A Sleeve placket is like an accessory for the sleeves; They serve a function (neat opening ) and make it look attractive as well. For long sleeves like the Bangle sleeves or shirt sleeves, the plackets are a necessity, unless they are made in knit fabric.
There are many ways of making the placket as described below. No. 1 and No. 3 are my favorites
1. Inseam Sleeve Plackets or Mandarin Sleeve Placket
This easy placket is a continuation of the seams in the sleeves. The opening is in the seams.
To make this placket you should mark up 3 inches from the sleeve hem edge. Finish the edges of the seams with a zigzag or any other fabric edge finish. Stitch the seams of the sleeves as usual till you reach the mark you have made for the placket opening. Top stitch along the seam opening. You have a very easy to sew placket on your sleeve hem.This is a perfect placket for a beginner.
2. Faced Sleeve Plackets
Cut out the sleeves ; Mark the location of the placket ( I mark it opposite to the seam on the center fold line of the sleeve)
Measure the placket opening you need.Add 1.5″ to this. I usually cut out two pieces of rectangles measuring 3 inch by by 4 inch from the same fabric as the sleeve; 4 inch for the placket length. Make the placket marking on this piece as well ( 2.5 inch long opening)
Overlock or zig zag the fabric edges of the rectangular facing pieces at the sides ad the top edge. You can turn under the edges as well. No need to finish bottom short side
Keep the sleeve and the facing piece RIGHT SIDES together. Align the facing piece placket marking with the placket mark you have made.
Very slowly and with a short stitch length sew over the placket marking line. At the top point make a single horizontal stitch and then pivot to stitch till below
Cut, Slit and then turn facing to the wrong side. Press in place. Optionally Under stitch the seam allowance to the facing piece so that it will roll to the back easily.Top stitch along the opening.
You can make tiny whip stitches to attach the facing piece to the sleeve. If shoddily done it announces home made clothes, so use a single thread on the needle and do very small stitches. Alternately you may press a piece of 1/2 inch square piece of fusible web to the top edge catching the facing piece top edge and the sleeve under it.
3. Continuous Sleeve Placket
This is another easy placket.
Cut out two pieces of fabric strips ( on lengthwise grain) which are 1 inch wide and double the length of the placket.
Fold this strip by the center lengthwise.
Mark the placket opening on the sleeve
Stitch a straight line along the placket marking , with a 1/8 inch seam allowance. Make one stitch made horizontally at the top before pivoting to stitch down. This is a reinforcement stitch to strengthen and hold the seam.
Cut the slit till the top point of the placket opening.
Keep the sleeve placket open and straight right side up. Place the fabric strip lengthwise edge along this opening under the sleeve placket opening. Pin in place,.
Make sure that the edges of the either sides are matching but in the middle it would not be matching. The binding will be slightly ahead of the sleeve portion in the middle.
Stitch these fabric layers together, in a straight line. Use a 1/4 inch seam allowance.
Fold the strip over the seam. Press in place .Make a diagonal stitch at the top to keep it in place.
Top stitch the binding strip in place.
4. Mock Sleeve Placket
Make a sleeve pattern with the sleeve hem at least 2 inches wider when folded than the normal sleeve pattern.
Mark your correct sleeve hem. The extra fabric will be buttoned up at the sleeve hem to create a mock placket. Pin The extra together. Fold it to one side
On the fold 1/2 inch from the folded edge. Stitch a buttonhole catching the two layers of the sleeve. Stitch a button in the layer under the button. You have a mock placket with a fastening.
5. Hook Placket
This is a variation of the seam placket. The hook placket is made with the seam allowance near the edge. This sleeve placket is also used in the legs of leggings and other tight pants and on the hands of tight sleeves.
You will need to cut a wide seam allowance to make this placket – 1″ seam allowace. Then from the wrong side turn under one of the seam allowances twice so that its folded edge is aligned with the seam line( see picture below). Now you get a small projection. This will slightly overlap the other edge. You will be attaching the hook in this portion.
The other edge is turned under properly as you normally do, fully under. This is where you will be attaching the thread bar for fastening the hook.
Checkout the picture below which shows the placket from the inside. If it is used as a button placket (for small buttons) you will need a bigger projection, hence a wider seam allowance.