Yesterday i was roaming around on one of my favorite sites, the fashion incubator, and found a whole tutorial on waistbands. I am beginning to think that the site is magical. Every time i need some very specific patternmaking information, it just floats my way on the fashion incubator -- like when i was having camel-toe problems with the jeans i was patterning, and then poof! there was a full three part tutorial on how to fix camel-toe! And it worked..
Anyway. According to Kathleen Fasanella, the reason waistbands are traditionally cut cross grain, is that it is practical for the industry -- it can be fed in long strips, whereas if it were cut on the straight of grain, it would have to be cut across the bolt, and it would be impossible to have long continuous strips to cut from later. Sometimes they even leave the fabric in a roll, and just slice it jelly-roll style -- hundreds of yards of continuous waistband to use as needed.
The problem this causes however, is that the crossgrain and the straight of grain behave differently -- or course the crossgrain have more give, which is why it is situated horizontally on our bodies, but also, the staight of grain shrinks at a rate of 3 to 1 -- obvious when you have jeans that may not get tighter, but do get shorter over time with many washings. When waistbands are cut on the crossgrain, they tend to shrink dispropotionately to the rest of the pant, which distorts the fit of jeans over time. I've experienced this so many times, but it wasn't until reading this blog entry yesterday that it began to make sense.
Apparently the couture way of making pants always involves waistbands cut ongrain. Also, there was a lot of discussion about whether bias or contoured waistbands were better for lower waisted pants -- as mentioned in the comments from the previous post. I made a couple pairs of highwaisted pants last fall, where the waistband was at least 3 inches thick, and found that contouring the waistband with the CF and CB on the straight of grain and the sides on a semi-bias worked nicely.