Another obligatory New PM-833TV and PM-1340GT Ordered!

Not sure I’m convinced with the direction I’m getting but I’ll work through it and I have some ideas of my own to check. Short version, I was told to shim the tail stock side of the bed to remove the convex dish, then re-tram the spindle. Can’t see that fixing .002 over a 5” cut.
 
Thanks for the update. I am of no help but paying close attention and learning.
 
That would cause the cutting tool to elevate and pull away from the spindle as the carriage is moved forward. This could easily cause a facing cut to be convex.
 

And...


I am incredibly annoyed right now after my support call with PM/QMT. Wanted to put this here. Am I crazy for thinking. the combination of the lift on the head side and the dip on the tail side directly confirms why I am cutting a facing cut convex dish? If so, then am I crazy in believing that this should be addressed by the manufacturer BEFORE I try twisting the bed to fix?

I am thinking that because I am indicating from the spindle, to a fixed point on the cross slide that IF twist was responsible for my issues, that my reading here would stay at ZERO, since I am measuring a fixed point in space, and that point would remain zero even if the cross slide was sloping an inch every foot. This proves IMO that the cross slide is not co planar to itself as it travels down the ways.
 
You aren’t crazy for thinking that.

It’s also not crazy for the PM support people to want you to follow a structured debugging procedure before sending you replacement parts.

First rule of tech support is believe the user’s observations but never their conclusions.
 
davidpbest said:
Yea, what @jaek said.
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The suggestion was to adjust the head to remove the dishing. I get that if you are close...but I was getting 2 thou convex over less than 4 inches.

I did adjust the head at one point to where I would get a flat facing cut. The result was an 8 thou taper over less than 4 inches. Shimming the tail stock for that would be ridiculous.

You all have been great hanging in with me during this saga. I appreciate all of your inputs. I think today I am just a tad annoyed. I sent the videos over to QMC and Matt. I am hoping for some kind of solution that addresses the cross slide instead of accepting the cross slide as "it is what it is" and solving AROUND it.
 
Scratching my head here, thinking out loud. With just those last two posted videos, the issue could be a misaligned head stock (spindle CL pointing upwast toward the tailstock), or bed twist (front tailstock end too low). Your precision test bar alignment test seems to rule out headstock misalignment. So it would be reasonable to assume it’s bed twist. How that relates to the Rollie Dad dumbbell test you did causes me to sake my head in wonder.
 
davidpbest said:
Scratching my head here, thinking out loud. With just those last two posted videos, the issue could be a misaligned head stock (spindle CL pointing upwast toward the tailstock), or bed twist (front tailstock end too low). Your precision test bar alignment test seems to rule out headstock misalignment. So it would be reasonable to assume it’s bed twist. How that relates to the Rollie Dad dumbbell test you did causes me to sake my head in wonder.
Click to expand...
Was thinking the same David, but why would twisted bed ways manifest in a change in the cross slide being coplanar to itself throughout its travel. The DTI would stay at zero unless I was moving the carriage, and changing the pitch of the cross slides plane.

In other words, even if the cross slide was pitching up 5 degrees and in 5 degrees, that DTI shouldn't move as it is cranked in and out, as long as the cross slides plane is true.
 
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