How much nod is too much nod?

[Vogavt]

I have an X2 and over a space of 3.5" I'm seeing 0.003" difference from front to back in the Y-axis. Spot on in the X-axis.

I realize that's just a tad over 0.001" per inch, but was wondering what most folks would settle at.

[photomankc]

I could settle at about 4 times less than that. 0.0015" over 6" maybe. At that point it really only becomes a problem with the large diameter cutters.

[1HobbyMachinist]

I could settle at about 4 times less than that. 0.0015" over 6" maybe. At that point it really only becomes a problem with the large diameter cutters.

Me too, that's about what I've got on my 45.

[wizard]

I have an X2 and over a space of 3.5" I'm seeing 0.003" difference from front to back in the Y-axis. Spot on in the X-axis.

I realize that's just a tad over 0.001" per inch, but was wondering what most folks would settle at.

The question I have is why you believe it is nod? It could be obviously but it also could be gibb adjustment or issues with the gibbs and ways on the X & Y.

[Vogavt]

Thanks for the reponses! Now I have something tangible to work toward.

See that's why I asked here. I thought about the gib or the ways, but how could I know for sure? I previously adjusted the nod with the column flat on its back wyile using a drill rod in the spindle. I separated the housing from the spindle head and put the shims in until I got it as close to zero as I thought possible.
Come to think of it, now that I've got the column mounted back up in the vertical, this is the first time I've used the spindle tram (dual indicators like the ProTramm) to verify what I'd measured before.

So what you're saying is that I might be able to make some adjustments to the fitting of the gib the way and possible reduce the number? Correct?

[wizard]

In my case at least what I'm saying is that you need to do a bit of diagnostic work. Your problem could be many things so you can't really rely upon anybody here getting the diagnostic right via remote control.

For example loose or poorly fitted Gibbs on the head might cause your problem as could a poorly machined spindle bore. Then there is the potential issue that the column is not square. This doesn't even get into the potential issues on the X & Y.

The first thing to do in this case is to make sure the axis of rotation is parallel to the Z Gibbs. Further it must remain so when the column is upright. Then go from there.

Thanks for the reponses! Now I have something tangible to work toward.

See that's why I asked here. I thought about the gib or the ways, but how could I know for sure? I previously adjusted the nod with the column flat on its back wyile using a drill rod in the spindle. I separated the housing from the spindle head and put the shims in until I got it as close to zero as I thought possible.
Come to think of it, now that I've got the column mounted back up in the vertical, this is the first time I've used the spindle tram (dual indicators like the ProTramm) to verify what I'd measured before.

So what you're saying is that I might be able to make some adjustments to the fitting of the gib the way and possible reduce the number? Correct?