Tailstock Alignment Considerations - Page 4
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  1. #61
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    Qt; [I was thinking the ways are wore at a tilt. . . so setting it ways down on mag chuck is not helping me.]

    I have ground the like with setting the V on two rolls (dowels OK), raise the flat with Jb blocks or the like, and the slide in my tapers to just touch, setting a bump-stop in the go-direction and the front and back, ground with an open-wheel-wet. for the likes of a tail base a block might be set in the hold-down place and a hold-down screw added..

    A little tricky, yes.

    Milling one might use a bolt in the T slot..but need indicate the top lose first.. and shim under so the hold-down (s) does not distort the part.

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    Quote Originally Posted by texasgunsmith View Post
    This discussion and my own progress is a little ahead of what I've posted in my own thread. Kevin T started this thread, so I didn't want to step all over it with every little detail. We both have South Bend 16's, and are addressing the TS at similar times. For those interested, I'm just starting the tail stock here:
    Getting Another South Bend 16x6 Operational
    HA! Your awesome threads are where I get all my questions from but don't want to fill them up with my detours. In this place I am just trying to elevate my knowledge and trade craft! Thanks for any contributions!

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  5. #63
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    Quote Originally Posted by texasgunsmith View Post
    . . . Maybe I could shim base, or tilt it on mag chuck, and grind top side of lower base....
    This is, in a way, a worse hack than just shimming it, because by doing it this way, you've compesated for wear on the sliding surfaces (bottom of base)
    by altering the geometry of an unworn, completely original surface (the upper part of the base). In doing so you have left the wear items alone, so you
    can't improve the bearing and fit of those on the bed.

    Ideally you would fixture the base top-side down and machine the sliding faces, including the V-ways. And then scrape them in. Because the TS base
    is small it can be done on a small milling machine. Horizontals work well for this, and you can buy an included angle cutter to do the V-ways.

    Looks daunting I know, but consider: the machine has a somewhat worn bed so you're not going to remanufacture the bedways. Consider that
    a project like this is practically tailor-made to learn the rudiments of hand-scraping. (the other one is one of those AA products 6" lathes, so much stuff
    to scrape on one of those, and if you it turns out bugger-all you're not out much....)

    Needed: scraper, some bluing, a halfway decent surface plate, a dial gage or two.

    What was the *first* machine tool that Richard King ever worked on in earnest?

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  7. #64
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    Quote Originally Posted by jim rozen View Post
    This is, in a way, a worse hack than just shimming it, because by doing it this way, you've compesated for wear on the sliding surfaces (bottom of base)
    by altering the geometry of an unworn, completely original surface (the upper part of the base). In doing so you have left the wear items alone, so you
    can't improve the bearing and fit of those on the bed.
    I trimmed your quote just to save real estate. But all that is real sound advice.

    In retrospect, im thinking i could use a single steel plate, use surface grinder to cut tilt into it, instead of grinding top of lower base. But again, i need to what the numbers are first.

    Im not opposed to learning and trying with mill and scraping etc. But I really need to finish this machine and get on other projects, one of which is a horizontal mill. Once i get those next two projects functional I'd like to work on my scraping & flaking skills.

    Richard typically has classes local to me at PM member Swatkins once a year. Hopefully catch the next one if it doesn't get covid canceled.

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    Ready to get on with the alignment. To begin with, I'm going to post the pics of current numbers, starting from scratch, and the checks I've done. This will take maybe 5 posts to get all the pics in.

    To begin with, I'll start with eye candy. At least it looks nice !

    515.jpg

    Just checking old shim packs, it was .018" on quill side, and .017" on hand wheel side.

    516.jpg

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    Considering possible shim or plate paths. Here's some visuals of the surfaces.

    Bottom side of the upper body:

    517.jpg

    Top side of lower base:

    518.jpg

    Ways side of lower base:

    519.jpg

    Measuring the thickness of lower base on flat way, hand wheel side. 1.3505"

    520.jpg

    Thickness of lower base on flat way, quill side. 1.3477"

    521.jpg

    I'm measuring only a .003" difference. Seems odd as the ridge worn on flat way seems larger than .003"

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    A lipstick blueing to check how lower base is sitting on ways.


    522.jpg

    You hear people mention saddle or apron sitting like a rocking horse on ways. . . That is the kind of contact I have here. The center of lower base is contacting hard on both sides of ways. The furthest 4 corners not so much. Kind of funny as it was shimmed on all 4 corners. Curious if it was shoving it down flat when hold down is pulled tight.

    523.jpg

    Camera and lighting not perfect. But here's flat way of bed and flat of base lined up for a visual on the contact pattern.

    524.jpg

    Two pics of vee way lined up. One with camera flash, one without:

    525.jpg 526.jpg

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    Setting up lower base on ways with a dial indicator. Going to run the base along ways and take readings from hand wheel side to quill side. Setting zero on hand wheel side. The marking you see are for .001"s, 1 equals .001", .5 equals .0005", etc.

    A couple of notes. Don't roll saddle for readings, it throws the readings off for unexpected numbers. Keep saddle stationary. Push TS base while dial indicator is fixed on something else.

    Also I swapped dial indicator or one I could grab pointer easy, for jumping over center block on base. It helped repeatability a lot, as I wasn't bumping the set up.

    Set up starting on hand wheel side. Setting zero there:

    527.jpg 528.jpg

    Sliding base along ways, getting readings to the quill side. I was taking three readings on each side of side adjusting block.

    529.jpg

    Setting up to do the same on vee way side:

    530.jpg

    Final numbers as I see it. Results as expected with normal wear to quill side. Starting at zero from hand wheel side, all number are minuses moving toward quill end:

    531.jpg

    Need to get test bar numbers, and getting to center number.

  12. #69
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    Another way to do this is to flip the base upside-down on a surface plate if you have one, putting a couple of parallels under it to account for the boss that engages the top. Then you can sweep the entirety of the flat ways at once. The v-way can be checked to some degree with a long piece of shafting in it.

    Your numbers seem to show about 4 thou of wear, low on the leading edge which would make sense. Not sure how you reconciled the flat vs the V-way sides though, given how you had the indicator set up.

    Also I was unaware there were shims in there to start with.

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    Quote Originally Posted by jim rozen View Post

    Also I was unaware there were shims in there to start with.
    I had posted a pic of them placed in order in post #28, when showing splitting the base from upper. But I hadn't mic'd them at that point:
    Tailstock Alignment Considerations

    This thread might get confusing as to who or what, . Its Kevin T's thread. We have just been looking at the same thing at the same time, both 16" swing lathes. This thread is titled right for long term searching, and an interesting discussion, so I've been chiming in too with the alignment consideration.

    The thread on my lathe, and where I start the tail stock is here:
    Getting Another South Bend 16x6 Operational

    Edit:
    Quote Originally Posted by jim rozen View Post
    Your numbers seem to show about 4 thou of wear, low on the leading edge which would make sense. Not sure how you reconciled the flat vs the V-way sides though, given how you had the indicator set up.
    The numbers are decent, not perfect. Allow for about .0007" variance in repeatability, though I think I did better than that. I'm not looking for total perfection, I was thinking I'd roughly average the numbers between vee and flat ways. example: calling it -.004" on quill end.

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    Setting up to figure out what height I need, and in conjunction with that, what amount of correction to correct downward tilt.

    Going for the height first. Using a test bar in spindle of head stock, and a dead center in tail stock.

    532.jpg

    Guess-timating, experimenting with shims as I go, just to figure out what I need.

    533.jpg

    Initially I was too high on the height:

    534.jpg

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    After seeing where height was, I would swap to a test bar in tail stock, prior to making any changes. With the test bar in TS, I would begin to judge the the tilt. I would run all sorts of tests, quill locked, unlocked, extended, retracted. . . Rolling saddle, moving TS, and check different locations on ways.

    Finally I got both height and tilt into decent numbers. The shimming of tail stock at .002" at hand wheel side, and .013" on quill end. The numbers reflect both wear on base, as well as some droop from quill as it extends.

    My head stock alignment was set based on numbers I was reading off saddle, which adjusted for bed and saddle wear. So when setting tail stock, I prefer to err in that direction also, with indicator mounted on saddle.

    Quill retracted and locked. Indicator set to zero near quill, mounted to saddle:

    535.jpg

    Then rolling saddle to far end test bar, the result is +.002" :

    536.jpg


    Running all the above mentioned tests, quill locked, unlocked, extended, retracted etc, I have about an .011" variance from one extreme to other, depending on what I am doing. So as part of the height and tilt adjustment I aimed to get one extreme at +.005 and the other extreme at -.005"

    Which I'm pretty much there. At a 5" quill extension its at -.006". While fully retracted and locked up closer to chuck and quill I'm at a +.005".

    Examples:

    537.jpg 538.jpg

  16. #73
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    Again with .002" shim on hand wheel side, and .013" on quill end, I have tilt correction and height squared away as far as I'm going to go with it.

    Looking at the height with quill retracted at locked, you can see its a C hair high:

    539.jpg

    Height with quill extended about 2 inches, I'm about dead on:

    540.jpg

    Quill extended 5 inches, still right in there:

    541.jpg

    Knowing the numbers now, I need to sort out which method I'm going to apply them permanently. I have a plan for that, but supplies won't be here till Monday or Tuesday.

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    Be aware that many lathe manufacturers (hardinge for example) shipped their new machines with the tailstock bore a few thousanths high, with the idea that the part would have double the lifetime, in specification. Bore is 0.003 high to start, wears to dead center, and then wears 0.003 low.

    Twice the life in spec.

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    I got around to taking mine apart, pretty simple I don't know why I procrastinated but...

    I thought it was odd to have all the oil on the mating surfaces.

    p10700202.jpg

    p10700213.jpg

    Cleaned up nice though.
    I decided to start with .010 shims and see what it did to the alignment. Actually .011 on quill end and .010 on handle side.

    p10700257.jpg

    When I put the points together the TS one looks about .010 low but if I tighten the quill lock it gets to about .005!

    I am probably going to add .005 shim to the quill side and call it a day. If I am correct that will put me dead on center with quill lock when locked but slightly low when feeding as in with a drill. hmmm or maybe go a little higher and split the difference? What is better? Dead center between two points or slightly below center when feeding in? vs high between points and dead on for feeding in with TS Quill?

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    I like splitting the difference, but that's me.

    Alternatively, if you don't glue shims down, you can do both, or maybe 3 options. Let's say split the difference for your general use. But you create shims that have small finger tabs sticking out. In the case of doing sensitive drill or center work, just swap shims for the particular specialty. Now that mating surfaces are clean, you don't need to fully raise. Just bust bed clamp loose, and use flat tip screw driver between base and upper at the raised block section. Once you get your system down, it only takes a few minutes.

    I would guess the oil between halves was incidental from lubing quill/TS. But when I assemble mating parts like that, I wipe a thin film of oil or grease just for rust prevention. In this case more handy if you were using coolant.

    Side thought, no intention of such shenanigans, just day-dreaming out loud. Hypothetical way one might bore the tail stock, if you only have a lathe. Mount tail stock between head stock and saddle. Bed clamp lightly snug. Boring bar in headstock chuck. Use saddle longitudinal feed to push TS toward HS and into boring bar. Alignment should be close to begin with. I would guess you might do alright opening the hole and pressing bushing material in. Re-bore to quill size. If you're .010" or more to begin with, with wear, I would think by accident you might cut that down to .002" finished product.

    Anyone ever do this way ? Or any other thoughts ?

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    Quote Originally Posted by texasgunsmith View Post
    I like splitting the difference, but that's me.
    I like this, everything else you mentioned is not for me. I haven't used the lathe the same way twice since I got it! So there is no...normal general use, at least not for now.

    Better for me to get 'er close and not think about it again!


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