Am I being silly?

[brman]

Tack weld opposite points. Progress slowly and methodically, setting up as accurately as you can and measuring as you go. All you need is a stick welder, a grinder, and a tape measure.

Then level with epoxy. It's completely doable, loads of people on here have written about their experiences and how to do it. If you screw it up (like I did my first time) chip it off and try again.

Alternatively, skip the hard stuff and use aluminium profile. You'll be bolting your rails on in minutes rather than days or weeks (or you know, in my case, months).

Which I think highlights my problem. careful welding (with lots of practice first), epoxy levelling. It just isn't going to happen. I need to find a easier route or just not bother.

If you want to cut metal on the machine,just find an old mill and add ballscrews and steppers.It may go over budget but it will work.Cutting metal on a woodworking machine may,just,sort of,be possible.That doesn't mean its a really good idea and trying to do it on a machine with a lot of Z travel, with all the consequent magnified play in the system won't help.For a hobby machine that just cuts wood you can do some stuff with a wooden machine.There are some extremely lightweight machines all over youtube delighting their owners,even if they wouldn't be much use in an industrial environment.You just have to be realistic about balancing budget,usage and building ability.The answer is out there once you carefully consider which features matter most.

Which is where I am at the moment, trying to balance time, budget and quality. I've seen pictures of high quality machines and, while I probably have the ability to make one, I don't have the time (or inclination). I have also seen MPCNC cutting ally acceptably (to me, not a production engineer) on youtube. So the question is really how low can I go without wasting my time?
I am tempting to try and see but I just know that will be followed by a lot of people saying I told you so...... ;)

[JAZZCNC]

while I probably have the ability to make one, I don't have the time (or inclination).

That one statement right there is why you should give up right now.!

If you don't have the budget to buy one and you don't the time or inclination to build one then just call it a day and save your money for when you do. If you proceed then it's highly likely you'll just blow money or as often the case when taken on half-hearted you'll fail and give it up.

[brman]

I won't criticise anybody for doing their best to make something work.I started with an MDF machine and drawer runners,which gradually got changed to SBR12 rails.I also use a much derided breakout board off a parallel port running LinuxCNC and it has never let me down.The crux of the matter is that we have the freedom to build with materials we are comfortable with and running software of our choice.If it doesn't meet our hopes,then clearly we made at least one wrong choice-at which point we get to decide what we do about it.

Thanks, yes, I have read enough to know what are the "best" ways of do things but "best" is not necessary most suitable for me at the moment. In my mind it is a compromise between making enough wrong decisions to learn and not making so many I give up

That one statement right there is why you should give up right now.!

If you don't have the budget to buy one and you don't the time or inclination to build one then just call it a day and save your money for when you do. If you proceed then it's highly likely you'll just blow money or as often the case when taken on half-hearted you'll fail and give it up.

I can see why you said that but I think we have different priorities. I see nothing wrong with experimenting for experimentations sake, even if it is not the "best" or conventional way of doing it.
Plus, there is no such thing as failure in my view. If I did nothing that would be a failure as I would have learnt nothing. If I do something and it does not perform as I hoped then fine, there is no failure there as the success is in the learning.

Then you need to be looking at purchasing a solution. Although even those will require you to put some effort in to diagnosing and troubleshooting problems along the way.

As above, I guess I should have made it clearer why I am doing this. It is not just to get a machine that makes parts I want. If that was the case I would just take my cad models to a cnc prototyping place and pay them. It would probably work out cheaper in the end! Lastly, time wise, I am not saying I don't have the time to tinker and fix things, just that I have to take that into account overall. ie. there is no point me spending all my available time making the best steel frame in the world but not having the time to sort the drives/control etc.

This might all sound like I am trying to justify to myself ignoring the good advice here. I am not, honest! I am still concerned about the effort of making a square and flat steel frame though, so I think I might need to consider ally extrusion again. Something for me to think about anyway. If I go that route then the choice between supported rod and profile rail is mainly one of cost vs performance.

Which I think leaves the other question. Fixed gantry, is that the right way to go for a small machine like this?

[JAZZCNC]

I can see why you said that but I think we have different priorities. I see nothing wrong with experimenting for experimentations sake, even if it is not the "best" or conventional way of doing it.
Plus, there is no such thing as failure in my view. If I did nothing that would be a failure as I would have learnt nothing. If I do something and it does not perform as I hoped then fine, there is no failure there as the success is in the learning.

I try to help people avoid problems they cannot see by using all my experience of building machines and helping 100's no 1000's of people over 15yrs+ who have taken similar routes and nearly gave up due to either poor design and build frustrations or woeful under budgeting. You gave a Budget of £500 so all my advice was based on this. You also proposed design material that is neither cheap or suitable for a successful machine.!

I understand the experimenting for experimentation's sake I do it every week in some way or another. But what I don't understand is why to do it when you are being advised by an experienced builder that there are better ways which won't cost any more money and in fact, will probably cost less.? All it would take is to experiment with a Welder.?

I also don't understand why anyone would join a forum seeking advice then ignore it.? Also, don't get why someone would seek to build a machine but state they have no time or inclination to build one.? . . . This seems to me you just like wasting people's time so you'll get no more from me I'm afraid. Good luck.!!

[brman]

I try to help people avoid problems they cannot see by using all my experience of building machines and helping 100's no 1000's of people over 15yrs+ who have taken similar routes and nearly gave up due to either poor design and build frustrations or woeful under budgeting. You gave a Budget of £500 so all my advice was based on this. You also proposed design material that is neither cheap or suitable for a successful machine.!

I understand the experimenting for experimentation's sake I do it every week in some way or another. But what I don't understand is why to do it when you are being advised by an experienced builder that there are better ways which won't cost any more money and in fact, will probably cost less.? All it would take is to experiment with a Welder.?

I also don't understand why anyone would join a forum seeking advice then ignore it.? Also, don't get why someone would seek to build a machine but state they have no time or inclination to build one.? . . . This seems to me you just like wasting people's time so you'll get no more from me I'm afraid. Good luck.!!

I am clearly not expressing myself very well.
To be clear, your (and everyone elses) input is appreciated. I am taking note of it and it will not be ignored. I am not stupid, it is clear already that part of what I was proposing is silly. But that doesn't mean it was stupid to ask the question and it doesn't mean it was stupid to question to try to understand where the posters were coming from and try to put across another point of view.

You might have noticed that the last few posts were me discussing with ericks his ally framed machine?
You will not be aware that I spent part of my evening looking at steel prices and thinking about how that might affect the design. You will also not be aware that I also spent some time looking at whether a converted mini mill might suite me better. Until I actually start buying stuff nothing if fixed in stone.

Am I wasting peoples time? I thought this was a discussion forum for, errr... discussions?? With that in mind, thank you for your input so far, it is genuinely appreciated (apart from perhaps that last post), it would be a shame but I will not lose any sleep if you feel you don't want to contribute any more.

[AndyUK]

It just isn't going to happen. I need to find a easier route or just not bother.

Then you need to be looking at purchasing a solution. Although even those will require you to put some effort in to diagnosing and troubleshooting problems along the way.