Latch Needles And Compound Needles Compared

The Latch Needle Closes Itself

A latch needle carries a pivoted latch behind the hook. The old loop, riding up the shank as the needle rises, swings the latch open. On the downstroke the same loop swings it shut over the new yarn and is cast off. No separate mechanism is needed.

The advantage is simplicity and tolerance: coarse gauges, heavy yarns, open structures. The cost is stroke length. The needle has to rise far enough for the loop to clear the latch, and that limits speed.

The Compound Needle Splits The Job

A compound needle has an open hook and a separate closing element that slides in a groove. The two are driven independently, so the needle only has to move far enough to clear the loop, not far enough to work a latch.

The advantage is a short stroke and therefore speed. The cost is that two parts have to stay matched. Wear on the closing element shifts the moment of closure, and the machine starts dropping stitches at production speed while running cleanly slow.

What Each One Costs In Spares

A latch needle machine stocks needles and needle bars. A compound needle machine stocks needles, closing elements and the tongue units that carry them, and it inspects both together because a worn tongue scores the needle groove.

On this catalogue that maps to two different routes: raschel latch needles and latch needle bars on one side, compound needles and tongue units on the other.

How To Tell Which You Have

Look at the needle out of the machine. If there is a pivoted latch behind the hook, it is a latch needle. If the hook is open and there is a separate sliding element in a groove along the needle, it is a compound needle. Photograph it either way before ordering.