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Thread: Reground bed

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    Default Reground bed

    Hello. A question for the experts. I have been offered a 9" SB(36" bed). The bed has been reground. Is there anything I should be looking out for, before parting with my money.
    Cheers

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    Regrinding the bed is only part of the solution. Once ground, the headstock, carriage and the tailstock have to be "raised" up to compensate for the amount ground off. Think "turcite" and other raising options. Unless you are getting it super cheap, I think that I would pass on it, simply because you don't know what all was done and if it was done properly. At the very least, remove the tailstock and look for some type of build-up material on the slip ways. If the seller will let you, also look under the headstock. If these two were brought up to the correct height, chances are that the carriage was too.

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    I'm not a 9" expert, so consider that really. Need to confirm what I say here with a 9" owner. What I'm saying I know applies to 13 - 16", but from what I have seen, I believe applies to 9 and 10" as well.

    But one advantage I found on South Bends over even premium lathes. If you regrind bed, you do not necessarily need to lift any parts of the lathe, i.e head stock, carriage, qcgb, lead screw bracket etc.

    On other lathe brands, often the gear train is fixed. So you must raise components to get gear back lash, and certain fits.

    On a South Bend, left end gear train has adjustable banjo to adjust gear lash to head stock. Qcgb, lead screw end bracket, and bed rack can all be shimmed down very easy to account for a regrind. That is not possible on many lathe brands, but is on a South Bend.

    What you would absolutely need to do is scrape in saddle and tail stock to fit new bed ways. You can't just drop the parts on and go. They won't slide until fit proper. The saddle is trickier on a South Bend though, two vee ways, scraping would be quite the trick. One vee way and a flat would be easier.

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    How about some more info. They ground the bed. Does it have hardened ways? SB had both soft and hard... more were soft. Did they rebuild the machine after the bed was reground? Take some photo's so we can see what your talking about. I find it hard to believe someone ground the bed and assembled it as is. Soft beds should be scraped after the bed is ground, otherwise it will begin to scratch wear as soft ways need to have shallow .0002" to .0005" deep oil pockets. If they installed Turcite or Rulon under the saddle then that helps eliminate the wear issue. If you are looking at it at a used machine dealer, I would be a bit suspicious. A real simple way to check if a machine was rode hard and not many people replace the feed rack. look at the rack up near the chuck or at the far right end. That will be original as it never gets worn there. Then move the carriage to the right and look at the rack where it get worn the worse. A simple way to evaluate a lathe.

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    Quote Originally Posted by Richard King View Post
    How about some more info. They ground the bed. Does it have hardened ways? SB had both soft and hard...
    The 9" lathes didn't have a hardened ways option. I don't think that the 10k did either. Only 10L and larger.

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    Regrinding the bed is only part of the solution. Once ground, the headstock, carriage and the tailstock have to be "raised" up to compensate for the amount ground off. Think "turcite" and other raising options. Unless you are getting it super cheap, I think that I would pass on it, simply because you don't know what all was done and if it was done properly. At the very least, remove the tailstock and look for some type of build-up material on the slip ways. If the seller will let you, also look under the headstock. If these two were brought up to the correct height, chances are that the carriage was too.
    There are a lot of ways to grind a bed wrong, so if you can't inpsect, i might be inclined to pass.
    That said, the above quoted is not true.

    I planed and re-scraped my 54" bed 10K (& documented much of it on PM)
    The only factors that the bed changes when re-assmembling are the lead screw/gearbox location; and the rack will need shimmed down. You might also prefer to take a cut on the back carriage clamp loose piece so it will snug up, but that is seldom used snug on a SB. If you do that, you will be able to check if they ground the ways parallel to the underside flat way. (Or if they bothered with the undersides of the ways, say under the TS clamp.)

    smt

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    In many ways, re-grinding or re-fitting a lathe bed/saddle poorly can make the machine worse than before. Doing so might make it look pretty, but fix none of the issues it started with. I like seeing how a machine has worn before it is re-fitted as it gives clues as to what areas are problems and you have the original surfaces to reference for squareness and alignment. If they ground away all of the surfaces with no reference as to how square everything was, it'll be harder to fix the second time. If they've used it since it was refitted and will let you inspect and cut on it before you buy it, then it might be a good deal, but I'd be warry of buying it JUST because it was refitted (supposedly).

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    Thanks fir the input. I will probably pass on it. As far as I can tell, the bed was ground. Nothing else has been done to the machine.

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    Quote Originally Posted by SLK001 View Post
    The 9" lathes didn't have a hardened ways option. I don't think that the 10k did either. Only 10L and larger.
    The 10K did have hardened bedways for a time, near the end. I know because I purchased my first SB new in 1984, and it was a 10K with hardened bedways. These were machines that were (at least partially) made in Asia. There were some quality issues with the lathe, but the hardened and ground bed was not one of them, as far as I could tell.

    However, having owned a 1947 9A for the last sixteen years, I can see that my 10K was not representative of the quality level that prevailed in South Bend's heyday.

    Paula

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    Quote Originally Posted by gwelo62 View Post
    Thanks fir the input. I will probably pass on it. As far as I can tell, the bed was ground. Nothing else has been done to the machine.
    If it was done well, you wouldn't notice it had been done.

    Few BOTHER to re-grind an SB bed as it costs much the same as having a more expensive lathe reground and you still only have a modest SB when it is done.

    Somebody went to the trouble and expense on this one? It would be most unusual to stop with nothing else improved.

    Could be a previous owner's labour of love and a very well-restored machine, overall..

    Can you not go and actually check it out 'hands on', by making test cuts, applying measuring instruments?

    Where's the real risk?

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    A hardened and ground bed was available in 1978 for the 10K lathe. It was a $247 option on the $1929 lathe. ($1039.18 on a $8115 lathe in current dollars.)


    sb-receipt-extract.jpg

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    Just looked in my 1966 South Bend catalogue. It shows both the 9" and the 10-K could be ordered with a flame hardened bed as an option. For either model a flame hardened 4 foot bed cost $118. A flame hardened 4 foot bed for the Heavy 10 was $184.

    BTW nice to see you back Paula.

    David

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    Quote Originally Posted by old_dave View Post
    Just looked in my 1966 South Bend catalogue. It shows both the 9" and the 10-K could be ordered with a flame hardened bed as an option.
    In my 1967 catalog, it only shows the 10k as having that option (by now, all lathes 10L and above came with a hardened bed as standard). My 1963 cat does show a 9" option for it. I guess that SB changed options like the Detroit automakers.

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    Quote Originally Posted by SLK001 View Post
    In my 1967 catalog, it only shows the 10k as having that option (by now, all lathes 10L and above came with a hardened bed as standard). My 1963 cat does show a 9" option for it. I guess that SB changed options like the Detroit automakers.
    Thank you for this information regarding when flame hardened bed ways became standard for the heavy 10 and larger South Bends. (And how it ceased to be shown as an option for the 9")

    David

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    My 10k that I bought new from SB in 1980 has a hardened bed.

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    I parted out a 9" workshop lathe that had the bed ways reground by someone. They seemed to be done fairly well.

    My observation from it was that you had to account for the amount of material taken off of the ways with spacers/shims under the lead screw bracket, apron rack and either bracket or qcgb that held the leadscrew on the headstock side. This lathe had 0.100 spacers between everything.

    The tailstock also had shim stock in between the base and the main casting to account for the height the base was ground to level it with the headstock centerline.


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