Tailstock Alignment Considerations - Page 3
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  1. #41
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    Quote Originally Posted by michiganbuck View Post
    Shimming inside the Ts at the parting line would be a poor fix because that would distort the bottom base when tightened so wearing convex or concave on the bed. Shimming with perhaps three shim sizes would be better but still a poor fix.
    Richard's plastic and scrape is a better repair so full flat supported and no distortion.
    I agree this could be an issue. For some, I think people won't care, as the distortion is minor, or personal skill set level concerns.

    I do have a solution though. It could bridge the difference between plain shims and shim material you grind. It is an anaerobic sealant. When air is removed it gets hard. By Loctite, but not a thread locker.

    It is a flange sealant that can fill gaps to .010". Loctite makes a variety, for different strengths, metals etc. I intend to use either Loctite 510 or Loctite 574 between shims and lower base. None between shims and upper body.

    Specs on 510:
    LOCTITE 510 - Gasketing product - Henkel Adhesives
    481.jpg

    Specs on 574:
    LOCTITE 574 - Gasketing product - Henkel Adhesives
    482.jpg

    You can read the links for additional details. I am leaning toward 510. I have seen a trick on marine gear boxes when setting a preload on end bearings. No shims on hand. Fill the gap on flanges with the anaerobic sealant, but put feeler gauges on each side of flange and tighten down. Let it sit for a day. Remove feeler gauges, and the cured anaerobic will now act as a shim. It gets hard, wont compress out.

    By using this with plain shims, you could still complete the job quickly and easy. Set height with shims first. Once figured out, add a thin film of anaerobic sealant between each shim, and to lower base. Set upper housing on. Pull bed clamp snug enough to push excess out, but not tight enough to distort base. Wait 24 hours. Done.

    Now you'll have even pressure when pulling TS tight.
    Last edited by texasgunsmith; 11-22-2020 at 04:32 PM.

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  3. #42
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    Or one might just add a .005 shim for the entire parting area and call that good enough.
    This giving .003 low and perhaps .003 down tip angle for a very good functioning lathe.

    .007 or .008 if that can be found might be better.

    Two sheets of oiled copy paper would be .008 and last near forever. cut 1/2" less wide would allow the Ts taper plenty of travel.

    For perhaps .002 high (Ok)
    WHITE STYRENE POLYSTYRENE PLASTIC SHEET .010" THICK 12" X 12" LIGHT DIFFUSING | eBay

    Back in the day with clunker lathes, I would scalp the center drill intention with a tool bit to assure that the center drill would be to perfect center of the headstock. Yes, with a poor chuck that would not prove the perfect center of this part.
    With having no part OD stock to true a finish, I would 4jaw the part to center zero and then tool bit scalp the center drill intention.

    for a part with no Od stock and running out because of a poor/damaged center I would mount a 60* point mounted wheel in the tail and the push on the part while hand back and forth the part to move the existing center back to zero center.

  4. #43
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    Not paper, not plastic. Typical material is brass shim. Cut with ordinary scissors, will not compress over time.

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    You guys are getting pretty serious about this fix!!! I like it! I have walked over to the lathe a few times this weekend to take the TS off and take it apart but then I keep telling myself, "Well what if I want to turn something tomorrow!" LOL

    It is tough for me to imagine flex from that casting being a show stopper if I only shim the corners and snug it down into position but I am not accustomed to these things. If this is a "thing" for the 16" TS then I do like the uniform shim idea that was presented. Closer than it is but no flex. I've got a lot of experience with 2 part epoxies and the like and the shim and fill the void technique sounds good too. Disclaimer I didn't look at the presented specs in the earlier post. I may even have some good Loctite stuff in the freezer left over from a ball joint replacement a couple years ago! hmmmm

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    Quote Originally Posted by Kevin T View Post
    You guys are getting pretty serious about this fix!!! I like it! I have walked over to the lathe a few times this weekend to take the TS off and take it apart but then I keep telling myself, "Well what if I want to turn something tomorrow!" LOL

    It is tough for me to imagine flex from that casting being a show stopper if I only shim the corners and snug it down into position but I am not accustomed to these things. If this is a "thing" for the 16" TS then I do like the uniform shim idea that was presented. Closer than it is but no flex. I've got a lot of experience with 2 part epoxies and the like and the shim and fill the void technique sounds good too. Disclaimer I didn't look at the presented specs in the earlier post. I may even have some good Loctite stuff in the freezer left over from a ball joint replacement a couple years ago! hmmmm
    I think the biggest variable will depend on shim height difference, between quill side and hand wheel side. If the number was .002", your going to have decent contact across all the shims.

    If it's like .010", you'll have some air gap at the low tension area of shims. A minor number, but something.

    I have no way to give a scientific number, but at face value, you will be more rigid with full contact as well.

    I feel like two things we continuously seek, or strive for, is greater accuracy and greater rigidity. And maybe more power !

    Edit: I'm about halfway though my TS, just didn't post yet. I know you replaced quill. Curious how your key for quill was. Mine is wore, I could rotate quill back and forth about a 1/16" or so. I'm making a repair. I mention, because if you are yanking TS off, might want to address it before reassembly, I figure its a tougher job on the machine.

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    re- shimming

    the tailstock body to the base is a fitted interface.
    i dont recommend shimming in a manner that will geometrically affect the relationship between the two parts, shim IMO should be of the same thickness all around and cover all contact surfaces.

    barring a real fix,IMO its best to shim so that at 1/2 of the quill travel its centered...it will be a little off at the extremes but will give you a close enough average to do good work.

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    Quote Originally Posted by texasgunsmith View Post
    I think the biggest variable will depend on shim height difference, between quill side and hand wheel side. If the number was .002", your going to have decent contact across all the shims.

    If it's like .010", you'll have some air gap at the low tension area of shims. A minor number, but something.

    I have no way to give a scientific number, but at face value, you will be more rigid with full contact as well.

    I feel like two things we continuously seek, or strive for, is greater accuracy and greater rigidity. And maybe more power !

    Edit: I'm about halfway though my TS, just didn't post yet. I know you replaced quill. Curious how your key for quill was. Mine is wore, I could rotate quill back and forth about a 1/16" or so. I'm making a repair. I mention, because if you are yanking TS off, might want to address it before reassembly, I figure its a tougher job on the machine.
    Re: Quill and condition. I can rotate mine maybe .01-.015 so it seems pretty good. Is everyone who is commenting on flex familiar with this tailstock? I am having a hard time envisioning flex with the tension point "boxed" in as it is. Maybe I don't torque that wrench down as tight as some of you guys? I usually shoot for enough that it wont move and that's it. If flex is a thing do you think we're talking about .000? flex? If I'm shooting for close and flex is predictable and makes it perfectly align would you consider this a problem?

    p10609973.jpg

    p10609995.jpg

    p10700016.jpg

    p10700021.jpg

    p10609984.jpg

  11. #48
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    Guys like Richard King are going to be operating at a bit of a higher level of expectation, craftsmanship etc. If were talking surface plates, scraping, Prussian blue, etc we're looking at low .0001"s or better.

    For South Bends I'm thinking most are not going that hardcore, but with a little effort we can do pretty good.

    A 16 South Bend is heavier than the smaller ones, so i expect flex less on those. Plus you're right, you're pulling maybe 40-60 lbs of torque when tightening TS. So you're not mangling it.

    Still, if we can get it as flat, and full contacting as possible, that would be more desirable.

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    Quote Originally Posted by iwananew10K View Post
    re- shimming

    the tailstock body to the base is a fitted interface.
    i dont recommend shimming in a manner that will geometrically affect the relationship between the two parts, shim IMO should be of the same thickness all around and cover all contact surfaces.

    barring a real fix,IMO its best to shim so that at 1/2 of the quill travel its centered...it will be a little off at the extremes but will give you a close enough average to do good work.
    The droop is probably only several thou, he can make the front one thicker by that much. I've seen that many times.

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    I would use one flat shim and ignore the drop/anglr. perhaps just a flat.008, If a shim is to be used or figure on 3 shims to try not to bend the bottom.

    If the bottom is bent .003 then the way set has to wear that amount.

    .003 drop should not bother as much as stressing the bottom.

    *Better that Richard might give advice.

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    Psychic preditiction: Richard: "just do it right"

    He doesn't play around with shims like this. If an owner found that in a machine he worked on,
    he'd never live it down.

    Meanwhile in 'get it done' land.....

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    Quote Originally Posted by jim rozen View Post

    Meanwhile in 'get it done' land.....
    "I don't care who you are, that's just funny"

    With the anaerobic flange sealant I mentioned in post 41, Loctite makes a variety of similar. Its a gel type substance that turns into kind of a hard plastic when cured. It won't cure if the gap is too large, but works up to .010". On other industrial repairs you could peel it off with a razor blade and mic it to figure out what settings you're dealing with.

    Other options would be Loctite 515, and 518. In shopping prices and specs I'm going to use 518. The manufacture link:
    LOCTITE 518 - Gasket Sealant - Henkel Adhesives

    Some of the tech specs if you scroll down that page:

    483.jpg

    An ebay seller has 1.69oz tubes pretty cheap:
    Loctite 2096059 1 Pack Gasket Maker 518 Anaerbc50ml/1.69oz 79340010772 | eBay

    Haven't tried it yet, but I'm thinking using a real thin amount between each shim, and shims to lower base, that the shims won't move after its cured. You could side to side adjust the upper half if need be. I'd put thickest shim at the top though.

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    Another note. Looking at where bed clamp goes though base, it is biased toward quill side quite a bit. I think michiganbuck has a real point with a 3 point shim stack being a lesser evil. Getting the two shim stacks on either end, then the third in the middle, opposite side of bed clamp hole.

    484.jpg

    I say figure out the height on four corners, pulling be clamp just snug. Then use feeler gauges to see what the shims in the middle need to be, with bed clamp snug, not wailed down tight.

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    For the hack job that would likely last for 30 years easily and not distort anything a careful placement of 3 plastic shims with any non-water based glue, likely $5 to $35.
    3M Medium Strength Synthetic Polymer Adhesive 7.3 oz. | Max Warehouse
    .010 to .015 would be good bought as professional shim stock or just found ay Walmart on some notebook or other product.

    First, the need would be mapped, a $15 caliper would measure good enough for the fitting after gluing, after gluing a sanding block and sandpaper could be used to size and blue in to near dead match to TS top half (non-professional plastic may not scrape very well.. overnight glue drying and the about an hour of sanding, good to wear a mask.

    If the taper angle is less than .003 it would not be tearable to just use a flat shim to bring the tail to +- .001 (or zero) to the headstock. perhaps a .008 flat shim on the entire might be the choice. Gluing would be good(IMHO)and the glue might add.001 to .003 (?).

    The right way: (* in my opinion but I am not the professional)
    Find a local guy with a mill or surface grinder, mill or grind it to match the map at needed fix taper to a size that would allow .015 professional way shim to leave .001 to .003 after gluing for finish fitting, use a scraper and scrape it to blue-in fit the TS top half.
    (Machining the bottom would be needed if the plastic and glue would be very thin, if not then machining would not be needed.)
    I likely would grind such a job for free as it would be a half-hour job at +- .002 or so.

    Likely one would make test gluing on a slug to measure how high the glue and shim would add, so to be closer to finish target after gluing.

    A non-professional shim.
    https://www.amazon.com/Polyvinyl-Chl...id=11260351011

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    Another way to do this would be to remachine the TS base to correct the tilt (this means some careful setup and a milling machine) and then use the same size shim all around.

    An example of this sort of thing is a 9" SB tailstock I recently converted to fit a smaller lathe. The flat/v way on the bottom piece was remachined and scraped to mate an unusual
    dovetail bed lathe (Potter) and then the upper part of the TS had to be cut down to make it fit the 7.5 high centerline of the new headstock. Some brazing and some paint,
    now it fits. Key here is careful fixturing on a solid milling machine before taking the cut. He'd also have to get a 90 degree included angle plain milling cutter to do the V-way.
    Attached Thumbnails Attached Thumbnails dscn0005.jpg   dscn0002.jpg   dscn0004.jpg  

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    Quote Originally Posted by texasgunsmith View Post
    Another note. Looking at where bed clamp goes though base, it is biased toward quill side quite a bit. I think michiganbuck has a real point with a 3 point shim stack being a lesser evil. Getting the two shim stacks on either end, then the third in the middle, opposite side of bed clamp hole.

    484.jpg

    I say figure out the height on four corners, pulling be clamp just snug. Then use feeler gauges to see what the shims in the middle need to be, with bed clamp snug, not wailed down tight.
    Did you put the base back on the ways and indicate it? I was curious as to how much of the droop is dovetail wear vs. quill area? Great pic!

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    Quote Originally Posted by Kevin T View Post
    .. I was curious as to how much of the droop is dovetail wear vs. quill area? ...
    Typically the tailstock base wears where it slides on the ways of the machine, and most of that wear tends to be
    at the leading area of the base. The bore for the ram tends to wear bell-mouthed, so it will look like droop but
    often this can be pulled up as far as it will droops down.

    In those photos above, I did not even bothering to check how much wear was on the underside of the base, as
    it was machined away before I made it into a dovetail base.

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    Quote Originally Posted by Kevin T View Post
    Did you put the base back on the ways and indicate it? I was curious as to how much of the droop is dovetail wear vs. quill area? Great pic!
    No, I didn't get that far yet. I tend to multitask or hop around when I'm motivated. . I was working on another subsystem entirely, but had painted, i like paint a minimum 2 day cure. During that time i stripped and cleaned TS, and painted relevant pieces there. Hopped back to the other parts. . .

    I'll be back on TS more directly the coming days. Probably double post or link that lathe's thread here as I sort out pics, etc.

    Just using eyeballs though, I'd say from flat way on lower base, that way wear to base is slanted down toward quill side. Quill bore in upper housing has some wear as well. I can feel a ridge from key slot in quill, having NOT worn with the rest of bore.. However, grabbing quill with both hands it doesn't feel sloppy in bore. The key wear feels sloppy though. Going to address that.
    Last edited by texasgunsmith; 11-24-2020 at 09:22 PM.

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    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

    What Jim Rozen posted with milling the ways of lower base, and scraping and fitting like Richard King. . .Is a bit outside my skill and tool set atm. Though I do own micrometers ! Also some of the previous talk of grinding on a plastic shim or the like. . . I was thinking I was not going that route.

    I still may go the plain shim route, however I want to get readings and line things up before a total decision.

    One thing got me thinking today. Michiganbuck's post on using a surface grinder. I have a surface grinder. I dismissed the idea previously. First, I didn't think I could get the lower base on mag chuck proper, I have a raised edge at rear of mag chuck. But also I was thinking the ways are wore at a tilt. . . so setting it ways down on mag chuck is not helping me.

    Plus the TS slides nice on ways, if I get to grinding ways side of lower base that will change. . .

    But now I'm wondering. If I get my readings and map it out. . . Maybe I could shim base, or tilt it on mag chuck, and grind top side of lower base. If I get top side of lower base parallel to ways/HS spindle I could use an even number of shims or the phenolic sheet Richard mentioned.

    I'm curious if the phenolic sheet can be ground on surface grinder also. And which glue to hold it down. Searching I believe the brand name is Garolite. There's a bunch of grades.

    Easy to machine garolite, but low impact strength:
    McMaster-Carr

    High temp garolite with better impact strength:
    McMaster-Carr

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    To make it right the lathe bed ways need to be redone and the tail fitted and restored for height.
    Most guys don't have the tools or talent to do that.

    If the bed is is .004 low when the tail is close to the headstock and dead perfect height when the tail is out at the far end that has to be considered.
    if the tail is tilting down at all places and tilting down more when close to the headstock that has to be considered.

    A Plate check of the tail set on rolls and jo block the flat side would tell the tip down amount.
    To micrometer or caliper check the tail bottom plate on the flat side would be a rough but ok method to evaluate the taper, likely it was .001 or so flat at new. That should be made right to close if possible.
    The amount to raise up the tail to the headstock center might be made to be the average if the machine is often used close and far.

    To grind or mill the tail base/bottom's top side back to the original flat seems logical because that would make it still fit the top half and not distort the fit to the ways. But then it would need to be raised to the decided height. Height rasing could be an attached flat shim the right size, or a flat shim attached and scraped or machined to proper thickness/height.

    A shim pack might be simply set in, or glued in the parting space, but that should be done in a method that least distorts the base fit to the existing condition of the ways. The tail top is so much more solid so the bottom /base will be the part that might distort.

    The simple hack would be to build up the tail with layers do double-back tape, then loose shims, glued shims, glue and scraped or machined, a full rebuild of the entire lathe.

    Again I am not the expert on this, Richard is one expert here and a few others...

    Most of my experience comes from tweaking not perfect grinders to make near perfect work so tail and head tweaking needed to be done... and some lathe tweaking.


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