Drilling for resin anchor bolts

  1. howardm

    howardm Yorkshireman in exile

    Posts: 197
    I need to drill a total of 26, 25 diameter holes in my Reinforced concrete base for resin anchor bolts..

    Is there a machine I can hire to do this.?
    Like a Mag-Drill but with 8 inches of travel.
    I don't want it wandering if it should hit the reinforcement.

    I can't do it with a hammer drill as I pulled a bicep muscle 3 weeks ago, healing very slowly.

  2. dan.taylor.1

    dan.taylor.1 General Tinkererer

    Diamond core drill from the likes of Hilti would do it, SDS would, but if you hit the rebar it might not like it?

    Was the base new or existing, if its new I'd have made sure there were studs stuck in the right place as I poured it but hindsight is a wonderful thing!

  3. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    The only thing that will go through Rebar is a diamond core drill. Not worth it for 25mm holes IMO. If you hit bar just angle the drill. Hilti drills are the best tool for this type of work: slow but have a LOT of torque. So make sure you have the extra handle fitted and brace it against your leg. Let the drill do the work, if you hit a bar you should feel it before it grabs.
  4. brightspark

    brightspark Member

    Posts: 13,314
    yarm teeside
    i have a 1200w metabo sds drill for core cutting up to 4inch .any powerfull decent drill will have a clutch fitted
  5. Welderpaul

    Welderpaul Moderator Staff Member

    Posts: 10,595
    A core drill will do it, but is an expensive way of doing it. Strictly speaking you should not drill holes for resin with a core drill as it gives a smooth bore. They should be persussion drilled to give the resin something to grab onto.

    We have various Hilti TE*** drills that would do that no bother. Their drill bits will go through rebar without too many troubles. They do special SDS drill bits designed for going through rebar.
    Do you not have anyone who can ride the drill for you? The missus?....:laughing:

    I bet i can guess what these holes are for....;)

    Through bolts (expanding anchors) are much quicker than resin as long as your edge distances are within 150mm or so
  6. Hitch

    Hitch Moderator Staff Member

    Posts: 10,494
    That size hole, get the bits with 4 cutting tips, much better on rebar, and don't tend to jam anywhere near as much.

    We did a test rig thing a while ago, lots of 25/26mm 300 deep into hard reinforced concrete without to much bother.

    You know when you hit the rebar, but take it steady, goes on through.

    You can get rebar cutting bits, never used them myself though, not sure how good they are.
  7. brokenbiker Spark that makes sparks

    Posts: 6,041
    Llanbobyll, south wales
    we used to used an sds drill in work to cut 18mm holes 500mm deep into reinforced.

    you could tell when you hit the rebar but the weight of the drill took it through slowly.
  8. Pete.

    Pete. Member

    Posts: 2,966
    Kent, UK
    It's a commonly-held misconception, but the truth is that resin into diamond drilled holes holds just fine. The bond is made at the microscopic level. I never yet saw a bolt fail pull-out because of the hole being diamond-drilled though I've snapped a few.
  9. howardm

    howardm Yorkshireman in exile

    Posts: 197
    Thanks folks,
    I can forsee more torn muscles from this project.

    Expanding bolts frighten me Paul, after seeing what they can do to concrete.

    I was hoping for a pillar drill with a concrete magnet.........just have to invent one ;-)
  10. edd Member

    You can get core drills with vacuum pads for holding the base, i can't imagine they are cheap to hire though!
  11. MattF Member

    Posts: 4,703
    South Yorkshire, England
    Any reason you can't just use a bench drill press, (the type where you can clamp an ordinary drill in there), and just swivel the holder around the column so that you're drilling down 180 degrees away from the base? You'd have lever operation and the base stuck out at the rear on which to apply weight/pressure, that way, and you could whack any half decent drill in there for the task.
  12. edd Member

    There you go


    Depends on how much you don't want to hurt those arms!

    As said by others it wouldn't take long or be very difficult to drill them with a good hilti drill and bit.
    There are only 26 holes, half a day would do it.
  13. howardm

    howardm Yorkshireman in exile

    Posts: 197
    OK, I see problems ahead.
    My O.C.D. fighting my Yorkshire impecuniousness.
  14. MattF Member

    Posts: 4,703
    South Yorkshire, England
    Being tight ain't half of it. Have they gold plated those beggars, wanting that much per day? :D
  15. Pete.

    Pete. Member

    Posts: 2,966
    Kent, UK
    What is it you have seen them do?
  16. madkayaker

    madkayaker Pro sparkey Pro Welder

    Posts: 13,725
    you can split a concrete slab with expanding bolts if you have to many and get carried away with the spanner
  17. Pete.

    Pete. Member

    Posts: 2,966
    Kent, UK
    Rubbish. My concrete splitter generates 165tons of splitting force. I have burst the edge of a slab by fitting a M12 rawl anchor right close - like 10mm from the edge, but I challenge anyone to come up with some evidence of concrete bursting via expanding threaded fixtures.
  18. Welderpaul

    Welderpaul Moderator Staff Member

    Posts: 10,595
    Have a look in the back of the Hilti catalogue some time, there is a good drawing showing how the forces from an expanding anchor work in a concrete slab. Basically like an tiny inverted cone centred on the fixing.

    I've put them in within 100mm of a slab edge and as long as the concrete is good it won't blow it.

    Thats some machine Pete. Run any Brokks?
  19. Pete.

    Pete. Member

    Posts: 2,966
    Kent, UK
    Got three Brokks going right now and another on the way shortly. 550tons of concrete to get out without using a breaker.
    Actually using the bigger C12 burster right now which is rated at 321tonnes effective splitting force, a pair of 180 Brokks with cc450 crunchers and a 150 with shears to cut the rebar.

    This is the biggest set of crunching jaws fitted to a Brokk. Pic from about 2002, nowadays we use the built-in intensifier models with renewable tips but we still got these brutes for when a bit of bully is needed.
    • peteatwork.jpg
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