Friday, August 27, 2010

Getting Tense, or MacGyvering the Katie


I'm in Haliburton this week, hacking my way through the classroom part of the OHS Handspinning Certificate Year 3.

Those of you who know my spinning know my only wheel is a Bosworth JourneyWheel, and know that I love it - it's an exquisite piece of art and engineering, and an incredible tool. There is only one aspect of the machine I would consider, well, slightly sub-optimal, and that is the bobbin design. There are only two ways in which I would articulate this, one of which has not bothered me much so far. The first is the bobbin size. They are small, it's a challenge to pack on more than 50 grams of yarn. This is OK, I knew this when I bought it, and I'm not a production spinner (yet!). I'm content to make 50-60 gram skeins of yarn, for that's enough for one sock and a common size in commercial yarn balls.

The second shortcoming, though, wasn't apparent until I got the wheel and has only become an issue, really, since starting the OHS course, but it needs some redress. The bobbins cannot be tensioned for plying. I know Mr. Bosworth believes they don't need to be, but I respectfully disagree. There is some frictional "drag" on the bobbin when it just rests on a Lazy Kate, however, this is not enough if trying to ply high-energy singles which will ZING off the Kate at a first pull of take-up then coil back on themselves.

As we are required in this year's class to work exercises in 3-ply yarns with tension on the bobbins, I'm struggling with this. The bobbins needed more resistance, but it's not possible to do so with tension. So, I turned to increasing the friction between the bobbin end and the surface of the Kate. I tried some different materials, and now have a couple of different options for this. Here's the how-to for what I ended up with.

Materials had to be sourced from what there was, but a trip to a grocery mart and dollar store procured a few possibly helpful substances: non-slip shelf liner, a thin plastic cutting mat or placemat, and a variety pack of little stick-on feet like you'd put under a plant pot or something to keep it from marking surfaces.









I used my bobbin as a template and traced and cut out circles of the shelf liner, and the plastic sheet.










The shelf liner circles alone provided TOO MUCH resistance, and the bobbins could not spin - somewhat expected. Note in the above picture that the little stick-on feet came in two sizes in each of two materials - cork, and a non-slip rubber similar to the shelf liner.

I cut plastic disks, and tried both sizes of both types of feet on either side of a disk.










After trying each version out for spin and drag, I felt that the smaller rubber feet on one side, with the larger cork on the other, provided the best resistance for the 3-plying I was doing this week. Note that the disks can be flipped, and because of the type of Lazy Kate I have, they will drag differently depending on which side is against the bobbin and which against the Kate.






Here's a better view of how it fits. Black dots up - less drag, I think, as the black will stick to the bobbin and the cork will slip, with some friction on the Kate. Cork dots up, the black will stick to the Kate, but not as much surface is in contact, and the cork will have all its surface in contact with the bobbin.

Or maybe these work out the same - I obviously haven't calculated all the physics of it.




Here's the final set up with one bobbin. Still not perfect - for example, tension in spinning changes dynamically, and there's no way to "adjust" these. They can still tangle, or if the drag is too much, the Kate comes flying forward. However, it did the trick for now, and I have another idea in mind for a mod, though it's going to require some woodwork to do it.

Off to adequately ply some homework, for now.