Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 31

Thread: Help to identify 6.75 vs6.91 track pitch?

  1. #21
    Join Date
    Nov 2006
    Location
    Pittsford NY
    Posts
    4,251

    Default

    Thanks Bruce, yes I can imagine they need to be robust to withstand all the shaking and rattling. I spent a few years as a kid running wheel tractors for a local contractor in the early eighties and that was just as he was buying JDs with SG2 cabs, but being the kid, I got the crappy old David Brown open station with no muffler (hence I'm also deaf). The long drives down the road on frosty nights was what killed the "fun" for me - gonedang it was cold! I don't think he really got that a comfortable operator did a better job.
    Cheers,
    Neil.

  2. #22
    Join Date
    Dec 2018
    Location
    Lacrosse, Washington
    Posts
    21

    Default

    Hello Neil, I think Bruce summed it up pretty well, no two ever seem to be the same. I have never ran this tractor, not even home yet, but it has a Henley cab. They were built in Hay Washington, just a few miles away. They are a fiberglass cab so as long as the door latches are kept tight they are actually pretty quiet. This one has a red dot AC unit which should be good, fresh air is filtered through a D5 dry air cleaner element

  3. #23
    Join Date
    Nov 2006
    Location
    Corralitos, Ca.
    Posts
    14,463

    Default

    Be aware when working witht the 6.75" pitch (28 tooth) sprockets that they are not hunting tooth and need to be jumped one tooth to distribute wear. Another advantage to the 6.91" with 27 tooth sprockets.

  4. #24
    Join Date
    Dec 2018
    Location
    Lacrosse, Washington
    Posts
    21

    Default

    Ok, thanks for the info. Reading that made me realize the easiest way to tell how many teeth are on a sprocket is going to be by looking at the wear pattern. Shiny teeth are the only ones engaging tracks. Lots easier than trying to count teeth behind rock guards etc... thanks again everyone, now I know that I am looking for usable sprockets to match my good tracks, Mike

  5. #25
    Join Date
    Jan 2009
    Location
    Colorado Springs and Waitsburg WA
    Posts
    933

    Default Ques re Hunting Tooth

    If it's a hunting tooth sprocket then it must always be odd tooth count right? Even tooth count will always be repeating?
    John Liebermann
    2 9U's, 5J, IHC544, Ford860, (All working farm tractors)
    cojhl2@gmail.com

  6. #26
    Join Date
    Nov 2006
    Location
    Port Alice BC Canada
    Posts
    74

    Default

    An odd tooth sprocket is non repeating so distributes wear. An even tooth sprocket with an odd link chain is also non repeating and distributes wear.

  7. #27
    Join Date
    Jan 2009
    Location
    Colorado Springs and Waitsburg WA
    Posts
    933

    Default

    Quote Originally Posted by BobPV15 View Post
    An odd tooth sprocket is non repeating so distributes wear. An even tooth sprocket with an odd link chain is also non repeating and distributes wear.
    OK, I guess I'm finally understanding this(I'm a thick headed Kraut). The term "hunting Sprocket" kinda threw me all these years I think. As I understand it now the track link count if even or odd must have the opposite characteristic of the sprocket.

    Is this correct?

    Yee gads how can I not get this through my head??
    John Liebermann
    2 9U's, 5J, IHC544, Ford860, (All working farm tractors)
    cojhl2@gmail.com

  8. #28
    Join Date
    Nov 2006
    Location
    Corralitos, Ca.
    Posts
    14,463

    Default

    Not many even tooth sprockets were used.
    Some that I know of to watch for...
    6.75" pitch 951 has 30 teeth
    6.75" pitch D6 and 977 has 28 teeth
    6.91" pitch 951 has 30 teeth

    An interesting combination is the early D8 8.00" pitch (skip tooth) sprockets. Base system is 38 links, 14 tooth sprocket, so it appears they start out with a repeating mesh pattern but if you go to 39 link chain with large front idler they become non- repetitive. Correct me if my thinking is off.

    On that same note be aware that adding or subtracting links may shift the wear pattern.

  9. #29
    Join Date
    Nov 2006
    Location
    Faunsdale, AL USA
    Posts
    3,933

    Default

    Even tooth count sprockets cannot hunt and must be jumped to put ANY wear on half the teeth
    This is because the track chain pitch is 2X the sprocket tooth pitch on every machine I know of. There were some old even tooth count sprocket rings that didn't have the alternate teeth cast with the normal gullet, just a wide web there.

    When you get to track chain link counts,,,,,,,,
    The worst case......even chain paired with even sprocket puts the same bushing back on the same tooth fairly quickly. and as mentioned ALREADY, half the sprocket teeth get no wear

    Change to the odd tooth sprocket and it will take a lot longer to repeat the same bushing on the same tooth AND all the sprocket teeth are in wear, but it still repeats in a fairly long interval pattern. This repeat pattern is long enough that it probably has no practical effect on track life.

    Change to an odd track link count and the repeat interval increases dramatically (good) in most cases
    D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time

  10. #30
    Join Date
    Nov 2006
    Location
    Corralitos, Ca.
    Posts
    14,463

    Default

    Been awhile since I had to calculate it but the number of sprocket revolutions to match the same tooth with the same bushing can be determined by finding the "Lowest Common Denominator" or "Lowest Common Multiple".
    Any change in tooth or link count affects the repeatability, some combinations much more frequent than others. Optimum combination is the least repeating possible.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •