design choices when the budget will not stretch?

[MATT]

Here's a topical but tricky question for the illuminatti that keeps coming back in various guises:

Assuming the budget will not stretch to ALL of the following features, which one (or two) would you choose to compromise on?

Welded steel framed gantry
20mm alloy Z and Y axis
Water cooled 2.2kw spindle and VFD
M542 drivers
50v power supply
1610 ballscrews
20mm supported rail
variable height table

Unsure on how you budgeted for all the above items, but I need to ask how you intend to, or what you mean by variable height table.

I am also building one with a variable height table (large scale things don’t need as much rigidity, whereas steel does so tighten up the size and specs for cutting smaller steel parts).
Only now I am nearly finished it, I wish I had compromised on the space of the X axis and had a moving X table with a fixed YZ gantry that could be dismounted and adjusted up or down) instead of moving the whole fixed bed up and down. But sometimes you got to learn the hard way (I was told, but am always too stubborn, haha).

Have fun, and let us know how it goes, I will post my machine once the frame is welded.

[mocha]

Unsure on how you budgeted for all the above items, but I need to ask how you intend to, or what you mean by variable height table.

I am also building one with a variable height table (large scale things don’t need as much rigidity, whereas steel does so tighten up the size and specs for cutting smaller steel parts).
Only now I am nearly finished it, I wish I had compromised on the space of the X axis and had a moving X table with a fixed YZ gantry that could be dismounted and adjusted up or down) instead of moving the whole fixed bed up and down. But sometimes you got to learn the hard way (I was told, but am always too stubborn, haha).

Have fun, and let us know how it goes, I will post my machine once the frame is welded.

Hi Matt

In this context, it's a hypothetical question. It supposes that you are in the planning stage of a CNC build and that the feature list of the desired machine had those items in it. It also assumes that the budget can not be stretched, cajoled or persuaded to pay for all of them. So, which would be the areas that could be compromised with the minimum effect or to put it another way, for the benefit of those yet wanting to do a build but thinking they don't have the cash; what priority to give to the various elements. My initial design criteria were none of the above and my plans don't include any of those features. The width of my shoulders, the doorway is needs to go through and the price of jaffa cakes were higher on my list. :-)

For me the answer was simple, wait until I can afford to get the bits that I wanted. Simple but difficult if you see what I mean.

There are some great methods in other threads showing how the question of raising the bed can be accomplished, jazz posted a link for a good one as I recall. I went for an asymmetrical bed that I could just flip over and get different heights but if I was doing it again, I'd have a longer look at a packing system to lift the work to the optimum height.

Look forward to seeing your pics too.