Hey all,

Thanks for the great input so far, I'm sure there'll be more as we go ... :).

mitchejc
Ah, good to see another South African on the forum...
Thanks man,
been lurking for a while now, and now I'm sorry I didn't get my act together and post a lot earlier.
Thanks for the links, already learned from them...

I'm really glad to hear the steppers are good enough, was a bit concerned there. I've used their smaller steppers on a project and also found them to be very good.
Yep, Greg's stuff is very good, and he's a very knowledgeable and approachable guy as well. I'll definitely look into Wendy's. I sourced the local (jo'burg) Hiwin agent and got what I thought to be very reasonable prices from him. My main concern with China was the shipping time, but your deal is great as far as that's concerned. Also, I've heard that a lot of the Hiwin stuff coming from China is not the same quality that comes from the Taiwan factory. Apparently they pick up the stuff (from Hiwin) that doesn't quite make Hiwin's standard, and sell that. i.e. it's not reject, just not what you'd get from the original manufacturer. I'd be interested in hearing how yours go for you.

As for the 4th Axis, you guys are all right, I'm probably overstepping the bounds. I'm going to reduce the 4th axis radius to around 75mm (1/2 it). Then again I hear what you're saying, and will look into the whole software thing in a lot more depth ... even if I have to look at writing something to accommodate (on the longer term).

EddyCurrent
There are other things but for a start these jump out at me...
Thanks for this.
1. I'll take your good advice and source the suggested spindle and collet.
2. I am going to reduce the working radius on my 4th axis (hence the longer travel) and go to around half of it. I'll also increase the distance between the blocks as suggested. What should I look at for a minimum please?
3. Hopefully jazzcnc does comment, I'd be very interested in hearing his suggestions.
4. I started out on 20mm rail originally, only to be told by the manufacturers that 15 would more than suffice in terms of loading, etc. As I downsize the Z axis, I'm going to also downsize on the other axis as well. Not a whole lot, but a fair amount.
5. With the reduced Z axis and added other suggestions, I don't think I want to go adjustable table (for now anyways).

routercnc
That is a large machine to also cut aluminium...
Agreed. The main materials I'll be working with will be hardwood and perspex. For the occasions I'll want to work ally, it probably doesn't justify it anyway.

You have a very large offset from the Z axis to the Y rails - ...
There's another way I can do the Y-axis, and that's to use 2 of those profiles atop of each other, i.e loose the center piece - but that's if I insist on going that route. If I do, although simpler, it's a hellova lot more expensive and again, probably not worth the expense. I'll look at going back to an earlier design which was an all steel machine (and stop being so damned lazy :) ). In that version, I got the the ratio down much better.

The end plates on the gantry look very thin.

My bad! I should have said the end plates are 5mm steel plate, as are the gantry cross plate (bottom plate) and 4th axis mount plate.

Will you add a bed to this?

Yep, 32mm MDF, and I'll add 2 additional cross members to stiffen it up as well as suggested.

X axis motors
Yes, I got THAT one wrong, didn't I :). Not quite sure what I was thinking of on this one, probably one of my earlier version designs!

Clive S
If you are going to slave your x axis you might have to re think Linuxcnc ...

Thanks for pointing this one out to me. I'll rehash it and also better research it.

Thanks all so far for the great feedback. With you all pointing me in the right directions I'm really looking forward to getting this thing done.