The Mannequin Arm Updated

Several years ago I posted a pattern and instructions for creating a custom arm for your dressform. Since then, I’ve made a few improvements to the pattern and written more detailed instructions.

Here’s the new and improved pattern. It has cut lines for adjusting the width of the biceps as well as length.

The pattern is available here:

Download and print the pdf file. Pages should be assembled as shown.

Be sure to set your printer to print at “actual size” or “no scaling.” The test square on page 1 should measure 2 inches square. The file is 7 pages. Tape together as shown and cut out the pieces. You will have an upper arm, lower arm, wrist cover, armseye cover, and shoulder attachment which will enable you to pin the arm to your dressform. The pattern has NO SEAM ALLOWANCES. This is to make any alterations you need to do easier. It is drafted for a bicep measurement of 11 inches. If you want a smaller or larger biceps, cut on the dotted lines and overlap or spread the pieces to desired measurement. Measure along the balance line located at the underarm on the lower arm and corresponding balance line on the upper arm. The length of the two balance lines added together are the finished biceps measurement. You can also lengthen or shorten the length between shoulder and elbow and elbow to wrist as desired. If you alter the biceps width, remember to add to the circumference of the large oval the same amount you added to the biceps. The wrist circumference can be increased or decreased in the same way. Adjust the wrist oval in the same way so that the circumference of the oval matches your desired width.

Here’s a sample layout if you want to increase the biceps width. Cut the upper and lower arm patterns apart on the dotted lines. Spread by the desired amount (if you want an additional 1 inch, spread the sections 1/4 inch). Notice I’ve increased the wrist only 1/8 inch at each cut line for a total of 1/2 inch more at the wrist circumference. You’ll also need to alter the wrist and armseye covers to compensate. This can be a bit of trial and error as the circumference of an eclipse (oval) isn’t straightforward math the same as a circle. Smooth out the seam lines over any spaces.

Cut out pattern pieces and lay out on sturdy muslin. I use this heavy weight muslin: Cloning Couture ~ Products ~ Muslin, Heavy Weight ~ Shopify (myshopify.com) but cotton drill cloth is a good sub. Add 3/8 inch seams with these exceptions: 3/4 inch seam allowance around the armseye oval and 1/2 inch around the wrist oval. Cut two shoulder attachment shapes. I prefer to mark the cutting lines lightly in pencil. Tracing with dressmakers carbon paper can leave unwanted marks on the finished arm form.

Mark all balance lines and match points with an erasable marker.

Stitch two rows of machine stitching 3/8 and 1/4 away from the cut edge along the elbow. Pull bobbin threads to take up ease in the elbow area. Tie threads.

Steam the elbow area to smooth the seam. Make sure you don’t have any creases. Join the upper and lower arms along points A, B and C. Press the seam open.

Close the dart at the top of the shoulder. Press towards the back.

You can add the balance lines now. Either stitch along the vertical and horizontal balance lines with contrasting thread or draw lines with a permanent marker. The lines can also be added when the arm is completed but it’s easier to do now when it’s flat. Smooth out any little jog at the elbow.

Stitch the remaining seam along points D,E and F. Press the seam open. I use a sleeve board and seam stick made from a length of stair rail handrail with one flat side.

Stitch along the top of the arm with a longer (about 3.75mm) stitch at 3/8 and 1/4 from cut edge. Pull bobbin threads to create a curve at the top of the arm.

Steam the seam allowance to shrink excess fabric. Be careful not to press in creases. Tie thread ends. Place the two shoulder attachment pieces right sides together and stitch around the outer convex curve. Trim seam to 1/8 inch, turn, press and stitch close to the edge. Clipping the seam isn’t necessary if you trim the seam allowance to 1/8 inch.

Matching shoulder points, pin the shoulder attachment piece to the top of the arm. Make sure you orient so that front and back are correct. Start at the shoulder point and work out from there. The shoulder attachment will end just past the seams.

With the arm on top, stitch the arm to the shoulder attachment.

Turn the seam allowance towards the arm.

Cut the batting to stuff the arm. I use high loft quilt batting to stuff the arm. Using small bits of batting to fill out the arm shape will result in a lumpy, bumpy arm. A better way is to use a larger piece of batting rolled. I start with a piece of high loft (about 3/4 inch) polyester batting cut 30 inches by 24 inches. Roll up the 30 inch width and determine if that gives you a roll the measurement of your biceps. 30 inches of my batting loosely rolled results in a tube 11 inches in circumference. If you adjusted your biceps, then the 30 inch dimension might need to be adjusted. 24 inches is the length of the arm from tip of shoulder to wrist. If you lengthened or shortened the pattern, adjust as necessary. Tear, rather than cut one 24 inch side. This will give a smooth edge when rolled. Start rolling from the short (13 inch) side. The resulting roll of batting will be fatter at one end and taper to a smaller diameter which will be the wrist. Temporary quilt adhesive spray helps adhere the edge. Test the dimensions of your roll and when all looks good, spray the feathered edge with adhesive spray, roll and press the feathered edge down. You should end up with a roll that is fatter at one end and tapers at the other, like an arm.

To pull the roll of batting through the arm, pin a length of ribbon to the narrow end. Attach a weight and drop the weight through the top of the arm. Pull the ribbon through while pushing the batting in from the top.

Turn up 3/8 inch seam allowance at the wrist end of the arm. Cut cardboard the size of the wrist cover pattern. Hand sew a running stitch 1/4 inch from the edge of the fabric. Pull the threads to gather the fabric around the cardboard shape And tie securely. Press to flatten. Mark all match points. The wrist should be an oval with the longer side of the oval matching the marked balance line on the upper arm.

Check that all points match and whip stitch, using strong thread, the fabric covered oval to the wrist.

Cover the armseye oval in the same way. Handsew a running stitch around the edge, pull thread and tie, covering the armseye oval. Mark the match points. Make sure you have the underarm and shoulder points oriented correctly. The back armseye length is slightly longer than the front, so the shoulder point is slightly forward of center. Press to flatten.

Check that there isn’t excess batting in the armseye area and the arm will sit flat against the dressform. You want enough batting to fill out the top of the sleeve but not so much that the arm is pushed away from the dressform.

This is the hardest part: attaching the armseye cover. Pin match points at the shoulder. Work around to where the shoulder attachment ends on both sides, pinning in place as much as possible. I use a sturdy needle and upholstery or heavy duty polyester thread. Begin sewing so that you will attach the section along the top of the arm first, then moving towards underarm section. If you can use a thimble, it will help immensely. I’ve found stitching like this: bite into the arm section and take a small stitch parallel to the seam line. Pass needle through the fabric on the armseye cover along the edge of cardboard, then back to the arm. Pull tight every stitch or two. Keep an eye on your match points to be sure all will line up.

Take a couple of extra stitches where the shoulder attachment ends as that will be a stress point when you use the arm form. The area along the underarm can be sewn with a whip stitch as the arm is flexible and easier to sew along that area.

Attach the arm to your form with pins. I use Clover double forked pins and angle them so they are pointing inwards. Use one pin at the shoulder, one in front and one in back. Push them in parallel to the surface so that just the tiny curve is visible. There are no pin heads to snag on clothing. Determine the best pitch (angle) for your arm. Some arms are pitched with the arm more forward, others figures have the arm angled more towards the back. You can draw the shoulder line on the shoulder attachment when you’ve determined the ideal placement.

I use Clover forked pins to attach the arm to dressform. Angle the pin so it’s pointing downwards. It holds the arm securely and the rounded tip doesn’t snag on clothing.

The idea for a flexible arm came while watching Signe Chanel. The film gave an inside view of Chanel workrooms and all their mannequins were outfitted with these wonderfully flexible arms. I’ve tried the arms supplied with commercial forms which are rigid and heavy. I’m much happier with this version. No wonder this is what Chanel uses.

This pattern makes an arm for the right side. If you want an arm for the left side, just flip the pieces over and duplicate. You can also print the pattern at 50% and use it for a half-size dressform. If making a half-scale arm, use regular quilting weight muslin as the heavier weight will be difficult to handle. I keep seam allowances at 3/8, maybe trimming slightly, but 1/4 inch tends to fray easily and makes things difficult. Enjoy!