Evening All

[Fivetide]

Here’s my tuppence worth on “low-cost” cnc’s. (my real life analogy) I bought a DSLR camera for £1,800 (sold along time ago) about 5 years ago because I fancied doing a bit of photography. Then I realise I actually liked making video’s just as much. The camera was amazing at photos but it had limited capability’s when it came to video. So by this time I was skint but really wanted to make some decent video footage. Now a half decent video camera or broadcast ready one would cost me about £2,000 + 2^nd hand, that would produce really good footage straight out of the box. My budget was less than £300. So I hit google and spent a good 2-3 weeks looking for a solution. Finally, after many - many forum posts youtube videos and emails I bought the camera, a 7-year-old Cannon E50. I won’t bore you with the details, but with a bit of free software a couple of very cheap prime lenses (£20 each of fleabay) and decent CF card I could take RAW video the same as some of the much-much more expensive cine cameras. But no auto focus, limited continuous filming time and overheating problems just to mention a few. And the learning curve was steep because it involved a lot more post production with editing, colourisation software etc. If I was patient and took time to set up the shot and managed my expectations I could achieve, in my opinion, good results. I wasn’t going for an Oscar or a career in film making, it was just something I wanted to do. However, one day a friend of mine who has a web design company, had a client who was having a company intro video filmed by a professional production company. He had spoken with the film makers and asked if I could go down and watch, do a bit of filming pick up some tips and tricks etc. After spending the whole day with them and seeing the results I realised that there was a vast difference between, what I was doing and what professionals do.
But I realise my limitations the same as I realise the limitations of my CNC and work accordingly and know what results I will get. However, if I decide to move to a better video camera or a more expensive CNC I will take with me all that knowledge and I expect to build on the capability’s and produce better quality work.
You can make money out of the cheap Chinese CNC’s, I know I have done it. When I was totally skint about 3 and half years ago (under threat of eviction and not in a good place in my life) I designed a bit of a fancy bird box, that looked like an old clock. I used cheap ply and even cheaper external paint. I worked a good 8 hours a day and.. less overheads + 20% I was putting away for any breakage of the machine, I was bringing in on average of £100 per day. That got me out of the shit, but it was hard work and frankly the machine took a beating. People still ask me if make them even though it’s to replace the ones that had rotted to bits lol, and yeah I bang a couple out on a weekend just for the fun of it for them (that sounded rude).
I have an ambition now and I’ve set my goal’s to achieve it. I will be buying another cheap CNC and making a bit more money from that, then when I have scrimped and saved buy a half decent CNC and continue like that. Each stage with let me know if I’m on the right path, but nothing will be lost when it comes to experience. And of course I can always sell it and get some money back for the next project.
BTW I looked at making my own cnc, and rejected the idea, really because I don’t have the confidence. If JAZZ was my next door neighbour I would have no qualms about attempting to build one. And who knows, in the future I might go for it.
So that’s my story, hope this helps you towards your decision.

[Robin Hewitt]

No problem, he has already succeeded. By setting the tool clearance to 60mm his machine is already 20 times more rigid than someone who thought 200 mm might be necessary for some unlikely job in the remote future. He can chuck a sacrificial 20mm MDF sheet over the bed and get an even more sensible 40mm clearance when the penny drops. If you are not engraving there is no point having a clearance greater than your tool sticks out the chuck.

[Chimestrike]

Thanks for the input guys, (I'm leaving the bad joke about knocking up a bird(in a)house out) but I get the point that you are getting at with the you get what you put in, I know I could hack some bits on it but I know it's not ideal.

But I've been thinking and I could put up with the extra cost if it means I get what I want/need after a good think and dig around I think the below would be my asks on it:

Needs:
Cutting area of 1250mm x 650mm (quarter sheet 8x4)
Z axis 60mm (unless you think I would need anything more)

Recommendations on easy to grasp designs software as currently I do the 2d vector work in adobe illustrator and open it in aspire (if that works do I need to change it, is there an easier way?)

Wants:
Mill aluminium / Other soft metals (no idea on steel?)
Cutting area of half 8x4 sheet (would love it but as you said it would sacrifice quality so..)
Some sort of self homing would be nice (if only on the Z axis)

Also as I'm making space this weekend do I need a metal stand for the machine or will a well built wooden unit work ok?

[JAZZCNC]

Needs:
Cutting area of 1250mm x 650mm (quarter sheet 8x4)
Z axis 60mm (unless you think I would need anything more)

Perfect dimensions and you'll have much stronger machine.

Recommendations on easy to grasp designs software as currently I do the 2d vector work in adobe illustrator and open it in aspire (if that works do I need to change it, is there an easier way?)

Nothing wrong with that setup so if your used to it stay with it.

Wants:
Mill aluminium / Other soft metals (no idea on steel?)
Cutting area of half 8x4 sheet (would love it but as you said it would sacrifice quality so..)
Some sort of self homing would be nice (if only on the Z axis)

Light duty Aluminium work will be possible but don't expect too much. Don't Even think about Steel.!!

Homing is easy and on All axis. However when you say Homing do you actually mean Homing to Fixed location using HOME Switch or are you meaning touch plate for setting the Z zero work coordinate.?
Two completely different things but both very easy to have and for hardly any cost.

Also as I'm making space this weekend do I need a metal stand for the machine or will a well built wooden unit work ok?

Good Strong wooden bench will work fine.

[Chimestrike]

Yeah the homing I was referring to was the end of the bit in the spindle, but if its easy enough to add in great !!

I am in your hands then please let me know what I need to do to go from here so I can get this started (other than make some space and a bench lol

[Boyan Silyavski]

60mm Z axis?

i have worked a lot of time on 90mm Z axis machine limited to 60mm travel due to sacrificial sheet and that's the absolute minimum i would ever wish for sb. In fact i don't wish that to sb. Having just double the travel /120mm/ will be like sleeping in 5 star hotel compared to a hostal/



Why:
-10-20mm for MDF, wood, laminate or expanded PVC sacrificial layer ,

-20mm wood or aluminum fixture when producing many repeatable parts, double sided parts, etc.

-20mm material / the typical




ok, 60mm till now.

so what we do with the typical 30mm bit extending from spindle +5mm Safe Z . sometimes even 50mm /when using 12mm or 1/2 cutter/

what about work holding - chucks, vice?

what about boxes engraving and other thicker than 20mm stuff?

what about vacuum table?





Cheap cheap, but : Mehh, i say the saving from this is no more than 200 pounds, including Z plates, Z square Hiwin, gantry or table sides.


The only reason i see to make a Z axis 60mm is to use only 2 long Hiwin blocks on Z and one block each gantry side. But who would do that? 4 blocks saving is 120 pounds approximately.


IMHO 120mm is the minimum Z travel and 160 table to gantry/Z clearance, not counting the bit protruding from spindle. I am saying anything below this is not worth spending the money, except if not for some special purpose machine, that is clear what exactly will do all day.


Also is worth noting that when we start digging deeper, having in mind the ball screw nut length, the ball screw end supports, and all Z parts like pulleys, we arrive at a precise relation between Z travel and gantry clearance, when machine properly designed.

[Chimestrike]

So Boyan, you mean have a longer z travel but increase the bed height so you only use what you need, then if required lower the bed for the deeper cuts?

[JAZZCNC]

Boyan think your missunder standing not saying 60mm clearence between gantry and bed. We are talking actual cutting depth so obviously there will be clearance for at least 60mm plus shank and to be honest I always design for Drills rather than tools because they tend to be longer.

All this will end up at around the figures you quoted.