Price and Name does not a good tool make;

[kwgeorge]

Well, my Web site has been troublesome to say the least for a couple of months now and I have been unsuccessful in getting the hosting company to fix it. I have since decided to move to a new hosting company that I hope will be more stable.

I also bought a new chuck and decided to try a Oneway. With the spindle lock on the Nova I decided to just buy the Oneway scroll chuck and also some accessory jaws. I have written a review of this chuck which I was initially impressed with.

http://www.theturnersshop.com/turnin..._scroll_1.html

That was until I found it to have more Run-Out than any other chuck that I owned including the cheap Chinese. It is bad enough that you can physically see the piece mounted in it wobble. This incited me to delve much deeper into the subject of Run-Out and the testing and measuring of it.

http://www.theturnersshop.com/turnin...t/runout1.html

So if you’re bored or perhaps can show me a better methodology;

[GeekMom]

Ken, I'm sorry that you seem to have gotten an inferior chuck. I bought the same model that you reviewed, and I really enjoy using it. I haven't actually measured it for run-out, but it seems pretty true. Nothing like what you're describing. Hopefully you will be able to exchange yours.

[gerti]

The only chuck I own is a Oneway Talon, and I have not noticed any problem with it (unlike my mandrels, but that is a topic for another thread which I will promptly add). But unless I am mistaken runout would only show if/when I re-chuck, correct? Meaning even with runout, once turned round all the runout would cause is a slightly angled tenon?

Gerd

[kwgeorge]

Karen, I do like the chuck, as I said it is the smoothest operating chuck I have ever seen! I just really found it surprising that it also had so much Run-Out compared to my other chucks. I intend on contacting Oneway for there thoughts on it.

Well Gerd, that is my opinion also. Once a piece is roughed to round and left in the chuck a bit of Run-Out does not mater. The problems would come in if I was chucking a spindle and it was rather long I would end up turning it tapered instead of round. Of course I really don’t think I will be chucking a 12” or so spindle anytime soon. The issue I would have with this chuck is in box making and such but I believe I can fix most of the Run-Out with just a file on the face of the jaws. A very good habit to get into that you see a lot of the pro’s do is to mark the piece and its location in the chuck prior to removing it if re-chucking becomes necessary.

[LCHIEN]

I'm not a machinist or a lathe user, but I'm always interested in how things are measured.

First comment is, that when you find the lowest point and set zero, then
measure the highest point you are actually measuring twice the runout which is OK because it magnifies it somewhat, but I think in fairness you have doubled how bad it seems.

Still, .009" runout (measured .018) is bad and probably quite visibly wobbling like you say.

Another issue is you are measureing at 3.5" out. Runout there can actually be caused by one or two factors.
One is actual centering errors where the workpiece is parallel to the center of the axis of rotation but not concentric.
The other kind of error would be as you showed in your illustration, where the axis of the item being held is not parallel to the axis of rotation due to jaws being non parallel.

By measuring just past the jaws instead of 3.5" out, then you can determine which or both you have. The concentric kind will be equal everywhere and the nonparallel kind will be worse as it goes farther out.

I'm not sure that helps much, but really what I think you should do is contact Oneway customer service and complain and see what they will do for you. It may or may not be in warranty but a good company will stand behind their product if it had a defect originally as delivereed which yours seems to have. That may be where the name helps.

[Tom Miller]

quote:Originally posted by LCHIEN

Runout there can actually be caused by one or two factors.
One is actual centering errors where the workpiece is parallel to the center of the axis of rotation but not concentric.

Actually, I think this is the more common source of runout than the one Ken is describing. The good thing is that you can largely mitigate it's effect by taking care to rechuck your piece in the same position.

When you think of it, it's hard to imagine being able to perfectly rechuck a piece without doing this even in an ideal chuck, as the wood fibers will compress differently each time.

Regards,
Tom

[kwgeorge]

Loring and Tom, I agree to what you are saying. I actually measured very close to the face of the chuck and you are correct that at that position the Run-Out is reduced. The problem is for me anyway that most of the re-chucking done in box-making as well as other things is from reverse chucking the piece. So with that the Run-Out is much more visible and damaging away from the chuck. I also measured the jaws internally to check to see if one was not closing to the same spot as the others and one it was only .003” off.

To me the most important part of the chuck as far as accuracy is the face where the work piece meets the chuck jaws and its ability to center the work piece. In my case I was able to remove almost all the Run-Out I had found by placing the chuck into my metal lathe and machining the face of the jaws just a bit. I plan to contact Oneway as it appeared that the entire problem with this chuck for me was the jaw faces were not level to each other.

I also understand that the measurement is actually double just like taking material off of a spinning cylinder removes twice the material per rotation. There is no real reference material on measuring Run-Out other than in the machining areas. My test were based on that and modified for the type of work that I do on the lathe. I had considered producing much more detailed tests but my point would have been made no better and the write up would have been 10 times longer.

I guess what prompted all this for me was the constant discussions of chuck Run-Out that pop ups and my surprise at seeing this high rated chuck display it so predominately.

Thanks so much for the comments.