Unicycle or Bicycle?

If you have ever quilted on a longarm, have you noticed that sometimes the machine seems to want to go in squares, even when you want to quilt a circle? I have, and sometimes my students have asked me about this too.

Recently, at a show I asked the folks at Grace Frames about this and -- mystery solved! (I was so happy to learn that it wasn't "just me".) Here's what I learned:

The frame that holds a longarm machine (or a domestic machine, for frames that hold one) has a chasis that holds the machine (red arrow) and a set of rails that hold the chasis (yellow arrow). Under the machine, the chasis has wheels that let the machine move forward and back (red arrow). Under the chasis, there are more wheels that ride on the frame to move it side to side (yellow arrow). It's the combination of forward-and-back plus side-to-side that let the machine move in all directions.

How the wheels that ride along on the frame are configured makes the difference between the machine wanting to quilt squares, or the machine moving in smooth circles.

The wheels that ride on the frame can be either single wheels or pairs of wheels.

On lower-priced frames (Grace's Q-Zone Hoop Frame, for example), the wheels that ride along the frame are single wheels, mounted vertically.

The vertically-mounted, single wheel moves in a straight line. Even though the two sets of wheels can combine motions to move in every direction, the single wheel on the frame tends to move more easily along the side-to-side direction. So, when you want to quilt a circle, you will feel the frame try to carry you along horizontal and vertical lines, and you may end up with more of a puffy square than a circle.

On higher-priced frames (Grace's Continuum II, for example) the wheels that ride along the frame are in pairs, mounted diagonally:

The paired, diagonally-mounted wheels allow the machine to move MUCH more smoothly in every direction, so when you quilt a circle, the frame will move smoothly around the circle without pulling you toward forward-and-back or side-to-side.

If you are shopping for a longarm, keep this important difference in mind. Even thought the double-wheel type costs more, you may be much happier with how the smoothly the frame lets you quilt.

If you have a single-wheel frame and want to upgrade to a double-wheel frame, Grace does have an upgrade package; the cost is around $1500 (August 2022 price).