I'm making a pair of wool dress pants, and as usual I'm lining them. Or rather I'm half lining, half underlining them. I have invented an order of construction that lets me assemble the pants almost completely, including inserting the lining, but continue to check and refine the fit at critical seams without taking the lining out. (I'm not saying I'm the only person ever to have had this idea, but it's one I didn't acquire from anyone else, so I'm claiming it as my invention!)
I cobbled the pattern together from two different ones I've made before. The first is a Burdastyle pattern from 2005 that I made in 2012. I had adjusted this pattern for fit when I first made it and they still work for me. However I wanted a more standard fly front/pocket combination, and loving the comfort of my Style Arc Kew pants, I attempted to graft the waist/pocket/fly from it onto the Burdastyle legs.
So I did not make a muslin. I figured it was a risk worth taking because I'd made these pants before (sort of). However I don't fully trust my pattern-drafting skills so I wanted to be able to refine the fit as I went. The outer leg seam is for me the main and critical one, since it allows me to refine the hip curve and hip/waist circumferences. However the CB seam is also a good one to be able to adjust.
First, I made the pockets and fly front. To sew the fly I had to sew the front crotch seam but I did not sew it all the way to the inseam. I left it open a few centimetres so I could later attach each front leg to a back leg along the inseam. I like to sew the crotch seam in one pass from the bottom of the fly to the back waist. As Style Arc says, this improves the crotch shape. If you sew the front and back crotch seams before sewing the inseam, the result is to flatten the crotch curve seam allowances where the seams intersect. It's better to have that crotch curve seam allowance vertical - you can trim it for comfort and fit.
After sewing the back darts, I sewed the fronts to the backs at the inseam in each of my layers - the fashion fabric and the lining.
Then I basted the lining to the pants (one layer of lining, one layer of fashion fabric, wrong sides together) along the back crotch curve and all side seams I used a 2 thread serger stitch to neaten all the raw edges.
Next I sewed the crotch seam through all layers. At this point I'm treating the lining as underlining. The seam allowances will be accessible inside the pants rather than being sandwiched between two separate layers (fashion fabric and lining).
The fact that the front crotch was already partially sewn in the fashion fabric meant that I could stop sewing this seam a few centimetres away from the lower point of the front fly. I'll be attaching the lining to the inside of the fly later by hand.
After all that I was left with something that looked like this.
As you can see, this treatment is partially lining the pants (inseams, darts and all front details are sandwiched between the lining and fashion fabric) and partially underlining them (at CB and side seams).
Now to baste the side seams and check that pesky fit... I'll be back soon.