Announcement

Collapse
No announcement yet.

Replicating a Sickle Bar Drive Assembly.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Replicating a Sickle Bar Drive Assembly.

    I am in need of a plan for replicating the pitman arm assembly on a 1960's vintage combine I plan on purchasing. The combine has a windrow pickup attachment on it and the factory linkages for driving a sickle knife are long since gone. I need to convert it back to a direct cut header with a sickle for harvesting beans. Factory or salvage parts are non-existent. It does not need to look factory, it only needs to work.

    The mechanism is shown between 1:04 and 1:07 on the video linked below. Parts that need to be made include the eccentric that is shaft driven (towards the right side of the frame), the long (red) linkage rod, and the triangular shaped pitman arm (on the left).



    I have the fabrication abilities to pull this off, however I am somewhat stuck on how/what to attach the linkage rod to the eccentric with (right end of the red linkage rod). I am not sure how they did it originally and do not know of any examples that I could go look at.

    In my mind a joint similar to a heavy duty steering tie-rod end that has a ball bearing that would allow for high rotational speed and long life would be ideal. A tapered stud mount into a tapered hole would keep the joint from hammering itself loose over time. However, I cannot seem to find anything like this, no less a reamer for the hole. Do these exist, and if so what are they called and where can I find them?

    The other idea I currently have is to use a high-speed rod-end bearing similar to these.

    http://www.mcmaster.com/#rod-end-bearings/=mc70e8

    I figure I would want one with at least a 3/4" stud for strength. Cost is a factor as well, $200 or more for the joint would make this project cost prohibitive.

    Ideas, vendors, opinions?


    Thanks as always!

  • #2
    What about a tie rod end for car steering? Those should be strong and cheap.

    Comment


    • #3
      No need to reinvent the wheel. Use google image to see lots of examples of pitman arms. Think of the eccentric end like a connecting rod. No need for a unversal joint (hardy/spicer if I recall). Too complicated, expensive, and too many degrees of freedom. On the end which connects to the sickle bar we find one of the most elegant bits of engineering on the farm. The sickle bar has a big, hardened steel knuckle formed which mates with the assembly on the end of the pitman arm. Two side plates form a socket which is clamped to the ball with a clever spring assembly. You can see this clearly on the pitman arm images which popped up on google.

      The pitman arms are made of straight grained hickory or ash preferably quarter sawn to increase the strength. There will very likely be a shear pin somewhere in the linkage as well. One of the biggest culprits in damaged farm machinery is someone using higher grade bolts cause shear pin replacement is slowing down the work. We had real mechanics in the family so I never made this mistake myself!! Nothing beats a picture so have a look. There are also some examples on ebay though I doubt you'll find your particular assembly for sale, you may find some parts which will save you a lot of time and money in fabrication.

      Hope this helps,

      Jim (an old farmboy)

      Comment


      • #4
        1.) Get thee to an agricultural museum. The plowmen/threshermen type museum/show/run days will get you most of the leads and info you need. Google the search terms plowmen run day or some such for a show near you this summer. There's a couple in nearly every state in the American midwest and all the prairie provinces of canuckland.

        2.) Hook yourself up with ag equipment wreckers/recycle parts yards. There is a "parts finder" network that would be able to find original perts for you.

        3.) Again google your machine model, and search for parts manuals that would illustrate the assembly parts.

        4.) Look for similar vintage McCormick harvesters or even haying equipment. For the most part, a sickle bar drive is a sickle bar drive....
        Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

        Comment


        • #5
          Originally posted by dkhntr04 View Post

          In my mind a joint similar to a heavy duty steering tie-rod end that has a ball bearing that would allow for high rotational speed and long life would be ideal. A tapered stud mount into a tapered hole would keep the joint from hammering itself loose over time. However, I cannot seem to find anything like this, no less a reamer for the hole. Do these exist, and if so what are they called and where can I find them?
          Thanks as always!
          The reamers can be hard to find, google "automotive" or "sae taper reamer".

          Gammons Hoagland (sp?) is one company that makes them, I have seen others that I can't remember at the moment.

          Dave

          Comment


          • #6
            Have a look on the combine forum on www.ytmag.com
            Last edited by R W; 04-16-2013, 07:52 AM.

            Comment


            • #7
              Daddy used a tie rod end from a 2 ton chevy truck on our 715 IH

              Comment


              • #8
                A fat wheels mentions, don't over-engineer this. The wood pitman arm is sacrificial. I will look a little later today (still kind of wintry out there) and see if I have anything. Many years ago I disassembled an IH corn harvester with a hay head and sickle bar, and converted it into a brush chopper (and yes, it works, disposes of just about anything up to 3 inches thick). I can't remember now if the previous owner had left the pitman arm on the hay head, and if so whether I still have it, but I might. If so I'll post back.

                Comment


                • #9
                  I got lucky, a 500 mile drive and $50 got me the parts I needed from another combine that had been tucked away in the corner of a barn for years. Thanks for the input and advise.

                  Comment


                  • #10
                    I'm glad. I looked and looked and whatever I once had has disappeared after 20 or so years.

                    Comment


                    • #11
                      There are several tractor forums that also have attachments (old ones). I am into old case tractors, here are some. Yesterdaystractors, mytractorforum also
                      tractorhouse (auction site)

                      Comment


                      • #12
                        Originally posted by GEP View Post
                        There are several tractor forums that also have attachments (old ones). I am into old case tractors, here are some. Yesterdaystractors, mytractorforum also
                        tractorhouse (auction site)
                        I used to be the same, but I got over it.

                        I'm an ex-tractor-fan
                        Peter - novice home machinist, modern motorcycle enthusiast.

                        Denford Viceroy 280 Synchro (11 x 24)
                        Herbert 0V adapted to R8 by 'Sir John'.
                        Monarch 10EE 1942

                        Comment

                        Working...
                        X