What is a free arm on a sewing machine and when do you need it?

A free arm is the narrow sewing surface exposed when you slide the accessory box or extension table off a sewing machine: a tube of fabric, such as a sleeve, a trouser leg or a cuff, fits over it so you can sew round the opening without the rest of the garment bunching under the needle. Almost every domestic machine made since the 1970s has one; industrial flatbeds and some dedicated quilting machines do not. You need it for hems and bands sewn in the round, anything with a small opening, and children's clothes, where the openings are too tight to sew flat.

What is a free arm on a sewing machine?

Look at the bed of your machine, the flat surface the fabric slides on. On most domestic models the part to the left of the needle is a removable box or table that holds the feet and bobbins. Lift it off and what remains is a narrow horizontal arm, typically 7–10 cm (2 3/4–4 in) around, with the feed dogs and the needle plate on top. That is the free arm.

Its purpose is to let a closed tube of fabric pass around the bed. With the extension table on, a trouser leg has to be flattened and fed under the foot, and the far side of the leg keeps sliding under the needle. On the free arm the leg slips over the arm like a sleeve on a sleeve board, and only the layer on top is sewn.

Elna's first machine, launched in 1940, is generally credited with introducing the free arm to home sewing. By the 1970s it had become standard, and at the time of writing (October 2026) nearly every domestic machine from Brother, Singer, Janome, Juki, Bernina, Pfaff and Husqvarna Viking is a free-arm model.

When do you need a free arm?

Whenever the piece you are sewing is a closed tube narrower than the width of the machine bed:

• Hemming sleeves and trouser legs after the seams are closed, including narrow hems and twin-needle hems on knits.
• Attaching cuffs to a sleeve, and neckbands to a T-shirt, where the band and the opening are both rings.
• Elastic casings on pull-on shorts, a skirt or a scrunchie, when the casing is stitched after the side seams.
• Children's clothes, where a sleeve hem can be 18 cm (7 in) around and will not open flat enough for any other method.
• Mending: a torn trouser pocket, a split inseam, a bag strap, where the item is already a tube.
• Bag bottoms and bucket hats, where a circular base or crown meets a ring of fabric.

The circumference of the free arm itself matters for the smallest openings. Most adult-size machines have an arm of 8–10 cm (3 1/4–4 in) around; a child's cuff of 16 cm goes over it but with little room to turn. Machines sold for sewing children's clothes and some embroidery models have a slimmer arm.

How do you use the free arm step by step?

Take a sleeve hem as the example:

1. Remove the extension table or accessory box. It slides off to the left; some models have a latch underneath.
2. Prepare the hem. Press the hem allowance up, 2 cm (3/4 in) for a shirt sleeve or 2.5 cm (1 in) on a knit, and pin or clip it from the right side with the pins parallel to the edge.
3. Slide the sleeve over the arm right side out, with the hem edge toward you and the bulk of the sleeve hanging over the back and the left of the arm, so the layer under the needle is the hem and only the hem.
4. Lower the needle at the underarm seam, where the start and finish will be least visible, and sew with the fabric feeding away from you as usual.
5. Rotate the sleeve on the arm as you sew, keeping the edge aligned with the guide on the needle plate. Stop with the needle down every few centimeters to shift the tube if it tightens.
6. Overlap the start by 1–2 cm (1/2–3/4 in) and backstitch, or on a knit sew off the end without backstitching and tie the threads.

The foot does the feeding; your hands only steer. Let the tube rotate on its own and keep the part of it that has already been sewn from catching under the arm or on the foot control.

When don't you need a free arm?

Many hems in the round can be sewn flat instead, before the seam that closes the tube. On a shirt or a woven top, sew the sleeve hem while the sleeve is still flat, then close the underarm seam through the finished hem. The same works for a T-shirt neckband: attach the band to the neckline flat, with one shoulder seam open, then sew the shoulder through the band. The T-shirt neckband post shows both orders.

Sewing flat is faster on a long run, keeps the stitching line straighter on light fabric, and is the only option on a flatbed machine. The trade-off is a seam through the hem at the end, which is bulkier at the crossing and shows on a very narrow hem.

Large pieces never need the free arm. A skirt hem of 1.5 m (60 in), a quilt border or a curtain sits on the extension table, and the table should go back on for them: it supports the weight of the fabric, which otherwise drags to the left and pulls the seam off line.

Which machines have a free arm and which don't?

• Domestic sewing machines (mechanical and computerized): nearly all, with a removable accessory box or extension table.
• Sewing and embroidery combination machines: yes, once the embroidery unit is detached.
• Mini and toy machines: often not; the bed is a small fixed platform, one more reason the mini vs full-size comparison favors full-size for clothes.
• Industrial machines: flatbed as standard, built into a table. Cylinder-arm industrials exist for bags, shoes and sleeves, with a slimmer arm than any domestic, but they are specialist machines.
• Quilting-focused domestic machines with a very long throat: some are flatbed, since quilting never needs a tube; check before buying if you also sew clothes.
• Sergers and coverstitch machines: most sergers are flatbed with a small bed; many coverstitch machines have a free arm because hemming sleeves in the round is their main job.

If you are comparing models, the features that matter for beginners put the free arm among the things to confirm, together with the stitch controls and the foot lift.

Does a free arm change the order you sew a garment in?

A little. Garment instructions are usually written in an order that assumes a free arm: close the side seams, then hem in the round. If your machine has none, or the opening is too small for its arm, change the order and hem before closing, taking care to match the hem edges exactly at the seam. If you are following a Sewly sewing guide and are unsure whether a step can be done flat instead, you can ask the guide that question for the step.