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Drilling out bolt hole on blade?

Discussion in 'Mechanic and Repair' started by justgeorge, Aug 14, 2012.

  1. justgeorge

    justgeorge LawnSite Senior Member
    Messages: 353

    I just went from a Turf Tracer HP to a Turf Tracer S Series and the new mower takes a different blade, the bolt hole is 15/16" instead of the 5/8" on the old mower. I've got a lot of sets of blades, I have a guy that does an AWESOME job sharpening them for me (for only $4/blade!) and I can drop off 5-7 sets of blades once a month or so.

    So, I found a 15/16" drill bit on Amazon for $10; I have a drill press; would simply drilling out the holes work? Would a $10 bit last to drill 18 holes?

    Anyone ever tried it? I did a search and didn't get any hits.

  2. orangemower

    orangemower LawnSite Silver Member
    from pa
    Messages: 2,768

    I'd say as long as you have a drill press it would be ok. I think the problem you'll run into is the bit won't last to drill all the holes. Blades are much harder material then a piece of angle iron. If you CAN drill them out, you can balance the blade after you're finished drilling the holes. If the hole in the blade gets opened up too much you'll never get it to balance out and will most likely cause vibration. Sure it will balance if you use a balancer tool but once you bolt it on the mower, it's might not tighten up dead center, hence never being balanced.
  3. Kelly's Landscaping

    Kelly's Landscaping LawnSite Platinum Member
    Messages: 4,657

    What is the drill bit made out of? HS is high speed steel and that would be the bare minimum for this job. Colbalt Would be ideal only you aren't gonna find one that size for no 10 dollars. Carbide is the best but they are very brittle and I wouldn't recommend them Iv broken one just tightening up the chuck once. There is a lot of them with coatings but make sure it says HS or Colbalt under that coating. They make steel drills that are meant for wood and stuff like that and if you get one of them you may not make the first hole. Also the holes need to be perfect so this needs to be done by a drill press or drilled in a milling machine like a bridgeport do not do this with a hand drill.
  4. Kelly's Landscaping

    Kelly's Landscaping LawnSite Platinum Member
    Messages: 4,657

    Do this get a 3/4 drill bit and a 15/16 drill bit in HS place the blade on the press and have a 5/8s bit in the chuck. Now lower the chuck when its not on and insert into the hole so you now have the chuck centered. Clamp the blade down tight this will have a lot of pressure to break lose when you start. Then put in the 3/4s bit drill out the hole then the 15/16s to enlarge it further you don't want to be drilling that much out in one shot also have oil preferably cutting oil but motor oil will do and keep adding as you drill so you don't burn your drill.
  5. pugs

    pugs LawnSite Gold Member
    Messages: 3,024

    I would recommend buying new blades.

    It would be nice if Toro/Exmark would stick to one blade hole size like the rest of the world.
  6. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Kelly's Landscaping,

    Have you ever done this to a blade with a drill press ?
  7. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,279

    I didn't realize anybody used a bolt hole size of 15/16". That is the nut size right?
  8. jsslawncare

    jsslawncare LawnSite Bronze Member
    Messages: 1,673

    I see the bit catching the blade, spinning it around until it hits the drill press after cutting his fingers off. Buy new blades. 10 sets of blades are cheaper then one ER visit.
  9. justgeorge

    justgeorge LawnSite Senior Member
    Messages: 353

    Thanks for the replies guys, I bought new blades this afternoon. I figure I save on one round of sharpening, and if I can sell the old blades for a few bucks apiece then the new ones only cost me a few bucks a blade net cost.

    BTW, the bolts are not 15/16", Exmark now has the bolt go thru a splined sleeve that is 15/16". The actual blade bolt itself is smaller than on the old model.

    Of course they also changed how you tighten the bolts, the old model had two flat spots on the spindle where you put a 1 1/16" open end wrench to hold it. Now I need a 1 1/4" socket on a nut on the top side, and of course now I have to take off the deck cover to get to the middle nut.

    But man the new mower sure mulches nice! Slightly bigger engine, who knows what changes they made to the mower deck, but it definately mulches better than the old machine.
  10. Lbilawncare

    Lbilawncare LawnSite Bronze Member
    Messages: 1,116

    For future reference, if you have a hole you want to enlarge, use a step bit. They won't grab like a regular bit will and they cut steel really well. I use step bits for all holes drilled in steel, first using a small pilot bit.

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