A few weeks ago, I flirted with folly. I thought about knitting sweatpants. No, not those IK sweatpants, but something in a 4-ply weight cashmere. (With a knitting machine. I’m not crazy.)
I successfully fought off that demon, but the thoughts about pants coincided with a couple of recent magazine articles.
The most challenging part of fitting trousers is getting the crotch right. You don’t want it so deep that the seam intersection feels like it’s suspended around your knees (unless that’s the look you’re going for, I guess) or creates that weird horizontal pouch in front when you’re walking; and you don’t want it too shallow, either, for obvious reasons. If you decide to alter the depth of the crotch, you might wind up adversely affecting the fit around the hips. Of course you can plan for this challenge by adding extra-wide seam allowances for fitting purposes or by making a muslin first, but even so, fitting the crotch was always a hit-or-miss sort of thing for me.*
Usually, pants-fitting advice involved measuring your crotch depth (sit on a hard chair, use a rigid ruler to measure from the chair seat surface to your waist), then slashing and spreading (or overlapping) the upper portion of the pants pattern so that the crotch depth on the pattern matched your measured crotch depth. Murphy’s article describes a method in which the contours of your “negative space” are taken, and transferred to the pattern, altering the side seams to accommodate the changes.
The “negative space” is the cross-sectional area defined by the crotch seam — it’s more or less U-shaped. Imagine you’ve got a pair of trousers in your hands, and you turn them inside out. Then you stuff one leg inside the other so that you’re holding half a pair of trousers. That edge of fabric running from the center front waistband to the center back waistband is the crotch seam, and that empty area is your negative space. Taking a measurement and copying the curvatures of your own negative space is an improvement over the measure-your-crotch-depth technique: while lots of people can have the same crotch depth, the, um, bulges defining their negative space can be different.
At about the same time, the most recent issue of INKnitters came out, with Bonnie Triola’s machine knitting column in which she answers questions sent in by readers. This time around, one reader wanted to make his wife a pair of square crotch pants, but lacked a pattern. Triola supplied the formula: basically, these elastic-waisted, pull-on pants are knitted from the hem to the waist in two pieces (left and right, each piece comprising the front and back leg), and the crotch is shaped by binding off 1 inch at the front, 2 inches at the back, and knitting the remaining stitches until the work measured from the bind-off rows equals the measured crotch depth plus waistband casing.
I’m not certain what I found more alarming: the ultra-short crotch seam in the square crotch pants, the fact that someone was willing to publish the fact that he wanted a loved one to wear a pair of square crotch pants, or the opportunity to start making jokes about box-shaped… never mind.
If you’re having difficulty visualizing what’s so alarming about these square crotch pants, I’ve got an illustration for you.
Do you want to see my negative space?
I knew you did.
In order to find the shape of the negative space, Murphy used a flexible curve with a tape measure affixed to one side. It’s flexible enough to bend around a body part, but will hold its shape sufficiently to allow a relatively accurate curve to be traced onto paper. Flexible curves (with or without the measuring tape — the one at right is without) are available from art supply shops.
The flexible curve I had on hand was about eight inches too short to take a proper measurement from my center front waistline to center back waistline. I needed to eyeball the upper 3-4 inches on either side when I traced the curve, but this is still an accurate portrayal:
The curved line is the tracing from my flexible curve. The dashed segments represent Triola’s square crotch instructions. Ouch.
Both have the same crotch depth, but they certainly don’t have the same cross-sectional area or crotch length, and I don’t think the knitted fabric would stretch enough to make the square crotch comfortable. Even if the fabric could stretch to make the square crotch fit the body, I simply can’t (or perhaps I don’t want to) visualize how it might look when worn. I’m sure it’s possible to make a pair of successful square crotch pants, but I’m guessing that such a pair would involve a looser fit around the crotch than the formula described above. (And I’m not about to squander my cashmere trying that out.)
But however you might decide to approach your crotch fittings, please be sure to practise good hygiene if you plan to share your measuring devices.
* Actually, the last five pairs of pants that I made (not very recently) fit rather well without too much tweaking, but they had nothing to do with my fitting skill. Two pairs were the voluminous-amount-of-material type of maternity pants, so all discussion about crotch measurements beyond a Brazilian cut went out the window. The other three were made from a pattern traced from perfectly fitting (as they then were) but worn out biz-casual pants. So I didn’t have make any real attempt to fit those five pairs to my body. The last pair that I made before that was an excellent job in terms of the actual sewing, but the crotch didn’t fit very well; it had the “pouching” problem caused by a too-long front crotch and a too-shallow back crotch (I think that was the cause).