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Thread: Comet II tailstock quill wobbly when quill lock is loose- any adjustments?

  1. #1

    Comet II tailstock quill wobbly when quill lock is loose- any adjustments?

    Turning newbie here. I just got a new Comet II lathe with a Nova brand Jacobs chuck recently. I just drilled my first holes with it and was surprised to notice the tailstock was a little wobbly when the quill lock is unlocked. When plunging the drill, I could jiggle the bit around, changing where it entered the part by several millimeters. With the quill lock engaged, it was quite rigid (in other words, it's not the taper lock or drill adapter- I think it's the quill itself).

    Is this expected? I haven't used many wood lathes before, but I would assume you'd want the quill to be pretty rigid when drilling things. On the metal lathes I've used the quill lock is only needed when locking the depth adjustment. Are there adjustments I can make to tighten this up? Could this part have been made just a little off? I've already sent an email to Teknatool but they probably won't be able to get back to me until next week.

    I was able to get the hole started. Once it was "going" it seemed to straighten out somewhat, but I kind of had to snug up the quill lock lever and "ride" it with my left hand while my right hand turned the crank to plunge it.

  2. #2
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    12,298
    Bert, I'm not familiar with that lathe. To remove slop some of the lathes I have include a set screw with a locking nut on the back side that engages the slot in the quill that keeps it from turning. The set screw should be tightened then loosened a bit to allow free quill movement with as little play as possible. The set screw in one lathe was rough on the contact point so I sanded and polished it.

    For drilling I always make a starter hole with a machinist's center bit, inexpensive, available from Amazon and elsewhere. This results in much more accurate holes.

    center drills.jpg

    I like to use taper drills if I have the right size. Eliminating the Jacob's chuck removes several possible sources of error.

    taper_1_IMG_20160919_094408.jpg taper_2_IMG_20160919_094945.jpg


    JKJ

    Quote Originally Posted by Bert McMahan View Post
    Turning newbie here. I just got a new Comet II lathe with a Nova brand Jacobs chuck recently. I just drilled my first holes with it and was surprised to notice the tailstock was a little wobbly when the quill lock is unlocked. When plunging the drill, I could jiggle the bit around, changing where it entered the part by several millimeters. With the quill lock engaged, it was quite rigid (in other words, it's not the taper lock or drill adapter- I think it's the quill itself).

    Is this expected? I haven't used many wood lathes before, but I would assume you'd want the quill to be pretty rigid when drilling things. On the metal lathes I've used the quill lock is only needed when locking the depth adjustment. Are there adjustments I can make to tighten this up? Could this part have been made just a little off? I've already sent an email to Teknatool but they probably won't be able to get back to me until next week.

    I was able to get the hole started. Once it was "going" it seemed to straighten out somewhat, but I kind of had to snug up the quill lock lever and "ride" it with my left hand while my right hand turned the crank to plunge it.

  3. #3
    Just as JKJ mentioned, my lathe has a setscrew to take out the free play in the quill. It is located about 3/4" from the quill lock. If for some reason there isn't a setscrew then follow John's instructions. One suggestion that I would add is to get either a brass tipped setscrew or a steel one with a polished nose. Anything other than the common cup tipped setscrew found in hardware stores. those are made for digging into metal to lock two pieces together ... forever.
    Last edited by Bill Boehme; 08-04-2018 at 12:29 PM. Reason: left out an important word
    Bill

  4. #4
    Join Date
    Jan 2009
    Location
    Harrisburg, NC
    Posts
    814
    I don't think there is an adjustment to tighten it up. On my daughters there is some play but I did not notice anything excessive; I'm not sure how many "several" mm are. It could be the quill was not turned at the proper diameter.
    I always just loosen the lock enough to allow travel.
    Unless they have changed, the slot is 2.5" long but the pin is 1" away from the end so there is only 1.5" of travel.
    The quill is pretty stout and IIRC the bit I used to extend the slot another inch+ was called a mill end bit. I just used a cross vice in with my drill press to extend it.
    I don't think you can expect the tolerances with a wood lathe that you may be used to with a metal lathe but it should not be sloppy either.
    It may be quicker to phone the Nova service center rather than wait on an email from them
    "I became insane, with long intervals of horrible sanity." - Edgar Allan Poe

  5. #5
    Solving a problem by email is just a modern version of using passenger pigeons. Discussing it over the phone is infinitely better and faster.

    A woodturning lathe isn't exactly a high precision machine so a suction fit for the tailstock quill on a woodturning lathe just ain't gonna happen. And given that the parts are cast iron, a fit that is too snug is at risk of sticking. All the lathes that I know of (which is actually not a very long list) have set screws to remove the free play. In my Robust the amount of free play was small, but it could be felt with the quill fully extended. With just the right amount of pressure from the setscrew the quill moves smoothly and I can't feel any free play.
    Bill

  6. #6
    Join Date
    Jan 2004
    Location
    Fredericksburg, TX
    Posts
    2,576
    I used my Comet II today to make a little lidded box and tried a drill chuck in the tailstock. I did not see any appreciable slop to drill when the tailstock was locked to ways and the lock on the tailstock was not set. Travel with drillchuck is less than 1" since the tailstock has to be extended before the #2 MT will connect. How does the live center act? Is there slop with the center? If so, you may have a defective tailstock assembly and might be hard to determine which parts are at fault.

  7. #7
    I checked it again over the weekend and tried to measure the slop. I also spoke with Teknatool (via email) who gave me some reasonable info on making sure it's lubricated properly and everything was snugged up.

    I was measuring a little less than a millimeter at the tip of the drill with the quill lock fully disengaged. It's not ideal but I think that's just life with a cheaper tailstock. I will try adding a setscrew or something to it to get it more snug. For now I can just barely snug up the locking lever. I think some of what I thought was wobblyness was the tailstock rotating to hit the pin.

    I may also try broaching out a keyway and adding some kind of gib to it that I can tune with setscrews. It shouldn't be too tricky if I can find a linear broach the right size

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