A feed dog is a small part with a hard life: rows of teeth pushed up through the needle plate hundreds of times a minute, gripping fabric on the way back and releasing it on the way down. Repair here is mostly a decision about wear. Teeth that have lost their edge cannot be sharpened back into service, and a dog sitting too low cannot grip however clean it is.
Tooth marks tell you which row is failing
Sew a scrap of firm cotton and look at the stitch length rather than the seam. Even spacing means the transport is working. Bunched stitches at the start, or a seam that shortens as it goes, means the fabric is being held rather than advanced.
Then look at the fabric itself. Marks on the underside that deepen toward one edge point at a dog sitting high on that side, or a plate that is not seated flat. Marks that are barely visible while the fabric still slips are the opposite fault: the teeth are not reaching the fabric at all.
The wear patterns that end a feed dog’s life
| What you see | What has happened | What it does |
|---|---|---|
| Teeth flattened to rounded bumps | Years of fabric and lint abrasive | Grips only on heavy fabric; fine fabric slips |
| One corner of the dog polished bright | Dog tilted, or a bent carrier arm | Feeds one side faster; seams curve |
| Chipped or missing teeth | Needle strikes, or a jam cleared by force | Snags, pulls, and runs in knits |
| Burred edges on the teeth | Metal-to-metal contact with the plate | Cuts thread and marks fabric |
| Rust pitting across the rows | Damp storage | Rough grip, then thread shredding |
Rounded teeth are the ordinary end of the part. Chipped teeth usually mean a needle has come down out of time, and replacing the dog without checking the needle path just sacrifices the new one.
Height is a relationship with the plate
The dog has to rise above the plate by the amount the manual specifies, and it has to sit level across its width. Check both with the plate fitted and the machine turned by hand to bring the dog to its highest point.
A straightedge laid across the plate shows whether the rows come up evenly. A dog that is high on one side rocks the fabric; a dog that is low everywhere cannot reach it. If the manual gives a height and a gauge, use them. If it does not, the observable standard is a dog that clears the plate by a visible margin at the top of its travel and disappears fully below it at the bottom.
The rows do different jobs
On a four-row dog the front row pulls fabric in and the rear row pushes it out. A dog worn on the front row shows up as a hesitation at the start of a seam; a worn rear row shows up as a seam that stalls at the end.
On machines with differential feed the two rows are driven at different rates on purpose. Before condemning a dog on those machines, confirm the differential setting is where you left it, because a dog blamed for stretching a seam is often the dial.
Why a dog will not sit flush
Four causes cover most of it:
- Lint under the dog. Fibre packs into the well and lifts the carrier. The dog looks high and feels spongy.
- Screws not seated. A dog held by two screws will tilt if one is loose. Tighten evenly, in stages, and check the height again afterwards.
- A bent carrier or fork. Usually the result of a jam cleared with force. The dog sits at an angle no adjustment fixes.
- The wrong dog for the plate. Slot width and row spacing differ between machines. A dog that fits the screw holes but not the slot will rub.
Adjust, clean, or replace
Clean and re-check first, because lint imitates wear convincingly. If the dog is clean, seated, at the right height, and the teeth still fail to hold fabric, the teeth are worn and the part is finished.
Replace rather than adjust when the teeth are rounded or chipped, when the rows are uneven, or when the part is no longer flat. Adjust only height and seating, and only within what the manual allows. A dog filed or bent to grip harder will mark fabric and cut thread, and the marks are permanent.
The first seam after the change
Test on the fabric that was failing, with a fresh needle:
- Sew a straight seam at a moderate length. The stitches should be evenly spaced for the whole run, and the underside should show no new marks. Deep marks mean the dog is now too high.
- Sew over a folded seam. The fabric should be neither held back nor yanked forward. If the machine is louder than before, recheck the plate screws; a plate that is not flat lets the dog rub.
Where the owner-technician boundary sits
Owner work: cleaning the well, checking height with the plate on, tightening plate and dog screws, and replacing a dog that matches the machine and the plate slot. Technician work: bent carriers and forks, a dog that will not sit level after cleaning, anything inside the feed drive, and any chipped tooth that arrived with a needle strike. A strike means the hook timing needs checking, and that is not a bench job for most owners.
Related guides
- Feed dogs not feeding fabric — when the dog is fine and the fabric still will not move.
- Feed dogs won’t rise — the drop linkage and the return spring.
- Feed dog tooth types — what the tooth profile is for.
- Sewing machine feed mechanism — how transport works as a system.
- Sewing machine needle plate — the slot the dog works through.