Under Tension

First published in Creative Fibre vol.16 no.3 (December 2013)

We all know that our spinning wheels work because the flyer twists the yarn and then winds it on the bobbin. A spinning wheel is basically a machine to do these two things. The winding-on happens because the flyer goes round faster or slower than the bobbin. There are three main ways this can work.

FLYER LEAD/SCOTCH TENSION

For New Zealand spinners, probably the most common system is scotch tension. The pulley (“whorl”) on the flyer shaft is driven by the drive band, and there is a little cord (“scotch brake”) round the bobbin groove that makes the bobbin travel slower. The flyer leads the bobbin around.

Scotch tension

Flyer lead, showing the scotch brake around the bobbin groove: Beulah wheel by Les Peacock.

Oddly, old Scottish wheels more often have double drive, not scotch tension. How come the name? One theory is that when wagons were the main means of transport, if you wanted to make sure your wagon wouldn’t run away on a slope, you “scotched” the wheels – you put a wedge of wood against them to act as a brake and stop them turning. So when spinning wheel makers wanted to slow the bobbin, they scotched it with a little string brake. Scotch tension may have nothing to do with Scotland.

BOBBIN LEAD/IRISH TENSION

Bobbin lead is the opposite of flyer lead: the drive band drives the bobbin, and a brake on the flyer slows it down. It’s often called Irish tension, but (surprise!) it’s not found on older Irish wheels. The best guess is that once upon a time someone thought if one system was “Scotch” its opposite should be called “Irish”.

Bobbin lead

Bobbin lead, with a little brake band around the flyer near the orifice: Mud River wheel from British Columbia, Canada. Such wheels were developed by the Cowichan Indians of Vancouver Island to spin the thick, softly-twisted singles yarn used for their famous Cowichan sweaters. This is why modern bulky wheels are sometimes called “Indian spinners”.

If you see a wheel with no flyer whorl, and no space for a missing one, chances are it’s bobbin lead.

DOUBLE DRIVE

This is one drive band driving both whorl and bobbin: one very long cord in a figure of eight going twice around the drive wheel. It works because the groove on the bobbin is smaller in circumference than the groove on the whorl. If the two grooves are the same size, the yarn won’t wind on, and the bigger the difference between them the faster the takeup will be. The drive band has to cross over itself.

Double drive

Double drive: Husfliden wheel from Norway. The cross of the drive band is visible below the flyer – the wheel has been spinning “Z”.

With most wheels, when the drive wheel goes clockwise (z, the usual spinning direction) the cross will automatically end up underneath. If you start to ply (s, anticlockwise) after a few treadles the cross should magically come up to the top. A few wheels, usually older ones with two separate grooves around the drive wheel, will not move the cross by themselves but throw the drive band off instead. If your wheel does this you will have to adjust the cross manually when you want to ply.

It’s best if at the cross, the strand that goes around the bobbin is inside the strand that goes around the whorl. This keeps the two strands slightly separate. If it’s the other way round, the strand from the bobbin groove (which is smaller) rubs at the cross against the strand from the whorl. The friction can wear out the cord and also, if the wheel is pernickety, may make it throw the drive band.

If you get this right for spinning, it will mean that when you ply and the cross goes from bottom to top, with the strand that was outside going to the inside and vice versa, it is now wrong. Some people with fussy wheels keep two drive bands on their wheel, crossed differently, and tuck away the one not in use. Most of us don’t bother changing anything and it works fine.

WHY CHOOSE ONE SYSTEM OVER ANOTHER?

Flyer lead/scotch tension is simple to understand and set up, and you can get fine adjustments of the bobbin brake without altering the tension on the drive wheel (and vice versa). It is very responsive and when you let it take up the spun yarn it shoots in quickly. If you treadle very slowly and watch your bobbin as you let the yarn flow freely into the orifice, you will see that the bobbin comes to a complete stop while the flyer busily winds the yarn around it. You can draft – draft – draft – windonfast. I find this particularly helpful for long draw, especially spinning cotton.

If you try the same slow-spinning test in double drive, you will see that nothing stops. Takeup onto the bobbin is relatively slow: how slow depends on how big the difference is between the size of the whorl groove and the bobbin groove. If you try to shoot the yarn into the orifice quickly, it just won’t go. The rhythm has to be more like draft – draft – draft – windon – windon – windon. The feel is different, and I find double drive very relaxing.

Once correctly set up, it should need almost no adjustment to spin a consistent, smooth yarn. Incidentally, you can’t switch between these two systems in the middle of a bobbin. You will find the yarn winds on in the opposite direction. Result: an unwound mess.

Bobbin lead is different again. Notoriously strong in its takeup, it’s particularly suited to bulky and novelty yarns that don’t want much twist, though it can be adjusted to spin finer. Many spinners find they can leave the flyer brake off altogether.

Direct drive

Direct drive: WeeQT wheel, age unknown. A scotch brake can be seen on the lower end of the bobbin. The treadle is on the far side hidden by the drive wheel. (Photo: Heather Nicholson)

I should also mention direct drive/friction drive, which does away altogether with drive bands. A rough edge on the whorl is driven by friction against the drive wheel. The whole thing can be very small, making for a portable travel wheel. With such a small drive wheel, ratios tend to be low. Only one was ever produced in New Zealand, the WeeQT, but several are made in the US.

So, double drive, scotch tension or bobbin lead? – this is a matter of personal preference, spinning style, and what you are spinning. It’s good to try all of them and be able to choose what suits you and your current project.

Acknowledgements: I thank Mike Keeves, who first told me about scotching a wheel (and a lot of other interesting things about spinning wheels), and as always the collective knowledge on Ravelry, particularly the Antique Wheels and Working Wheels groups.

Part 2, on drivebands, is here.

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