How Does A Keyhole Buttonhole Sewing Machine Work? Let’s Find Out

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The first time I noticed a keyhole buttonhole sewing machine, I didn’t even realise it was different. It was on a store-bought, smooth, curved finish around the buttonhole’s edge that looked a little too perfect compared to the boxy ones I usually stitched at home.

Later, while sewing a thick coat with heavy buttons, my usual straight buttonholes just weren’t cutting it. That’s when I found out what that rounded shape was all about.

The keyhole buttonhole stitch is designed for strength and movement. Unlike the regular rectangular buttonhole, it has a round or teardrop-shaped end. It’s perfect for larger or shank-style buttons. 

Most modern sewing machines offer a keyhole buttonhole option, typically marked by a symbol resembling a keyhole or an exclamation mark.

Keyhole Button Hole

To sew a keyhole buttonhole, select the keyhole stitch, attach the buttonhole foot with your button, align the fabric, lower the lever, and let the machine sew the buttonhole automatically.

And once you try it, you’ll wonder why you didn’t switch sooner.

keyhole buttonhole sewing machine

What Is A Keyhole Buttonhole Stitch?

A keyhole buttonhole stitch is a type of buttonhole with a rounded end on one side, resembling a keyhole shape. It’s designed to provide extra space and strength for shank buttons or larger, thicker buttons.

What Is A Keyhole Buttonhole Stitch

It allows them to move more freely without pulling or damaging the fabric. The round end reduces fabric stress and helps prevent fraying over time.

Can Every Machine Do Keyhole Buttonhole Stitch?

Not every sewing machine can sew a keyhole buttonhole. Some basic or older models only offer the standard rectangular or 1 step buttonhole, which works fine for most projects.

However, if you’re using thicker buttons, such as those on coats or jeans, then a basic machine can’t do that. You need a Keyhole Sewing Machine.

Can Every Machine Do Keyhole Buttonhole Stitch

You need a feature that usually comes with modern or computerized machine. Here is the list of button hole machines I tried keyhole button hole stitch, and I love it,

Best 4 Keyhole Sewing Machine
  1. Brother CS7000X / CS6000i
  2. Jack Jack T1790GS-1-D
  3. speedway SW5780AS
  4. MORSE L900

How To Sew A Keyhole Buttonhole By Sewing Machine?

To sew a keyhole buttonhole stitch by sewing machine, follow the bellow steps,

How To Sew A Keyhole Buttonhole By Sewing Machine

Select the right Button Types

Before I sew, I take a moment to think about why I’m using this buttonhole. Regular rectangular buttonholes work fine for flat buttons. I have 3 options for myself,

Select the right Button Types
  1. Flat buttons sit flush against the fabric.
  2. Shank buttons have a raised part underneath.
  3. Denim buttons often feature a full-circle shape.

The keyhole buttonhole is ideal for shank or denim buttons, as the rounded end makes it easier for the button to pass through.

Measure & Mark Your Button

Start by measuring the diameter of your button, and if it has a shank, add a little extra (about 1/8 inch or 3mm) to the total length. This provides the buttonhole with sufficient room for the shank to slide through without straining the fabric.

Once you know the size:

  1. Use a ruler or measuring tape to mark a line on your fabric the same length as your buttonhole.
  2. Mark the centre point where you want the buttonhole to sit. I also use this technique when stitching leather.
Measure & Mark Your Button
  1. Draw a straight line from that center mark
  2. If your machine has guide lines or a crosshair on the foot, match them up with your markings for precise alignment.

If your button is an unusual shape or doesn’t sit well in the buttonhole foot (like a curved shank button), it’s better to measure it manually rather than relying on the foot to size it.

Setting Up the Buttonhole Foot

Slide the buttonhole foot onto your machine. Adjust the slider on the foot to match the button measurement.

Setting Up the Buttonhole Foot

Line up your fabric so the red crosshairs on the foot match your chalk marks on the fabric, like an overlock stitch.

Position the Fabric Under the Foot

Slide your fabric under the buttonhole foot, making sure your marked line (or center guide) lines up with the red alignment marks or crosshairs on the foot.

If your machine has a built-in laser or guide light, use it to double-check your alignment.

Position the Fabric Under the Foot

Double-check that the foot is locked down and flat against the fabric. If your fabric isn’t completely flat or the presser foot is crooked, the stitch could go off-track.

Select the Keyhole Buttonhole Stitch

On your sewing machine’s stitch menu, choose the keyhole buttonhole option. This is usually grouped with the other automatic buttonholes and may have a rounded end in the stitch diagram.

Select the Keyhole Buttonhole Stitch

Once selected, your machine should automatically switch to the correct stitch width and sequence for the keyhole design.

Start Sewing With A Green Button

You now have 2 options to begin sewing:

  1. Press the green start/stop button if your machine has one (common with computerized models),
    or
  2. Use the foot pedal like you would in normal sewing.
Start Sewing With A Green Button

Once you start, the machine will automatically sew one side of the buttonhole using dense zigzag stitches. Create the rounded bar tack (the keyhole part) at one end

Sew the second side in reverse. Finish with a flat bar tack at the top.

Note: The machine completes this entire process in one continuous motion—no stopping between steps, unlike the 4-step method.

Watch the Fabric While It Stitches

You don’t need to guide the fabric—just let it move on its own. Avoid pulling or pushing the fabric, or the stitches may shift or become uneven.

Watch the Fabric While It Stitches

Stay alert and make sure the foot doesn’t lift or shift, especially around the rounded end where the stitches change direction.

Keyhole Buttonhole Pattern

If you wanna experiment with some button holes kind then try some of this pattern,

Keyhole Buttonhole Pattern

When To Use Keyhole Buttonhole Stitch?

The keyhole buttonhole isn’t just decorative. It’s designed for function and strength. The rounded end helps distribute tension evenly around the button’s shank, making it ideal for thicker fabrics and heavier buttons.

Use the keyhole buttonhole when you need both durability and a polished finish. Ideal Situations for a Keyhole Buttonhole:

When To Use Keyhole Buttonhole Stitch
  1. For buttons with a shank
  2. On thick or layered fabrics
  3. When sewing heavy-duty garments
  4. On horizontal buttonholes

Frequently Asked Questions(FAQ)

Do I need special tools to open a keyhole buttonhole?

You can use a seam ripper, but for extra precision, a buttonhole chisel works best. Place pins at each end of the buttonhole to avoid accidentally ripping the stitches.

Can I use keyhole buttonholes on lightweight fabric?

You can, but it’s usually not necessary unless the button has a shank. For lightweight fabrics and flat buttons, a standard rectangle buttonhole often appears cleaner and functions more effectively.

How do I determine the correct size for the keyhole buttonhole?

Measure the diameter of the button, and if it has a shank, add about 1/8 inch (3mm) to the length. Your machine will usually do this automatically if the button is placed in the foot.

Final Result

You’ll now see a clean, neatly stitched keyhole buttonhole. That rounded end leaves space for shank buttons to rest without pulling or distorting the fabric. It is especially important on thicker garments like coats, blazers, or denim.

Maisha Soumee

Maisha Soumee

Hi there! I’m Maisha Soumee, the proud torchbearer of our family’s sewing legacy and the driving force behind this website. With Grandma Manha’s teachings as my foundation, I’m honored to continue the tradition of craftsmanship and creativity. As a passionate seamstress, I’m dedicated to sharing the joy of sewing with you, our valued community.

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