Transference of the measurements to the material {not fully checked yet} first created 11/12/05 - last modified 12/12/05 Page Author: Ty Harness

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Manual techniques

If you can plot a 1:1 paper plot or make a 1:1 paper pattern by combining several smaller paper sheets then you can simply centre dot (or pin) through the paper to transfer the pattern to the material. If you making more than one then it's always worth making a more substantial pattern out of hardboard or thin sheet so you can then simply scribe or chalk round the pattern for further copies.

Figure XX - Plotting a 1:1 pattern directly from the Square-to-round application on Encad A0 plotter

There are mechanical methods out there to transfer patterns point and even scale the dimensions up or down at the same time. The simplest device is the double ended dividers (Proportional dividers). These are usually made for a fixed scale (1:2 ~ 2:1). Scale below or above 1:5 ~ 5:1 becomes impractical.

The the most elegant mechanical method is the pantograph. Here's a nice to link by IES ( http://www.ies.co.jp/math/java/geo/panta/panta.html) showing how to use a pantograph mechanism.

A nice web pageshow showing a pantograh and other drawing tools

You can ask the draughtsman to produce a fully dimensioned drawing of the pattern . Using the DXF export of the 2D elevations it only takes 15mins to fully dimension up the square-to-round.
Fully dimensioned square-to-round. The DXF files were imported into TurboCAD and then dimensioned. You can easily transfer the pattern to the material with dividers - it's just a copying exercise.

NC/CNC: If you've got a CADCAM interface to your machine tool (M/T) then the 2D DXF file format is going to be your simplest method of getting the data to the M/T.

Figure XX - JetCAM free DXF viewer. JetCAM is a fairly common interface to get from DXF to the M/T language.

If you do need to type in co-ordinates into a G code program then you can see the pattern coordinate list from the View menu. You probably need to reduce the round resolution down to 24 points otherwise you'll be there all day typing the coordinates.
If you're using CNC then you're also talking mass production: It always pays to make a couple of samples before you commit to a production run. You don't need me to tell you mistakes are costly. Check everything twice and then get someone else to check the pattern twice as well.

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