What is Canvas anyway?

[Lekpij]

@Greger
Interesting points on cutting the canvas on the bias for different purposes. A thought I had on this, would it be correct to think that the angle of the bias can "match" de angle of the movement the arms make for the intended activity? like in the golf example you would match it in the direction the arms make the swing or in the loan example you could cut it so you can write that signature more easily

Thank you all for taking the time to give these great answers, I wil be getting some samples soon and can then make an informed decission!

[Gerry]

When body canvas is angled, it's done to create a degree of softness in the body of the coat. The arms don't really come into it  They don't have canvas for a start; and sleeve cap height determines how much mobility you have in casual jackets. Things like hunting coats have pleated backs and extra ease in the crown of the sleeve, especially over the back part, which allows greater movement.

If you go back far enough, lounge coats were worn for all sorts of manual activity. I remember when I was a kid that many of the older generation used to wear them as workwear as if they were an overall. They were even worn when taking part in sporting activities (skiing etc). Hence the term sports coat.

Modern golfing jackets are more like bomber jackets. If one were to interface them, whatever you used could be put on the bias I suppose. It would be more like an underlining though. Just something to thicken the material and prevent it from creasing. Similar principle as when a waistcoat has the canvas placed on the bias, I guess. It doesn't really have the dual purpose of creating sculptured shape. Not to the extent that it does when used to reinforce lounge coats.

As mentioned earlier, there's a limit to how much you can angle the canvas when creating a sports/lounge coat. Angling it too much will cause the lapels to collapse and roll and the body will be too soft.

[Lekpij]

@Gerry
Ah I was way off. I thought it had to do with how the sleeves could pull on the rest of the jacket but it has more to do with the softnes. For now I wont be messing too much with biased canvas but in the future I will definetly experiment more with that aspect.

[Greger]

The 1949 tailor and cutter has a page or two with a few ideas of canvas angles. Could be three pictures. One angle you don't need haircloth. It's not always about rigidness. On the bias is more flex. Like the seat of the pants. Straight grain on the seat of the pants would not be good. The crotch area the same.
Granddad talked about boys who were very good artists. They come up with ideas they want to make. And his instructor would be teaching him something and come back to see how the lesson is going only to find him working on a shirt art idea (fashion/style). Some boys were unteachable. Canvass are for support and created for the need of the idea (art). Take for example an 1478 coat. The ideals and need of the coat is different than today. Men carried swords. The shoulder needs to be flexible for quick movement. The other canvass went into the stomach area. Armor, and while you are at it, fancy shaping. I remember granddad explaining how to make that coat to a previous apprentice. Anderson and Shepard cut the main canvas for drape and the secondary canvas is much smaller than other Saville Row tailors. Pad stitches are far apart. Even the lapels are stitched looser on some of there coats. An 1990s book,I think, explains padstitching six rows to the inch for some coats. Cheaper coats less and less and less. And there are different ways of padding. Back to the boys that couldn't be held to the lessons, had great designs, but didn't understand structure, their achievements were less.
When you have the front coat cut out put an incut canvas on it, or other way around, and keep shifting it, thoughts in-between, how the movements wanted will work with the angle and muscle development of the person to wear it. And then how much of the next canvas if there are more. And how you are going to pad stitch the various parts.
We want a nice hanging garment that fits. But, if I changed part of it, cut, canvas, stitching, would it be just as nice and better movements? Just because a book or instructor or famous tailor says so, well, maybe something else is better for that coat and person. Muscles can change a coat a lot. Be a thinking tailor instead of, we have to follow these rules. The old books talk about ever changing styles and fashions. Tailors have to be adaptable. And the one that figures the best methods brings in the most money.

[Lekpij]

Be a thinking tailor instead of, we have to follow these rules. 

And how else are you going to discover something new if you only stick to the rules.

But as an absolute beginner some guidelines are very helpfull!

[Greger]

You can drape the canvas over the shoulder at different angles, pin what you need out of the way and see how it effects movements. Tape and pocketing can help hold the lapel roll. Some people like a flat roll and some a very round roll. And there are different ways of pad stitching lapels.
Also. A person's body shape can have reasons to change the "general" shape of the canvas. Might need to add canvas, felt, wadding, etc.