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  1. #41
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    Quote Originally Posted by hsracer201 View Post
    Okay, thanks. I've gotta walk away from it from it for a few days. My frustration level is off the charts.

    I'll come back with a new thread (so I don't further hijack this one) with pictures, test cuts, etc.
    Relax man, this stuff isnt rocket science.

    If your bed is as nice as you suspect and the spindles pointing where it should, could be as simple as the tool getting pushed away or the saddle jacking off of something.
    One step one step or youre off into the woods

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    [QUOTE=Demon73;3296043]
    "What would do if your buddy had started before you,..."

    He would not do that. I was there with him when we picked up, disassemble it, and loaded it into my pickup.
    I helped him clean, check, and reassemble it in his shop. He's quite pleased with the overall effect.

    Gee. There was no high-zoot level of any kind used for that. Huh. Go figure.
    Next time YOU go help him if you got the inside scoop on how to do it better.

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    Quote Originally Posted by michiganbuck View Post
    Post 26 it was .004 for a 4" long chucked part..Then in post 36 it is .004 per inch but not saying between centers or chuck held part.(?)
    I was giving a hypothetical situation in post 26, post 36 was a reply to hsracer201s post. My ball tipped indicator is telling me youre not paying attention

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    Still for a head stock to be off angle or off square it would likely take a bug, burr or chip to make it that way.

    Seems like bed twist might be only .004 in full bed length on a small lathe.

    I am really surprised you can't see what I am saying about some uses of test indicators..

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    Racer, real easy no power ballpark test....stick your indicator to the sadle wing with the point on the inside of the tailstock v way and crank from one end to the other....do you see results that suggest a problem with the actual ways not being parallel??

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    Quote Originally Posted by hsracer201 View Post
    Timely thread.

    Suppose a heavy 10 with cast iron legs and very, very little bed wear is cutting a taper of .004” PER INCH, the work piece is getting smaller as it gets further from the chuck. Now suppose you shim one of the tailstock legs .050” and cut again with no change. You continue to add shims under one leg until the thickness is a .375” steel plate and your lathe is now a tripod, with absolutely zero influence on the .004” per inch taper.

    The bearings are good, properly shimmed with .0009” indicated on a lift test. There is no adjustment screw on the tailstock end like on a floor stand or cabinet model. You’ve done a complete headstock swap, complete spindle swap, complete bearing swap. No chips or debris between the base and bed, bed and headstock, bed and foot, and foot and leg.

    What then?
    OK, Going by the information given, you have a major problem, like some serious misalignment of something, or a very minor one like the tool post slipping or something. If it is a machine related problem, it could potentially be caused by any one of a number of factors, or a combination of them. Trying to fix the problem without completely understanding what the cause/causes is/are is a complete waste of time and will never get the machine completely right, so I'll outline the steps I would take to sort it out. I will first, venture a guess that at least the majority of the problem comes from the "head swap". I say that because of the huge amount of taper you're seeing. If the new head is not fitted to the bed, it could very well be sitting on the bed in some wonky way that would produce huge alignment issues. This may or may not be all or some of the problem, but it's my best guess before further testing.

    To start you want to know the the condition of the ways. You need the bed to be as straight as possible, FIRST. The machine's saddle is one of the best tools you have to assess this, but first some quick checks of the saddle itself. The ways on the underside of the saddle can wear irregularly, causing it to rock, or bear on the wrong surfaces, causing it to not properly follow the bed ways.
    Place a mag base on the outermost corner of one of the carriage ears and have an indicator contact a flat spot of the bed ways. Push down on that corner of the carriage as well as the three others to try to detect any movement. Move the mag base to the three other corners and repeat. Record your findings. If there is a good amount of movement, it may mean that your saddle is worn to a point that repair is needed, however a bad twist in the bed can also cause this.

    If everything checks out good so far, then

    A great way to account for twist, as well as wear, in the bed is to place a level(.0005"/ft. or better) on the carriage, either on the carriage wings or I prefer right on top of the compound. This level should be perpendicular to the bed ways. (If you have a second level, it can be placed parallel to the bed ways, so you can do two checks at once, if not you can turn your level after as a second check.) Run the carriage the full length of the bed, and note the bubble reading at approx. every six evenly spaced points along it's run, allowing time for the bubble to settle. Record the readings.
    If you didn't have a second level, turn your level 90* and repeat the procedure. You can now precisely map out the condition of the ways and make a plan to correct for errors by shimming/jacking various points of the bed.
    Bear in mind that the errors you are seeing may be a combination of twist and wear. If the machine is in very good condition and the main error is only twist, this should be fairly easy to remove by restoring the bed to it's factory alignment. If wear is also an issue, which it will be to some degree in most cases, perfection may be a pointless goal. At best, many errors can be averaged out, by slightly twisting the bed to raise the most worn areas slightly. This will of course introduce slight errors where there may otherwise be none, but, if done correctly, this can reduce one small area of large error(usually right near the chuck where the most wear occurs) into a larger area of very small error, making the machine overall much straighter.
    Go slow, planning every step. Make small adjustments until there is no movement of the bubble, or the error is averaged out such that no more improvement is possible.
    Next repeat the checks you made of the saddle corners earlier.

    At this point, if all is well, you will know that your bed ways are as straight, your saddle is a good fit to the ways, and your tool path should be as straight as possible.

    Checks of your head stock can now be made. If the machine is operational, I'd turn a two, or three collar test bar at this point. For a lathe this size, I'd use a piece of bar a couple of inches or so in diameter with six or eight inches hanging out of the chuck. Aluminium is fine. Turn the collars to exactly the same size. You can than mount an indicator on the carriage and compare the top of the collars and the front. This will be a true check of head stock alignment as other variable have already been eliminated. You can further confirm your bed straightness by moving the indicator to off the left side of the carriage so you can compare the readings with the carriage in different positions along the bed. The readings should all the same.

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    Quote Originally Posted by jim rozen View Post
    He would not do that. I was there with him when we picked up, disassemble it, and loaded it into my pickup.
    I helped him clean, check, and reassemble it in his shop. He's quite pleased with the overall effect.

    Gee. There was no high-zoot level of any kind used for that. Huh. Go figure.
    Next time YOU go help him if you got the inside scoop on how to do it better.
    Jim, youre just dodging the hypothetical question.
    If youre looking down at a machine, and despite your beliefs, its demonstrated to be tight, level, and practically unworn, but it cuts a heavy taper on a chucked slug.
    Would you seriously start twisting that machine to try and make it cut 'better'?

    Regards having the inside scoop, its more like basic common sense, an open mind, and a reasonable understanding of machine alignment.
    Edit:- See Dereks post above for that in spades.

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    Another good question is did this machine turn straight before the work was done on it..

    Is it so wore out the carriage is running on the top of the V way..riding over a bang/bump in the bed way..

    One could see .004 per inch looking over an aluminum hardware store level used as a straight edge looking at the bed ways..

    A center point to center point check would easily show if tail was off enough to make that. Perhaps .150" in 36" bed length.

    What diameter the part turned? turning perhaps a .250 part a bed wear problem would show more taper error than on a larger part..suppose the bit started below part center, and down bed rose up to part center.

    Just like the ball nose ind......

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    Quote Originally Posted by michiganbuck View Post
    Still for a head stock to be off angle or off square it would likely take a bug, burr or chip to make it that way.

    Seems like bed twist might be only .004 in full bed length on a small lathe.

    I am really surprised you can't see what I am saying about some uses of test indicators..
    It would take something big for sure, but I wouldnt put anything past some o the bubbas out there .

    I do understand about what your saying DI vs DTI, cosine error. For a comparative measurement, its no biggy unless youre a wally with the arm. Indicator tips climbing over the high point while sweeping the bar is another mute point in this situation imo, unless the machine is more than Fd and youre using a tiny diameter bar.

    Maybe we can indicate 3" slug and see how far we have crank in the compound to get -1, 0 , -1. Just for the lulz

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    Quote Originally Posted by michiganbuck View Post
    Another good question is did this machine turn straight before the work was done on it..

    Is it so wore out the carriage is running on the top of the V way..

    One could see .004 per inch looking over an aluminum hardware store level used at a straight edge
    Totally, we just dont know yet.

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    when you find the primary source it's going to jump up and smack your mom.

    Demon and Derek will get you there.

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    There's too much going on in this thread now. The original 9a discussion, the purse swinging, the hypothetical question, my question, and its just too jumbled up. I can't tell who's properly talking to who, about what lathe.

    Besides, I can't even take a picture of anything right now because my phone is busted. Got a new phone on the way should be here tomorrow or Friday I hope. After that I'll start over in hopes of less confusion.

    Thanks.

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    Quote Originally Posted by hsracer201 View Post
    There's too much going on in this thread now. The original 9a discussion, the purse swinging, the hypothetical question, my question, and its just too jumbled up. I can't tell who's properly talking to who, about what lathe.

    Besides, I can't even take a picture of anything right now because my phone is busted. Got a new phone on the way should be here tomorrow or Friday I hope. After that I'll start over in hopes of less confusion.

    Thanks.
    OK. You can start a new thread if you want, but most of what has been stated here applies to any machine that is cutting taper for unknown reasons. I'd suggest rereading post #46 and doing the checks in order.
    Twisting the bed into a pretzel is not gonna help if the problem is caused by something else.
    Sounds like you're really frustrated at this point, we all know what that's like, and it usually leads to mistakes being made in haste.
    Step back, relax, then come at the problem methodically, one step at a time, you will sort it out.
    Do you have a precision level(.0005"/ft. or better)?

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    Quote Originally Posted by iwananew10K View Post
    Racer, real easy no power ballpark test....stick your indicator to the sadle wing with the point on the inside of the tailstock v way and crank from one end to the other....do you see results that suggest a problem with the actual ways not being parallel??
    TO be clear- the indicator tip rides the vertical facet of the way, not the vee itself. If a guy had 2 indicators, he'd take it a step further and monitor the underside of the tailstock way at the same time.

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    QT Op post #1: [Should the HS just drop in place & get tightened down]
    Yes it should…

    Agree we were getting way off base with this .004 stuff. *Perhaps not mentioned is the original/found position of the head stock before removal may have been in slight error due to one hold down being torqued more than the other, not being a clean mounting from a prior removal and in a rare case even having a shim. So just setting it on expecting it to be perfect may not be the case/or work and so a tail adjustment might be needed.

    A short drill rod in a collet or a test bar in the spindle taper can tell much about the HS.
    Drill rod in a chuck not perfect..but nothing is ever perfect often good enough is OK.

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    [QUOTE=Demon73;3296389]Jim, youre just dodging the hypothetical question.

    Not dodging. Simply don't care. Enjoy your hypothetical discussion.

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    Quote Originally Posted by jim rozen View Post
    Simply don't care.
    Id agree with you on that one mate. Happy New Year!

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    I didn't mean to open a can of worm's . but thank's for everyone's input . I have a lot to study before I get out to the shop & start to investigate . My rebuild book just say's "set teh HS flush with the left side of the bed & secure with the 2 bed clamps & mounting bolts"
    is there any torque spec for these bolts ?
    thanks again for all the info
    animal

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    Quote Originally Posted by animal12 View Post
    I didn't mean to open a can of worm's . but thank's for everyone's input . I have a lot to study before I get out to the shop & start to investigate . My rebuild book just say's "set teh HS flush with the left side of the bed & secure with the 2 bed clamps & mounting bolts"
    is there any torque spec for these bolts ?
    thanks again for all the info
    animal
    Just stone the mating surfaces of head and bed very lightly, removing any high points from burrs/dings etc. You can use engineers blue to check the fit of the HS to the bed if you like, a nice fit might point to an original head. Just tighten down by feel for now, check the torque and go over them and make sure they are equal. If you find a setting later your can re torque.

    When youre done chuck up a slug 2"-3" bar, and cut 2 (or 3 if you like) collars of equal diameter, that can serve as or test bar. Then we can begin. Some pics would be great.

    Relax and enjoy the process, its really not so difficult

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    Army tech manual is handy but doesn't give assembly information
    http://www.wswells.com/data/9_workshop/CL670Z_army.pdf

    Parts book STILL NO ASSEMBLY INFO.
    http://neme-s.org/Shaper%20Books/Sou...ch%20Lathe.pdf

    Think I would use he grade 5 to grade 8 spec. or just one hand pull with std length wrench.
    Bolt Depot - US Recommended Bolt Torque Table
    Last edited by michiganbuck; 01-17-2019 at 11:31 AM.


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