Second part of a post by Sator -- T.
Like Poulin, Cabrera also gussets open the shoulder cut with a strip of canvas:
His method of cutting a fish shaped front dart that is not cut through to the edge of the canvas should be avoided as this produces too much distortion.
Cabrera then makes two cuts on the chest piece at the shoulder to either side of the one in the canvas and holds them open with French collar canvas:
Cabrera cuts his chest haircloth with a rounded base, extending partway towards the armscye. There is a waist dart corresponding to the one on the coat. There are cuts held open at the shoulder and a closed chest dart at the front of the haircloth to give the chest roundedness:
Here is another way of doing it, this time from Croonborg in his Blue Book, 1905:
Of interest here, is the horizontal dart at letter A that in conjunction with the dart at C, which is preferable to the fish shaped front dart shown by Cabrera, as it helps to reduce distortion.
Croonborg cuts his chest piece with a puff gusseted open by another piece of canvas at letter E (in place of an armscye dart held open like Dellafera) and the armscye is shown stretched:
This comes from Regal's (1930s) and clearly indicates that the plan of a canvas cut on the full bias:
This brings us to the issue of cutting the canvas on the straight grain vs. cutting on the bias vs. cutting on the cross grain. Unfortunately most texts, such as Poulin and Regal's, just say to cut both canvas and chest piece on the bias but leave it at that without explaining it any further.
One text (quoted in Doyle - source unclear), interestingly, says that when cut on the straight grain (section A), the canvas gives a more severe, firm finish to the front. By contrast, a canvas cut on the cross grain (section B) results in a "more flexible and softer finish, often used in sports jackets and in women's canvases", but that it will require a strip of linen cut on the straight grain to be placed along the front edge to support buttons and holes.
Large darts can disturb the balance of a coat. For a discussion on the impact of darts on balance see this thread.
Putting Together the Chest and Body Canvas
This is a translation from an article previous posted elsewhere by Schneidergott. I assume they are from circa 1960-70s editions of Rundschau. In particular note the technique of cutting along the weft of the chest canvas. The cut is then allowed to cross over to form a dart. This avoids cutting a wedge shapes segment out of the chest canvas. The advantage of this is that it places the cut directly along the weft where the horse hairs run, and avoids cutting the horse horse, as would occurs if the cuts were on the straight or bias.
The cuts are first closed with fusible tape before being sewn over:
The following shows the shoulder support above, and below it the chest piece:
Observe how the arrowed lines shows the maximal spring of the hair in the cloth [along the weft/crossgrain]. You can see that they run in the opposite direction for the intermediate layer and the chest piece so as to give the area around the armscye extra support. The intermediate layer also covers over the cuts made in the chest piece at neck seam and armscye.
The outside of the canvas:
The fullness of chest sits somewhat forward of the canvas.
The next picture shows the canvas from the inside:
The cut in the neck seam is shown. It is covered over by the intermediate layer, the spring of which is placed so as to optimally hold it closed.
Notice too that the cuts in the chest piece are made to run exactly along the woof. This is so that you don't cut through as many of the horse hairs running in the woof, as this will weaken the chest canvas.
Here is yet another instalment from Schneidergott's collection of Rundschau journal articles. This appears to be a 1960s article when the fashion for omitting cuts from the shoulder was widespread in the German literature. Notice the way they advise against an excessive number of cuts in the canvas and they have given up the older practice of cuts inserted around the shoulder to hollow it out, preferring the softer look that this results in. Note too how in this article the chest piece has been cut so it is oriented with the straight grain sitting vertically as it lies on the canvas. Compare this with methods in which the chest piece is cut so as to sit on the bias once placed on the canvas.
The canvas helps to maintain the shape and form of the coat. On modern styled coats the canvas should be soft and supple rather than being like a coat of armour. This makes it important that the canvas cloth match that of the coat in its weight and strength. The canvas should be worked up to follow the shape of the wearer's figure as well as the dart placements on the coat.
An excessive number of cuts in the canvas should be avoided. Good canvassing is springy and every cut in it passing through either warp or weft will weaken it. A single 2.5-3.5 cm wide dart in the waist should therefore suffice. It should extend 1 cm higher than the front dart on the coat:
The dart is sewn together using a piece of lining cut on the bias - preferably thin sleeve lining to allow the dart edges to be cleanly opposed. The dart is then secured using a normal sewing machine or a zig zag stitch machine. It is then pressed flat using a pleater (wooden block).
The canvas front dart should be a little wider than that of the coat panel. The dart on the chest piece which lies inside of the canvas must be sufficiently long so as to give ample fullness of chest to enhance the shape of the whole canvas. This work can be done either using a tailor's ham or on a flat table, as shown in the following picture:
After the centre dart on the chest piece has been sewn up there should be extra length at the front and back of the seam. Additional cuts are then placed along the weft from front and back to provide extra fullness of chest:
The canvas is then placed again on the table supported from behind by a pleater so as to allow the fullness of chest to basted into place:
A second line of basting is placed along the length of the armscye.
The canvas is then turned the other way and laid down with the cuts in the chest piece lying as shown:
The chest piece is then basted again lengthwise onto the canvas.
The chest piece can now be pad stitched either by hand or machine. In either case it must be clean and free of bubbles.
For that the canvas must be padded from the outer edge with stitches that are not too fine, allowing canvas and chest piece to be rolled in the fingers. With delicate materials a fine yarn must be used.
In the last picture the completed canvas is shown after it has been worked up with iron to give its final form with a fullness in the chest but flat at front and back:
The former practice of infusing hollowness into the shoulder with cuts or darts has gone out of favour, as in modern men's tailor a softer, more lightly flowing shoulder is now favoured over a more upholstered look.