Counter sunk disc bolts

Discussion in 'Competition Ploughing' started by spindle, Feb 11, 2018.

  1. spindle

    spindle Member

    Location:
    Hertford
    Looking for some advice on size of counter sunk screws to replace the disc rivets on a Ransome's disc as I can only seem to get hold of 10mm thread size and the rivets that come out measure 11mm, I know they would have been imperial size but wondering if anyone has used a slightly smaller size and if they stay tight when done up as I was hoping the counter sinking on the disc will hold it all centrally allong with the axel hub :scratchhead:?
     
  2. Howard150

    Howard150 Member

    Location:
    Yorkshire
    Nearly certain M8 are on mine. Make sure they are at least 10.9 (HT grade - not diameter) Might need to sharpen a masonry bit as you would an ordinary drill bit to countersink them though - unless you can get a carbide countersink. Disc should centre on the hub and bolts should pretty much self centre in the holes.
    Lot easier than riveting. If you do decide to rivet with countersink rivets then locate the disc with bolts first. put all there rivets in the take one out and bolt it up tight. Then take another out and boltit up tight the same. Rivet the remaining one but whatever you do don’t use any heat whatsoever or you will distort the disc - even if you warm the rivet out of the hole. Best to be shy with the countersink then sand the proud bit off the top. Use a proper rivet snap to form the head on the boss.
    Bolting is a lot easier. Trust me. Just in passing original rivets would probably have been 3/8”
     
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  3. spindle

    spindle Member

    Location:
    Hertford
    Thanks for that advice Howard much appreciated, I learnt the hard way a year or so ago with the heat on the disc so I will do it the way you have said , I done a trail one last week very much like you have said but will have to get the counter sinking a bit more accurate I some large masonry drills I will try out (y)
     
  4. Howard150

    Howard150 Member

    Location:
    Yorkshire
    Forgot to say earlier that the countersink depth on an M10 is deeper than the thickness of the disc which means the boss would need to be counterbored.

    Never had an M8 come loose and had them for years. Benefit is you can put the skimmer wherever you want and also soil does not build up around the centre of the disc.
     
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  5. spindle

    spindle Member

    Location:
    Hertford
    I have just brought some new skimer arms and the skimer's will travel the full length of the disc so like you say you don't want the soil building up around the centre of the disc
     
    Last edited: Feb 12, 2018
    Howard150 likes this.
  6. arcobob

    arcobob Member

    Location:
    Norfolk
    I use M10 bolts but you are right, you have to counterbore the hub. I use an M20 carbide masonry drill bit appropriately sharpened to cut 60 degrees. I also skim the hub on a lathe to clean it and make sure it is true.
     
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  7. spindle

    spindle Member

    Location:
    Hertford
    I did wonder about using a abrasive grinding peg similar to the Dremel ones but I have some industrial type pegs or sticks don't know what they are called, and grinding the counter sinking in so long as they are at 60 Deg ?
     
  8. Howard150

    Howard150 Member

    Location:
    Yorkshire
    Don’t lose sight of the fact that if you put the skimmers too far forward in very hard ground which incorporates a lot of stone then there is always the risk that you will rip them off - especially if the arms are mild steel. A few years ago I pulled one off at Southwell ploughing match due to a combination of hard ground and windrows of fist sized cobbles after a destoner - an arm made of EN8
     
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  9. spindle

    spindle Member

    Location:
    Hertford
    That was something that crossed my mind I was thinking of of hard packed tramlines so will have to watch out for that (y)
     
  10. Howard150

    Howard150 Member

    Location:
    Yorkshire
    Getting technical now Kevin. If you do sharpen a masonry bit you can always check it on a piece of scrap - similarly once the angle is right you can always check the depth by inserting a bolt.
    I have some 21mm carbide countersink both 3 and 5 flute but they were £120 apiece.
    Look online for HMT Or Hole Maker Technology. They can be found at any really good plant hire firms as well. They make countersinks and broaches in HSS which we have had really good results on site and they are reasonably priced.
     
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  11. Howard150

    Howard150 Member

    Location:
    Yorkshire
    Experiment with the disc setting. Sometimes a better shine is obtained with the disc high and behind the point as opposed to low and in front of the point. Countersinking the holes in the disc allows for placing the skimmer wherever you want to give either whole or broken work.
     
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  12. arcobob

    arcobob Member

    Location:
    Norfolk
    The biggest danger to forward skimmers is when travelling too far on the ins and forcing them in too deep at a steep angle. Mild steel arms help protect other parts and they also allow the pinch bolts to bite a little. I had some high tensile arms and it was hell's own job to keep the skimmers tight.
     
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  13. Howard150

    Howard150 Member

    Location:
    Yorkshire
    Proper square headed set screws with a knurled point sort that out bob.
     
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  14. spindle

    spindle Member

    Location:
    Hertford
    :playful::playful::LOL: I wish my ploughing was as technical:woot:i need these mods to give me an edge:whistle::LOL::LOL::LOL::LOL:
     
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  15. spindle

    spindle Member

    Location:
    Hertford
    I can't remember who it was who said on here in an earlier post Bob, Harry, or yourself Howard about having the disc back enough to put pressure on the share to create pressure on the share and create shine on the furrows, it dose make sense
     
  16. Cordiale

    Cordiale Member

    I just hope it doesn't tip you over. The edge I mean.
     
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  17. Howard150

    Howard150 Member

    Location:
    Yorkshire
    Most countersinks have a 90degree point. In an ideal world then the major diameter of the countersink should be just slightly more than the OD of the bolt head - that way you can counterbore the countersink which means that the bolt head sits flush and you don’t have a sloping shoulder left round the bolt head. Somewhere else for soil to gather
     
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  18. spindle

    spindle Member

    Location:
    Hertford
    I found a counter sink yesterday but the the major diameter was smaller than the heads so will probably purchase a new one i recon Cordial will want his discs doing as well when he sees them(y):LOL::LOL::LOL:
     
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  19. arcobob

    arcobob Member

    Location:
    Norfolk
    Pressure on the board should be firm and uniform from front to back. This is enhanced by a slightly backward and shallower disc. The board creates the shine and must do the work so don`t break everything up before it gets its chance.
     
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  20. I disagree on this,its the share that put the shine on the work, not the board,
    but it needs a good clean board to keep the shine on the furrow,
    as regards to pushing the board out to get more pressure, only works the first time around, after that the furrow bottom is wider, and you can only fill the gap, not get any more pressure is available,
    in order to keep the furrow more in one bit, its best to pull the board back as far as you can, but still leave room for the tractor wheel, the less angle of exit from the end of the board will leave the furrow more in 1 bit, the bigger the angle the more shattered the furrow slice will be,

    think of it like painting, and think or the board as the thinners, the share, disc and skimmer are the paint,
    if the have crap paint it will never look good,
    and the thinners are only a way of transporting the paint to a finished surface,
    cheap thinners with good paint will look better, than cheap paint and good thinners,
    as long as the board does not stick with soil, then its good enough to win with,

    90% of the work is done with the point, disc and skim,

    cut it out badly, you cannot polish a turd
     
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