After several seconds of hard thought I’ve come up with a name for the machine the “Doozer V1”. My nick name is Doozer and I can’t think of a better (imaginary) creature to name the machine after than one that spends it’s days building things. After tiring myself out thinking up a name I didn’t get much research done but what I did manage is detailed below.

Update: I realized that Doozer is probably trademarked so the name got changed to Wyvern. I don’t like the name as much but at least I’m on safer ground.

One of the things that bothers me about building a CNC is the rails that the three axes run on. I think it’s fair to say that the rails are just about the most important piece of the machine because if the rails are out the machine will never cut reliably or accurately. That’s not to say the correct choice of stepper motor, software, router etc etc isn’t important – they are – it’s just that the rails are at the very heart of the machine and if they are wrong there isn’t much you can do about it.

At one end of the spectrum are rails that are basically box or angle sections of aluminium with roller blade bearings and at the other are specially ground laser levelled flat surfaces. While the idea of trying to build a CNC very cheaply appeals at this stage I’m more interested in getting a machine that is acurate and capable and I’ll work on cheap later. For that reason I’ve set my sights on buying accurate rails for use on the machine. I think this will be quite an expensive solution but I really want the rails to be right.

The V90 runs on these supported linear shaft rails I believe which looks to be exactly what I want. The only problem is that they are in the US but I’m not and shipping a set of rails over here would cost a fortune. A quick Googling has turned up this company, Euro Bearings Ltd, which seem to do a range of supported rails that are pretty much exactly what I want.

There’s a good video about choosing rails here. Basically the conclusion is that round rails are much easier to install but they aren’t as stiff, size for size, as square rails. I also turned up a post on CNC Zone discussing the merits of support shafts and other rail systems. The dedicated builders are apparently using a system from Hiwin which I think is this.

Update: I’ve decided to change the name to Wobblycogs CNC Mk1 as I’m documenting it here I think it’s a better name.