Plain-Cut Trousers

The side seam has to be stabilized and sewn together before we can install the pocket, and it involves a few steps. I choose to add linen interfacing and stay tape in certain areas, but realize they were not used in all trousers during the period, especially of the military variety. I find the trade off worth it though in prolonging the life of the trousers.

To begin, cut two strips of linen, about 1″ wide by 1″ longer than you want the pocket opening to be. I prefer a larger opening so I made my strips 9″ long, for an 8″ wide pocket mouth.

It’s great if you can cut them square but as you can see, I had a bit of trouble this time.

Baste the linen strips to the wrong sides of each trouser front.

Adding this strip of linen alone greatly strengthens the area around the pocket.

It’s now time to attach the trouser fronts to the backs. Lay out the front on the table, and lay the back over the top, right sides together.

Now pin the very top of the side seam at the waist, ensuring that when we baste the side seam, the tops will be aligned properly.

Now, starting from the bottom hem, baste to the position of the knee (you can be precise about this and lay it out on the pattern, or just estimate).

Be sure to match the plaids as you’re going, if necessary.

Now baste from the knee to the waist, positioning the trousers so that the back piece is underneath and in an orientation that is most comfortable for your you.

As you’re basting, you’ll notice that the underside has a bit more fabric than the top side. This needs to be distributed evenly, moreso around the pocket opening, with the remaining excess distributed just below the pocket and tapering off to an even tension by the time you get to the knee.

The idea is to have the back piece have a bit of excess for the seat and hips, as well as the pocket opening to be slightly under tension in the front piece, ensuring it stays closed while wearing.

Sorry it’s not more photogenic! But here’s the basted side seam.

It’s a good time to check how the plaids are aligned, and if necessary, redo them. Really depends upon how fussy you want to get.

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Your Progress

Finally, it’s time to attach the fly itself to the trouser front. Begin by trimming away about 1/4″ to 3/8″ of the fashion fabric and the linen interlining from the fly, being sure not to cut into the lining underneath.

Lay the fly in place on the wrong side of the trousers. I like to set the fly back a little to reduce bulk, so that the eyes of the buttonholes are about 1/2″ from the edge of the trouser. Baste securely down the center of the fly.

Turn the fly lining under itself – ideally it will encompass all of the layers that make up the fly and fly facing. Baste closed along the folded edge.

Fell along the folded edge of the fly from the waist to the bottom of the fly.

The very bottom can be a little unwieldy depending on just how you’ve trimmed and aligned things. Just get everything looking as nice as you can without making too big a deal out of it, as this area will be mostly hidden when the trousers are finished.

Using a machine stitch or back or side stitch by hand, top stitch through all of the layers about 1/8″ away from the folded edge of the fly. I like to use two different threads here for the machine, the bobbin matching the fashion fabric and the top thread matching the lining.

Use the edge of the fly and your presser foot as a guide while sewing.

The finished result should be a nice line of stitching on the inside.

As well as a smooth line of stitching on the right side which follows the shape of the fly perfectly.

Finally, we need to finish up the fly by making several rows of stitching across the fly, between the buttonholes, to keep the fly from opening up too widely while wearing the trousers.

Start by drawing some guidelines midway between the buttonholes and perpendicular to the edge of the fly.

Start by taking a knotted thread and passing the needle between the layers of the fly, catching the knot inside where it won’t be seen.

Tack the edge of the fly down with about 6 to 8 stitches in place through all layers except the outer layer.

Then begin back stitching across the fly, following the chalked guideline.

Be sure not to let the stitches show through to the right side! Finish off the back stitching with a few stitches in place. Repeat as necessary. This concludes the trouser fly construction.

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Your Progress

Before attaching the fly to the trouser front, we need to add the fly facing, which will prevent the buttons from wearing through the front of the trousers. You’ll need one fly lining piece as well as an optional length of stay tape.

Baste the lining fabric to the front of the trouser, right sides together.

Mark the seam allowance at the bottom of the fly facing, 1/4″ from the bottom.

Machine or back stitch the fly facing to the trouser front, from the mark to the top of the fly.

Remove the basting stitches, and open up the seam with your fingers. On the wrong side, baste in the optional stay tape about 1/16th from the stitch line.

As you get towards the bottom of the fly, hold the stay tape with more tension than the fabric underneath, continuing to baste as you go. This will serve to pull the fly area in towards the body.

Trim off the excess stay tape along the bottom and top as necessary, even with the stitching.

Now cross stitch the stay tape to the trouser front, being careful not to let the stitches show through to the right side.

With the tape stitched in, fold the fly facing back into place, allowing the facing to be rolled back 1/16th or so away from the front edge. Baste securely in place.

Now press using a tailor’s ham so as not to disturb the fulled in section. You’ll want to smooth out any wrinkles that formed when you held the stay tape tightly to the fabric.

Here’s the completed fly facing. Notice how it naturally pulls in towards itself near the bottom of the fly.

Finally, you need to trim the very bottom of the fly area directly to the bottom of the fly facing stitching.

This allows the fork area to open up and lay flat for stitching later on. I try to trim to within about 1/32″ of the bottom of the stitching, to prevent any potential fraying. Press the fork area back open.

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Your Progress

It’s time to work the buttonholes on the trouser fly. If you’ve never made a buttonhole before, please see my course The Art of the Buttonhole and practice on some scraps first, as this will just be a general overview.

Begin by laying out the buttonholes on the fly. The top buttonhole I usually place about 1 1/2″ below the top edge, and the bottom buttonhole about two inches from the bottom. Then fill in the remaining buttonholes equally (you may have more or less than I do, according to your size). Mark the width as 1/4″ to 3/8″ from the edge, and 1/8″ to 1/4″ wider than your buttons.

Baste around each buttonhole with a diagonal basting stitch to secure the layers.

Fell along the edges of the buttonholes to secure the edges permanently.

Attach the four-cord or gimp along the edge of the buttonhole using a couching stitch.

Now work the buttonhole stitch evenly around the edge.

Finish up the buttonhole by working a bar tack across the end.

And finally secure the thread by passing it beneath the stitches in multiple directions on the wrong side.

Here are the completed buttonholes. I find these go a lot faster than usual because the layers are (usually) thinner than on a coat and they’re typically smaller as well.

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Your Progress

Now that the button catch is complete, we can start on the fly itself. You’ll need three pieces as shown: the fabric itself, the lining, and a linen interfacing. These are all right sides up in the photo, the lining should be closest to the body when this is complete so you need to make sure they’re cut the correct way.

Lay the trouser fly and lining pieces right sides together, and baste along the outer (straighter) edge.

At the bottom end of the fly, mark the seam allowances at 1/4″ from the edge to get the position of the end of the stitching.

Stitch from the top of the fly to that mark along the straighter edge. Remove the basting stitches.

Now press the fly into its final position, wrong sides together. The lining should be pressed back about 1/16″ to 1/8″ as shown below.

The bottom can be a little fiddly because of the curve, so I had to go back and straighten things out with my fingers before pressing again.

Now open up the fly again and baste the linen piece to the wrong side of the fabric.

Next, baste in a piece of linen stay tape along the length of the seam. This is optional, and I’m not sure if all trousers would have had this added during the 1860s period, but it adds a nice firmness to the edge and more durability. If your fabric is on the thicker side you could leave it out as well.

Stitch the stay tape in place using a cross stitch.

Finally, fold the lining back over the fly and baste it securely closed along the edge. We are now ready to move on to the buttonholes.

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Your Progress