Joe90's BIG RAT Build.

[JAZZCNC]

I hadn't really thought of doing this as construction of anything still seems a long way off, but as Jazz said a BL is a good way of keeping all related content and stupid questions together, 'stupid' is my addition, not jazz's ;-)

Like most people, I've been lurking for quite a while and whilst I feel I'm starting to get an idea of what I want, it seems that my path diverges upon the turn of every corner and I'm left feeling overwhelmed at the complexity of making so many decisions.

Wise choice and over time you'll see why it's best to ask questions all in one place that relate to the machine your building.

Ideally, I'd like a machine that has a cutting capacity of 1.2m X 0.8m but I'm also looking at the possibility of using it for Aluminium (I'd like to be able to use it to machine any parts and plates for future machines/upgrades) but I'm worried that in trying to make the machine at this particular size, that I'll end up compromising things and that it will do neither well unless I throw a lot of money at it. Whilst money is not too much of an issue, if I can keep the overall spend under £2k that would be good.

With 2K you can just about do it but you will have to be very careful with what you buy and where from. First off forget buying things like Rails and ballscrews from inside UK or EU. They will need to come from China if you want to do it the cheapest way, but don't be put off by this because if you bought them in Uk then chances are they came from China anyway and marked up 300%.

Regards the structure then cheapest way to build a strong machine is to use steel for the mainframe and epoxy the rail mounting surfaces for accuracy. The gantry can be built from steel but it's simpler to use Aluminium Profile and makes mounting rails etc very easy.

The best advice I can give you don't buy anything until your ready to build and don't buy any electronics until needed.

Next would be don't try to reinvent the wheel. Machines like what Andy and Joe Harris built which use the L shape gantry design and high frame sides work very well, I know this because they are mostly based on my original design which I've built dozens of machines using that are used to cut all materials up to aluminum and brass. Often by users running a small business.

Finally don't be shy or worried about asking what may feel like stupid questions, they will have been asked before.

Good luck.