I want to DIY.. some questions please!

[JAZZCNC]

Trouble is I can't weld! I only have a gas bottle torch for doing a bit of plumbing, and I have little experience with it.

Learn.!! . . Buy a cheap £40 quid stick(Arc) welder and give it a go you'll be surprised just how easy it really is.!!
DONT buy a cheap Mig thou they are NO GOOD for boxsection, you need good quality high power for material over 3mm. . . . Stick is cheap, relatively easy and eats 3mm boxsection for breakfast. With a few hours practice on some scrap you'll be surprised what you can do and how much you improve.

That said you don't need to weld!!. A steel framed machine can be easily bolted together using plates. You will need an half decent drill press which you'll need regardless whether you use profile, steel or what ever and it's a must have tool for building a CNC machine, and a good grinder with a selection of grinding and cutting disc's.
When you buy the steel buy a strip of 80 x 6mm flat bar and chop it up for the required plates with grinder.
Doing it with plates means you have loads of adjustabilty which you need in a DIY machine to account for the lack of precision grinding and equipment you don't have.!!
It will also save you a shit load of money compared to profile and be stronger.

There are a couple of things with profile just about every body who hasn't used it before doesn't realise.
1: It's even more expensive than they thought because the extra's like T-nuts and brackets etc which you need to keep it easy simple bolt together cost nearly as much as the profile it's self and if you try to skip them to save Wonga your into a world of pain and akwardness that's just not worth the cost.
2: Often it's not just simply bolt together and often needs counter bores drilling so bolt heads fit between slots etc so again requires a good drill press and little jigs so every thing aligns together.
Personnaly I find it far simpler and quicker using steel and the slight plus profile as in that it makes mounting things like switch etc easier is far too costly IMO and with good design every thing can be done with steel and Alu plate for less than half the price and really not that much longer to build.

I would have thought the honeycomb over time would eventually crush under plunging forces which can be very high. With a bit of experience you learn to avoid plunge machining and try to avoid it as much as possible because it knocks the shit out the machine.

Personally I don't like 1 piece beds like the German stuff because one cock up and the whole thing is knackerd. Far better to use individual pieces which can then be replaced relatively cheap if you Foo bar. On my steel framed bed I used 16mm x 38mm strips of Ali to create a T-slot bed and it works very good and is about the cheapist way (at the time) get a good bed.

The other route I'd consider is to use profile side by side with the bennifit being you have 2 shot's at killing it.!!! So if you damage a piece you can turn it over and use the other side before it's knackerd. These guys also sell single sided 80x16 at £14mtr which aint bad. http://www.metallin.co.uk/shop/index...ory&path=3_125