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Thread: Atlas Shaper Gib Issues

  1. #11
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    Wheels17: If you make a new gib, please do your self a favor and make it from cast iron, or as a secondary choice, bronze. NOT STEEL OF ANYKIND. The locking setscrew was for a special application. This was probably done so the clapper would not raise up while cutting an internal keyway. If you will look carefully, your original gib was cast.

    Sarge41
    Last edited by sarge41; 12-01-2018 at 03:42 PM.

  2. #12
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    Quote Originally Posted by sarge41 View Post
    ... make it from cast iron, ...
    Check w/ your suppliers to see whether they carry Dura-Bar or other brands of continuous cast iron bar stock in sizes suitable for your needs.
    “History never exactly repeats itself, but it does some rather good impressions”

    ― John Dean

  3. #13
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    There is no particular reason to use CI for the gib. With one side CI and the other steel, it still has the benefit of the CI graphite content.

    Southbend made tens of thousands of lathes with steel spindles running in CI bearings, and thousands still are around and working without excessive wear. They also used steel gibs on CI dovetails in lathes for decades.

    Atlas and Logan made several hundred thousand machines with steel gibs sliding on CI. No issues even with crosslides.

    And your application is a low usage one, far less use than a lathe crosslide. Much less wear or other potential issues.

    If you WANT TO, go ahead and make it of CI and if it makes you feel better, that's good. But you are not short-changing yourself the other way with steel gibs. There are a huge number of lathes made that way, and they work fine.

    The CI gib is much more typically made as a fitted taper gib, adjusted not with side screws, but with screws on the ends that move it along the taper to adjust. The superiority of that type is mostly in the fact that it is more securely held, being backed up along the full length, and not just by a few screws at certain spots. It really is not a matter of it being CI. In fact, the CI might not hold up well as a thin gib pushed in by a few screws. CI does not like being bent.
    1601

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    Hashim Khan

  4. #14
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    Mar 2012
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    A few items:

    I'm pretty sure the gib that's in there is plain low carbon steel, not CI. A quick tap on the grinding wheel gives straight sparks with no showers, which I understand indicates low carbon steel. It's not the conventional taper fitted gib that is used on high quality machines. It's a flat gib adjusted by four dog point side set screws. It's very similar to the gibs on a south bend cross slide and compound. The gib measures a bend of .035 over 2-3 inches. I don't think cast iron would survive that.

    The hole that created the damage is not related to the clapper lock. That's on the side of the clapper housing and is present. This is down on the dovetail, and has created a mess. It's clearly a hack, and not present on any pictures I've seen of Atlas shapers.

    I was tied up today, I'm planning to see if I can chase down a local supplier of flat stock tomorrow. If not, I'll have to order.

  5. #15
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    To be fair, the bend in the gib that you describe is not a "feature", but actually a defect of sorts, although not a serious one.

    But, don't bother with a CI gib, not worth it, and might cause trouble with breakage. Regular CRS is fine, just make one and put it in.... and de-burr that hole...
    1601

    Keep eye on ball.
    Hashim Khan

  6. #16
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    If you recut the dovetail, made a fatter gib... would that fix everything ?

  7. #17
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    Mar 2012
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    @754, the damaged dovetail is on the opposite side from the gib. I've lost about 20% of the very tip of the dovetail. I think the remaining 80% should be sufficient to carry the load. I'm not confident in my ability to properly recut the dovetail. If it doesn't work after I clean up the burrs, I'll have to dive into that.

    The real problem with the gib is the galling and other damage.



  8. #18
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    The original was from a low carbon flat stock. Get some PG low carbon stock from McMaster - $8.45 for a 12" chunk of 1/8 x 1/2 (pretty sure that's what I used when making a similar gib).

  9. #19
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    Quote Originally Posted by sarge41 View Post
    Wheels17: If you make a new gib, please do your self a favor and make it from cast iron, or as a secondary choice, bronze. NOT STEEL OF ANYKIND. The locking setscrew was for a special application. This was probably done so the clapper would not raise up while cutting an internal keyway. If you will look carefully, your original gib was cast.

    Sarge41
    Sorry, I've got an Atlas shaper as well, and that gib isn't cast iron, its low carbon steel. A cast iron gib would need to be about double the thickness to avoid fragility.
    The locking setscrew has got nothing to do with the clapper, it isn't even in the same component as the clapper or clapper box.
    Its there to stop the toolslide from working down during a cut, and is a good idea, just that the moron who did it put it in the wrong place. Re-drill in the other side, so its in line with, and between 2 gib adjustment screws, not too near the end.

    You don't have to, but I generally dowel my gib strips, just drill and ream an 1/8" hole through the casting and the gib strip at either end and pop in an 1/8" silver steel (drill rod) dowel. It stops any end movement of the gib strip and IMO does make the movement smoother.
    'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

  10. #20
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    Quote Originally Posted by Richard P Wilson View Post
    Sorry, I've got an Atlas shaper as well, and that gib isn't cast iron, its low carbon steel. A cast iron gib would need to be about double the thickness to avoid fragility.
    Double thickness my eye!
    I used to own a 1940s Atlas 10" lathe.
    The gibs were cast iron.
    Steel gibs are a horrible idea.
    Just cheap junk designed to fail.
    I know some joker on here will say
    I had steel gibs for 40 years, blah
    blah blah blah. Well keep it. Good
    for you. Spin the wheel. Get your rocks
    off at Harbor Freight. All I can say is
    if you want predictable results with
    making a new gib for your lathe,
    make it out of cast or ductile iron.

    -Doozer

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