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Automotive Sprockets, chains, and gears question

  1. Apr 10, 2017 #1
    hello. I'm tring to find a compatible sprocket for my chain. I need to know what these abbreviations mean here: http://www.ebay.com/sch/i.html?_odk...ket+40+3/4.TRS0&_nkw=sprocket+40+3/4&_sacat=0

    For example, what does a 40B10H-3/4 mean? Or a 40BS13 3/4"?
    I think the 40 represents the chain # it supports, but I what numbers represent the size of the gear? Is it radius or diameter and what unit is it in?

    Thank you!
  2. jcsd
  3. Apr 10, 2017 #2


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  4. Apr 11, 2017 #3


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    #40 Roller Chain. (½” roller pitch).
    Type B, finished bore.
    10 Tooth.
    3/4" diameter bore.
  5. Apr 11, 2017 #4
    Thank you very much! Do you know what the S means in 40BS13 3/4? Thank you!
  6. Apr 11, 2017 #5


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    The 'S' is a variation of hub design. Maybe; Set screw(s) to position sprocket and key on the shaft?
    You will need to see the manufacturers data for that one.
  7. Apr 13, 2017 #6
    There are 2 main standards in the western world for chain specifications being the US ANSI system and the British BS system. The BS System uses the chain pitch identifier as multiples of 16 to theinch. So a bs16 chain is 1 inch pitch while a bs 10 chain is 5/8 inch pitch etc. The ANSI system uses multiples of 8 to the inch. So an Ansi 40 is 1/2 inch pitch standard chain. It it is heavy duty it will have H afterwards. Both chains standards are not interchangeable for the same pitch.
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