Bulk defeats an overlocker in two ways: the foot cannot climb it, and the blade struggles to cut it cleanly. Both have settings that help.
Reduce presser foot pressure. Full pressure on thick or lofty fabric compresses it so hard that the feed cannot advance it evenly. This is the single most useful adjustment and the one most often forgotten.
Lengthen the stitch, towards the top of your machine’s range. Short stitches on heavy fabric pack thread into an edge that becomes stiff and perforated.
Widen the stitch, so more fabric sits inside it. A narrow stitch on a thick edge pulls off.
Fit a heavier needle, in the correct system for your machine, and make sure it is new. Deflection on thick fabric is what strikes loopers.
Slow right down, and let the blade cut rather than pushing fabric at it.
Check the presser foot lift before you start. Every overlocker has a limit, and it is generally lower than a sewing machine’s. Fabric that will not pass under the raised foot will not be sewn, and no adjustment changes that.
Reduce bulk at the junctions. Where seams cross, trim and grade the allowances first, and flatten the crossing with a hammer or a clapper before it reaches the blade. Most jams on heavy work happen at a seam crossing rather than in open fabric.
Consider whether the overlocker is the right tool. On very heavy fabric, sewing the seam on a sturdy sewing machine and finishing the allowances separately is often the better result.
Questions people actually ask
My machine stalls at seam crossings.
Flatten and grade the crossing before it reaches the foot, reduce pressure, and turn the handwheel by hand over the thickest point.
The blade will not cut through it.
Check the blade is sharp and correctly overlapped, then trim the edge by hand first and overlock the pre-cut edge with the blade disengaged.
Last reviewed 2026-08-11