fixing hardened ways.
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  1. #1
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    sorry i was blindly cloging the old forum with pics and my thread about these ways. I moving it here.


    my nardini tt1030 has hard ways. It also has a lot of wear near the chuck. such that a test rod that I turn has a diameter variation of 0.003" over a distance of about 1" as it rides over the wear/no-wear hump.

    it effects my collet work, as the use of the chuck puts me out past this "lump"

    Question.

    If I get creative and take my tool post grinder. and mount it to my tailstock (or something riding on my tailstock ways, could/should I re grind my bed with it?
    I just finished diagnosing this with a tenths indicator. My tailstock ways are great.

    with an indicator on the tailstock and hanging off the front 6" I have TIR 0.0003" on the tailstock ways I figire hanging off th front will find a local variation before the tailstock run past it.

    when I measure the v-ways of the carrige to the tailstock there is a big valley at the high wear location on the inboard side of the V. About 0.004" TIR and only about 0.0015" on the outboard side. and 0.001" on the rear flat way.

    net effect is the carrige simotaneously shifts, rotates away, and drops down slightly from the part as it rides through the trough. mostly it rotates & shifts away.

    I am trying to figure out a way to attach my dumore toolpost grinder to the base of my tailstock such that can run the wheel all the way up to the headstock.

    this will leave me with a surface I cannot cut without reversing the setup at the tailstock end. but only about the last 4" of way which is accessible to my carrige anyway.

    I can re-set and grind to match. or loose travel. or have a bump.

    I have never ground anything like this.

    I'm wondering how to present and dress the wheel.

    thanks for the encouragement pepo

    here's my situation.







    I'm well on my way. [img]smile.gif[/img]

    I've got this plate tith a groove that pivots on a 1/4" rod I milled two matching grooves in the ribs under the tailstock and two clamp bolt holes (and two jacking screw holes after this pic)- so I can flip it all around to do the far tailstock end.



    I can move it in tenths easily with the hex key on the right



    I'm planning to use the compound to dress the wheel once I figure out how to mount it at a precise 45?
    I will have a 1/3 carat dresser tomorrow



    I want to say thanks to PEPO for these suggestions:

    Have a 15" lathe at work that one morning all of a sudden developed an identical problem. (we had a night shift at the time) I stoned,filed,fiddled and cussed but couldnt get rid of the spot. With the chuck you were out past it,but,the collets put you right on it. About 3 weeks later I found a 1" boring bar holder(KDK)in some junk that had been in a trainwreck. For $1000 I dont think I could have done this to this holder. Anyway,I did exactly what you are thinking. It had a 90 degree v-way at the front and a flat way at the back. The tailstock split in half like most do,mounted an air motor from a toolpost grinder on the tailstock base vertically and dressed the wheel with an angle dresser to look like a 90 degree countersink and swung the head from a pivot point on the tailstock base to control the stock removed. Then used a cup wheel to make the back match the saddle. You need to be able to move the wheel only .0002 at a time to stay in control and to keep from breaking the wheel down before you complete a pass. It worked really well,the lathe is still running many years later and cuts straight as a string.

    A cup wheel will be the coolest cutting and most forgiving but,it would also be the hardest to arrange at the needed angles. I think I would lean towards the plain wheel dressed at 45 deg. Keeps the center of gravity lower and the dresser setup would be almost the same for both sides of the v-way. Also you could flip the wheel over to do the other side of the v-way,youll need to redress of course. As far as wheel diameter,your grinder needs to have the groceries to keep the wheel up at speed during a pass. A 60 grit I,J or K hardness at 4000 to 5000 sfm is the middle of the road. You will, without a doubt,need some type of diamond dresser to dress the wheel at the required angles. Do it by hand and it will end up rough as a cob and the wrong angle. If I remember right I dressed at least 3 times on each side of the V. Probably took off a total of .002 or .003 off each side.

    Pulley it for 8000 rpm with a 3" wheel. Remember you just want to tickle across the top of the surface. You are looking for happy,fluffy sparks with smiles on their faces.Sneak up on it. Go for 80 to90% clean up.
    and Precision Works suggestion too.

    ...I understand what the problem is and what you feel you need to do. Even though I've modified my lathe nineteen different ways, I'd be more than hesitant to do what you're proposing.

    Not counting the 48" Niles, our other two lathes have substantial wear in the ways & saddle. Like your machine, the wear can easily be measured with a test bar. But instead of grinding the ways, we use a much more simple method to make these lathes turn straight.

    Both our machines turn a taper of .001" per inch of travel (about one third as much as your lathe). So a 6" part that starts at 2.000" on the tailstock side, finishes at 2.006 near the headstock. The simple way to work around this is to make a mark every inch while the part rotates, so there's a mark at 1", 2", 3", etc. Attach a mag base to the compound & touch the indicator tip to the toolpost. As the toolpoint reaches each mark, tap in the toolpost .0005", which reduces the diameter by .001".

    Most of our shafting work is +/- .001, and the above technique, while primitive, always keeps the diameter within the tolerance range. This may not work in your situation, as your wear is much greater in a shorter area. But it will work on any machine that has worn ways where the wear can be measured & calculated.

  2. #2
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    now my question is about dressing?

    is the 15 degree angle important to the tip? or does this just keep it from catching and digging like it might on a surface grinder?

    I figure I will hang some bent steel arm off the compound side and clamp the diamond to it pointing at the front of the wheel.. it wont likely be very ridgid. I know the picture looks like the diamind could be held right in the t-slot but it will need to hand over about 2" down about 1" to get on center.

    is ridgidity a necessity?

    any better dressing iedeas?

  3. #3
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    I'll defer to the true experts, but I don't see why you can't scrape the hardened ways. I would just follow Connelly's MTR book.

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    Some hard ways can be scraped. Chilled iron ones may be too hard. Regardless, you might get grind marks on your bedways but they will be a long way from being precision ground. A 3" wheel will not hold a dress long enough to do more than scratch up the way surface. It will be a long slow process.

    Futher, grinding them will generate clouds of abrasive dust that will settle everywhere including the tailstock ways you are using to guid the grinder from. If you elect to grind your ways in this manner isolate the grinding operation from the rest of the shop and install a good dust vac to pick up swarf as its generated.

    You will also have to deal with heat. A skinny lathe bed will move an amazing amount from the heat produced by a 200 watt grinder head.

    I suggest you bite the bullet and hire the job done in a qualified grinding shop, that is if you can't scrape them.

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    Keep in mind also,

    Grinding the ways,.005/.010 +/- may have adverse effects on bed rack and acme threaded rod.

    How much will this difference make?
    Will it increase tolerence to make greater the freeplay in your compound?(moving rack farther away from traverse gear)
    Will it decrease tolerence to make the freeplay to tight.(on screw)
    Will it have adverse effects on the rod and nut?

    If you overcut, will you need to shim the compound?

    Many possibitities, and not to discourage you, but way it all before making your first pass if that is your intention.

    Just my thoughts,

    Patch

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    Here is an article about a fellow, that did the thing another way:




  7. #7
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    Ill agree that everything thats been said so far on this is dead on. And without a doubt the best thing to do would be to send it out and have it ground. I know the machine that I did this to didnt just cut a taper,it cut a woopdedoo triple gainer all of a sudden bout an inch long then was good again. It was the keep open for a quickie lathe for 4 or 5 of us and we ran it like this for a year or two,always working around this spot on the ways. I just figured "what am I gonna do,screw it up?" dsergison...one thing for sure,it will either work,or it wont. The good part is that its totally up to you how it turns out. The funny thing is the guys that looked at me like I was insane when I did this are the same ones that bring their special "gotta be real close" stuff to this lathe to run it.

  8. #8
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    about scraping, I cant file it, even a scratch.
    does this mean I can not scrape it? I dont have any scraping references either. and I think V ways would be a bad place to learn scraping?

    grinding cautions duly noted. Right, yeah. well I'll just say I've never been one to listen when told I cant or shouldnt do something. I'm allready determined to try. I'll see what couple passes gets me. Pretty sure it cant be any worse. and if I can get it to look good I'll keep going.

    About sending it out.
    That sounds ideal. If I could disassemble this thing. If I mess it up myself I guess this is the next step.

  9. #9
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    How about plating? can I nickel plate it with a home plating kit?

    then I can scrape / grind the plating on the low spot instead of the entire way?

  10. #10
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    dsergison,

    Interesting you should ask that.

    hansw2, excellent post.

    Several years ago I had to make a wood planer
    knife grinding bench that I could regrind 3 (12")
    blades at one time. The grinding bench turned out to be 40" long on the stationary bed and 46" long for the traverse bed with the grinder.(3" overtravel both ways)
    After several years of heavy use I found much deviation of the blades I was cutting.
    It seems as I also used it for smaller and more frequent grinds to 2 or 3 jointer blades being 6" long, this area of the traverse bed and dolly got most of the wear.
    I decided to regrind the (V) of traverse bed (If I recall, it was near .020 out. I did something similiar as to the above. I used the stationary bed as my setup since there was no wear to it.
    Then mounted a grinder carriage and reground the (V) of traverse bed.
    This turned out great.
    I now had a straight and true (V) on the T bed.
    Next, I was faced with the problems of the carriage dolly.
    The (V) way was also worn in a bit of an arc due to the feed and retreat of the grinds because of the pressuse excerted against the grinding wheeel.
    I first thought I would cut and notch the old (V) from the carriage, make a new one, and install it with shoulder bolts below use useline.
    I knew I had to make it oversize to compensate for the amout of take-off I ground from the traverse bed (V) way.
    Then too, I got the idea of plating the carriage dolly way and regrind it to tollerence to fit the new regrind size of the traverse bed (V) way.
    You see, not only the T bed wears but also the carriage (V).
    The carriage of this Planer knife grinder is just a little smaller than most lathe compounds.
    It made better sense to plate something smaller and with more control than to just grind, then shim the traverse bed.
    If I did shim it, I would then need to regrind the carriage (V) way and shim it as well.
    I decided to once the traverse bed was ground true to make my adjustments on the carriage only.
    (less to shim) or, smaller to take in and have it plated, which is what I did, then reground the (V) way.
    I needed only plate 12", instead of the entire traverse bed.
    After plating the carriage, regrinding way and mounting, I decided I would on the next machine like this, make the traverse bed and carriage ways replaceable.
    Well, that was about 8 years ago.
    I still do about the same amount of knife grinding today but doggone it, the darn thing is still well within tollerence after regrind and fit.

    FWIW, I think I would grind the bed ways true in its total length then plate and regrind the ways
    follower of the compound instead of just trying to regrind the worn area of the bed only and
    shimming.

    It would also be feasable to plate something smaller such as the compound than to try to plate the bed worn area.

    anyways, best of luck.
    Some thought I was a nut case too for what I did.
    But, to refabricate a new one would have taken longer.

    Patch

  11. #11
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    Ouch and oops,

    I just recapped and remembered my project was a one of a kind. There was no other tooling with it.

    To use what I did to my machine would mean you
    would need to do it to all the lathe attachments as well.ie: steady rest, tail stock ect.

    ick, not good.
    Back to the beginning again.

    Patch

  12. #12
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    I think I smell an ebay machine coming up.Nice lathe, freshly reground bed,no returns or warranty.
    I'm no expert on way regrinding but I'd sit back and reasess what you are doing.That set-up looks ripe for failure.

  13. #13
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    Having seen the results of "precision grinding" as compared to bluing and scraping, I can only say...."You are a braver man than I, Gunga Din."

  14. #14
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    I would be more than a little hesitant to risk the ways- and fill the shop with grinding grit.

    I belive you would be better off to make a collet holder which extended out so the work was past the area with the problematic wear.

    Another alternative is to make a carriage attachment which allowed the carriage to be back in the uniformly worn area, and extend the cutting edge out. An alternativ would be a mini carriage which rides on the tailstock ways. It would be easier to make the collet extender

  15. #15
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    I looked at several Nardini lathes and they all had induction hardened ways. I was not able to find your model. I think you could scrape the ways with carbide scrapers.

  16. #16
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    I worked in a shop that rebuilt lathes and mills. I can tell you that if you grind the ways using the tail stock ways you will end up with any miss alignment that is in the tail stock ways in the carriage ways. We always sent ours to a shop in Nashville Tn. They ground the bed and sent specs of what they took off where. We then had to shim the saddle up dam it and pour a special two part epoxy type stuff in between the ways and the saddle to get it back to the right height and centered. If you grind yours you will have to build up the saddle to get the original height. This is not an easy thing to do and it always took a lot of hours. There is a lot of fit and finish involved. We also had to scrape the new ways and used a power scraper. It will be hard to grind the whole bed without the wheel breaking down and getting an uneven finish. You will have to use special wheels and I don't know if using a small wheel will ever work. I know they use large wheels to do it. Why don't you look into using some two part epoxy to coat the ways and then scrape or dress the epoxy down to take the sway out of the way.You are not talking about very much of a sway and a thin coat would work and you can check it with a good straight edge. You may be able to use Devcon plastic metal. It's expensive but real good and tough.

  17. #17
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    Here ya go desergison,

    Some interesting reading and perhaps a solution to follow suit.

    testamonial:
    http://yarchive.net/metal/lathe_bed_regrind.html

    What type of machine to use and how:
    http://www.galleryofmachines.com/page1.htm

    Who can do it:
    http://www.gahrmachine.com/rebuild.htm

    Choose a Co. nearest your location:
    http://www.thomasnet.com/products/wa...6205003-1.html

    OK, the average cost of another lathe, perhaps in better or ? worse condition is near $2500/$3500
    should you find one.
    You may find one on Ebay but then what? Perhaps the same senario.
    You may wish to inquire these rebuilding companys before taking it on yourself.
    If they could do it under $1500 you are the big winner.

    It takes some pretty good and precise equipment to do what you wish.

    Give them a call and see what they say, then get back and let us all know.

    best wishes,

    Patch

  18. #18
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    As Carl says, before you use the tailstock ways as the master to grind the saddle ways, check them against a parallel test bar in the spindle and make sure that they're straight. If you don't do that you'll just transfer and amplify the error in the tailstock ways to the saddle.

    The other thing is that if you have wear in hadened ways you're have some serious wear in the unhardened saddle. To correct that you'll need to remove more material and replace it with way material - Turcite is commonly used, Moglice is a moldable compound. You really don't want to use either in less than .032" thickness, the Turcite needs about a .004" glue bond when using the appropriate 3M epoxy, and the Moglice needs some thickness for strength.

    I faced the same problem you're facing, and decided to bite the bullet and do it right rather than cheap. Regrinding all the worn stuff (bed, cross slide dovetails, taper attachment and some cosmetic grinding such as the top of the saddle and the cross slide) and refitting appropriately cost something like $1000 and gave me a lathe with a perfect bed and cross slide.

    If you have a lot more time than money I'd suggest checking Harry Bloom's articles in Home Shop Machinist, particularly the rebuild of the Monarch CK. Look at how you really should do it with a scraper and all and you'll see why I paid someone else my hard earned cash to grind it and return to me an accurate bed.

  19. #19
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    Small sections can be brush electroplated with nickel to build up thickness. The area has to be very thoroughly cleaned and degreased. The plating solution is applied with a graphite rod wrapped in spongy material or even a wool rag. The power supply is connected to the work-piece (negative) and the graphite (positive). Nickel plating solutions, and indeed the brush plating supplies, are available commercially. Some types of continuously variable older style car battery chargers can be used as power supply.
    The built up area can be scraped or lapped to the final dimension.

  20. #20
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    wow. thanks.
    damn the torpedos. I'm going grinding. [img]smile.gif[/img]
    if it sucks I'll quit before I take off more than is allready gone and move on to something else.

    here's my dressing set up:

    align spindle perpendicular


    compound dressing rig to 45


    and mount dresser here.


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