Adjust Colchester headstock

  1. fizzy Member

    Messages:
    6,806
    uk
    No matter what I do the lathe turns a taper.
    It says you can pivot the headstock but how does that work if it is sitting on a V bed?
     
  2. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,883
    essex england
    How much of a taper
     
  3. ukracer Forum Supporter

    what colchester is it?
     
  4. carbon

    carbon Member

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    1,687
    Location:
    S. Glos. U.K
    I think it’s a triumph. In the student manual it shows how to check for alignment after the lathe has been transported
     
    fizzy likes this.
  5. awemawson Forum Supporter

    Headstock pivots on a peg at the rear / front and is moved by bolts between the ways under the change wheel cover. When set right all hold down bolts get tightened.

    The Vees in the headstock are WIDER than those in the Vee ways so it can move
     
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  6. fizzy Member

    Messages:
    6,806
    uk
    Yes it is a Triumph.
    It was those Vs that made me wonder how it could move - now I see there is a tiny gap - there was me thinking it could swivel 45 degrees each way :laughing:
     
  7. awemawson Forum Supporter

    Have a procedure and a picture - this is actually a Master 2500 but they are all the same in the principal that they work

    Headstock-#adjustment.jpg
     
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  8. fizzy Member

    Messages:
    6,806
    uk
    3 thou over 6"
    Bigger at the tailstock end tapering smaller towards the headstock.
     
  9. minimutly Member

    Messages:
    1,496
    Location:
    Pembrokeshire Wales
    Machine a bar as described, put the toolholder on the end, slacken the headstock and move it to a distance of 1.5 thou, clamp up and remachine to test.
     
  10. fizzy Member

    Messages:
    6,806
    uk
    So much easier said than done - looks like gears and banjo need to come off to get at it?
     
  11. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,883
    essex england
    Different bed, square heads have a flat for the headstock 0D163819-27D2-404A-B4E2-0DFAF4E07BF2.png
     
  12. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,883
    essex england
    Check the chuck
    A bad chuck can cause the same effect
     
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  13. fizzy Member

    Messages:
    6,806
    uk
    I am using a Jacobs Rubberflex collet chuck.
    38mm aluminium bar with a very light cut
    The collet chuck is in good condition - grips very well and I trued it up so the internal taper is within 0.0005"

    Of course it may still be the chuck?

    Or could it be a levelling problem? I have checked it but need to level my level again first.
     
  14. pressbrake1

    pressbrake1 Forum Supporter

    Messages:
    2,883
    essex england
    Is it gap bed
     
  15. ukracer Forum Supporter

    What's that?
     
  16. mtt.tr

    mtt.tr Member

    Messages:
    4,041
    Essex England
    bed is deffinetly level not really level, but out of twist



    @pressbrake1 am i right in thinking a test bar on centres clocked in the tailstock then run a dti down the bed will show you where the ways are worn
     
  17. minimutly Member

    Messages:
    1,496
    Location:
    Pembrokeshire Wales
    Fizzy reckons his lathe is very little worn, mine (same machine) is really worn, and it cuts close enough to call it true, so I'd be surprised if bedware was an issue.
    Actually I was going to say - I'm sure I can see the inverted "V" of the bed continue under the headstock - @pressbrake1 confirms it!
    So how is it corrected? And how does a wonky chuck differ to a poor 3 jaw to produce a taper? I don't see that?
     
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  18. minimutly Member

    Messages:
    1,496
    Location:
    Pembrokeshire Wales
    IMG_2645.PNG IMG_2644.PNG From the Triumph parts manual...
     
  19. minimutly Member

    Messages:
    1,496
    Location:
    Pembrokeshire Wales
    I have no idea how you'd get at these - from behind the motor through the suds tray? As you say the front gearbox looks like its in the way?
     
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  20. fizzy Member

    Messages:
    6,806
    uk
    Screenshot_20201111-205204_Video Player.jpg
    Yes it is. But the gap looks like it has been cut out of the bed. The Vs continue under the headstock.
    There are bolts each side holding the headstock down can't see how it can swivel.
    There does appear to be some sort of adjuster at the back though.

    This is looking from the chuck towards the back.

    Screenshot_20201111-205204_Video Player.jpg
     
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