Draft lines perpendicular to Line 1, with the following measurements. Point O, 1/12 breast -1/2 inch.
At the second point, 1/2 Width of Back plus two seam allowances.
Measuring at the breast point, mark a line which is 1/2 breast measurement, plus 2 inches. Point A on this line is 1/4 breast measure (plus the 1 inch), and Point B is measured (one half) of the across chest measure.
At the natural waist point, measure 1/18th of breast measure (Point C), then 1.5 inches across to Point D.
From this new point, draw the shoulder line, connecting to the width of back. On this line, draw a slight hollow betwixt Point M (which appears to be 1/18th of breast from the end of the line) and the top of the shoulder.
Add 1inch to the above measurement, and sweep again, from point H. The intersection is the neck point.
For the third sweep, deduct the measurement of Point 3 to Point M from your over shoulder measure. Take this measure, and sweep again from Point B--With your finger 1.5 inches above this point, so the actual pivot point is 1.5 inches above Point B. The distance between Points I (sweeps 1 and 2) and J (sweep 3), is the same as the measure of the back shoulder line, minus 1/4inch.
Sketch a straight line between Points I and J, and round it up about 1/2inch at about 1/3rd of the way from point J.
To draft the armscye; first mark points 1.5inches, both horizontally and vertically from Point B (Points K and L). Draft the curve from Point J to Point K, with 1/2inch of hollowing, then smoothly curve betwixt K and L. Smoothly curve this up through points A and E, on the sidebody piece (you are redrafting this). Add a 1/4inch gap between the two pieces at E and redraw, keeping a point of contact part way along the curve.
When it comes to drafting the neckline, you have two options--either use the 1/12 breast measure, minus 1/2inch, or 1/6th of the breast measure. I chose the first, as it gave a slightly smaller measure. Measure over by the result--then down by the same amount--and draft the curve of the neckline. Remember that you can remove some fabric here later, as needed.
Draft a line down the front, from the bottom of the neck, through Point H, W, and to the bottom. Remember that this does not include any overlap for buttons, nor lapels. Add 1.5inches to the front for the overlap, and shape the lapel as desired.
At fashion waist on the back, step out 1.5inches on both sides--this is the overlap and the pleat. On the inside, slant that 1.5inches up, by 1/2inch. Extend straight down, to the desired length.
At the bottom of the 9inch line, mark out 1inch. Slant a line outwards from the top, through that line, which is the skirt length (remember that straight, inside seam on the back piece? That will be your skirt length). Mark out 1/2inch, and curve.
Measure up 2.5inches from Point F, and mark a line from Point 1, with a slight hollow. On my skirts, I extended this line another 10inches, to allow for extra pleats.
There are two ways to determine the slant of the front.
If the front of the coat body slants outwards (as in the Huntsman's frockcoat), you can continue that line.
The other option is to measure up another 2.5 inches at Point F, marking a line to Point 1, and square out from there.
I used the second of the two options, since this frockcoat is fairly fitted.
When drafting the bottom, make sure the front, back, and middle are all the same height.
That's it. The sleeves will have their own, separate tutorial.
These directions are from The Cutter's Practical Guide (to body coats), 1893-98.
I have not tried them, but here is The Tailor's guide: a complete system of cutting every kind of garment to measure, containing upwards of five hundred diagrams. Imprinted to 1856.
The author's masterpiece; a correct method for measuring and drafting coats. 1855
A treatise on cutting garments to fit the human form: containing fifty diagrams and designs reduced to mathematical principles. Dated to 1841.
I dream someday of making 3-4 frock coats of the same materials, using the instructions from different systems through the period, just to see what the differences are in the end garment.
© John Frey, 2014. The Author of this work retains full copyright for this material. Permission is granted to make and distribute verbatim copies of this document for non-commercial private research or educational purposes provided the copyright notice and this permission notice are preserved on all copies.