Tailstock Measurement?

  1. James Williams 007
    James Williams 007
    Would someone with a G0766 be willing to measure the tabs on the tailstock that ride in the ways. The gap in my ways is exactly 1 1/2" and the tabs on my tailstock are 1/64" smaller. This translates into a good bit of play side to side and puts it off center. I have the machine completely level side to side and front to back. I went up to the local woodworking store today and looked at the Powermatics, Jets, and Lagunas and their tailstocks were tight and dead on center with almost no noticeable side to side play. I called Grizzly and got a very helpful tech who suggested a few things that didn't work and weren't relevant because its the machining on the tabs that's not tight enough. He also said I would have to send the tailstock in so they could check it and then they would send one back which he said could take up to a month The tabs on the headstock are just right and it slides perfectly in the ways and has very little play.
  2. Brice Rogers
    Brice Rogers
    James,

    I have had bad luck with the live centers from Grizzly. I found them to be very sloppy. I would not use one to determine if I were perfectly lined up. I am on live center #3 from Griz and the tip wiggles at least 0.015". (One had no wiggle but also could not be rotated. ha ha ). So, in order to determine how close the tailstock is lined up, You need to buy an MT2 (dead) center. They aren't that expensive.

    But, on the other hand, using the Grizzly live center - - with only a single bearing - - will be a little forgiving. So if things are off by say 0.015, the live center gives a bit.

    What do you anticipate cannot be done or done well with your current tailstock? I'm not trying to be provocative or argumentative with this question - - I'm hoping to learn something.
  3. James Williams 007
    James Williams 007
    Brice if they don't line up and aren't on the same axis the turning will get wobble. The other lathes line up and my midi was dead on. I can get my G0766 to line up but it's not automatic, sometimes it's a little to left or right. I was curious if this was normal for these lathes. Won't being off center be more pronounced with smaller turnings?
  4. Roger Chandler
    Roger Chandler
    1/64th" should not make any difference, but just allow enough room for the sliding headstock & tailstock. I am thinking you probably do not have the clamp plate pressure adjusted correctly, or the clamp plate has a burr or something that is making it not clamp in a true position. There are additional clamp plates in the shipping crate that were used for hold down...try one of those, and see if it helps. The nut puts pressure on the clamp plate. Also check the tailstock eye bolt for correct position as it might put torque to one side if it is off center on the shaft going thru the tailstock.
  5. James Williams 007
    James Williams 007
    Thanks Roger I'm going head out to the shop and give that a try.
  6. Roger Chandler
    Roger Chandler
    James....also try moving the headstock and tailstock to a new position along the bed and check for centers aligning.........if they do, then it might be that the original location has a bit of casting slag on the bottom of the ways where the clamp plate seated. If it has a bump or some abnormality, then a file might help that out, and make the centers align at that position. Let us know how things work out. This is a good lathe, and I personally know a number of guys who have it, and theirs is dead on in alignment, as is mine.
  7. Brice Rogers
    Brice Rogers
    James, I checked my G0766 and the tailstock has about 0.007 clearance total. That means that if the middle of that were perfectly centered that the adjustment would be +/- 0.0035". My live center has about 0.020 wobble at the end. So, if I want to check the alignment, I would need to put in a dead center rather than my sloppy live center.

    In regards to "wobble", that would only occur if you put in a previously turned part and used the tailstock and the dimple in the part to re-align it. If you put in a spindle blank and trued it up (by turning some wood off) there would be no wobble on the finished item.

    continued...
  8. Brice Rogers
    Brice Rogers
    Part 2:
    I have made some turnings with the piece intentionally offset by as much as an inch. I have done this by both moving the part at both the headstock and/or the tailstock. After I removed enough material, I had a tapered cone, but no wobble. I have also turned away only a small amount of material to intentionally introduce sort of a "wobble". I've also made some three sided turnings using this technique. On my metal lathe I can intentionally offset the tailstock "center" in order to produce a slight taper. But after I turn down the entire surface of the part there is only a taper and no "wobble".

    Perhaps it is just me, but I don't see much of a problem with the exception of repositioning a previously turned part. But wood moves all over the place and even if the center could be replaced exactly, it is typically likely that the wood may have moved a few thou. So when I reposition a previously turned piece I kind of expect some initial wobble that needs to be removed.
  9. James Williams 007
    James Williams 007
    Thank you all for the advice. After adjusting the clamp pressure it does lineup a little better. It's not dead on every time but after Brice's comments it seems that it shouldn't effect the operation. I'm going to build a ballast box out of the crate today then turn some burl!
  10. Brice Rogers
    Brice Rogers
    James, I googled the topic and saw some old posts from AAW. It seems like the alignment is more important when drilling/turning pens. But if you're keeping your smaller lathe, perhaps that is a good use for it. Some posters mentioned that if the alignment is bad enough that you could shim it. You can buy shim packs on Amazon. Sometimes common items like an aluminum soda can could be used.

    Also, some people mentioned that the small "slop" of the headstock can be used to your advantage.

    Some posters mentioned that you need to confirm that the centers you use are accurate. I would think that if you put each in the headstock and turned the lathe on you could confirm whether or not they are true.
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