Convert a Two Piece Sleeve to Three

A distinctive feature of many French (Chanel) style jackets is the iconic three piece sleeve. Vogue 7975 is a favorite starting pattern for many; however the sleeve is a standard two piece. I’ll go through my method for converting the pattern from a two to three piece sleeve.

First, trace the pattern onto translucent pattern paper. Eliminate the seam allowances. It’s much easier to alter patterns when you aren’t dealing with seam allowances. Make changes to the pattern, then add seam allowances back if you are more comfortable working with patterns which have seam allowances included. Include the marks indicating underarm and shoulder points as well as grain lines. Mark the front and back of the sleeve cap to eliminate confusion.

Working on a grain board/cutting mat makes it easy to keep the pattern properly aligned. Arrange the pattern pieces as shown with grain lines parallel to each other and seam lines just touching along the back armseye seam. Tape or weight the paper so it doesn’t shift.

Using a second sheet of pattern paper large enough for the entire sleeve, trace the shape of the sleeve cap from the underarm point to shoulder point, continuing through the front armseye seam. Mark the underarm and shoulder points. Also draw a line at a 90 degree angle to the grain lines intersecting the underarm point. This line represents the biceps width.

Move the undersleeve pattern to the front, arrange grain lines parallel to each other and trace the remainder of the arsmeye seam to the underarm point.

Also shift the grainline on the upper sleeve section so it is in line with the shoulder point. Connect underarm points with a horizontal line which should be perpendicular to the grainline.

Your draft should look like this:

Draw dashed lines from the underarm points to the hem. They will be parallel to the grainline and be the same distance apart as the biceps width. Measure the distance along the biceps line from back to the new grainline (intersects the shoulder). Measure distance from grainline to front underarm point. Compare the measurements. I’m working with a size 10 pattern. The back measures 7”; front measures 6.5”. Therefore the grainline is offset 1/2” from the midpoint of the front and back underarms. If your pattern size varies slightly, then use the measurements from your size. The additional curves which are mirror images of the armseye seam will be covered in upcoming steps.

Now calculate the sleeve taper from underarm to wrist. Measure the wrist on front and back sleeve sections and add them together for total sleeve wrist measurement. Size 10 is 9 inches. I want to offset the wrist by the same amount of the biceps. Divide 9 by 2 equals 4.5”. Add 1/4” to 4.5” for 4.75” back wrist. Subtract 1/4” from 4.5” for 4.25” front wrist. 4.75” plus 4.25” equals 9” so the total matches amount measured in the previous step.

Also draw in the elbow line. There are various methods for determining the elbow placement. You can measure from underarm to elbow. If you’re not sure, divide the underarm seam in half. Place the elbow about one inch higher than the midpoint.

Where the elbow and underarm seam intersect on the sleeve back, mark a point 1/4” wider than the elbow. Measure the distance from this point to the center grainline. Divide this distance in half (should be about 3 inches). Measure 3/4” down from the elbow line. Draw a line from this point to the halfway point just plotted, forming a dart at the elbow.

At the back wrist, mark a point 3/4” towards the center and 3/4” below the wrist hem. Connect the lower elbow dart leg to this point. The wrist will be shortened 3/4” so 3/4” needs to be added to the front underarm. Draw a line from the elbow to a point 3/4” to the right of the original seam.

Connect the front and back wrist hem with a smooth curve. Also shift the center grainline from elbow line to wrist 3/4” as shown.

Fold the pattern vertically, matching back underarm to grainline. Turn the pattern over with underside up. You will see the armseye curve. Using a red pencil, trace the curve as shown. Repeat for the front.

Now you will draft the narrow under-sleeve. Starting at the underarm, measure 1 and 1/4” to left of grainline; 1 and 1/8” to the right. Move to the elbow line. Measure 1 and 1/4” to the left, 1” to the right. Move to the wrist. Mark 1 and 1/8” left of the angled line, 7/8” to the right. Connect the points to form the under-sleeve. Shown in green.

The under-sleeve now needs to be removed from the outer edges of the back and front sleeve. Measure towards the center of the sleeve on both back and front, the same amounts that were used to draft the under-sleeve. Back underarm, measure in 1 and 1/4”, front underarm 1 and 1/8” towards center. Elbow line 1 and 1/4” along the back, 1” along the front. Wrist 1 and 1/8 at back, 7/8” at front.

This is the right sleeve. The under-sleeve as drafted is for the left sleeve. To create a right side pattern, flip the sleeve draft over and trace the under-sleeve onto pattern paper.

Flip the draft back to the right side and cut the back and front sleeve sections as shown. The elbow dart won’t be sewn as a dart. When constructing the sleeve, you will ease about two inches either side of the dart, drawing up the excess length to match the under-sleeve seam.

Shorten the front sleeve seam about 1/4” and redraw the wrist hem curve. The front seam will be stretched during construction to produce a better curve in the finished sleeve. Yes, the front sleeve seam that attaches to the under-sleeve will be slightly shorter than the corresponding seam on the under-sleeve pattern.

If you want to add sleeve vent for buttons/ trim, tape extensions onto the pattern. I used 1 and 1/2” wide and 4” long. If you want longer vents for more buttons, then just make the vent longer.

The grainline of the undersleeve can be changed to bias providing a little more flexibility in the sleeve.