Sjogren Center Gear (Collet Closer Nut) Repair
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  1. #1
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    Default Sjogren Center Gear (Collet Closer Nut) Repair

    Presented for your amazement and amusement is a series of YouTube videos on the repair of a Hardinge-Sjogren 5C center gear, which is actually the closer on all Sjogrens, whether 5C, 2J or other.

    Hardinge got out of the Sjogren workholding market some time ago, and ATS Workholding is the successor.

    A few years ago, a center gear for a 2ADC (special 10EE model, Sjogren 2J collets, small 9" handwheel for operating up to 4,000 rpm) used to be about $120, but the prices have since doubled.

    If, as I was, presented with an eBay 2ADC (price, about $125) which would close a brand-new 2J collet, but would not and could not close a shop-worn 2J collet, it makes good sense to repair the center gear ones-self.

    This ...

    https://www.youtube.com/watch?v=aZfN...gBcnmIPCeQS379

    (Sjogren repair, Part 1, starts at about 11:15)

    https://www.youtube.com/watch?v=dFVg...eQS379&index=2

    (Part 2 of Sjogren repair)

    https://www.youtube.com/watch?v=QmY8...gBcnmIPCeQS379

    (Part 3, and conclusion, of Sjogren repair)

    ... series of YouTube videos shows you how, for a 5C Hardinge-Sjogren, but this technique would work for an original (pre-Hardinge) Sjogren, or a current (post-Hardringe) Sjogren, and probably for any version in between.

    Sjogrens have been continually made ... by someone ... since Sjogren patented his design in 1929.

    Yes ... nearly 90 years ago!

    Enjoy!

  2. #2
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    Hi Peter, thanks for the love. Is this type of failure common on these chucks? That chuck wouldn't grab any collet of mine, no matter the brand or age.

  3. #3
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    You're most welcome.

    The eBay seller who sold me the 2ADC Hardinge-Sjogren supplied it with a nearly new Hardinge 2J collet.

    That Sjogren would always close and eject that nearly new collet, but it failed on most of my used 2J collets (but my 2AD Hardinge-Sjogren on my Logan would close and eject every one of my used 2J collets).

    I, therefore, assume the seller did not know the center gear was badly worn ... really, it was worn-out ... or he did know, but provided an "exemplar" collet which would always close and eject, as a deceptive sales technique, perhaps in order to avoid a return or negative feedback.

    I had a 2AD (large handwheel) sitting around and thought I might use the center gear from that in the 2ADC, but they are different in diameter, hence number of teeth.

    Your repair technique is especially useful as ATS Workholding manufactures replacement parts in small lots, and it may take several weeks to perhaps months to obtain a new replacement, whereas your technique can be accomplished in less than a day (plus more time for the Loc-Tite to completely bond).

    I liked seeing your Rivett in action, too. In the no-holds-barred toolroom lathe class, every machine has a number of oddities, and it is instructive to see different machines in action.
    Last edited by peterh5322; 03-03-2015 at 10:15 PM.

  4. #4
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    Ah, I had not seen the thread where you had the same issue. The gear in mine was so worn it looked like a tapered pipe thread! I could easily push a collet straight into the thread so far as to fully engage the collet in the chuck.

    -jkilroy


    Quote Originally Posted by peterh5322 View Post
    You're most welcome.

    The eBay seller who sold me the 2ADC Hardinge-Sjogren supplied it with a nearly new Hardinge 2J collet.

    The Sjogren would always close and eject that nearly new collet, but it failed on most of my used 2J collets (but my 2AD Hardinge-Sjogren on my Logan [i]would[/] close and eject every one of my used 2J collets).

    I, therefore, assume the seller did not know the center gear was badly worn ... really, it was worn-out ... or he did know, but provided an "exemplar" collet which would always close and eject, as a deceptive sales technique, perhaps in order to avoid a return or negative feedback.

    I had a 2AD (large handwheel) sitting around and thought I might use the center gear from that in the 2ADC, but they are different in diameter, hence number of teeth.

    Your repair technique is especially useful as ATS Workholding manufactures replacement parts in small lots, and it may take several weeks to perhaps months to obtain a new replacement, whereas your technique can be accomplished in less that a day (plus more time for the Loc-Tite to completely bond).

    I liked seeing your Rivett in action, too. In the no-holes-barred toolroom lathe class, every machine has a number of oddities, and it is instructive to see different machines in action.

  5. #5
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    "The gear in mine was so worn it looked like a tapered pipe thread!"

    The very same in my case.

    At $120 ... then ... it was, for me, a "no-brainer" to buy a replacement from ATS Workholding.

    But, at today's prices, I would definitely use your repair technique.

  6. #6
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    A PDF of Sjogren's design may be downloaded at ...

    http://pat2pdf.org/patents/pat2311258.pdf

    I believe there is an earlier version which does not depend upon an actuating ring and internal dogs, only the handwheel and planetary gearset. This later enhancement was probably implemented to improve productivity with screw machine lathes.


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