Cracked Tail-stock Casting - Page 2
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  1. #21
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    Quote Originally Posted by Illinoyance View Post
    Can you run one or two through bolts front to back? If you can, no other repair is required except scraping the top part to thee base.
    What? How is it going to be adjustable with bolts from front to rear?
    The OP is learning about castings. They are breakable. They don't have extra metal on them to grind off because of blemishes. But, there are a number of brazing materials that are stronger than the iron he needs to repair. That will likely be as good as it gets.
    W

  2. #22
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    all of these machinists, and no build it your selfers?? If you want to fix it you have unlimited choices from making one yourself from stock, to welding, brazing, soldering (silver), bolting or pinning a reinforcement plate, or a combination of any mentioned. I recently bought a good American Pacemaker lathe because a large industrial machine shop couldn't get parts for the tail stock any longer, several bone heads had filed away part of the alignment blocks, tore out the rack and pinion gears and broke out the alignment nut from the base casting. the ironic part is this shop fixed much larger and far worse damaged parts regularly, but for some reason wouldn't do the same for the lathe (lucky for me). I repaired it all in a couple of months entirely in spare time. Now I've got a very nice industrial grade A lathe, purchased at less than scrap price, and functioning as good as ever. what's the fear? buying the parts for "meager" amounts to repair a lathe, then work twice as many hours paying for them as it would to make the parts yourself just doesn't make sense. make a repair of your favorite choosing, if it fails, you've learned. I just don't understand so called Machinists who won't make their own repairs. If they are really as precise as they claim, their lathes should be running better than new after a breakdown that they repaired in house and in less time than it would take to get a replacement! My recommendation, if you really want a good tail stock, build one. If time is an issue you have been given a number of acceptable options. or if you'd like, I'll build you one for far less than you've been quoted and it'll be of American iron! cast iron can be repaired many ways, in our shop we've used many methods. which is best? the one that you make work, cast is hard to weld but even bad import cast can be welded with enough patience and sweat.If necessary grind, mill or scrape to re-fit. In the end you'll be glad you did. best of luck to you!

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    Quote Originally Posted by gbent View Post
    From what I see, if you brought it to me I would: Put a stout C clamp on the part closing the tailstock crack. Mill the top of that piece of the tailstock flat. Find a suitable piece of flat steel to bolt and dowel to the face, and install. Then fix the fitment between the adjusting screw and the tailstock bottom. Fix the cam that made you overtorque the screw in the first place.

    A photo of the bottom would be very useful.

    This is probably the best fix for your issue.. If both sides are of an identical profile, mill them both.

  4. #24
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    Yep. If you wanted to be clever(ish) about it, put a set of keyways on both the slab and the casting, spaced so that when the slab gets installed hot, and bolted down, on cooling, it pulls the ends together. But that's all fancy.

    If you have to auger out the adjustment screw hole and replace the whole thing, make it part of the repair slab.

    You can hide the ugly stuff under a nice magnet mounted tool tray, a handy place for wrenches and chuck keys, eh?

  5. Likes naru liked this post
  6. #25
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    Quote Originally Posted by hvnlymachining View Post
    all of these machinists, and no build it your selfers?? If you want to fix it you have unlimited choices from making one yourself from stock, to welding, brazing, soldering (silver), bolting or pinning a reinforcement plate, or a combination of any mentioned. I recently bought a good American Pacemaker lathe because a large industrial machine shop couldn't get parts for the tail stock any longer, several bone heads had filed away part of the alignment blocks, tore out the rack and pinion gears and broke out the alignment nut from the base casting. the ironic part is this shop fixed much larger and far worse damaged parts regularly, but for some reason wouldn't do the same for the lathe (lucky for me). I repaired it all in a couple of months entirely in spare time. Now I've got a very nice industrial grade A lathe, purchased at less than scrap price, and functioning as good as ever. what's the fear? buying the parts for "meager" amounts to repair a lathe, then work twice as many hours paying for them as it would to make the parts yourself just doesn't make sense. make a repair of your favorite choosing, if it fails, you've learned. I just don't understand so called Machinists who won't make their own repairs. If they are really as precise as they claim, their lathes should be running better than new after a breakdown that they repaired in house and in less time than it would take to get a replacement! My recommendation, if you really want a good tail stock, build one. If time is an issue you have been given a number of acceptable options. or if you'd like, I'll build you one for far less than you've been quoted and it'll be of American iron! cast iron can be repaired many ways, in our shop we've used many methods. which is best? the one that you make work, cast is hard to weld but even bad import cast can be welded with enough patience and sweat.If necessary grind, mill or scrape to re-fit. In the end you'll be glad you did. best of luck to you!
    There was some good advice mixed in but the presentation was shaky. Snark aside, thank you.

    Anyways, I don't have lofty ideas of what my experience level is. Could I do it,? Sure. Is it a good use of my time? Probably not. Trust me, I love building my own tooling, fixtures, etc.. but I also know when I shouldn't invest my time into trying to build something that I'll scrap two times because I didn't like how it turned out just to decide I liked the first attempt after all.

    Moving on, I appreciate (most) everyone's responses, they gave me a lot of options to consider. For the now, I have a rigid clamp I welded together quickly that just uses set screws to compress the base inwards and prevent the crack from opening while adjusting the tail-stock. This has been fine for now while I get the important things I need to finish taken care of.

    I think my plan in the long term is to sleeve the bore. It's approximately 16mm and has about 12mm of thread at the end of it for an M10x1.5 SHCS to drive into for bearing against the adjustment post. The sleeve would need to be about 60mm,long or so, I figure thread half and overdrill the rest for clearance; that still leaves plenty of meat. I've considered JB weld or some form of epoxy, I work in marine industry so there's never a shortage of either. I could completely mill it all away and fill it back in with weld, but my welding is primarily in 316 stainless for stanchions and railing on sailboats, I'm not experienced in cast iron welding or brazing. Ultimately I'd just prefer to avoid heat altogether if possible. If it does need to be brazed, I'd prefer to have someone with more knowledge do it.

    I was bored and I keep forgetting to take pictures of the base of the tail-stock so I threw something together quick in inventor. It's pretty accurate to the actual piece and should give you a good enough idea of what it looks like. The pad itself is approximately 7.5" x 9.25" and for the most part has a .5" wall thickness.

    thing-1.jpg thing-2.jpg

    The image of the cross section should explain pretty easily why it failed (aside from me being a dumbass). I could spend some time messing around with some designs and come up with some really complicated insert that would lock into place and prevent expansion, but I think all of that may be somewhat overkill. I did consider just leaving it alone as suggested but the gib being tightened down stressed the crack pretty badly, I was afraid that would make it worse. There are two locking bolts in the underside, those take up most of the stresses anyways.

    Yep. If you wanted to be clever(ish) about it, put a set of keyways on both the slab and the casting, spaced so that when the slab gets installed hot, and bolted down, on cooling, it pulls the ends together. But that's all fancy.

    If you have to auger out the adjustment screw hole and replace the whole thing, make it part of the repair slab.

    You can hide the ugly stuff under a nice magnet mounted tool tray, a handy place for wrenches and chuck keys, eh?
    There's not enough clearance between the bottom of the compound and the top of the tail-stock base to make that work or I would! Half of my stuff ends up stacked haphazardly on the base and top of it anyway. When I'm done with whatever repair I end up doing, I think I'll move the clamp I made over to the back side and attach a bracket for a shelf somehow.

  7. #26
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    The Chinese never discard a casting......no matter how bad it is is,it gets machined and the defect hidden by thick filler.........I ve seen big lumps come off the tables of milling machines were just filler replacing missing cast iron.

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    Through bolts would run horizontally through the cracked casting. Tension on the boles would hold the crack closed and prevent propagation of the crack. In no way would it compromise adjustment of the tailstock.

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    Quote Originally Posted by Illinoyance View Post
    Through bolts would run horizontally through the cracked casting. Tension on the boles would hold the crack closed and prevent propagation of the crack. In no way would it compromise adjustment of the tailstock.
    If you were to run bolts parallel to the ways through the base, how would they not pass specifically through the adjustment bolt bore? It takes up almost the entire thickness of the base. I don't think it would be possible.

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    special-bolts.jpgI'm just kidding.

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  12. #30
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    Quote Originally Posted by David_M View Post
    special-bolts.jpgI'm just kidding.
    Looks like a standard parts-bin item to me.

    Ford "Edsel", was it?

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    Mill the top of the shelf where the crack shows, nice and flat. Drill and tap four 5/16-18 holes using a mill with DRO, then make a steel plate to fit that is 5/16" thick top to bottom and as wide as the shelf and flush on the front and the ends, and drill and countersink 82 degree the top to recieve flathead socket screws flush, but make sure the left two holes are .010" closer together then the right sides two, so when you drive the four screws in they will pull the casting inward into the crack, apply bearing and sleeve retainer loctite to the threads of the four 5/16-18 flathead bolts first so they never come out. That's how I'd do it and leave the adjusting hole alone unless it strips. Oh, and stop drill the end of that cack too of course.

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    Quote Originally Posted by naru View Post
    There was some good advice mixed in but the presentation was shaky. Snark aside, thank you.
    Maybe you NEED more snark?

    How about you take a look at what is "out there" used - actually abandoned, mostly - in the way of bed mounted hex turrets?

    I bought one - Enco, 5/8" turret bores, which hold all sorts of handy ex-Hardinge tooling - for a third the price 10EE tailstocks usually command.

    Yes. One has to figure out and make an adaptor that

    A) fits the bed Vee and flat,

    B) gets the turret bores to the proper height.

    But one does NOT have to make the rest of the turret.

    Now.. a one-hole TS with handwheel, not hand lever, capstan, or power feed is not a very useful device, even brand-new and perfect.

    Whereas.. a bed turret can still hold a center in one hole.. plus drills, reamers, and all sorts of other handy stuff... or NOT.. as well.

    Might end up less total effort to make that adapter plate than to mess with a bustid TS that will still be a one-holer, slow operating handwheel not even very useful for drilling, even if you "get it right".

    Surely makes a manual lathe more all-around useful as a byproduct, a turret can do.

    3CW


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