One thing which did worry me before I started sewing it was the fact that all the seam allowances are ⅜"/10mm. For as long as I have been sewing, the seam allowance on patterns has been ⅝"/15mm. I'm so used to this that I even use it when I draft my own patterns. So I was convinced that at some point I would forget, and merrily start sewing up ⅝" seams.
However a quick look through some of my vintage patterns shows that the ⅝"/15mm allowance has been far from universal in the past. Although initially patterns had no seam allowance included, this Butterick pattern from 1923, which is one of my oldest, has an allowance of (mostly) ⅜".
|Butterick 4530, 1923|
The exceptions are the wonderfully-named "outlets", the areas which you might want to let out. These are described on the Deltor (instruction sheet) as having "an additional amount", which on measuring the pattern turns out to be an extra ⅜".
|Outlets! and seams! on the Deltor|
McCall were a forward-thinking company in the early twentieth century, being the first to introduce both printed patterns and coloured artwork, so I assumed that their patterns would include seam allowances. They did, and the information is on the envelope flap. Again the allowance is ⅜".
|McCall 283, 1935|
Advance patterns allow a whole ½", a point which is stressed on the envelope back.
|Advance 2229, 1939|
|There could be no missing the seam allowance information|
Meanwhile Simplicity continued with the idea of variable seam allowances. The envelope back for this blouse pattern includes the information that ¾" is allowed for underarm seams, while all other edges are ½".
|Simplicity 4139, 1942|
I'm not sure if this difference is because the underarm seams need to be stronger, or if it is to allow for 'outlets' (although that would seem an odd place for them). The coat pattern Simplicity 4896 has wider seam allowances at the sides, "to permit alteration".
|From Simplicity 4896, 1944|
Also allowing for alterations is this pattern from Bestway, a British pattern brand mainly associated with women's magazines. Most of the allowances are ½", but the side edges of the skirt (but not the bodice) have 1" allowances "for fitting".
|Bestway 18928, 1940s|
Vogue does not seem to have been an especially innovative brand; for example it was very late moving to printed patterns. By 1955 however it had adopted the now-familiar ⅝" seam allowance: it is mentioned on the instruction sheet of this pattern.
|Vogue S-4644, 1955|
Meanwhile Maudella, another British brand, were clearly late adding 'turnings' (seam allowances) at all. At least the fact is made very clear on the envelope.
|Maudella 4279, 1950s|
On the back of this pattern envelope however, it states that "⅝" allowance added on all seams".
|Maudella 5151, 1960s|
And the Grace dress? It's early days, but so far I've remembered to sew ⅜" seams. In fact, for things like attaching the collar to the bodice, the narrower seam allowance makes the whole thing far easier to handle. Perhaps I need to rethink my attachment to ⅝" seam allowances for everything.