More questions about my tailstock

Discussion in 'Tools' started by CraigLD, Sep 11, 2019.

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  1. Sep 11, 2019 #1

    CraigLD

    CraigLD

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    The tailstock for my 7x14 appears to be pretty standard for this level of lathe. It is attached to the bed by a bolt the goes through the bed and uses a small square metal plate with a nut to secure it to the bed. I have noticed that if I tighten the nut too much it won't slide along the bed. If It is too loose the entire tailstock becomes "sloppy". Is there some rule-of-thumb on how tight this nut should be and should there be a lock washer to keep the nut from becoming too loose? Or should I use loctite or something to secure it once it is set?

    A more important issue is that if I insert a live center in the tailstock, It doesn't align with the center of the chuck. It is a couple mm below and to the right of the chuck center. Is there a way to adjust how the tailstock sits on the bed. The left side of the tailstock appears to sit slightly lower than the right side which I guess accounts for it being off. Should I attempt to attach a shim to one side to even it out?

    As always thanks for any guidance you can provide
     
  2. Sep 12, 2019 #2

    goldstar31

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    I would assume that you have made a copy of the excellent guidance of the write up from the Little Machine Shop.com and to continue , I would suggest that you follow the 'words and music' from GadgetBuilder.com to guide you further especially about the tailstock problem.

    I wonder how with a new and therefore unworn lathe that the height of the tailstock is too low. Maybe you lathe is 'in twist' and should be aligned with two good spirit levels so that it is true both correct in both planes and vertically too. John Moran as GadgetBuilder.com gives an excellent description of what you should do

    Norm
     
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  3. Sep 12, 2019 #3

    Cogsy

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    That lock nut is for locking the tailstock in place. You loosen the nut, position the tailstock where you need it, tighten the nut, do your work, then loosen the nut and slide the tailstock back to the end of the bed for 'parking'. There is a common modification that is done (I think Little Machine Shop even sells a kit) to change the nut to a cam-lock lever so it's easier and faster to move the tailstock.

    There is side-to-side adjustment on your tailstock but from memory there's no vertical adjustment. I would suggest you take it off and check the underside of it for a burr or trapped chip or something that may be cocking it over. I can't see that size lathe being able to be twisted under its own weight without being bolted down to a rigid, crooked surface. Also check the lathe ways for a raised area where the serial number is stamped - it's common to have to run a file across the serial number area once or twice to knock off the high spots caused by the stamping.

    Definitely have a look at a copy of the procedure for setting up/ cleaning a brand new 7X lathe. There's lots of tips to found in there that will make your lathe a lot better than how it comes out of the box. Something like this guide LINK and also a handy (well written) user guide LINK.
     
  4. Sep 12, 2019 #4

    goldstar31

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    Their kit is :-

    2018 costing $29.95

    Actually I was after a UK variant of the 7X lathe which was advertised for for not much more than peanuts i.e £130. There was no tooling other than the very limited 3 jaw chuck but cannibalising it would have produced spares for the vertical mill attachment which uses the same circuit board etc.
     
  5. Sep 12, 2019 #5

    ShopShoe

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    Craig,

    On my tailstock, I found a "gloppy" paint job on all surfaces of all the parts. I disassembled all parts of the tailstock, and scraped off the paint from the bottom surfaces and from the top and bottom parts of the assembly. On reassembly, I used new hardware for the side-to-side adjustment lock and then was able to achieve much better alignment between the tailstock and headstock centers.

    You may find it useful to check the alignment between centers at different tailstock positions along the bed. On my lathe, I found the center-to-center alignment had the tailstock higher at the extreme end of the bed because (I guess) the stamping of the serial number on the top of the bedway distorted things a bit (The 7x lathe beds are not hardened). I stoned the area where the serial number is and improved things a bit.

    Over the years, I have taken the approach of making small improvements from time to time, but not trying to fix everything all in one go. Whenever I can, I consider whether the next thing I try to do is reversible. Things will never be "perfect," but this lathe is getting better in tune with my skills at all levels. I would really like a bigger, better lathe, but this is where I am and what the money allows.

    Best of Luck and keep posting

    --ShopShoe
     
  6. Sep 12, 2019 #6

    CraigLD

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    Thanks for all of the replies. That GadgetBuilder site is great, not sure why I haven't encounter it before. Obviously, there is a lot of reading I need to do there. I have inserted a couple pictures to show the end of the tailstock that shows it leaning to the left. I also inserted a picture showing the live center meeting the chuck.

    These are my first attempts at inserting an image. I apologize if it messes anything up.
    [​IMG]
    [​IMG]
     
  7. Sep 12, 2019 #7

    CraigLD

    CraigLD

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    Boy! Those pictures are bigger than I meant them to be.
     
  8. Sep 12, 2019 #8

    Cogsy

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    Something definitely seems off there. I'd start by looking at the bottom of the tailstock myself. When it comes time to align the tailstock horizontally, you can get very close by having a dead centre in the spindle and the tailstock and sandwiching something like a feeler gauge blade between the points. There's plenty of info around about the method but before you get there you need to figure out what is so far out right now.
     
  9. Sep 12, 2019 #9

    goldstar31

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    Graig- I'm pleased about your appreciation of GadgetBuilder BUT !!!!!.

    It is quite wrong to do your tests using the 3 jaw chuck. It can be 'out' by several thous.You should put a piece of round steel in it and machine a point like a centre.

    In the OLDEN DAYS, there were hard and soft centres. The Hard one went into the tailstock 'poppet' whilst the Soft one was always re-machined IN the spindle.

    Perhaps you will get a different 'height' if you obviously align the tailstock and machine perhaps using the chuck as I suggest.
    a new point

    Let us know, please

    Norm
     
  10. Sep 13, 2019 #10

    ShopShoe

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    Craig,

    Norm raises a valid point. I did not realise that you were lining up to the chuck.

    Here are some suggestions. Do the ones you can, or find "as close as" methods you can. These are not necesarily inorder of priority.

    1. Remove the chuck. Use a Dial Test Indicator and rotate the spindle to see if your spindle is running out or "wobbling" as it turns. check the face of the spindle as well (where the chuck backplate screws on.)

    2. Get a MT3 collet and use it with a test bar to check the alignment of the headstock to the bed (A bar salvaged from a computer printer will work for a test bar - larger diameter is better.) (This bypasses the use of the chuck entirely.) The procedure is written up in many places and shown on lots of YouTube videos.

    3. Put a MT3 center in the spindle directly and a MT2 taper in the tailstock and do as Norm suggests to check the alignment between headstock and tailstock.

    4. Remove the lockdown bolt and nut from the tailstock and check the tailstock alignment with only the bedways directing it. It is possible the bolt is out of spec or installed wrong.

    5. Disassemble the tailstock and clean and check all parts. You can check the taper assembly for straightness by rolling it on a surface plate with a light behind it, or use the cast-iron table of a drill press or other machine tool. Pay attention to the line-up of the taper to the casting and all of the bearings: Is something out of round?

    6. I should have mentioned this earlier: Check the inside of all tapers for burrs or even pieces of who-knows-what. Do it by feel, but also use a strong light and your eyes.

    7. Use precision squares to check the perpendicular alignment of parts where this could be an issue. Use in conjunction with lights from behind and also with feeler gages, as the need arises.

    8. If you have a micrometer, you can turn your own go/no-go gages for measuring holes and bores.

    Chances are you will find some things you were not looking for and that may not affect your immediate problem, but you will get some insight as to how your lathe was built and aligned at the factory.

    Let us know what you find.

    --ShopShoe
     
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  11. Sep 13, 2019 #11

    goldstar31

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    Craig
    ShopShoe gives excellent advice but you mentioned both a drill chuck and a rotating centre. Neither has a place in the tests which you should be conducting.
    I hope that this finally solves the problem.

    Cheers

    Norm
     
  12. Sep 13, 2019 #12

    awake

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    To me, the first picture suggests that the tailstock is defective, badly so. It appears that the v-groove is not cut sufficiently deep, so the base does not sit down on the ways properly. Notice how the right side, which should be sitting flat on the flat ways, appears to be distinctly tilted.
     
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  13. Sep 13, 2019 #13

    goldstar31

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    In the first explanation, the tailstock is LOW whereas 'Awake' says that it is HIGH.

    It cannot be both!


    I'd loosen the clamp bolt to the lathe bed (or remove it altogether for first checking). At least, we can determine where it sits- or doesn't.
    The last thing that we all want is -------CRACK---- and that will be the end of things

    Concerned

    Norm
     
  14. Sep 13, 2019 #14

    awake

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    It may well be that the business end of the tailstock is low ... but it sure looks like the base is sitting high - unless it was cockeyed in that particular picture. Honestly, my first thought on seeing the picture was, "that's the wrong tailstock for that lathe"!
     
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  15. Sep 13, 2019 #15

    bobden72

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    Come on chaps you do not need a centre in the tailstock and head stock to see its out, the chuck shows it perfect. Yes when you come to actually align it then a test bar, but he is only doing an assessment . Looks like the wrong tailstock to me as it should be mating on the two flats surfaces and the V.
     
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  16. Sep 14, 2019 #16

    Cogsy

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    Awake is suggesting (and that's how it looks to me also) that the tailstock is cocked to one side as it is not sitting down on the V properly. Effectively this would be inducing a rotation about some point above the base of the tailstock. So it could indeed be sitting high on one side but be out of a alignment low and to one side.
     
  17. Sep 14, 2019 #17

    goldstar31

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    I quite agree but whereas, all my lathe tailstocks are accurately aligned, sadly the OP's isn't.
    Again, I don't think for a moment that he has been sold the wrong tailstock- Heaven forbid, I merely thin that he has done something wrong. However, I am trying to get to the bottom of things to find out what is wrong and perhaps more importantly, that he doesn't damage his machine.
    If I have got it wrong and have created the wrong impression, I humbly apologise.
    Norm




    So my 'guess' is that the bottom retaining plate has been either inserted 90 degrees out or it is , more likely, 'cocked'.

    Again, I apologise.



    N

    Breaking News!!!!


    The plot thickens

    N
     
    Last edited: Sep 14, 2019
  18. Sep 14, 2019 #18

    TonyM

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    Exactly my thoughts.
     
  19. Sep 14, 2019 #19

    goldstar31

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    So the only quick way to find out, is to get the poster to tell what the Morse Taper is.
    Gentlemen, if you are right , dare I quote what the great John Ruskin had to say on Price?
     
  20. Sep 14, 2019 #20

    Cogsy

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    I went out and had a look at my old 7X tailstock and, somewhat surprisingly to me, it looks to sit very similar to how the one in the picture sits. Mine sits just a smidge deeper into the V way but not much. If there is a bit of a burr under your tailstock then that's likely the issue.

    Norm - I don't think the bottom retaining plate can have anything to do with how it sits on the ways, at least from what I remember of how the tailstock mounts on these lathes.
     

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