How Much is Too Much?

[Charlie Barnes]

Good Evening Everyone,

Long story short, I'm looking at an old Rockwell lathe, model 46-450. I went to see it tonight and it seems to be in good running order. It doesn't make any unusual noises and the variable speed works nice and smooth. I don't have any idea how old it is, but I'm guessing 40-50 years. I've been wanting to get into turning and want a good, solid, basic machine to learn on.

Here's the concern - I set up a dial indicator and I measured .004 runout on the head spindle (right term?) measured on the shaft right behind the drive spur/mounting plate. Of course the shaft I was measuring could have been out of round too, but it's the best place I could see to get a measurement.

Question: Is that too much runout? If it is, what is the "limit" for basic turnings (bowls, spindles, table legs, etc.)?

Thanks.

Charlie

255430

[Jim Barrett]

Post this in the Woodturning forum...

[Frank Drew]

Charlie,

You might mount centers in both the head- and tail stocks, move the tailstock up close so that the points of the centers are almost touching, then start the lathe and see if the point of the drive center shows any eccentricity in relation to the tailstock center point.

[Charlie Barnes]

Thanks for the tip Frank. I did slide the tailstock by the headstock last night, but I turned the spindle by hand (not under power). I couldn't see any variation doing that. I need to check it out again under power as you suggest.

FYI, I did also post this on the Wood Turning Forum last night too.

Thanks.

[Ronald Blue]

If I understand your place of measurement correctly it is behind the drive spur/center location or closer to the headstock. That is a non critical location unless I am missing something here and doesn't need to be concentric with the working surfaces. Put the indicator right on the center if you can. I don't think you have anything to worry about though if you couldn't observe any run out with the tail stock center as a reference.