Rod's point here is a good one. I just emailed Denny off-line that the factor is 0.7348, which is

64/87.1. Some copiers will do this level of precision, but even those are not COMPLETELY reliable.

Using the known length of line to get a reduced length so one can check the machine's capabilities

is a very good idea. One more thing, a machine I had in my office would be different reductions in

the two principal directions. 85% LtoR would be about 83% Top to bottom. That machine got

replaced. But putting lines in both directions will reveal this.

If it's critical, you should get this done photographically. It's increasingly hard to find shops

that can do this, but not impossible.

SGL

toggle quoted messageShow quoted text

-----Original Message-----

From: STMFC@yahoogroups.com [mailto:STMFC@yahoogroups.com] On

Behalf Of Rod Miller

Sent: Wednesday, January 18, 2006 9:12 PM

To: STMFC@yahoogroups.com

Subject: [STMFC] Re: Conversion percentages.

Hi Denny,

The method Jerry White showed me was to draw/tape a line that

was a specific length in the scale of the image to be

enlarged/reduced.

E.g., an O scale (1:48) drawing would have a line, say, 2.5

inches long which represents e.g. 10 feet.

Start with an approximate enlargement/reduction setting and

make a copy. Measure the length of the line on the copy and

determine its scale length for the scale you want. When the

line is 10 e.g. feet long in the scale you want, you have the

correct reduction/enlargement.

E.g., suppose you want to reduce an O scale (1/4 inch = 1

foot) drawing to S scale (3/16 inch = one foot, or 1/64 inch

= 1 inch).

A 10 foot long line in O scale is 10 1/4s or 2.5 inches long.

A 10 foot long line in S scale is 120 1/64s or 1 7/8 or 1.875.

When your line on the copy is 1.875 inches long the copy is

accurate for S scale.

IMHO that is more accurate than calculating a reduction/

enlargement percentage.

Regards,

Rod Miller

Message: 18

Date: Wed, 18 Jan 2006 13:51:26 -0800

From: Denny Anspach <danspach@macnexus.org>

Subject: Re: Conversion percentages.

Off hand, does anyone know what percent rule of thumb

reduction (e.g.

as would be set on a copying machine) to accurately reduce S-gauge

plans to HO (1:76 ---->1/87.1)?

Thanks!

Denny

--

Denny S. Anspach, MD

Sacramento

Yahoo! Groups Links