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Smiths Chronometric

Discussion in 'Triton' started by Morgy, Nov 14, 2019.

  1. Morgy

    Morgy

    Joined:
    Oct 14, 2019
    Managed to pick up a set of Smiths Chronometric Speedo and rev counter a few days ago..

    Sold in a non working state but have managed to clean them up and get them to work, OK, They were really dirty and the cases were scuffed up pretty bad, Chrome is ok but would need re-chroming to make 100%
    I would like to know what bike or bike these actually came from.
    SC 5301/09
    1476 (ratio?)

    [​IMG]F1568D3D-DCD1-430F-B8B4-D1EB6842B13F by mark morgan, on Flickr

    Rev counter
    RC1307/00
    4-1
    [​IMG]060CF308-95C8-4802-989D-B91FB79BA46F by mark morgan, on Flickr
     
  2. Morgy

    Morgy

    Joined:
    Oct 14, 2019
    There are more photos if you click on the image and follow to my Triton Flickr account

    Both gauges now work although there not smooth when connected to a Cable and drill... They climb and descend very notchy.. if that make sense? is this normal or do they need more work to free up slightly.. Speedo Main drive was completely seized in the drive port/body but is now 100% free.. Both a little sticky but i guess at 65 they would be?
     
  3. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Chronometric clocks do NOT go smoothly, they ‘tick’ in increments up and down.
     
  4. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Your description "notchy" fits the normal way Chronometric gauges operate, both up and down.

    There is no way to make them operate as smoothly as magnetic instruments.

    These instruments are mechanical marvels, prize them highly. Should you ever need service or recalibration on these, I would recommend Greg Poirer.

    Oops, i see you are in the UK ..... Greg is in Washington state, USA.

    I think the number 1476 is a calibration factor, and might be a clue to the bikes the instrument was intended for.

    Slick
     
    Last edited: Nov 14, 2019
  5. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Various 1960-61 AJS, Matchless, T120 US Bonneville, Triumph TR6 and Trophy TR5A (Competition Export model).
    1476 = Should be cable turns per mile.

    1961 T120 US Bonneville and TR6 Trophy.
    1962 TR6S
     
  6. Morgy

    Morgy

    Joined:
    Oct 14, 2019
    Thanks.... I thought as much...

    Thank LAB.. will look into them a bit more when i have some time..
    Had a look on Evilbay Bloody expensive clocks and i thought old RD350lc clocks were expensive!
     
  7. Matt Spencer

    Matt Spencer

    Joined:
    Jul 25, 2010
    They go in 1 mph increments , working properly .
    accurate & without the lag & swing of the cheaper later magnetic ones .

    A lot of T 120s ran 140 mph speedos .
     
    Last edited: Nov 14, 2019
  8. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    I bought my Atlas new. The Chronometric Speedo jumped by 10 - 15 mph when new, and still does so after a Greg Poirer rebuild, when hard acellerating in first gear. Hard braking results in a similar jumping lag, as the instrument tries to adjust to the decreasing speed.

    The jump increments decrease as the instrument "catches up" with actual speed, either going up or down, and becomes rock steady at a steady speed.

    This behavior is due to a mechanical interruptor that "cuts out" the cable drive by a clockwork type escapement, hence the name "chronometric". Reference: Smiths_Chronometric_Speedo.pdf

    Slick
     
    Last edited: Nov 14, 2019
  9. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    No, they update the speed every 0.4 seconds (or somesuch time period).

    Edit: it’s 3/4 of a second.
     
    Last edited: Nov 16, 2019
  10. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
  11. Staytite

    Staytite

    Joined:
    Oct 15, 2011
    Hi Morgy
    Looks like you live near father and son David and Philip Woods in Bognor who specialise in
    servicing and repair of Chronometrics. They have done several for me over the years (decades!)
     
  12. oldbeezer

    oldbeezer VIP MEMBER

    Joined:
    Nov 2, 2017
    In other words you know how fast you were going about 0.4 seconds ago.
     
  13. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
    3/4 second (edited) is the most late that the reading can be.

    Depends how long into the 3/4 second interval it is, when you look at the speedo.
     
    Last edited: Nov 16, 2019
  14. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Actually, if one reads the pdf link i gave above, it is 0.75 seconds ago, which explains why, under hard acelleration or braking, there can be as much as a 10 mph jump when the instrument updates.

    Slick

    BTW ..... The soul of a British bike resides in these "clocks".

    BTW, X2 .... There is a Law, the Heisenburg Uncertainty Principle, which says, anytime you try to measure anything, you change it! Therefore, it really doesn't matter.
     
    oldbeezer likes this.
  15. Triton Thrasher

    Triton Thrasher

    Joined:
    Feb 10, 2009
  16. oldbeezer

    oldbeezer VIP MEMBER

    Joined:
    Nov 2, 2017
    THAT never occurred to me.
     
  17. Morgy

    Morgy

    Joined:
    Oct 14, 2019
    What would these be worth? Not that i was or am selling but I have been offered some very low and some fairly high prices for the two clocks Via my Facebook Profile when i asked about what bikes these were fitted on.. It seem'd some were just after a sneaky bargain but others were fairly, I won't say desperate but very pushy...

    Are these rather rare and valuable
     
  18. baz

    baz VIP MEMBER

    Joined:
    May 26, 2010
    I'd take a look at completed listings on evilbay to see what they actually sell for
    At a guess I'd say £200 + for the Speedo and £300 + for the tachometer
    The tachometer being the hardest one to obtain
    To get my tachometer I bought a Speedo as a core unit and had it converted to a tachometer
    But my guess at prices could be way out
    Cheers
     
    Morgy likes this.
  19. texasSlick

    texasSlick VIP MEMBER

    Joined:
    Jan 2, 2013
    Agree that they are rare and valuable. +1 with baz above.

    Slick
     
    Morgy likes this.
  20. oldbeezer

    oldbeezer VIP MEMBER

    Joined:
    Nov 2, 2017
    Yes
     

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