Tom Senior

  1. Piero

    Piero Member

    Messages:
    1,168
    Location:
    Uk
    Hi Guys

    After a VERY long time, (to many other jobs) I have finaly compleated the full rebuild of a Tom Senior S head or quill head as some call it

    I have searched all over the internet but cant find the differant speeds this thing can do

    The lathe website was not interaly usfull

    does and one know for certain ????

    Ta
     
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  2. brightspark

    brightspark Member

    Messages:
    27,359
    Location:
    yarm
    stick a taco on it
     
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  3. MCKDAVID Member

    as above, a Tacho is probably the easiest way. have a wee digital one here if you want to borrow it...
     
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  4. brewdexta

    brewdexta Member

    Messages:
    3,698
    Yorkshire
    Where's the rebuild thread? :) I renovated my Tom Senior light vertical a few years ago, apart from the head which is on my to do list.....
     
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  5. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    9,583
    Location:
    Bedfordshire England
    Have one of these very useful Screenshot_20191205-164538.png
     
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  6. pressbrake1

    pressbrake1 Member

    Messages:
    1,514
    essex england
    Counting revs is hungry work
     
  7. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    9,583
    Location:
    Bedfordshire England
    thats a bargain btw. see them go for silly money
     
  8. brightspark

    brightspark Member

    Messages:
    27,359
    Location:
    yarm
    I bought one and seen another 2 go for 15 quid from autojumble:)
     
  9. Piero

    Piero Member

    Messages:
    1,168
    Location:
    Uk
    Thought it might be writen somewere on a old Tom Senior manual or some were

    Ill add some photos but its not the full rebuild,

    I didnt feel happy about the intire head inc motor being held down to the backplate by only two small bolts, The two bolts you lossen to rotate the head,

    The Quill head is so much havier than the knuckel head (I am lucky enough to have both) but the Knuckel head has much bigger clamping bolts

    so I set about turning down a solid bar and fitting through the backplate (the one with the gib that holds every thing down the to coloum), I then wealded a round plate the the end and counter sunck 5 bolts to this and the back plate

    so now when I slide my quill head onto the back mounting plate, it slides onto this solid bar, I then used the same system (a pinch bolt) as used to hold the support arbor for the horizontal milling

    There are two on the very top of the main coloum that hold the round suport arm for the horizontal arbour.

    I drilled a hole through the quill head body and fitted this pinch bolt,

    So now, not only do I tighten the head down via the normal two small bolts, but it has this massive solid bar running through it with the clamping from the pinch bolt,

    I dont think I have photos of this being done, But you might be able to see the brass pinch bolt to the right side of my quill head

    PHOTOS TO FOLLOW
     
  10. Piero

    Piero Member

    Messages:
    1,168
    Location:
    Uk
    some photos of the head prior to paint, and after paint,

    I will add some photos from my phone of the finnished item,

    you can see the long brass non standard pinch bolt at the right hand side of my quill head

    I tried to make the quill lock bolt old looking (can bee seen on second photo)
     
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  11. Piero

    Piero Member

    Messages:
    1,168
    Location:
    Uk
    Finished head

    Polished the main body

    Side gear covers that are not shown in the photos are green like the other bits
     
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  12. citizen kane Member

    Messages:
    160
    UK Hampshire
    Not sure of the actual speed but generally too fast. Mine has a 1400 rpm motor and the 4 step pulleys give typically range of 3 either side of the motor speed, highest speed is probably around 4000 rpm and lowest speed of 450 rpm. I run almost exclusively on the slowest setting with a VFD allowing me to dial in 100Hz.
     
  13. Piero

    Piero Member

    Messages:
    1,168
    Location:
    Uk
    please accept this as no more than a simple concern,

    BUT is it wise to run a electric motor at 100Hz with the VFD????

    yes it can be done, but my guess is the motor plate will state 50hz and a motor speed of 1400 odd rpm

    we gear the motor to achive spindle speeds to suit, not motor speeds to suit

    the Tom senior Quill head uses timkin bearings that are rated to suit the spindle speeds,

    I doubt pushing the electric motor to run at 100Hz will be any good for the electric motor bearings !!!!
     
    ronan likes this.
  14. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    9,583
    Location:
    Bedfordshire England
    Depends on the motor. Inverter rated probably not as much of an issue as an old 3p motor fitted from factory
     
  15. Piero

    Piero Member

    Messages:
    1,168
    Location:
    Uk
    I wouldnt advise it !!!!!

    as I mentioned, the motor plate will state what Hz you should input in the VFD paramiters
     
    ronan likes this.
  16. citizen kane Member

    Messages:
    160
    UK Hampshire
    The bearings don't seem to mind and the rotor hasn't exploded after more than 10 years of use, don't know if its wise but I seem to be getting away with it and I rarely need to change the belt speed.
     
  17. Piero

    Piero Member

    Messages:
    1,168
    Location:
    Uk
    ronan likes this.
  18. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    9,583
    Location:
    Bedfordshire England
  19. Piero

    Piero Member

    Messages:
    1,168
    Location:
    Uk
    A copy and paste from your link


    Paste The real limiting factors for over-speeding a motor are not so much electrical as they are mechanical. Bearing wear and rotational instability resulting from changes in mechanical balancing requirements at speeds above the nominal can lead to motor failure and/or unacceptable vibrations when operating a motor continuously at higher than its rated top speed.
     
  20. eLuSiVeMiTe

    eLuSiVeMiTe Forum Supporter

    Messages:
    9,583
    Location:
    Bedfordshire England
    I've set my ceiling at 80hertz
    It's a new inverter rated motor and it's not bothered in the slightest.
    Running it at very low speeds is going to cause it more harm.

    Quoting a small section of the article that suits your point of view is all well and good. we can all do that.
    Rules of thumb- a 3600 rpm motor can be run safely up to about 75 Hz (or 25% above its rated speed). An 1800 rpm motor can be run safely up to 120 Hz or 200% of its rated speed but…as the accompanying graph indicates, at double speed, the motor can only operate with 25% of its nominal full speed torque.

    Your not gonna choose a motor slower than your needs and run it overspeed for it's lifetime
    But using it for certain jobs requiring a higher speed isn't gonna kill your motor.
     
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