GL5 Forum

This request is aimed at all the design engineers amongst us. As nted in my last post I am undertaking a build of a Stanier 2-6-4 2 cylinder tank engine. Ihave not been able to track down a full set of drawings to-date, although one member has kindly offered to take copies of a GA and frame drawing in his possession. That's a great start but does leave a lot of detail un-specified.

I have a set of "Jubilee" drawings at 3 1/2" scale and I'm thinking of scaling these up to fill in the blanks. Now here is the problem; What is the actual figure used to convert from full size to 3 1/2" scale in the first place? It works out at .743" but I wondered whether this was rounded up to 3/4" for ease of calculations, similarly to 5" gauge rounding up to 1 1/16"?

Can anyone help me out with this?

Thanks in advance!

George.

George,

3 1/2" gauge is as close to 1/16 scale as you could reasonably get without introducing a decimal.Theoretically the gauge at 3/4" to the foot should be 3.531" but who's arguing about 1/32"? The models are definitely drawn 1/16 scale. Likewise 5" gauge should be 1/11.3 scale but it's taken as 1 1/16" to the foot which accurately translates to 5.003" - near enough for most purposes.

That said if you have 3/4" scale drawings, simply multiply the dimensions by 16 to get the full size dimension and then having converted it to feet multiply by 17, divide by 16 and that's your 5" gauge dimension in inches. (0.75*16/12 *17/16=1.0625)

The problem with that is the round offs. Many of the LBSC, Evans and other designs were prepared in fractional inches to the nearest sixty fourth or thirty second and this will introduce errors in your conversions.

If you can get a full size GA it will help you check important dimensions. Have you tried the NRM? They claim to have about 10000 drawings from Crewe & Derby. Last I looked they had not catalogued them but they might have progressed since then.

Good hunting

Eddie

Thankyou for your considered reply Eddie. That should keep me busy for a while! I'll have a word with the NRM and see what they have. I'll let everyone know what I find.

Cheers,

George.

Hi all,

There are approx. 60+ drawings relating specifically to "2-6-4T" engines, some are 2 cyl Stanier, some 3 cyl Stanier, and perhaps some Fairburn drawings too. The description on the archive list leaves a bit to be desired. There are also a lot with the same title that may be re-traced or ammended drawings and therefore duplicates.

If anyone is interested I can forward the list I collated yesterday, just drop me a line.

Cheers,

George.