Which side is best to mount headstock?

[blackhawk]

I am building my own indexer from a standard mid-size lathe. I am going to be mounting the indexer along the X-axis. I have a 48x96 PRT Alpha and I use the bottom left corner as 0,0. My question is about whether I should mount the headstock to the right (at normal X zero) or to the left? Mounting the headstock to the left makes things better for me as far as how the lathe is built and how I want to attach my stepper motor.

If I mount the headstock to the left, it sounds like I would need to add a negative sign to my X unit value each time that I run an indexer file. (My mind is configured to use the bottom left as 0,0 so I don't want to change this for my standard sheet cutting.) Only thing is that now I always have to remember to do this for an indexer file.

Are there any bad reasons not to use the tailstock end as my zero point and avoid having to remember to add the - sign to my unit values for indexer files?

[myxpykalix]

I get confused myself because of the position my bot is in the shop I sit at the 0,0 lower left end facing the X axis length. What i see is illustrated in the first pic (bot.jpg).

What still confuses me is that regardless of what direction you point your indexer, if you are behind it, one direction will always be clockwise the other will always be counter clockwise.

I mounted mine where the headstock will be 0,0 at lower left. If you have ever done any turning on a lathe you usually start from the headstock and move to tailstock.

I wrote a wizard in 08 (with a lot of help) that let me do spirals without writing them manually and all i had to do was check/uncheck a button.
Depending on what program you use today you don't need to put the minus sign for direction (unless you are writing a manual code).

I'm not sure how some of the newer programs are handling the directions in their wizards other then for X or Y orientations. I'm not clear on how it knows to start from lower left 0,0 (headstock) and move to the tailstock.

If it was me however unless you plan on writing all this code manually i would mount it like i have mine, and how many others mount theirs. Any code you write if it is not set up like mine, would not work on mine and any file i made would not work on yours.

[blackhawk]

Actually, I meant to say that I am mounting my indexer parallel to the Y-axis (short side of the table). I need to set my unit value for Y as negative. My question is still valid, just talking in the Y direction now.

I tried out the negative on my unit values and it works, so that seems like a valid option.

[Brady Watson]

I don't understand why the Y axis direction would have to be reversed???

It doesn't matter which way the B-axis/indexer is mounted in either the X or Y orientation. The headstock can be at the Y0 end or the Y48 end. The CNC does not know or care whether the stock is driven from what your brain would perceive as the 'headstock' or 'tailstock' end of the workpiece.

What is important from a cutting perspective is that if you are going to cut parts in front of the workpiece (instead of ON TOP of the workpiece) then, the B axis should spin towards you, just like a lathe.

Reversing the +/- sign of the B unit value is an easy way to create left & right parts in the round.

-B