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Unbolting headstock from bed? Alignment issues?

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  • Unbolting headstock from bed? Alignment issues?

    I think that I read somewhere that if you unbolt the headstock assembly from the lathe bed, that you can put things out off alignment when you put it all back together.

    Can someone shed some light on this? Surely it can't really be an issue?


  • #2
    Alignment on reassembly can be a problem if the headstock doesn't have alignment pins. I have completely disassembled 2 lathes for transport to the shop. In both cases they had alignment pins. Neither has had an alignment problem after reassembly.

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    • #3
      Why should it? If the alignment is non-adjustable then it can only go back on. If it's adjustable, adjust it after re-fitting the headstock and aligning the ways.

      Have you checked the alignment pre-disassembly? Is the lathe fixed down/levelled? There's a fairly good chance that in it's current state it won't be perfectly aligned.
      Peter - novice home machinist, modern motorcycle enthusiast.

      Denford Viceroy 280 Synchro (11 x 24)
      Herbert 0V adapted to R8 by 'Sir John'.
      Monarch 10EE 1942

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      • #4
        Every machine I ever took apart the head base has a V machined in it on one side so it has to be in alignment when put back on. The only thing I can see happening is you get some particle or chip under it and it doesn't sit flat. Think of it as like the tail stock. If you slide it off the bed and put it back on the alignment should repeat.

        JL...........

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        • #5
          Yeah thanks that's what I had been thinking.

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          • #6
            What JoeLee said. Just be sure to clean the mating surfaces before reassembly.
            Paul A.
            SE Texas

            Make it fit.
            You can't win and there is a penalty for trying!

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            • #7
              Don't assume anything... The Emco's I had have machined v-ways BUT the head stock is further shimmed into alignment (axially and radially) with either very thin (sub thou) metal shims or oiled paper (yep) on the SIDES on the V way. Doesn't take much to be a problem as you get further way from the head stock.

              When you put it back together, check it (many threads on how to do this) and adjust as required.
              Last edited by lakeside53; 08-24-2019, 12:33 PM.

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              • #8
                Originally posted by lakeside53 View Post
                Don't assume anything... The Emco's I had have machined v-ways BUT the head stock is further shimmed into alignment (axially and radially) with either very thin (sub thou) metal shims or oiled paper (yep) on the SIDES on the V way. Doesn't take much to be a problem as you get further way from the head stock.

                When you put it back together, check it (many threads on how to do this) and adjust as required.
                That a hack way of achieving alignment. Better lathe manufacturers scarped the headstock into alignment.

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                • #9
                  Depends on the lathe, unfortunately. Some smaller english lathes (particularly those with dovetail beds) have all kinds of weird gibs and adjustment screws. Inverted V ways generally have the headstock scraped to alignment. We'd need to know the lathe in question to be sure.

                  allan

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                  • #10
                    Look to see if the vees in the bed extend right under the headstock. It is probable that the headstock was aligned with the vees and then bolted down. The bolts play no part in the alignment.The manufacturers probably bored the head bearing housings in line with the bed and if cleaned carefully on re assembly, it cannot be miss aligned.
                    I took the headstock off the Smart & Brown model A and only had to carefully clean off years of old soluble oil stains off the mating parts.

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                    • #11
                      Boxford MK1 VSL

                      Finally go the spindle out.

                      The ways look like they do go right under the headstock.

                      I think has one bolt and a clamping plate each end of the underside of the headstock to pull it down to the vee rails.


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                      • #12
                        Taiwanese 14x40 with gap bed that I am refurbishing. Note that due to gap, headstock is NOT on the bed V-ways. Screw marked is presumably to adjust the lateral position of the bed. There is a similar screw in the rear of the headstock casting. I have dissembled everything else, but don't think I really have a need to remove the headstock from the bed. Some people have concerns about re-aligning the gap piece, and are nervous about removing it for similar reasons. I'm not worried about that.

                        "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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                        • #13
                          Why do you want to take it off? Unless you know there is an alignment problem, probably best left alone IMHO.

                          Pleased you got the spindle stripped, so what do the bearings look like?
                          'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

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                          • #14
                            There's a guy on UK ebay selling some used spindle bearings. He seems to have a good rep.

                            https://www.ebay.co.uk/itm/123885608843
                            Peter - novice home machinist, modern motorcycle enthusiast.

                            Denford Viceroy 280 Synchro (11 x 24)
                            Herbert 0V adapted to R8 by 'Sir John'.
                            Monarch 10EE 1942

                            Comment


                            • #15
                              Originally posted by lakeside53 View Post
                              Don't assume anything... The Emco's I had have machined v-ways BUT the head stock is further shimmed into alignment (axially and radially) with either very thin (sub thou) metal shims or oiled paper (yep) on the SIDES on the V way. Doesn't take much to be a problem as you get further way from the head stock.

                              When you put it back together, check it (many threads on how to do this) and adjust as required.
                              I'm sure there are or were companies that used shims to bring the head into alignment, but anyway........ take careful note when taking it apart. If you find any shims just make sure to put them back where they were.
                              I always felt that a quality made machine had the spindle bearing seats line bored off the bed way to ensure the spindle was in line on both planes.

                              JL............

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