[madeinoz67]

145 copper machines nice. So does 6061 and 360 brass.

I've used 1.250" inserted facemill and I've used .02" diameter ball mill (diameter, not radius)

On X and Y I can hold .0015". My Z axis wanders, aprox .005"





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I'm interested where you got the facemill from?


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[NFC]

So after using my new X8 with a black box for a couple weeks I have to say I'm pretty happy so far.

I've cut a few parts from cast acrylic, MDF, and done a decent amount of carving on pine and everything has gone fairly smoothly. I still have oceans to learn and the goal (what will pay for the machine) is carbon fiber and some very simple 2.5D aluminum parts, but I was really worried this was going to be cheap Chinese junk. So it's not perfect, but I was seriously concerned I would have to replace so much stuff that I would end up basically rebuilding the machine...and thus far, I haven't had to make any changes.

I was pretty worried after my first run as the bed definitely is not level...or something...I haven't bothered to mic it out yet...but after surfacing my spoilboard I'm pretty happy with the 2D stuff I've done.

I only have maybe 10 hours of machine runtime...so nowhere near enough for a review, but I can tell you I was scared to death sending that money via wire transfer and not having a clue what I would be getting. Worst case scenario I have an expensive engraver...which is really what it is marketed as I guess. Best case scenario is it was a surprisingly good buy.

I will be supporting American companies for my next machines (I need a plasma table and a bigger router table) but I wanted to see if this was going to be a viable direction for me and I wanted to find out on something that didn't require a bank note.

I know it works well enough out the box to have confidence to spend a little $$$ in tweaking it if I need be. I don't know how helpful this info is but...there you are. xD

As a side note...the machine is WAY quieter than I thought it would be. I was stressing about how to enclose it to reduce noise levels, but the vacuum system I use is so loud that it drowns out any cutting sounds. That will probably change with aluminum but even still.

[cincron]

I'm interested where you got the facemill from?


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It's an Ingersoll 1.250 w/.375 shank, 6 inserted facemill.

[madeinoz67]

It's an Ingersoll 1.250 w/.375 shank, 6 inserted facemill.

Thanks for that


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[dharmic]

I noticed that the table was actually four separate sections and any sort of leverage on the part being milled in a vise would cause serious deflection in the table. So I reinforced it. The only pieces I need to complete the reinforcement are some countersunk bolts to put into the gantry base to avoid hitting the cross bars.

So now I have my deck up and looking at this mod or other possibilities. I have to keep telling myself "No, don't get a 700 x 500mm MIC6 tooling plate" because it's a whole lotta money that I could put toward a real mill conversion later.

Question, Washuu: is that 3mm x 20 or 25mm steel bar you've used and was it enough to make a reasonable difference?

[RCaffin]

Those thin steel strips look far to thin to be effective imho. Try 25 mm x 3 mm box section instead.
Or buy the tooling plate and be done with all the hassles. (You can always use the plate for something else later on.)

Cheers

[dharmic]

I must admit, when I picked up a bit of 25x3mm strap I had, the bow in it under its own weight gave me pause as to just how useless it would be. The only advantage I could see is it might help hold the deck planks together to prevent one stepping up past the other when I cranked down a clamp or similar.

I'm now looking at getting a 500x700x4mm piece of 5052 from a local boatbuilder and screwing the t-slot planks down to that. Can't do thicker than 4mm else it won't clear the bottom plate of the gantry (that runs between the sides and holds the linear bearings and ballnut).

I just can't justify the cost of a tool plate for such a dicky little router.

Another alternative tickling the back of my mind is to make a new frame out of 50mm SHS mild steel with supports everywhere and move that bottom plate so it runs under the frame instead of on top of it - the feet will give me the clearance and I can move the rails so they mount to the sides of the gantry rather than under it. But, again, it's getting a bit of a big mission for what's only ever going to be a fairly bendy machine.

[Mmpie]

I had wondered the same, it was part of my thinking of filling the hollow parts of the bed with epoxy or cement. Quick, easy and cheap. You could fill the t slot channels on the underside too I guess. I think that with steel cross supports should offer a lot more rigidity.


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[dharmic]

Unfortunately most of the stresses of deformation on the bed are going to be tensile rather than compressive - in my mind epoxy or cement would just crack. Some kind of camlock between the slots might keep them together and lined up and spread the load across the planks but there isn't a lot of room to work with for such a mechanism inside those slots.

[RCaffin]

At what point do you accept the machine as it is - and start using the acquired knowledge to design a better one?

Cheers
Roger

[dharmic]

About the point at which I realise no amount of 4mm max thickness backing is going to make an appreciable stiffness to a bed which is only supported at the ends (not even side support) and a slab of 20mm 5083 is going to cost me $350 before I have it machined square, surfaced and drilled in a tooling thread/dowel grid?

Yeah, that'd be the point at which I murmur something along the lines of "fvck it", screw the deck back on as it is and find ways to work around it for the occasional job where it becomes a significant issue.

And investigate the price of getting three phase to the house

[RCaffin]

I suppose it would be too much to hope to find a second-hand cast-iron table complete with T-slots? (I find the T-slots very useful.) It might be worth seeking.

Ah yes, 3-phase. I got it installed before Elcom went all commercial with their charges. They mumbled, but provided. It cost me 4 rolls of 60 A wire, some 45 mm conduit, and an hour with a small ditchwitch. Yes, I went underground: power one side of the trench, telephone on the other side.

Cheers
Roger

[Mmpie]

I don't know enough about stress and different types of forces to comment on that. When I get round to it I will try it anyway and run whatever tests you can think of. I have a litre of epoxy expiring on the shelf doing nothing which will surely be enough. It's nothing ventured nothing gained as far as I'm concerned, it's not going to cost me anything so worth giving it a go. If it works - great.

Another option could be to flip the bed over, drill out some holes, slide some steel bar down the channels and bolt it in. With the 3/4mm strips running perpendicular underneath it should offer a lot more support?

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[dharmic]

That might be better, provided there were plenty of bolts. Or maybe epoxy the steel rod in - the epoxy with a steel spine is much less likely to crack as the steel would take the tensile load, preventing sufficient strain (deflection) to crack the epoxy.

The biggest one to sort out IMO is locking the adjacent planks together at the edges to spread the load.

Meh, over it now. I've put the deck back on as is and run a short job, it was fine.

[RCaffin]

I am trying to be realistic here, and not nasty.
Might it be appropriate to simply say "You can't get there from here?"
And then use it and appreciate it for what it is.

Cheers
Roger

[dharmic]

Not nasty at all, Roger.

Mmmpie, you'll see from recent posts I've gone through the whole "can I stiffen up the bed" thought process and abandoned it. I'm not going to say "can't", but I am saying "simply not worth it".

Because once you stiffen the bed and start depending on it being more accurate you'll discover that the frame isn't square, the gantry sides flex, the spindle mount plate flexes, the gantry twists on the rails because the carriages are too close together, it's impossible to reliably tram the spindle and a litany of other sources of error.

Much easier to say "It's good to about 0.25mm, maybe 0.1mm provided your part isn't too big, allow 0.5mm or more if it spans the bed" and get on with it. Most of what we do, those kinds of tolerances are workable anyway.

Need better? Put the hundreds, then thousands, that you'll burn chasing the OmioCNC down the rabbit hole in search of accuracy instead toward a Tormach or Haas or Bridgeport or converting a Hafco knee mill or something like that instead.

Oh yeah, got my quote - $1600 to a sparky plus another $600 to Western Power for the connection. If I end up getting a VMC or mill turn this wouldn't be a huge expense in the scheme of things, but I ain't going there until I'm sure I can't do it on a single phase

[RCaffin]

Hi dharmic

Right - understood.

Now, 3-phase. I run my manual mill off 3-phase, although single-phase would be fine. I run my machining centre off single-phase with (I believe) a 6 A fuse. This whole business of 3 kW spindles is imho a gimmick. I am machining steel and titanium with a 500 W Baldor DC Industrial motor. It is quite sufficient.

Cheers

[Mmpie]

Oh don't get me wrong I completely agree, you can't polish a turd. I'm just trying to put some ideas forward. Although I don't see any harm in making cheap, easy minor upgrades such as these ideas for the bed. £10 of steel and 30 minutes cutting, drilling and bolting it in is nothing if it helps even just a little. I'm not about to go spending a fortune on servo motors, fancy electronics and whatever other things people do chasing as close to precision as they can get. If I really need that sort of tolerance there's a machine shop over the road that gives us a decent hourly rate.


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[dharmic]

All on the same page.

I keep surprising myself with what a decent job this little machine does and how much of the tolerances we demand seem to be just chasing numbers.

I'm not saddened by the fact my deck went back on untouched and every time I look at a better machine I look at what realistically will be $20k (by the time I get power sorted, tool holders blah blah blah) which I'll never get back on a hobby machine.

Bang for buck, this little Omio is pretty ace.

[extent]

Some depends on where you are too, aluminum prices in aus sound really high. I got a sheet of 3/4" 6061 big enough for two full sized fixture plates (not full bed replacement) for about 200 bucks. Machined it myself and surfaced it in place, because that's plenty good enough for my needs.