1. Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
  2. ALL NEW MEMBERS READ THIS FIRST!! Thank you for joining Heavy Equipment Forums! If you are new to forums we communicate with "Threads", please search our threads to see if your topic may have already been answered and if not then click "Post New Thread" in the appropriate forum. This will allow all of our members to see your question and give you the best chance to be answered. After you've made a number of posts you will graduate to Full Member status where you'll see a few more privileges. Following these guidelines will help make this the best resource for heavy equipment on the net. Thanks for joining us and I hope you enjoy your stay!!

New Build, Thumb For A Kubota Mini X

Discussion in 'Compact Equipment Attachments' started by Danny Steel, Mar 29, 2011.

  1. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    I'm fabbing up a Thumb For my KX71
    Its already plumbed, And has the top cylinder ears welded from the factory.
    I'm planing on welding ears on the lower end of the stick, and pinning there.
    I'm once again using up scrap steel In the shop, I already have a cylinder, with the hoses and the quick disconnects
    Here's a pic of the stick, and what I have to work with:)
     

    Attached Files:

  2. Hendrik

    Hendrik Senior Member

    Joined:
    Mar 6, 2009
    Messages:
    1,232
    Location:
    Adelaide South Australia
    Just remember not to weld across the dipper arm, down it yes.
    Spot weld everything into place to check operation of thumb before going weld happy.
     
  3. maddog

    maddog Senior Member

    Joined:
    Apr 20, 2009
    Messages:
    730
    Location:
    middle TN
    good advice
     
  4. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    Thanks guys, And yes I do know now to weld In that area.......Today I have some time to make a template, To get the swingen of the grabber
     
    Last edited: Mar 30, 2011
  5. heavylift

    heavylift Senior Member

    Joined:
    Sep 5, 2009
    Messages:
    1,046
    Location:
    KS
    use the bucket pin for the thumb... no welding to the boom needed... just a thumb build project.... all you would need is a longer pin
     
  6. heavylift

    heavylift Senior Member

    Joined:
    Sep 5, 2009
    Messages:
    1,046
    Location:
    KS
    Last edited: Mar 30, 2011
  7. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    I thought of using that pin, But for some reason I went to making ears to weld to the stick......Maybe because It will be easier to remove....I have the ears already cut, But i could always change It to your Idea Of the longer pin.....I definitely open to opinions on this.
    Danny
     
  8. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    Well I spent some time out In the shop today......I have the ears tacked in place' grease nipples drilled and tapped
    And the Jaws cut.....I ran out of acetylene:cool2, And had to use the Plasma cutter...even though that cutter Is ratted for 7/8 plate, It just goes through 3/4"
    I keep on measureing the cylinder, Hopping It grew over night, I may be able to squeek by with the 14" stroke.
    At least now I can see were I'm going with this:beatsme
    Monday afternoon I will try to get this up and running
    This will be the 1st thumb I have ever made, Or used
    Danny
     

    Attached Files:

  9. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    Done Deal Pack er up Thumb Is Done

    Hey guys, I had time to work on the thumb, and finish It off:notworthy
    Enough of this welding:bash, I want to get diggin.
    I had It all tacked up, plumbed In the hydraulics, and the swing looked good to me
    It took me maybe 20 mins tops to weld every thing, what took all the time was tons of measuring, and I lost my tape many times:beatsme
    I just took It out of the shop, and pedaled the jaws back and forth, all seems to be working ok......Thanks for your Input, I'm done with the sparks for a while, I just want to see dirt

    Danny
     

    Attached Files:

  10. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    Ok I'm looking for something to grab with It now.

    One concern I do have Is, I dont know If there Is a relief valve In that line,
    I think that part I will leave to the dealer, and at the same time I wonder If they can tweak up my bucket pressure
     

    Attached Files:

  11. cps

    cps Senior Member

    Joined:
    Jul 13, 2008
    Messages:
    809
    Occupation:
    plant mechanic
    Location:
    Ireland
    Great job there Danny!! And a great looking well equipted shop you have there too!!
     
  12. joispoi

    joispoi Senior Member

    Joined:
    Mar 1, 2008
    Messages:
    1,284
    Location:
    Connecticut
    Looks good!
     
  13. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    Thanks guys, Its working real good for me.

    Cheers
     
  14. AirBornOne

    AirBornOne Well-Known Member

    Joined:
    Oct 17, 2008
    Messages:
    146
    Location:
    S.F.Bay Area
    Yowza Danny!
    A tree spade attachment in March then a thumb in April!Can't wait to see what you come up with in May.I've been thinking of a plate compactor (hint hint) myself.
    I do have a question about welding on the stick though...
    Hendrik pointed out not to weld across the stick.Is this a welding/heat issue or a problem with the stress distribution?
    The reason I ask is my little TB016 has a plate added on at the end of the stick.Looks like it took a beating too!
    Thanks for the info.
    Jay.
     

    Attached Files:

  15. AirBornOne

    AirBornOne Well-Known Member

    Joined:
    Oct 17, 2008
    Messages:
    146
    Location:
    S.F.Bay Area
    ...And speaking of questions,
    While I was checking over the stick I noticed the Y-link pins look to be setup to rotate while the bucket pins are static.What's the purpose with this arrangement?
    Thanks again
    Jay.
     

    Attached Files:

  16. Hendrik

    Hendrik Senior Member

    Joined:
    Mar 6, 2009
    Messages:
    1,232
    Location:
    Adelaide South Australia
    Not sure what you mean by the Y pins rotating, from the pictures I see all the pins are locked.
    Far as welding across the stick, it's a no no because you change the metal with heat and create a failure spot.
    A pro welder can probably explain this a bit better.
     
  17. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    That's the reason I welded 2 ears on the stick, and Not a plate with 2 ears attached

    But also adding a rectangular plate like you have shown to the stick, Is not the greatest thing even If you dont weld perpendicular with the stick because water and dirt will get trapped In there and could freeze and split.

    Plain and simply said, It becomes a week area because of the heat affected zone, after welding Is done.
    If Its a harder steel, then the stress would become greater.......example If you have a mild steel pin and welded a washer on the center of the pin, then put It In the shop press, It would most likely bend, If you did the same to a hard pin Like 4140
    It will break by the weld very quickly.
    Any extras welded to a stick or a boom etc, really should have a drawing stamped by a enginerr:drinkup
    Normally from experience, If theres a plate to be fully welded to a stick for example,
    the top and the bottom are cut on a angle, and dont go to a point.
     
  18. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    I found out that I dont have a releif valve In the lines going to the thumb......I put the squeeze to a pipe a bit too hard, and 1 hose blew..Called the dealer just out side of town, and there going to Install one for me back near the pump.

    Good time to get them to give me a bit more psi on the bucket and the stick........I will see what they have to say about that.

    Danny
     
  19. AirBornOne

    AirBornOne Well-Known Member

    Joined:
    Oct 17, 2008
    Messages:
    146
    Location:
    S.F.Bay Area
    ...And what happened to the pipe Danny?
    Will this be a relief valve on both lines to the thumb?
    Don't wanna hijack your thread,but given the quality of the weld,is it possible this is a factory plate?
    I certainly don't like the idea of water & dirt getting trapped.Freezing here is a not a worry.
    As to the rotating pins,when I first looked these over it appeared the link pins, being locked to the link, would have the pins rotating in the stick bushing each time the links moved.
    I guess they would have to wouldn't they, the same on the buckets too.
    Thanks Danny,Hendrik.
    Jay.
     
  20. Danny Steel

    Danny Steel Well-Known Member

    Joined:
    Jun 12, 2010
    Messages:
    187
    Occupation:
    Farmer/Landscaper/Welder/Fitter
    Location:
    NW Ontario
    I was just a old junk pc of pipe I picked up, and I forgot about being carfull with the thumb, untill I had the pros check to see If there was a relief valve In there.
    Just the water and crap getting Into open ares like that, can start to rust out......not good on the stick, or the boom, It may have been factory, but I have my douts...i wouldnt wory too much about It though, There not a heck of alot of load there