Sewing Machine Feed System.
Understanding The Sewing Machine Feed System.
How to Adjust the Sewing Machine Feed Timing.

What is the sewing machine feed system?

The sewing machine feed system is a system that feeds the fabric through the sewing machine during sewing.  This is a common element in sewing machine repair.

The primary drive mechanism of the sewing machine feed system is a set of feed dogs.  The feed dogs consist of a device with teeth or triangular ridges on top.  These feed dogs are designed to slightly lift and pull the fabric through the sewing machine.  The feed dogs are located directly behind the needle hole. During sewing these feed dogs pull the fabric along while the sewing machine is sewing.  When the sewing machine fails to feed the fabric properly, sewing machine repair is required.

The sewing machine feed system involves the lower drive shaft.  It drives a special set of levers that lift, move, and lower the feed dogs in proper rotation. When the feed dog timing is messed up even a little bit, the fabric will not feed properly. Sewing machine repair is required.  You may get gobs of thread when you try to sew a seam.  It may get worse you try to use short stitch lengths.

What is the sewing machine feed system?

The sewing machine feed system is smooth movement of fabric through the sewing machine. 

A properly functioning sewing machine feed system is essential.  The feed dogs should work in harmony with the needle movement. The needle falls below the needle plate. The feed dogs should be at their farthest back position and slip under the needle plate as well. The needle begins rising out of the needle plate. The feed dogs should rise from the front of their slot as well. The needle rises to its highest position.  The feed dogs should rise to their highest position and move toward the back.

In a properly functioning sewing machine feed system, The feed dogs should be centered in the needle plate track or feed dog slots.

There should be equal space between the left side of the feed dogs and the left side of the needle plate.  The right side of the feed dogs and right side of needle plate should also be even. They should be the same distance when the stitch length is set on maximum.  The space between the front of the feed dogs and the front of the needle plate slot should be the same.  The space in back of the feed dogs and in of the back of the needle plate slot should be the same. The feed dogs should not touch any of the needle plate sides.  It should not they touch inner supports on the needle plate. Variations require sewing machine repair.

The feed dogs should rise about a sixteenth of an inch above the needle plate at their highest position.  They should  completely disappear under the needle plate when the needle is below the needle plate.

In a properly functioning sewing machine feed system, the presser foot applies pressure to the top of the fabric. The feed dogs grip the fabric from below.  The feed dogs pull it to move it under the needle from stitch to stitch.

The stitch length adjustment varies the length of stitches by controlling how far the feed dogs actually travel. If they travel a very short distance front to back, the stitch will be short. If they travel longer, the stitch will be longer.  If the feed dogs do anything else, the fabric will not move properly under the presser foot.  Sewing machine repair is required.  Sewing Machine feed system must be adjusted properly.

You can check the proper movement yourself very easily. Remove the needle so you do not poke yourself, and remove the presser foot.

Observe carefully.  In a properly functioning sewing machine feed system the feed dogs must be properly timed. 

The feed dog timing must match the needle timing perfectly. It must also match the swing of the needle.  Adjust the rise and fall.  Adjust the height and drop.  Adjust the centering  forward and backward as well as sidewise.  Adjust the proper movement from front to back.  This sewing machine repair is managed usually by adjusting a few set screws on the lower feed dog drive mechanism.  Sometimes it must be adjusted on the camber of the upper shaft.

Your professional technician will know what the proper adjustment is for your sewing machine.  If you have a question about a specific model, contact your local dealer or regional sewing machine brand repair center.  Request a service manual for a specific model from an authorized dealer.  After you have had experience with a few  sewing machines, this sewing machine repair should become second nature.

Sewing Machine Feed System.
Understanding The Sewing Machine Feed System.
How to Adjust the Sewing Machine Feed Timing.