Sizing a smocked yoke by chest size

Before you pleat, you need three numbers: how many pleats the plate spans, how wide the pleated panel is, and how wide the raw fabric must be. This guide shows the arithmetic the Plate Designer performs.

The formula

Finished width = (chest + ease) for a full circumference, or half of that for a front panel.
Pleats = finished width divided by the pleat pitch, 0.25 inch.
Pleated width = pleats times 0.25 inch.
Raw fabric width = pleated width times the fabric ratio, 3:1 by default.
Widths of fabric = raw width divided by usable fabric width (fabric width minus 1 inch for selvages), rounded up.

Table for a front panel

Front panel, 2 inches of ease, 3:1 ratio, 45 inch fabric:

Chest (in)	Pleats	Raw width (in)	Fabric widths
18	40	30.0	1
20	44	33.0	1
22	48	36.0	1
24	52	39.0	1
26	56	42.0	1
28	60	45.0	2

Odd and even pleat counts

A mirrored plate needs an odd count so one pleat sits on the center line. Honeycomb and surface honeycomb need an even count because they work pleats in pairs. The designer rounds up to the next valid count and tells you when it did.

Ease

Ease is the extra width beyond the chest measurement. Smocking stretches, so many makers use less ease than for a woven bodice. Set it to your own preference in the Plate Designer; the limits are 0 to 8 inches.

After sizing, estimate your thread with the floss guide.

Worked example

For a chest of 22 inches with the defaults, the table gives 48 pleats. That is 12 inches of pleated width, and 36 inches of raw fabric at 3:1, which fits in a single 45 inch width. Change the ratio to 4:1 and the raw width rises to 48 inches, which needs a second width. The designer does the same sums live as you change the numbers.

Choosing ease and ratio

Leave ease near 2 inches for a first try, then adjust after making a test panel on scrap fabric.