Spinning Tops: The Beginning
So for the last couple of weeks, I've been working on a concept that started out quite simple, and has evolved from there into many different aspects. What is it? It's a spinning top. You know the classic toy that kids have played with for ages (quite a few adults too I may add.) It's been a rather fun object to work on, and I'm not done yet. But, let me share what's been going on with this project and where I am right now.
I suppose in some ways, this project actually began years ago when I carved two small tops on the lathe for my then two year old son as a present. Spinning toys are after all quite amusing, there's something about trying to make it spin as long and evenly as possible, and I thought my kid would enjoy this. The designs I carved back then were quite small, and actually featured a rather different shape than what I'm working with right now.
The first spinning top made on the lathe
Those initial tops have been laying around the house since then, on the coffee table, on the desk etc... and every now and then we take them out and play with them a little bit. However, a while ago, it struck me that it would be interesting to take this concept further and develop a new design that was more substantial and that could spin longer. After all, the initial tops were neat looking, but they didn't work all that great.
You can only spin in this configuration
A few things struck me as problematic with them. The first one was quite small in size, and I was thinking it would be neat to increase the mass here dramatically, which would give you something quite chunky to play with (and after taking a brief look online, any spinning tops you may come across to buy are very small).
We also have the shape to deal with. This one, while interesting looking is rather off in terms of balance. The narrow edge needs to go on top and that's what you hold on to when you spin (not great for getting a good spin going), you can't turn it around even though it kind of looks like you could (and that was my intention initially), because the balance doesn't work then. It's kind of cute visually, but not really that functional, even though you can make it work.
The second top has a different shape but is problematic in other ways. I noticed, the distance between the point that spins and the large rounder mass around it isn’t quite large enough. That makes it so the edges of the round easily touch the table surface if you don't get a perfect spin going. You can still get spinning, but it’s a little harder.
So that was my starting point. One top that had too much of a distance between the point that touches the table and the round, and one that had too little. The other thing to notice was how these tops spun. Neither one spun especially straight, however the 2nd one did it a little better. And after playing around with different shapes, I’ve realized that some tops can spin quite straight and narrow, while others can start moving around in a circle and sometimes wander off the table. It depends on the design, and also how you spin it.
Size was something that concerned me right away. There was something appealing about having a larger top. However a larger size overall, means you need a larger piece of wood to work with in the first place. So I started looking over my wood supply trying find large pieces that would accommodate a re-design in a larger scale, and I realized I needed blocks that were at least 2 1/2 inches in diameter (quite a large piece in other words!)
In terms of tools, while it's fun to use a lathe for one off pieces, I think it's rather interesting to design something that's repeatable, and for that the rotary attachment on my Avid CNC is perfect. It's pretty much a lathe in most regards, and what you do is, design a piece of 3d dimensional software and let the spindle cut it out from there. Of course what's so appealing about this, is you can start out with a design, cut it out, try the top out, and then make small adjustments. Next up you cut out a new version etc..... and continuously improve your previous version.
Now some people could probably do this rather exactly on the lathe, but the CNC is neat because of the exactness of the design, as well as the possible repeatability.
Over the past couple of weeks now, we've been cutting a fair amount of tops in different kinds of woods, making minor changes over time. The question quickly became: how long can you make a top spin? Of course that question is not entirely simple. Every design decision regarding the top affects its ability to spin, but it almost always comes back to balance. Where is the weight located? How balanced is it? How pointy should the point touching the table be? How steep should the angle be from the larger round? What should the upper section be like where you hold on to create the spin etc.... All of those are things to consider and in the next couple of posts (and later in a detailed video) I will go into the process and the problems associated to this project.