flues.
  • Non-stocked or expensive tube sizes in Australia of 5/16" or 7/16" means that the tube nests of some designs will have to be completely reworked.
  • 3mm copper throughout the boiler to reduce the number of stays, stays being 1/4" solid copper rod
  • 1/2" x 26" safety valves in most 5" gauge boilers.  If conventional valves don't relieve enough steam, go to pop valves.
  • All the papers on blast pipes and chimey chokes for the sizes we deal with can be summed up in the steam has to get out without foofing around in the smokebox and back pressuring the cylinders!
 Happy steaming!

Nigel

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