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tailstock to spindle height difference

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  • J Tiers
    replied
    [QUOTE=rickyb;n1876687]
    Originally posted by J Tiers View Post
    They were indeed typically a smidgen high in the tailstock, for wear. But lathes for small parts would have them dead-on, like watch lathes.

    "The height makes little difference for larger work"
    I'm confused. If it doesn't make a difference why compensate to begin with? Is it a small range like +\- a few thou to keep it in the "it doesn't mater zone" longer?
    How much difference depends on what you are doing, and what size the work is. As mentioned, the smaller the work the more difference it makes.

    Why compensate? Well, because things wear. If you have it HIGH by a "doesn't matter" amount, then it is twice as long before it DOES matter. And, since everything flexes, having it slightly high means that it gets closer to correct with weight on it, instead of getting farther away from correct.

    The amount that "doesn't matter" depends on work size, so a large lathe may have more compensation just because hardly anyone makes watch parts on (for instance) a 22" swing machine.

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  • Arcane
    replied
    Originally posted by sarge41 View Post
    Started my apprenticeship in a new shop that was equipped with new Monarch lathes. 1 new 10EE, 1 new 16" and three new 18" and 1 new 20" lathes. When doing a setup,we found that the 18" lathe tailstocks were .005" high. Our foreman told us that was intentional to allow for load and wear.

    Sarge41
    Has anyone measured the increase in "droop" at the tailstock end when it's supporting a heavy load as compared to a light but flimsy load? I'm curious but too lazy to check it out myself.

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  • rickyb
    replied
    [QUOTE=J Tiers;n1876493]They were indeed typically a smidgen high in the tailstock, for wear. But lathes for small parts would have them dead-on, like watch lathes.

    "The height makes little difference for larger work"
    I'm confused. If it doesn't make a difference why compensate to begin with? Is it a small range like +\- a few thou to keep it in the "it doesn't mater zone" longer?

    Leave a comment:


  • sarge41
    replied
    Started my apprenticeship in a new shop that was equipped with new Monarch lathes. 1 new 10EE, 1 new 16" and three new 18" and 1 new 20" lathes. When doing a setup,we found that the 18" lathe tailstocks were .005" high. Our foreman told us that was intentional to allow for load and wear.

    Sarge41

    Leave a comment:


  • dian
    replied
    schlesinger: quill 0-0.02 mm, mandrel in quill 0-0.03 mm rising over 300 mm.

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  • BCRider
    replied
    I wonder if tail stocks on bigger machines might have been set to be a couple of thou higher to average out the wear over the years?

    Makes it harder to drill nice neat holes though... Or to ream with the tail stock. We'd need to rely on the flex in the typical longer shafts on machine reamers.

    Me? I'll take spot on and apply copious small amounts of oil to keep wear at bay so drilling and reaming is correct.

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  • TRX
    replied
    Yes, the main purpose of the lever tailstock is to ger better 'feel' when drilling small holes. Pecking with a handwheel gets old real fast... The small second-op lathe I ran at work long ago had a lever, and I've pined for one ever since...

    Leave a comment:


  • J Tiers
    replied
    They were indeed typically a smidgen high in the tailstock, for wear. But lathes for small parts would have them dead-on, like watch lathes.

    The height makes little difference for larger work, but for watch size parts with mm diameters, and under 10mm long, any significant height difference could make for a taper. You can calculate the diameter error. In small pieces, it can be significant, but for something around an inch diameter, in any sensible length, you'd have trouble measuring it.

    Leave a comment:


  • TRX
    started a topic tailstock to spindle height difference

    tailstock to spindle height difference

    I bought an extra tailstock casting for my lathe to set up for lever operation. It's just the bare casting, no ram.

    The bore where the ram slides has several thousandths of wear. Since I'll be making a new ram anyway, I'll just bore it out, dragging it behind the carriage over a flycutter bar between centers.

    No big deal, but I remembered many threads where people found their tailstock and headstock weren't quite the same height from the factory. Most answers were "it doesn't matter" or "to compensate for bed wear."

    Just in case I'm missing something obvious, would there ever be a reason *not* to have both stocks at the same height?
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