Hello from Cardiff!

[i2i]

820mm, 670mm and 250mm, with nuts and bearings. If your picking them up you can have a nose at the router as it's currently being modded.

[Jonathan]

If you can afford little bit more on the rails then get the 25mm (at least for the X axis) as it has one more row of balls than the 20mm rail. On my machine I used 25mm and 20mm and the 25mm clearly has less play in it. Might be a bit over the top for an A4 size machine...

So it's just aluminium box section, not aluminium profile? It must be for that price...if it is just box section then how are you intending to fix the ends together? Steel+welding would be easiest.

Have you considered getting one of the water cooled spindles that are available on eBay? I was going to get a Kress but decided/was persuaded that the water cooled one is better as it's quieter, less runout, stronger in general and won't wear out as fast. The collets are also a lot cheaper than Kress. I got the 2.2kW version since it takes 1/2" collets.

Have you got a milling machine to cut the 10mm aluminium? If not I can help you there ...

[jcb121]

My budget is around £800~, Though I wouldn't like to spend this all On a CNC Machine as I need to buy ALU, motorbike parts and my Mod1+2

My current criteria are:

Supported Rails
A3 workable area

I plan to:
Mill Aluminium.
Acrylic

What would you recommend as you guys know best? is the LC spindle really needed over a cheaper alternate such as the kress.

is 40mm Alu Profile ok to build a machine of my needs with?

is making the leap to 25mm supports really needed for a A3 machine?

what Force Nema 23 motors will I get away with?

Thanks.


PS. I have a Drill Press, Some Cobalt bits, Files and Lots of time so I souldn't need anything CNC'd for me to make it :)

but if I do, You'll have a PM,

[Jonathan]

What would you recommend as you guys know best? is the LC spindle really needed over a cheaper alternate such as the kress.

The Kress is in the end still a router, not a proper spindle. It will have more run-out, be noisier etc and won't last forever. The minimum rpm is 5000 ... whereas you can go lower with the water cooled spindle. That's good for cutting metals.
Maybe get a really really cheap router to start with then save up for the spindle? I started out with a router for about £6 from the car boot sale ... one of the ones from Aldi. This is what I have now got:

http://cgi.ebay.co.uk/2-2KW-WATER-CO...ht_7977wt_1139

For an A3 size machine the only reason to get the 2.2kW version is because it takes bigger collets. The extra power wont be required.

is 40mm Alu Profile ok to build a machine of my needs with?

Do you have a drawing of it, or better know its second moment of area?

is making the leap to 25mm supports really needed for a A3 machine?

It's not needed, but every little helps. The more rigid the machine is the faster you can cut whilst still maintaining a good finish. I regret not getting 25mm for the Y and Z axis, but then my machine is much bigger.

what Force Nema 23 motors will I get away with?

These 3Nm ones are popular/economical:

http://www.ebay.co.uk/itm/3-X-3Nm-St...#ht_1617wt_905

You could use less, but the price per Nm goes up if you do. The main thing is to look for motors with a low inductance and run them on a high voltage as that gets more torque at higher rpm. With those motors 70V will work well, which means you'll spend about £40-£50 on each driver.

[jcb121]

So would these Stepper motors with these Stepper drivers hooked up to this breakout board with this 48v PSU or this 36V PSU

and that would be the electrical side done apart from the spindle?

[Jonathan]

Steppers good and drivers are ok but you will find equivalent much cheaper on eBay internationally and 75 volt would be nice.

The breakout board you have chosen is opto-isolated which would be good except the drivers you have chosen are already opto-isolated ... that makes it slightly more difficult to wire up and can lead to issues so it's best and also cheapest to use a breakout board which is not isolated or even just connect them directly.

The 48V supply is ok, but again 70V would get higher torque. It's also very expensive ... so go for this one if it's still availably and you stick with the 50V drivers:

http://cgi.ebay.co.uk/ws/eBayISAPI.d...ht_1179wt_1139

Though it looks like Zapp might have bought the lot to sell them for three times the price:

http://www.zappautomation.co.uk/ep00...b64aaf46d5274f

I dislike the way they are making so much on those bye claiming it's a good price by saying the RRP is £280.

[jcb121]

are there any benefits to having the cutting bed move along the x axis?

I know it will take more room in my workshop but surely it's more stable?