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Thread: anyone change out the bearings on a Nova live center?

  1. #1

    anyone change out the bearings on a Nova live center?

    I have the Nova https://www.teknatool.com/product/no...-stepped-cone/ live center and it sounds like the bearings are going out. It looks like a sealed system. Has anyone tried to change the bearings? I can't find anything on line about that particular live center other than a lot of positive reviews.

  2. #2
    Join Date
    Dec 2013
    Location
    Greenbush, Wisconsin
    Posts
    31
    I have the same problem. Curious, have you tried Nova support?

  3. #3
    Join Date
    Apr 2018
    Location
    Cambridge Vermont
    Posts
    243
    I have seen live centers for metal lathes that have a snap ring on the outer cone but one the one (unknown brand) it looks like they are just pressed into place.

  4. #4
    I sent a question ticket? to Nova for consideration. We'll see.

  5. #5
    Join Date
    Sep 2012
    Location
    Tampa Bay area
    Posts
    262
    Look on the back side for two round holes opposing each other. I have changed bearings on a live center before.
    The picture below is the type of spanner wrench I used when I changed mine.
    Spanner.JPG

  6. #6
    IMG_0358.jpgno holes, looks sealed. My Robust has a slip ring but there's nothing on the Nova.

  7. #7
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
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    7,068
    Quote Originally Posted by Dave Fritz View Post
    IMG_0358.jpgno holes, looks sealed. My Robust has a slip ring but there's nothing on the Nova.
    I'll take a closer look at mine tomorrow. It may be the bearings are pressed in. If that's the case, extracting them will probably destroy them but new bearings could be pressed in.

    How old is this live center, did it get a lot of use? I've been using one of mine for 5 years now with no noise yet. I turn a lot of smaller things - perhaps I don't use as much pressure as some who turn bigger things. What kinds of things do you typically hold with it?

    JKJ

  8. #8
    Join Date
    Dec 2013
    Location
    Greenbush, Wisconsin
    Posts
    31
    I have had mine since they first came out. Like it a lot. I use it on small things and large rough outs up to 15 inches. I suspect I put too much pressure on it. When I ease up on the pressure the grinding stops...so does the feeling of having a secure mount! I wish I could get just the live center without all the attachments.

  9. #9
    Same problem here Ron, only I use mine for small handles with the cone center in the hole to keep things straight. If I push too hard I'd split the wood so I don't think that's the issue. Funny thing I went out in the shop to video the sound and now it runs just fine. It may not after a little more use but right now it's fine. I'll certainly share what I learn from Nova when they get back to me on my request ticket.

  10. #10
    Join Date
    Jan 2007
    Location
    Orange County, CA
    Posts
    260
    I would approach the bearing change by purchasing a 3/8-24 X 6 inch hardened Socket Head Cap Screw, make a washer that just fits through the inside of the female taper and a sleeve to pull against the back side of the outershell. Insert the cap screw with washer through the nose taper, add sleeve, washers and nut and pull the taper shaft with both bearings. Hold the cap screw with an allen wrench. I’ve had to use lubricated spherical washers under the nut before to reduce the torque applied to the nut.

    Change the bearings on the shaft, make a tapered block that contacts the outside tapered nose of the outer shell, reverse the process and pull the assembly back in place. I would suggest that you don’t attempt to use a flat washer and pull against the small front surface of the shell. Distort that surface and the taper will no longer hold or be concentric. There is probably a small sleeve between the two bearings, if so, don’t forget to re-install it. It would be nice if one of the bearings were the annular contact type to accommodate the thrust load. Check the bearing numbers closely.
    Last edited by Joe Kaufman; 01-09-2019 at 2:41 PM.

  11. #11
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    7,068

    bearings and live centers

    Quote Originally Posted by Dave Fritz View Post
    Same problem here Ron, only I use mine for small handles with the cone center in the hole to keep things straight. If I push too hard I'd split the wood so I don't think that's the issue. Funny thing I went out in the shop to video the sound and now it runs just fine. It may not after a little more use but right now it's fine. I'll certainly share what I learn from Nova when they get back to me on my request ticket.
    I looked at mine. Those and two other brands I have are all the same as far as construction - the bearings are pressed into the housing and the mandrel is pressed into the bearings, (though probably not in that order). I use a hydraulic press for these. The problem is you usually have to construct special jigs since you can put pressure on the center race of most bearings without damaging them. One way to do it is first press the mandrel into the inner races of the two bearings while backed up with an appropriate sized tube that only supports the inner race. Then another tube that contacts the outer race presses both bearings into the housing. Or it may be simpler to first press both bearings into the housing then back up the inner races with a tube through the front and press the mandrel in. Hard to know without doing it once. Maybe Nova will give provide a suggestion other than "buy a new one."

    Press-fitting bearings are much easier if you freeze one part to shrink it and heat the other to expand it. Hot oil is sometimes used as well as a fridge or dry ice. Nearly any machine or good mechanic should be able to replace the bearings but I couldn't guess about the cost. The bearing specification is on the seal visible on the rear of the bearing. They are cheap, available from any bearing shop or Amazon.

    BTW, I almost never use the cone, partly because of the reason you mention. For woods prone to split, especially with thin spindles, I first make a small, shallow hole in the center then use a Steb live center. This has a spring-loaded point that will not split the wood. It is tightened until the teeth grip the wood. I turn very thin spindles with this, and probably use it for 95% of my spindle turnings. (use Steb drive centers for the same reason - the spring-loaded points.)

    Steb_Sorby.jpg

    As I've mentioned before, I love the Nova center because of it's flexibility. Since it has a 2MT socket I turn a variety of small wooden inserts with short 2MT sockets. These are for pressure, long extensions for clearance, and most of all with tenons sized to fit into holes drilled into the end of spindles.

    One nice thing about these wooden inserts is I can turn one between centers very quickly then mount it directly into the headstock to size and shape it as needed. Here are some:

    live_center_MT2_IMG_7914.jpg

    I use one of these every time I make a tool handle or other handles like these:

    crops.jpg

    JKJ
    Last edited by John K Jordan; 01-10-2019 at 9:10 PM. Reason: changed "steb live center" to "steb drive center"

  12. #12
    Thanks for the replies. I did get a reply from Nova saying no one has asked that question before, they'd speak with their mechanic. In the meantime I have cut threads for my regular live enters and can use the Robust dead center to form them into whatever shape I want. I'll just make the switch. I'll use the Nova until it protests too much.

  13. #13
    Join Date
    Jan 2006
    Location
    Chicagoland
    Posts
    2,584
    Quote Originally Posted by John K Jordan View Post
    I looked at mine. Those and two other brands I have are all the same as far as construction - the bearings are pressed into the housing and the mandrel is pressed into the bearings, (though probably not in that order). I use a hydraulic press for these. The problem is you usually have to construct special jigs since you can put pressure on the center race of most bearings without damaging them. One way to do it is first press the mandrel into the inner races of the two bearings while backed up with an appropriate sized tube that only supports the inner race. Then another tube that contacts the outer race presses both bearings into the housing. Or it may be simpler to first press both bearings into the housing then back up the inner races with a tube through the front and press the mandrel in. Hard to know without doing it once. Maybe Nova will give provide a suggestion other than "buy a new one."

    Press-fitting bearings are much easier if you freeze one part to shrink it and heat the other to expand it. Hot oil is sometimes used as well as a fridge or dry ice. Nearly any machine or good mechanic should be able to replace the bearings but I couldn't guess about the cost. The bearing specification is on the seal visible on the rear of the bearing. They are cheap, available from any bearing shop or Amazon.

    BTW, I almost never use the cone, partly because of the reason you mention. For woods prone to split, especially with thin spindles, I first make a small, shallow hole in the center then use a Steb drive center. This has a spring-loaded point that will not split the wood. It is tightened until the teeth grip the wood. I turn very thin spindles with this, and probably use it for 95% of my spindle turnings. (use Steb drive centers for the same reason - the spring-loaded points.)

    Steb_Sorby.jpg

    As I've mentioned before, I love the Nova center because of it's flexibility. Since it has a 2MT socket I turn a variety of small wooden inserts with short 2MT sockets. These are for pressure, long extensions for clearance, and most of all with tenons sized to fit into holes drilled into the end of spindles.

    One nice thing about these wooden inserts is I can turn one between centers very quickly then mount it directly into the headstock to size and shape it as needed. Here are some:

    live_center_MT2_IMG_7914.jpg

    I use one of these every time I make a tool handle or other handles like these:

    crops.jpg

    JKJ
    John - enjoy your posts they are very helpful.

    (Sorry if I'm taking this off topic)

    A while back another turner here that helped me with a pepper mill suggested a Steb drive center. I bought one and it works great. I see that there are Steb revolving centers. Was wondering which setup is best - drive side only/revolving side/or both sides?


    Thanks,

    Mike

  14. #14
    Nova replied and said they don't repair them. He asked if I had proof of purchase and he'd see what he could do, but I don't. It's been a long time and probably doesn't owe me anything. Ron, you may want to contact them, maybe they'd sell just the basic live center without the inserts? Greenbush huh, went through there many years ago on my way to Lakeland College.

  15. #15
    Join Date
    Apr 2018
    Location
    Cambridge Vermont
    Posts
    243
    If you have access (or plenty of use for one) to a hydraulic press you probably could figure out a way to remove the old bearings. It would be kind of pricey but if you can get it apart I would replace the bearings with high quality name brand bearings. Looking at your picture you can see the standard part number for the bearing on the rubber seal. Chances are Nove uses a less expensive Chinese brand and maybe it didn't get enough grease injected into it or maybe it reached it's lifespan. Either way, like you said, it doesn't owe you anything so why not try to take it apart and replace them when the noise gets too bad or it feels like it's grinding.

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