What is a low shank and a high shank?

The shank is the part of the machine the presser foot attaches to, and its height decides which feet will fit.

The three you will meet. Low shank is far the most common on domestic machines. High shank appears on heavier domestic, semi-industrial and some quilting machines. Slant shank is an older arrangement on models where the needle bar is set at an angle. Measure from the needle plate to the centre of the shank screw with the foot raised — low, high and slant are visibly different, and the manual will state which yours is.

Snap-on versus screw-on. Most domestic machines have a shank holder fixed by a screw, with feet that clip onto it. Undo that screw and remove the holder and you expose a screw-on fitting, which some specialist feet — walking feet, certain quilting and binding feet — use directly. Both fittings exist on the same machine.

Adapters. A low-to-high adapter is widely available. Bear in mind it changes the foot’s height relative to the plate, which matters for any foot with a guide, edge or measured reference on it.

Proprietary fittings. Some manufacturers use their own arrangement, and generic feet simply do not fit. That is worth knowing before you build a collection.

The rule that prevents broken needles. Fit any new foot, then turn the handwheel slowly by hand through a complete stitch cycle, at the widest stitch you intend to use, before touching the pedal. Generic feet are made to fit “most” machines, and “most” is not “yours”. A needle that strikes a foot at speed breaks, and can knock the timing out with it.