John's Alu Profile build

[JAZZCNC]

I think the Z axis I have is pretty solid though, it's foundation is milled from stainless. I know the opposite arrangement than most recommend, with the rails on the z plate which seems to be preferred, but it was a simple solution for me. I've tried to keep everything as close to moving bearings and having as little overhang as possible. The Z only has 100mm of travel but after using my other machine for a few years I realised I've never needed to mill anything over a couple of inches thick so the z overhang was really compromising the strength.

There's nothing wrong with rails on the rear plate, I've built dozens of machines using both methods and neither is better than the other because the difference between them is hardly anything and any advantage one as over the other is mostly dependant on machine design and user needs.
In your case with a short Z-axis, it's the best method because it allows you to make the most out of a short-stroke while allowing you to keep the gantry low and squat giving the best strength.

Edit:

Don't worry about the profile it will be fine. If you using my "L" Gantry design just make sure you bolt it together well.

[Evengravy]

There's nothing wrong with rails on the rear plate, I've built dozens of machines using both methods and neither is better than the other because the difference between them is hardly anything and any advantage one as over the other is mostly dependant on machine design and user needs.
In your case with a short Z-axis, it's the best method because it allows you to make the most out of a short-stroke while allowing you to keep the gantry low and squat giving the best strength.

Don't worry about the profile it will be fine.

Ah that's good to hear, I didn't go for the L design you have no, I wish I had of kicked around here before but that does look like a better solution than mine, unfortunately I'm quite a way through the build so at this point I'm just looking to get her done and running. I don't know if you would have any comments on the design as it stands? There's a few places I could reinforce around the gantry connection to the Y axis plates etc. I'm sure I can figure something out there.

I could always beef up the gantry with some steel plate on the back-side too, if that would help. I might just get the base/table done next and see how she does though.

[JAZZCNC]

I could always beef up the gantry with some steel plate on the back-side too, if that would help. I might just get the base/table done next and see how she does though.

I would look to beef up and brace the gantry ends but other than that it's nice and stiff looking.

That Z-axis is spot on for the size and you have half-decent material size. You won't get a much stiffer setup.

NOW just turn it on its side, or stand on its end and bolt to that wall.!!! . . . . You'll love it.

[Evengravy]

Thanks mate I'll do that,

Once the steel shops open again I'll have a crack with the MIG and see how I get on.