Build and Intro

[swisscheese]

Hi all,

Been a bit of a dweller and thought I better introduce myself and show my build, asking lots of questions in the process.

I'm from the land down under, Australia, it seems pretty much all of you are in the UK!

The Build

The frame is made out of 65x65x4 mm box section steel. I think I may have gone a bit over board in this department, I'm sure you'll be able to tell me if its too much or too little. Originally the rails being used (all 20mm fully supported round rail) were going to be 1600mm for x 1000mm for y and 300mm for z. When I went to buy them there were no 1600mm in stock so I got the 1800mm for the price of 1600mm. This also forced me to get 1600mm ball screw instead of the planned 1400mm ball screw. The thing is I had already built the frame so now the x rails overhangs one end by 200mm. Instead of just cutting the rail I thought it would be good to leave it and modify the frame to accommodate it by adding a triangular section under each rail. This will allow me to do cuts that otherwise wouldn't be able to be done.

To level the table I will be using the self leveling resin method. I've already drilled and tapped all the holes for the x rail so these holes will obviously have to the bolts in them when I do the resin. What do I do to stop the resin from sticking to the bolts?
Cover them in a little oil?
I was thinking of using fiberglass resin. Anyone had any success with this? Other options?

Now the gantry.
I really cannot find anyone that can supply any suitable aluminium section for the gantry. This means that I have to use steel. For a length of 1.2m do you think 200x100x3 mm will be sufficient? I'm a bit worried about the weight of it. That section just mentioned will weigh around 12kg. The two sections that will hold it above the x rail come in around 13kg. Thats around 25 kg with nothing else added or accounted for. The x axis is moved by a 425 oz-in nema 23 motor. Will this handle it? It will be run with 1610 ballscrew, one on each side with belts. 5mm pitch 15mm wide htd belts and pulley will be used. Thinking a ratio of 1, can be swayed either way though to change this ratio.
Both the other axis will be powered by, I think 312 oz-in nema 23 motors.

Are all these motors alright to be run at about 60-70 volt? Heres the drivers I brought

3 Axis CNC Kit Stepper Motor Driver Controller 2M982 Interface Breakout Board | eBay

I hope these will be okay??
I think I'll be asking lots of questions about the electronics part when it comes to that so be prepared!

And the spindle brought
1 5KW Water Cooled Milling and Grinding Spindle Motor with Inverter Drive VFD R3 | eBay

Again any specific things I should know about this spindle?

Also through reading the threads I've read its better to have the supported axis rail for the z axis on the bit that moves up and down. Why is this?

I think thats enough for now.

Thanks and will eagerly await the replies.