Acceptable chuck runout

Discussion in 'Tutorials and Tips' started by musky, Sep 22, 2007.

  1. musky

    musky

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    Have a Oneway 2436 with .000 runout at the spindle. Also have a Vicmark chuck with less than .003 runout on the outer diamiter. Just purchased a new Oneway Stronghold, that came with .006 runout on the outer diamiter. I could visably see it move. After taking the taper adaptor on and off a few times, I have now got the runout down to about .004. Is this good enough, does it really matter, or should I be calling Oneway?
     
  2. jdsilwones

    jdsilwones

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    I'm not sure what the taper adapter is but I would have troubles mentally if I could see my chuck wobble while I turn, weather it made any difference or not. With that said I would true up some stock in the chuck and the turn it around and re-chuck it a few times to see how it looks. Technically at some point the chuck error will be magnified in the work and then you can decide how big your problem really is.
    Best of luck,
    Dave
     
  3. Peter Skellenger

    Peter Skellenger

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    call oneway and ask them what the runout +/- is WITHOUT mentioning what your measurement is. Typically, a tech service person will ask what you have and somehow it seems to fall right in the accepted tollerance! I have never dealt with Oneway, I am talking generally. If your lathe runout is really actually zero, that is incredible. Runout drives me CRAZY in any machine. .006 will be magnified as you go further out from where you are measuring and it seems pretty high to me, especially if you can see it!
     
  4. Charles Henderson

    Charles Henderson

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    Similar Problem

    Have a similar problem...

    I have a Nova SN2, and until I just bought a new Jet Mini, but I had a Delta 46-700 w/ huge runout. I can't remember what the machine shop said exactly, but I don't really know how to measure it, or know if I have the right tools to do so...any help?

    My problem is when I put my SN2 chuck on the brand new mini - I discovered the body of the chuck still has visual runout. Much better than on the Delta, but I had attributed all of it to the lathe.

    Ugh...I hate runout too. Such a pain :mad:
     
  5. john lucas

    john lucas

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    I've had some crappy lathes and poorly made chucks over the year and still turned some awfully nice pieces. I don't think it really matters except in certain circumstances where you might be using the tailstock to drill holes or some other super precision process. I've done a lot of 2 part pieces there you had to have some very precise lips for glue joints and still no problems.
    That being said i love a machine with no runout. If the spindle doesn't have any runout then I would check the mating surfaces between the lathe a chuck. Even the smallest amount of dirt will keep it from setting flush and cause runout. I'm not that familiar with the oneway inserts but based on the many positive things I hear about Oneway customer service, you will get a no BS response and they will gladly help you.
     
  6. jwtaylor

    jwtaylor

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    I would be less concerned about the outside diameter of the chuck having a little run out than the object chucked in it having run out. I would mount a known true cylinder/rod in the chuck and measure it for run out. That would tell you if the chuck it is really out of tolerance.
     
  7. Steve Worcester

    Steve Worcester Admin Emeritus

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    I would measure the runout on the taper first. If it is accepatable, mount it on the chuck and use a dab of never-sieze or such in the taper.
    Then I would measure the chuck run out. It most likely will run high on one side, mark that side and tighten the bolt on the opposite side and measure again. It is usually from uneven torque on the bolts that causes runout. You should be able to get it way down. Don't crank down too much as you may snap the bolts.
     
  8. Richard Baker

    Richard Baker RIP

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    Taper adapter?

    Steve,
    For Dave and me, what is the "taper adapter"?
    Tend to agree w/ JWTaylor. Runout of the chuck body O.D. is irrelevant. Don't the Oneway chucks have straight jaws? if so, chucking a short, clean piece of CRS or the equivalent might be the way to check runout. Can't get very excited about .006 runout. My cheap (oops, economy) chuck is much worse than that, but grips the wood well and rotates it. And after just a little extra spot sanding a couple tear out places, the piece isn't round anymore, even if it was perfect a few minutes ago.

    Chakajo- Runout is often measured with a dial indicator. One might use a magnetic base to hold the d.i. The base would be "stuck" to the lathe ways and the indicator positioned on centerline with the tip against the chuck O.D. or whatever one is checking. The spindle is rotated by hand and the total range of movement is indicated by the d.i. Hope this helps.
     
  9. musky

    musky

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    chuck runout

    Thank you, everyone for your responses. Yes, the spindle face reads dead zero, and both it and the chuck mating surfaces are clean. As to the taper adaptor, I thought I might be able to pull it inline by the amount of tightness, but no such luck, as it is off 90 degrees to the screws. Also tried to rotate the adaptor 180 degrees, and ended up with slightly more runout. Too bad there isn't three screws holding the adaptor in, instead of two. Not sure if I have a straight round rod to chuck, and check that for runout, but will see what I can come up with. Will call Oneway on Monday, to see what they say. I also feel that they will not try to BS me, but would only want to make things right, if there were a problem.
     
  10. odie

    odie

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    The "taper adaptor" Musky refers to is that removable part on the back of the chuck that adapts the chuck to your spindle thread size.

    I have a Oneway Stronghold chuck, and have never checked for runout.

    I would think a little runout will make absolutely no difference at all, until you rechuck. If you use a chuck to rough out a bowl, and then rechuck after the bowl warps, I would imagine there too.....it would make little, if any, noticeable difference, since your stock has changed shape. I'm sure there is a point where runout would be a consideration.....but it would have to be much more than .oo6".

    My suggestion, for those of you who want a perfect match when you rechuck, is to mark your stock with a reference point that will match a particular feature of the chuck. That way, you'll get the stock back into the chuck with the same orientation between the two. But, then again.....I think some of you are worrying about something that won't be a practical consideration in bowl turning.

    There is a reason why John Lucas has had great success with chucks that are less than perfect......it isn't that critical!

    otis of cologne
     
  11. john lucas

    john lucas

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    I just went out to the shop and checked all my lathes and chucks. The Powermatic has no runout at all. The Jet and the Nova both had less than 1/2 thou. I put all my chucks on the powermatic. The worst vicmarc measured .003 and one had none. The really old original Nova had none. I also tried with the plastic washers and I have a homemade metal washer. This didn't change the readings by more than .0015.
    Now the way I chuck a bowl or vessel is to turn a short tenon that doesn't bottom out in the jaws. I turn a square shoulder on the tenon so the wood sits on top of the jaws. Therefore we should be checking the face of the jaws when they are under pressure. I will check that later today if I have time. I think the different compression of the wood will affect how these jaws align under pressure and that could affect the rounout of the bowl. Let me know what you all think and maybe I will have time to check it this afternoon.
    You can't expect to rechuck a bowl and get it perfect. You can crush the fibers unevenly by more than a few thousandths no matter how hard you try. I certainly agree that marking the bowls so they can go back into the same position when removed helps. I usually put a mark on the left side of Jaw #1.
    When you turn the tenon on a bowl you would think that since it was centered it would go in the jaws and perfectly center. I have only had this happen on rare occasions. Again I think the problem is the wood itself. I try to align the wood in the jaws so that grain runs parallel to the gap between the jaws. In theory this should allow the jaws to push on wood of similar grain direction on all 4 sides thereby reducing the runout. Of course this assumes that you cut square shoulder on the tenon and that the tenon doesn't bottom out in the chuck so the square shoulders sit on top of the chuck jaws.
     
  12. John Abt

    John Abt

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    At the risk of sounding like a dummy, how do you measure runout? Could someone either post the procedure or point me to a reference?

    I always appreciate the help I get from this forum.

    Thanks.
     
  13. odie

    odie

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    The best way to do it would be to use a dial indicator. I have one here that I've been using for precision reloading for a couple of my rifles, but never used it for checking on chuck runout.

    otis of cologne
     
  14. Steve Worcester

    Steve Worcester Admin Emeritus

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    And to go a little further, use a dial indicator on a magnetic base. You set it up so the base is stuck to the ways and the dial indicator is as close to 90 degrees from the object to be measured. You set the indicator at 0, mark the start and read the amount of difference as you slowly rotate the object.
    With a chuck, you would need to pick a spot on the body or jaws that would have no or little interruptions in the circumference so you don't have to pickup and move the indicators head.
     
  15. odie

    odie

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    After you have brought the stock to round, the chuck becomes nothing more than an attachment point. One thing to consider here, is to understand that when wood is chucked and spinning on your lathe, it is spinning in relation to the spindle, not the chuck. Once the wood has been trued, the chuck can wobble for all it's worth, but the wood is still spinning on the spindle's axis.

    If there is significant runout in the chuck, this is why it would be advisable to rechuck your bowl with the same orientation. Not even this is a panacea, though......as John Lucas points out. If you don't get the exact orientation and jaw pressure from one chucking to the next, I can see where it would be futile to expect an exact repeat of previous chuckings. (Now, if we were talking steel in a metal lathe, then things would be much closer to perfection......But even then, absolute perfection is only theoretical.....not a practical expectation.)

    I may check my Nova and Stronghold chucks later on.....but I do understand the role a few thousandths of runout will play (or, doesn't play) in the outcome of bowl turning. For anyone who is contemplating checking the runout, check back to jwtaylor's post yesterday. He understands that it's not the body of your chuck that should be checked for runout.....it's the gripping surface of the jaws. The best way to check on that is to take a known cylinder and chuck it up. Once you've done that, you can accurately check for runout in your chuck by measuring the runout on the chucked cylinder.

    .....odie
     
  16. Richard Baker

    Richard Baker RIP

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    Did my earlier post (#8 on page 1 of this thread) disappear? Nope, there it is.
     
  17. MichaelMouse

    MichaelMouse

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    Listen to the man.

    It's how well you form the shoulder for the tenon or the bottom of your mortise, followed by how well you snug it before you tighten those jaws. "Tighten" is a direction, not a directive, especially if you want to preserve what circularity and contact surface you have created. You want the load to be spread widely and at such low pressure that the fibers are not damaged. That's why I use slick dovetail jaws.

    Have to say that I rarely have problems when reversing or even remounting when I have a proper mortise or tenon cut. Most often what I initially perceive as non-circularity turns out to be fuzz left where I ran the gouge off the rim when I was doing the outside. I still check, and especially when turning to final on a dried piece, like to eliminate all shadow, even if it takes removing and blowing some sawdust out of the bottom of the mortise. Ninety percent of my problems come from that, or scraper fuzz where I didn't clean up the pickup grain on a rough-out.
     
  18. Paul Engle

    Paul Engle

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    In machine lathe r/o is critical , the further from the chuck the more r/o.
    check with the mfgr and get their spec and test procedure, then run it at home and see what you get. other wise nbd. I have an extension i made and it has about a 20thds jump but once the piece is roughed in it is not a problem. its just annoying (but the extension was made from 4160 chrome moly, and was no fun cutting the internal thrd)I made a 2nd one from stress proof and is a little better , these i can turn on , the ones from aluminum are not . the outside of the chuck on the jaw slides is going to have that kind of r/o as the jaws are not made to fit specific chucks as with a 1000$ + machine lathe chuck.
     
  19. JRutten

    JRutten

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    Runout

    I have a 1640 and got the spindle adapter so I could use my old chucks and stuff. First time I put it on there there was a VERY noticeable amount of runout. I tried to turn a platter and couldn't do it because it was so bad. I went out and bought a oneway chuck and put the spindle adapter to the side. I was turning something in the oneway chuck and noticed that same runout. Got to looking at it and what I had done was I hadn't tightened the chuck all the way down snug to the headstock. There is a valley in the spindle that the set screw for whatever you are putting on the spindle goes into. It is very easy to line up the set screw with the valley but not all the way to the headstock. Once I loosened the set screws and screwed the chuck the rest of the way down I had no more problems. I even went back to the spindle adapter and tried it and it solved my problem. Not sure this is what is happening with yours, but it might be worth checking.
     
  20. john lucas

    john lucas

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    JRutten you are 100 percent correct. If the chuck or faceplate does not mate with the back of the spindle it will not run true. This is why you can introduce runout by using spacers. If the spacers aren't perfect when you tighten the chuck up against them they will also pull it out of true. I believe he did say that he had cleaned the mating surfaces so that probably isn't the problem but it's a good thing to bring up for the new people
     

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