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Hammer Drill Question

Spring ChickenSpring Chicken Posts: 10,247
edited 5:42AM in Off Topic
It quickly became obvious that my 19.5v Porter Cable (woodworking) drill and some basic masonary bits was not going to drill 3 half inch holes through a 2" slab of Colorado Red flagstone, even with the full force of my weight behind the drill.

So I Googled for answers and was told I would need two things: a carbide tipped drill bit and a hammer-drill, or diamond core drill.

So I looked at renting a hammer drill vs just buying one. $48 for a day's rental. But at Lowe's I can purchase almost the same hammer drill for $59 so I'm leaning toward buying instead of renting.

I've never drilled into stone before, only concrete and brick. Any advice would be helpful.

Spring "Holes Drilled Expensively" Chicken
Spring Texas USA


  • triehle98triehle98 Posts: 208
    If it were me , i would buy the hammer drill and also purchase a bosch brand masonry bit , just remember to pour some water in the hole while you are drilling to keep the bit cool. depending on how many holes you have to drill I would say that one bit will last for about 4 holes . also keep a medium speed , that will keep the bit meltage to a minimum.
    Good Luck

  • Spring ChickenSpring Chicken Posts: 10,247
    Now that would be a photo for the Egg Album. Probably make Lily Large look like she had curlers on her head LOL.

    Spring "Don't Be Confusing The Recipe With Exactness" Chicken
  • KokemanKokeman Posts: 819
    Buy one, you can never have to many toys.
    Take it slow when starting so it doesn't jump around on you. Be careful flagstone has a tendency to crack while drilling.
  • Spring ChickenSpring Chicken Posts: 10,247
    Yes, the water sounds like a good idea. Lowe's has a pack of 5 half-inch carbide tipped bits for about $15 and a 7 amp hammer drill for $59.

    Now where is my Lowe's 10% off Project Card?

    Looks like I need the entire package and a cup of water.


    Spring "Think It Through And Buy It Right And Do The Job One Time" Chicken
  • Spring ChickenSpring Chicken Posts: 10,247
    Thanks. Yes, I started the holes with a carbide 3/16" bit to keep it from drifting around. I should be able to stay right on target.

    As for breaking the stone, that's what I was worrying about because of the intense weight/pressure I was putting behind it. One hole is very close to the edge of the stone. If it cracks I'll have to dig it out and use morter in it.

    Spring "Drills And Stones Are Wearing Out My Bones" Chicken
  • Little StevenLittle Steven Posts: 28,817

    I don't know what flgstone is like for cracking but you might be wise to start with a 3/16" carbide, then 1/4" then 3/8 and finish with 1/2".



    Caledon, ON


  • KokemanKokeman Posts: 819
    With the hammer drill you will not have to put that much pressure to drill it. If they are already in the ground that is better. The dirt will cushion the stone.
  • RRPRRP Posts: 22,058
    Leroy, whoa! backup a second...why are you needing holes in your flagstone? (curious guys wonder out loud!)
    L, M, S, &  Mini
    And oh yes...also a 17" BlackStone gas fired griddle! 
    Dunlap, IL
    Re- gasketing AMERICA one yard at a time!
  • fishlessmanfishlessman Posts: 23,020
    thinking a hammer drill will bust fladstone up, i would try that diamond core bit on your regular drill first. now is the rental the exact same drill, my hammer drills were more like 300 plus 10/15 years back. been breaking giant granite boulders with wedge and feathers in the basement for a few years now, someday it will be deep enough to put a floor in, maybe bar and pooltable, well atleast thats what i tell myself while busting them up :laugh: amazing what you can breal with those little wedges
  • Spring ChickenSpring Chicken Posts: 10,247
    Yes, I agree. I have a 3/16" carbide bit which I will use first. Then I'll try my non-carbide up to 3/8" followed by the 1/2".

    But I may have already worn out the smaller bits.

    Spring "Worn Before Starting" Chicken
  • Little StevenLittle Steven Posts: 28,817

    You will ruin a jobber bit pretty quick on stone. Better to pick up the carbides.



    Caledon, ON


  • Spring ChickenSpring Chicken Posts: 10,247
    Back when I did the first of the flagstone project I ran some electrical conduit and a raised plug near where I had a koi pond. I used it to run the various pumps and filters. The pond is gone and is now covered over with flagstone.

    Rather than pull the wires and cut the plug entirely I thought I would utilize it in some other way. At first I thought about just leaving it there but I kept tripping over it. So we finally decided to install a lamp post (I think they call them Garden Lamps) with the base fitting snuggly over the plug assembly. I wired it in yesterday. Looks good with some 'flicker' bulbs. Now I have to mount it to the stone.

    And you thought I was mess'n up my flagstone with another hairbrain project!!!

    Spring "Fe Fi Fo Fum, The Chicken's Work Is Never Done" Chicken
  • Spring ChickenSpring Chicken Posts: 10,247
    I went on line to a local rental place and checked out their prices. They have some really serious hammer drills but I only need one capable of drilling three half inch holes, two inches deep. Their rental price was a bit steep in my opinion so for a few bucks more I can own one that is comparabe in every way to theirs.

    Now with the Bosch carbide tipped drill bit and the use of water in the hole, I should have my project completed before the day is out, while collecting a new toy for my shop.

    Spring "There's Always Room For More Men-Toys" Chicken
  • Spring ChickenSpring Chicken Posts: 10,247
    So I've discovered.

    Spring "Worn Out Before My Time" Chicken
  • Hey there Spring Chicken... Have you decided which route you will go? I have a Bosch hammer drill and I have drilled through brick at a friends house with success. We drilled 3 3/4” holes for home theater cable routing (my friend is crazy and exhausted all interior options around a fireplace) Anyway, it went well and I didn’t damage any bricks. We did a test run with a spare brick and it crumbled to pieces, so i’m not sure how flagstone will do. You are welcome to try my drill, I have a 1/2" bit... Email if you are interested...

  • Spring ChickenSpring Chicken Posts: 10,247
    Wow, that's a much nicer one than the $69 Makita I bought. But I did buy a 1/2" Bosch carbide tipped drill bit for hammer drills to go with it.

    All I can say is flagstone is at least ten times harder than bricks and probably 25 times harder than concrete.

    Even with all that it still took me two hours to drill three 1/2" holes only 2" deep.

    Thanks for the offer. I sure could have used it.

    Spring "Drilling For Hole" Chicken
  • Sounds like a bunch of work, glad to hear you got the holes drilled...

    Yeah, I had to drill a bunch of holes in a concrete slab several years back and I went through a masonry drill bit connected to my Dewalt drill in no time and it didn’t do much of anything. I had 17 more to go - I was panicking. I bought this drill and I was amazed how well it did, basically drilled the rest in less time than I spent messing around with that one hole.

    Have a good one...
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