Doing it wrong all this time!

[Desertboy]

I gave up trying to decide what was what so now I go with bottom axis, gantry and Z axis then no one seems to get confused.

To me though it seems logical that the bed should be X, Gantry Y and of course spindle Z, wouldn't surprise me if the Americans fucked everything up as they don't even know how to spell colour lol.

[A_Camera]

I gave up trying to decide what was what so now I go with bottom axis, gantry and Z axis then no one seems to get confused.

To me though it seems logical that the bed should be X, Gantry Y and of course spindle Z, wouldn't surprise me if the Americans fucked everything up as they don't even know how to spell colour lol.

In a moving gantry, yes... well... maybe...

I still think it is more logical the way I see it.

The axis parallel with your belly is the X. Positive X movement is from left to right.
The axis moving away from you is the Y. Positive Y is movement is from you, negative is towards you.

This seems to work with every CAD, CAM software as well as Mach3 and UCCNC screens I used.

[Neale]

There are two things being discussed here, and it's important not to muddle them.

First - and least important - is this matter of whether X is along the bed (long axis) or gantry, with Y being the other one. Doesn't matter a damn. Do what you like. Better, do what works for you. On my mk1 machine, there were no side rails and I stood at the machine looking at the long axis. So, made sense for X to go from left to right along the long axis and Y along the gantry. My mk2 machine has high side rails so I tend to stand at one end to load and operate the machine. It would make just as much sense to have X on the gantry so it went from left to right and have Y along the long axis. I get the impression that the US tends to do it the second way and Europe the first, but as I say, as long as you know so you put the stock on the bed the right way round, it does not matter. People argue for hours about the "logic" of one way or the other; ignore them. The only logical way is the way that works for you. As Desertboy said, though, people talk about X and Y and assume that everyone else has these the same way round. Much better to talk about long axis, gantry, etc, to avoid confusion.

The second point is very important and must not be ignored. This is to do with making sure that the positive direction of the axes is correct, and this time there is only one correct answer so that your machine is consistent with every CAD, CAM and motion control system out there. This time there are two ways to do it - the right way and the wrong way. What is described below is the right way. This is not a matter of opinion. This is the convention that everyone uses, and you ignore it at your peril. Stand looking at your machine with the X axis running side to side in front of you (long axis, gantry, doesn't matter). X goes from left to right (typically, but not necessarily, X=0 at the left end, X=max travel at the right). Whatever the numbers, as the tool moves from left to right, X is increasing. Under these circumstances, Y must increase as the tool moves away from you. Again, typically, Y=0 is nearest you, Y=max travel is furthest away. For Z, lowest coordinate is down, highest coordinate is up. People often set Z=0 at the top so as Z moves down, the Z coordinate is always negative. This will then tie in with Fusion 360, Vectric VCarve, TurboCAD, Mach3, LinuxCNC, etc. It is called a right-handed coordinate system (although the name doesn't matter) and it's what the rest of the world uses. If you set up your coordinates differently so that the numbers run the other way, you have a left-handed coordinate system and you are screwed every which way. You will never figure out quite what is going to happen when you run gcode generated by any normal software.

What I have described here works for a router, where we can all see that the work is still and the tool moves. That's easy to follow. Milling machines (table moves in X and Y) and fixed gantry machines (tool moves on one axis, table on the other) can give problems. The trick is to see that the only thing that matters is where the tool is relative to the work. Doesn't matter which of them moved. Tape a sheet of paper to the bed of your router. Draw X and Y axes on it - X from left to right at the bottom of the sheet, Y from bottom to top along the left-hand edge. Bottom left is now X=0, Y=0. Now take your piece of paper and tape it to the bed of your milling machine (or fixed gantry machine). Move the table so that the tool is over the X=0, Y=0 point. The DRO or whatever you are using should say 0,0. Now move the table so that the tool is over the max Y position. The table moved towards you. Don't worry about that - what matters is the DRO increased its Y reading. Now move the table so that the tool is at the right-hand edge of the paper. Table moved to the left. Doesn't matter - what matters is that the DRO increased its X reading. Just try to think about where the tool is on the work, and whether the DRO readings go the right way when you move the tool over the work.

So, choose for yourself which axis is X and which is Y. Make sure that when you move the tool, X and Y DRO readings move in the correct direction. Then start using the bloody machine, and the whole business will become second nature in no time. I have a moving gantry router on one side of the workshop and a vertical mill on the other with its XY moving table. There is no confusion as long as you take time to set them up right from the beginning.

[Neale]

I still think it is more logical the way I see it.

The axis parallel with your belly is the X. Positive X movement is from left to right.
The axis moving away from you is the Y. Positive Y is movement is from you, negative is towards you.

This seems to work with every CAD, CAM software as well as Mach3 and UCCNC screens I used.

I stand looking at the short side of my router. Gantry runs left to right in front of me. Does it still make sense to say that the long axis is X?

Problem is, there are two right answers!

[Desertboy]

Beat me to it Neale lol, my 3d printer had the X&Y axis wrongly configured for years and I never noticed because being square it just printed everything at 90° from day 1 and with no reference point I never clicked lol.

Logically the lowest axis should be X going up from there just goes against common sense to have the Y axis as the lowest one lol.

On a milling machine things are more confusing I think we should rename the Axis Curly, Larry and Moe instead ;)

[Neale]

I still remember school maths when no-one could remember which way X and Y went when we were drawing graphs. "X is a-cross" has stuck in my head for more years than I can remember!

[Clive S]

Dare I bring the point up about if one axis is wrong you can get a mirrored image

[Neale]

Dare I bring the point up about if one axis is wrong you can get a mirrored image

Certainly a possibility! Other likely outcomes are smacking into limit switches or snapping tools off against hold-down clamps. Of course, none of these things have ever happened to me...

[spluppit]

I stand looking at the short side of my router. Gantry runs left to right in front of me. Does it still make sense to say that the long axis is X?


Sorry cocked up the quote.


This is why i ignored A_cameras post trying to slate me and 35 years in the sector. It seems years in the sector means nothing to a home, self taught user who has learn't from forums, YouTube and the Internet. Pretty disrespectful to be honest. And as i stated it's generally accepted the X axis is longest axis of out the two omitting Z on a standard 3 axis configuration This is the industry standard A_ Camera.. accept it or not. I'm giving you the benefit of my knowledge... you are not teaching me anything I don't already know. There are the odd few machines out there where the other way around but they are very few and far between, it's often to a more square table configuration and a technical reason why it's reversed rather than by preference, those very few machines where this applies is often due to an a slightly different configuration or machine design.

A _Camera this is not pie in the sky. It's fact from being in more workshops than you are probably ever likely to be in or see, being around more machines and styles than you probably know exist, from machine 30 odd years old to the most modern 5 axis Dmg mori. Go check Hurco, Mazak, Feeler, Dugard, Bridgeport. XYZ machine tools, Matchmaker, Haas, Matsuura. Dah lih to name but a few.

The rest of the post where you tried slating me I don't think I'm going to even bother with because i don't actually believe you are that dumb, I think points scoring was your actual objective, or you really didn't read the post properly which i find hard to believe as reading your blog and some post here you are are fairly articulate.

The bottom line is, no matter what you think or what makes sense to you A_Camera this is what industry does take it or leave it. Have you ever hard of the phrase. ' industry standard'? It's called that for a reason.

[A_Camera]

I stand looking at the short side of my router. Gantry runs left to right in front of me. Does it still make sense to say that the long axis is X?

Problem is, there are two right answers!

...but I didn't say anything about which is longer than the other. It actually doesn't matter... as long as you know which is which and your X screw is the X axis and the Y screw is your Y axis and those match the drawings and the codes.