Scaling from drawings

[standardsteam]

I was wondering if anyone can point me to any useful references with regard to scaling plans from full size dimensions to 5" guage? I guess I could take a back to back wheel measurement from the model and then use this, but this is sometimes compromised. What is the usual accepted scaling for 5" ? I'll probably take a few reference measurments and then use those to estimate how the actual model has been scaled, but any reference would be helpful.

Also, does anyone out there know what typeface was use for BR nameplates (were they all the same size/pitch)?

[Lee]

There is a scale dimension calculator that works with Excel available as a free download from AME's web site. www.ameng.com.au/downloads.htm
Lee

[chris vine]

Hi,

Be careful of back to back measurements in models as this is the one thing that is not necessarily to scale.

If you have a good side view then you can measure off the axle centres, they are usually marked and work from that. (the axle centre distances are one of the most easily available full size dimensions)

From a front view the od of the boiler should be a known size.

A digital caliper is a useful device for measuring on the drawing or photographs

Chris.

[standardsteam]

Thanks for the reponses, what I'm partly after is what the guages were designed to represent in terms of full size, I remember reading in one of the issues of Model Engineer at one time (in the pile somewhere) what they were suppose to represent in terms of feet per inch or similar...

[jackrae]

5" is the scale size of 1/12 or 1inch to 1foot but I'm sure someone will differ
jack

[GWRdriver]

Quotations to ponder:

"Works drawings should always be treated with suspicion."
Derek Mackenzie, Orion Models

"With regard to works drawings, whilst a drawing may show all the detail necessary for a nice representation in model form, the use of the dimensions shown on the drawing is the important thing. It was never intended that drawings should be used for anything other than as a means of giving a pictorial representation of the subject AND as a means of giving the dimensions - never as a template for cutting a full size component!
To try and scale from drawings is a dangerous thing for several reasons, most important of which is probably the distortion almost always present in the printing process. So whilst the general shape may be ascertained the 'truth' must always be tested by applying the scaled dimensions. Hope this helps a bit and serves as a warning that care is necessary when using drawings."
Dave Stick, G1MRA

"Never scale the print!"
All my old Mentors

[jgb7573]

Standard gauge (4' 8.5") full size translates to 5" gauge a 1.0619 inches to the foot. This is pretty close to 1 and 1/16" (1.0625) inches to the foot.

[baggo]

5" gauge locos are usually designed using a scale of 1-1/16" to the foot, at least that's what the drawings for Don Young's Black Five use. The Americans use a scale of 1" to the foot which gives a track gauge of 4-3/4"

3-1/2" gauge uses a scale of 3/4" to the foot and modern 2-1/2inch gauge uses 17/32" to the foot (although early 2-1/2" models used 1/2" to the foot).

John

[Donald G]

I am currently building a Class 2 standard tank, mainly using toe pipe and line drawings of an Ivatt and alos pictues from various books, and inforamtion from Don Yungs Standard class 2.

Usually the loco drawings are at a scale of 1 1/2 inc to the foot, which I believe is what 7 1/4 is based on.

I have made myself an Excel conversion table, as I didn't know, ( or to be more honest, never thought to check) if one already existed.

It can be a slow process, measuring, converting, and then drawing it up, but can give you a lot of satisfaction. I have made all the internal frames and stretchers out of 1/16 inch thick steel fabricated , and it looks very effective.

Good luck Donald