Gammill Stitch Quality Issues Q and A: Encoder O Rings

Q: My regulated machine is working fine stitching side to side, but when I move it vertically it hesitates and forms large stitches, or won’t stitch at all.  What’s wrong?

A: The good news is that this is one of the easiest fixes there is! On your machine are two little rubber O rings that are on encoders, which tell your computer where the machine is and how fast it is moving, and ultimately determine stitch length. One of these encoders (Y Encoder, dictates vertical stitching and the culprit in your case) sits on the cross track:


Above is the Y Encoder on a Vision (regulated) machine.


The image above shows the Y Encoder on a older Plus (Regulated) machine.


The other (X Encoder, dictates horizontal stitches) is on the back and is positioned either on top of the back right wheel or travels along the long track of the table.


These $2 parts are responsible for accurate stitch length. Because they are rubber, they are subject to cracking over time, especially if your pot belly stove is near your machine or sun beats in your uninsulated window, shining right on the encoder. Actually, the dry conditions of this region are also hard on these.

You’ll want to have some extras on hand in case cracks do develop. Carefully remove the old one (if it didn’t fall off and get sucked up in the vacuum) and gently roll the new one in place, and bam, you’re back in business.

A word of caution: you can bend the center post on these with excessive force. The O ring is cheap, a replacement encoder is not! Both encoders are pretty accessible on Visions. On older Plus machines, the X Encoder is harder to get to. Prop up the back end of the crosstrack with a 2×4 or several books, and remove the back right wheel to get to it. DO NOT pry it down past the wheel or you might be purchasing a new encoder! Replace it, push it up into position and then replace the wheel.

On Statlers, older machines have metal encoders that ride on a serrated track on the crosstrack, and there is a third long stretch of belt on the front of the machine that rides on an encoder. These don’t tend to have issues. Newer Statlers (2007 or so and later) have the same encoders that the Plus or Vision has (see above).

On Statlers, these are secondary encoders. The belts themselves are the primary encoders, and provide information about stitch length while the belts are engaged. It’s only when the belts are dropped and you are in regulated free motion mode that the rubber O ring secondary encoders are providing information to the computer. If you never drop the belts, you might be in for a surprise as the O ring may have disintegrated years ago!

To order new encoder O rings, click here. If the O rings look perfect, check the plugs going into the encoders and the ones on the back of the machine.