If you’re a knitting addict, like Elisabeth, then you might find yourself having to deal with yarn in big bundles called hanks. You might come across hanks if you’re making your own yarn, and some yarn vendors only sell it in this form. The hank isn’t a particularly good format for knitting from, as the wool will tangle quite quickly. You want your yarn to be in a ball.
You can wind yarn balls by hand, but you’ll quickly get very bored of this. So, you’ll want a ball-winder. You can buy these, but you can of course make your own (you can even 3D print one). Elisabeth had one she’d made that could be driven by a belt connected to a spinning wheel. Unfortunately, it was a bit rickety, which I believe meant that it could only actually be rotated by hand else the belt would fall of. I harvested the bearing from an IKEA lazy susan and reduced the ricketyness of the ball winder such that it was more suited to higher speed operation. We also motorised it. As luck would have it, I’d already got a motor with a pulley and compatible belt from my recent temperature-controlled oven project.
Now that we’d got a high-speed ball-winder, some new issues appeared. It now took three people to perform a ball-winding operation. One person would hold and untangle the hank, one would manage the tension and position of the yarn as it entered the winder, and the other would observe the other two and manage the speed of the winder appropriately. The solution to this problem in knitting-land is to use a structure called a swift. A swift holds a hank of yarn such that it can be easily unwound. It’s essentially a variable-diameter wheel around which the hank is wrapped. When its loaded with a hank, one just needs to pull the end of the yarn, and the swift will rotate allowing the yarn to be unwound. This avoids all the tangling of attempting to do it by hand because the hank maintains its shape until it is completely unwound.
So, we decided to build a swift. More specifically, we decided to laser-cut a swift. Johannes and I came up with a conceptual design for the swift relatively quickly. Johannes did the CAD (he seems to enjoy the QCAD interface more than I do). We’ve uploaded the design for our swift to thingiverse so others may make it should they wish.
A nice bit of the swift’s design is the use of cable ties as hinges for the top-most joints. Although they may look like they’re a bit clunky, they’re actually surprisingly smooth!
Here’re the swift and baller in operation:
Jeff and I recently purchased a laser cutter. Jeff and Johannes spent a long time adjusting the mirrors and lenses in the cheaply constructed machine until the beam was finally behaving in the right way (whilst I was experiencing my new guitar :). We’ve experimented with cutting through a wide range of things. Thingiverse is a brilliant concept: being able to download and print an object is amazing!
Johannes and I played around with sintering sugar. After tuning the laser power and speed to get the sugar to melt together, we decided to try out a multi-layer object. This object is made of something like 6 or 7 layers sintered on top of each other:
We printed the object the other way up from how it’s shown above. The criss-crossed interconnection between the cylindrical walls was added in the last layer we sintered.
There’s more to come on the laser cutter front in the future… The software that the laser cutter comes with is a piece of Windows software called “NewlyDraw”. It’s got quite a limited and inextensible feature set. I’ve currently got this confined to a virtual machine, but intend on reverse engineering the PC-to-laser-cutter protocol so that I can replace it with something significantly more flexible and Linux related.
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