How much run out is common/acceptible? Ever measured yours? Seen your chuck wobble?

[Joshua Dinerstein]

Recently I post a thread on being cursed. I have been fighting with my fresh out of the box but 1 year old Powermatic 3520b. I have have it a year but only set it up a month or so ago.

I have been turning for a few years now on an HF 34706 lathe. I was looking forward to a really nice upgrade with this new machine. In some ways this has been that but in others it is a resounding failure.

I started with adapters but in the end used chucks with the typical internal insert arrangement.

These chucks visibly wobble when the lathe is turned on running about 300rpms. Well they wobble at each speed choice this is just where I was testing at. I have tried several new chucks purchased new from CraftSupplies in Provo Ut. They are great to work with but in this case there wasn't much more than can do.

I just saw nothing like this on my cheap lathe using my cheap chucks. There is no visible wobble, no visible runout, and I have never had problems like I am having now.

I have contacted WMH's tech support and they are talking about sending someone out but I haven't heard anything from the local people yet. So I have a continuing concerns and worries.

Now just to be clear when I say wobble the chuck isn't loose, it is just visibly not perfectly aligned with ghost/shadow images... I am not sure how to describe it. But there we go. Ask if you need further clarification.

My questions:
1- Is this normal? Has anyone else noticed this with their lathes or chucks?

2- Is the visible wobble really a problem? I mean I am having troubles, serious troubles, but are they caused by this? Anyone had serious troubles getting a proper cut because of wobble?

3- Anyone measured theirs and remember what the measurements where?

4- Should the truing up of the blank counteract for the wobble in the chuck? Because in my case it is not. I get weird swirl patterns on my cuts so I am just trying to figure out if it this or something else.

Here is a link to the pics of the above swirls and the explanation I had already posted. http://www.sawmillcreek.org/showthread.php?p=1255875#poststop

Anyone have any comments on their own experiences with this kind of a problem?

Thanks,
Joshua

[Pat Johnson]

Hello
As some one touched upon in your other thread that is not from runout on your chuck that is something loose. Probably your spindle bearings. check to see if you have any axial or longitudinal play in your spindle. I think you will find your problem there.
Pat

[Joshua Dinerstein]

Hello
As some one touched upon in your other thread that is not from runout on your chuck that is something loose. Probably your spindle bearings. check to see if you have any axial or longitudinal play in your spindle. I think you will find your problem there.
Pat

Pat, Thanks for the reply. I read that response and I got a friend from the local turners group to come and help me verify. It is hard to watch the indicator while trying to manipulate the spindle. The spindle is solid. We wrenched on it in every way we could and there was no deflection. With the chuck on it when we smacked it hard with a hand we could get it to deflect about 4/1000ths but it would then come right back to it's starting position.

So the spindle won't slide front to back following the line of the lathe bed. It won't easily, or even with pretty darn hard pressure, deflect off of it's center line.

Basically we could find nothing that was loose. I had meant to post these findings in the other thread and if I didn't, I was pretty frustrated at that time, then I apologize as that was a straight up oversight on my part.

So what I was trying to ask here in this new thread was given that the chuck and spindle appear to be solid rather than loose but somehow "off". According to Vicmarc and to Powermatic's tech support a run out of up to 4/1000ths is within tolerance. Which means it should work properly. What I am experiencing when I try to use it is that it isn't working properly.

So while I continue to look for answers I am trying to figure out if the 4-7/1000ths that I have measured is really OK as they told me or if it really is the source of my problems.

In thinking about it the easiest way to determine that is to find out what those that are successful with their machines have. Do they see their chuck wobble but it makes no difference? If people have used an indicator of some kind in checking their own stuff out what ranges does it fall into.

Joshua


Joshua

[Rob Cunningham]

Joshua,
Sorry to hear you are still having problems.
Just so I am clear on this, where are you measuring the .004-.007" runout? Is it the face of the chuck, the diameter of the chuck or someplace else. Also, you say it's not working properly. Other than a visible wobble, what is not working properly?
Hopefully we can figure something out.

[Jim Underwood]

Even with a rigid, accurate lathe/chuck setup, you can still get the vibration/spiral mark on bowls and thin/long spindles.

When turning thin spindles you just have to have a very light touch, a sharp tool, and support of some kind.

When turning bowls and you get the vibration/swirl marks, there's nothing to do but start the cut over. It's caused by a combination of the end/side grain change every 90 degrees, and an improper technique- ie. you're using too much tool pressure and it's bouncing because of the grain change. You have to let the tool do the work, and just use fingers/body movement to direct the cut only. Once you realize what should be happening, you can literally just hold the gouge with one hand, and get a very nice cut.

It took two days of constant coaching from Stu Batty for me to get an inkling of what he was talking about....

As far as the chuck wobble, I've got the same problem with my Nova G3 with small jaws and 1x8 insert, and I still don't know what to do about it. I'm thinking it might be the runout in my Jet 1014 spindle, but I have yet to try it on another lathe. I can't seem to get a true cut even with my Talon 1-1/4 on my Jet 1642 either. When reversing a piece, I can't get it to run true to save my life. I feel your pain, but don't know what to tell you...

[Ken Fitzgerald]

Joshua,

Where are you measuring the 0.004"?

Standing at the foot end of the lathe....at the tailstock end....looking at the headstock and spindle.

Let X axis be the left to right

Let Y axis be vertical.....

Let Z axis be towards you or away from you ...

In which of the 3 planes are you measuring 0.004"?

And where are you measuring the 0.004"?

On the side of the spindle? On the side of the chuck?

Vertically on either spindle or chuck...

Or in the Z axis on spindle or the chuck?

Where are you measuring the movement and in what plane?

[Richard Madison]

Joshua,

A chuck could be threaded on the spindle either "crooked", or straight but off center, or some combination. Regardless, it should be possible to turn a smooth, round workpiece because the work rotates about the spindle axis even if it is held crooked or off center by the chuck. So if you cannot turn a smooth, round workpiece (assuming your tool use is anywhere near right), you have a spindle and/or spindle bearing problem that WMH needs to fix for you at their expense.

If there are places near the front and back O.D. of the chuck body for a dial indicator, you could measure the radial runout at both places as a function of angular position and get a pretty good idea about crooked and off center.

The pattern you showed on the face of a turning (IIRC) looks like a chatter tool pattern, or the bowl gouge was extended about 6" past the tool rest. Again suggests a spindle bearing malfunction.

Good points by Jim about tool usage and material flexing.

[Thom Sturgill]

Another issue might be the tool rest. If you are working off the end of a long rest, there could be enough vibration in the rest itself even if you are not hanging the thool too far off the rest. Take your long rest and lightly put your finger on one end and tap the other end to feel what I am talking about.

[Gary Conklin]

Any chance of you putting up a you tube clip of the action and you turning? Would help greatly.

[Jeff Nicol]

Joshua, I went out to my PM3520 and put the dial indicator on the spindle in all the places in these pictures. I had no more than a thousandth of deflection on any of the faces or spindle, and where I got the deflection was where I used a nasty set screw one time! Any way I have no troubles and I also checked the threads and the threads to the face with a little square. Everything was perfect. If you are getting 4-7 thousandths movement on the dial I think that is too much. Does it move all one way or does the dial go both ways from zero? It you put a little pressure on the indicator say.002 and rezero then turn the spindle you will see it move both sides of zero and that is better than having it deflect all in one spot.

The threads could be cut a little to deep or a little wide and the chuck or faceplate could possibly tilt in the threads when you put the blick of wood on and start to turn it. So put the wood on the faceplate or whatever and see if you can wiggle the faceplate on the threads, don't loosen it just pull it side to side and up and down to see if there is give in the threads. If all this is good then it really comes down to the tool operator, which no one wants to here.

Here are the pictures

Jeff

[Rob Cunningham]

Joshua,
Did you ever get the run-out problem resolved?

[Joshua Dinerstein]

Joshua,
Did you ever get the run-out problem resolved?

Rob, Well yes and no actually. I was just getting on to post my results from today.

So I tried using a nylon washer and tried not using it. As it stands I do not use one. I put the chuck on all the way each time make sure it mounts cleanly. Without anything in the chuck turning it slowly I do pretty well on wobble, but when I put in a good sized bowl blank to turn I get the same general wobble each time even after mounting and unmounting and so on over and over. It seems to have something to do with having a load on the lathe. So I think the previous suggestions about bearings and what not are right.

So today I was trying to turn a bowl, I took the week off from work so I had some time, I was experiencing the same problems. I cut and cut and cut and couldn't get rid of the wobble that caused bouncing in the tool. If I get it just right I get the swirls I have posted pictures of, if I cut it extremely lightly or using Grumbine's "Nuclear Weapon" it just bounces rather than cutting swirls. Bottom line it just wouldn't true up.

I got fed up and unscrewed the chuck with the bowl still mounted. I wanted to see what would happen on another lathe. I have taken the chuck to other places but not with a "problem blank" loaded on it. So I got it off and went over to a friend's house. He has my old Jet 1642 so it has a 1 1/4" spindle just like the Powermatic.

I screwed the chuck back onto the Jet lathe and of course the bowl wobbled. I mean it hadn't been cut true so I wasn't expecting that to be fixed immediately just by putting in onto a different lathe. But with it chucked up I was able to start taking some truing cuts. With the very first cut I was able to finally start truing up the bowl. It worked exactly as you would expect. After a few cuts it was running smooth and true and I was able to turn it properly. I kept cutting and altering the shape just to make sure. Every cut worked perfectly. I finally stopped when the bowl gouge got dull. Without my sharpening jig I couldn't fix it. (I need Robo Hippy to teach us all Stuart Batty's sharpening technique.)

My friend bought that Jet lathe but now sadly I want it back. :) What can I say it was fun to stop fighting the lathe and just turn and have it work. But it showed me something that was good to know. The chuck is good, the cutting tools and techniques I use are good. The lathe is bad.

So I called the local company that was supposed to call me about doing the repair. They haven't called after I had waited almost 2 weeks for them to do so. They already had the authorization but hadn't done anything about it. I now have an assigned repair time this coming Tuesday. A shame it isn't tomorrow or at least this week as I have time to use it right now but hey better to get it fixed period rather than continue to fight with it.

On the phone they told me after hearing the explanation and reading the paperwork from WMH Tool Group that they expected they would just be replacing the headstock. Which is fine with me as long as it fixes my problems. I don't care how they do it I just want it to work.

Thanks to one and all for the suggestions, help and being willing to talk to me about what is going on. I appreciate it all!

Joshua