Sherline mill z axis saddle nut adjustment?

[learninturnin]

Hello, and thanks for reading.

I am having an issue with my manual Sherline mill. The Z axis saddle nut has fallen out of alignment and I am having some trouble getting it realigned correctly. I can't find any documentation on adjusting it so I was hoping someone here may have experience fine tuning it.

In having fallen out of adjustment several things typically happen.

1) The headstock will jam and I can not lower the headstock.
2) When the headstock is near the bottom of the column, it will drop/stutter/skip a little, maybe as much as a millimeter as I am lowering it.

I have been adjusting the alignment through a combination of the gib and the three saddle nut adjustment screws. I just can't tell for example, what tightening the lower screw, vs tightening the upper screw, vs tightening the middle screw does. I am pretty sure that tightening say the lower screw should adjust the column movement as it goes down? But I can't really see any direct evidence of that.

Thank you very much for any insight.

Russ.

 

[DJP]

My mini mill had a similar problem but it was not related to gib friction. The issue is the support arm and spring that holds the weight of the milling head. There are some clever changes using gas cylinders posted on this site but just increasing coil spring tension and ensuring some light drag on the gib lock solves the problem.