A guide to fine-tuning your tension to make the yarn you want.
Your treadle speed, your drive ratio, and your tension all contribute to being able to spin different fibers into different yarns – the possibilities truly are endless. Today we’ll talk a bit about using tension in support of spinning the yarn you envision. As Spinzilla nears ever closer, this is a great guide for getting your wheel ready for the marathon week.
There are three main types of tension systems: Scotch tension, Irish tension and double drive. We will be talking in depth about Scotch tension and double drive, but will touch on Irish tension.
In Scotch tension, the tension of the bobbin, and the tension of the flyer are independent of one another, with the brake band on the bobbin, and the drive band on the flyer whorl.
In double drive, the tension of the bobbin and the flyer are in direct relation to each other.
In Irish tension, the tension of the bobbin, and the tension of the flyer are independent of one another, with the brake band on the flyer whorl, and the drive band on the bobbin. This system is ideal for larger yarns and production-style spinning because of the stronger intake of the yarn.
Scotch Tension on the Sidekick.
Scotch tension works generally the same on most wheels. There is a string that goes over the large flange of the bobbin attached to a spring that allows for looser or tighter tension controlled by a tension peg. This tension peg enables you to elongate or compress the spring. With the spring stretched there is more tension on the bobbin which provides a stronger pull on the yarn to draw on the bobbin. When the spring is compressed, the take-up will be less and more twist will build up before the bobbin draws on the yarn. If your yarn is drifting apart, you want more twist. If it is getting kinked, you want less twist. Elongate the spring more and more (adding more tension) as the bobbin fills with more yarn. This helps to keep a similar tension throughout the bobbin. This only requires small increases in tension. I usually give the knob a little turn each time I get to the last hook on my flyer.

This graph shows the general relationship between the weight of the bobbin as you spin, and the amount of tension necessary while in Scotch Tension
For double drive, your drive band goes around your drive wheel twice, with one loop over the whorl/pulley, and one over the small flange of the bobbin. You can find the tension sweet spot and it will stay consistent during the spinning of the whole bobbin of fiber. The adjustments are a little different than Scotch tension. For the Matchless, start with the flyer parallel to the Mother-of-all (the horizontal piece of wood under the bobbin) and tie a new drive band with the band in the groove of the whorl you would like to use and the groove in the small end of the bobbin. To attain more draw in, turn the drive band tension knob (the mushroom shaped knob on top of the castle) clockwise. This will raise the back of the flyer and put more tension on the bobbin for a quicker take-up. For less draw-in, turn the drive band tension knob counter clockwise so it drops the back of the flyer down, putting less tension on the bobbin.
The Schacht-Reeves drive band tension adjuster screw comes out the end of the table. It screws the whole Mother-of-all away from the wheel or towards the wheel to put more or less tension on the drive band. To be able to turn this adjuster screw, you must first loosen the wooden nut on the bottom of the table that holds the whole assembly in place. Turn the tension knob clockwise for more tension and counter clockwise for less.
The Ladybug tension adjuster for the drive band, is located to the side of the flyer assembly with a handle facing the front. Put the drive band in the groove of the tension wheel and with the handle, move the wheel out for more tension and in towards the wheel for less tension.
Double Drive on the Schacht-Reeves.
Large yarn: Everything is larger. Since there are so many fibers in the width of a fat yarn in one linear inch, less twist is required to hold the fibers together. To achieve a larger yarn, use a larger whorl (slow or extra slow speed), make the spring larger (longer) by stretching it (for Scotch tension) or turn the tension knob clockwise (for double drive) creating a larger amount of tension, treadle slower (a larger amount of time between each treadle), and feed a larger amount of yarn in the orifice.
Small yarn: Everything is smaller. In a linear inch of really thin yarn, you might have just a few fibers as the width of the yarn. In order to hold those few fibers together, a lot of twist is needed. To achieve a smaller yarn, use a smaller whorl (high or super high speed), make the spring smaller (less stretched) or turn the tension knob counter clockwise for a smaller amount of tension, treadle faster (a smaller amount of time between each treadle), and feed smaller amounts of fiber into the orifice. These are the two extremes on the spectrum of yarn, but hopefully, learning what to do to make extreme yarns will help with decisions about everything in between. What kind of yarn do you like to make? Do you have any other questions? Leave a comment or question below!
This is the clearest description of tension differences that I have ever read. Thank you!