First identify the button. A sew-through button has visible holes through its face. A shank button has a loop behind its face. A thread shank is the raised bundle of sewing thread you deliberately leave beneath a sew-through button. Those last two meanings are often confused in accessory listings.
For an ordinary two- or four-hole button, a compatible button-sewing foot can hold it for machine attachment. For a button with a rear loop, do not assume that a foot advertised as “shank” can sew it. Hand sewing through the loop is often the simplest repair. For extra clearance under a sew-through button, look for a documented thread-shank feature on the button foot you already use.
A real foot that combines the functions
The BERNINA button-sew-on foot #18 instructions describe an adjustable center pin for changing the thread-shank height. They also describe two- and four-hole button attachment. This is one accessory with an added spacing adjustment, not proof that every “button sewing foot” and “shank button foot” are separate competing products.
The pin creates room in the stitching beneath a flat button. It does not mean the machine needle can reach an arbitrary molded loop behind a decorative button. BERNINA’s accessory is also machine-specific: its construction does not establish that it fits a generic low-shank snap-on holder.
| Repair | Useful method | Buying implication |
|---|---|---|
| Replace a shirt’s sew-through button | Correct machine button foot or hand sewing | Check the supplied kit before ordering |
| Sew-through button needs clearance for a thick button band | A documented thread-shank adjustment, or a hand-sewn thread shank | Pay for actual spacing control rather than the word “shank” |
| Rear-loop coat button | Sew through the loop by hand unless your exact system documents another method | A generic flat-button foot is not a solution |
| Cloth beneath the button is damaged | Repair/reinforce the attachment area first | Changing feet does not fix weak fabric |
Choose clearance from the closure
The buttonhole layer needs room to sit beneath the button when fastened. Too little room can make the front pull; excessive looseness can leave the button poorly supported. Match the original successful closure or test the replacement with the actual fabric stack. Fabric weight alone does not tell you the required spacing.
For machine attachment, follow the exact manual for the foot, feed setting and stitch. Check both needle positions with the handwheel before powered sewing. Width must match the holes. On the documented #18 setup, the feed is lowered because the button is stitched in place; that detail must not be inferred from a foot’s marketing name.
What to buy
Buy a compatible standard button foot if your machine supports this operation and you want machine attachment of sew-through buttons. Choose an accessory with an adjustable thread-shank feature only if that feature solves your closure problem and the manufacturer lists it for your machine. Keep a hand-sewing needle for rear-loop or awkwardly placed buttons.
Search Amazon for BERNINA button-sew-on foot #18 as an exact-name search, not a claim of stock or universal fit. This guidance uses the original accessory instructions; no comparative speed or durability test was performed.
The Sewing & Craft Alliance button guide distinguishes a built-in shank loop from sew-through holes, and its button-replacement guide explains attachment and thread-shank choices. Choose the construction from the button and closure thickness, not the label flat alone.