I frequently have a reason to drill hard rock. I have never succeeded.

I have a half inch milwaukee rotary style hammer drill.  Is there a bit I can use to drill rock for fastening screws? 3/16 size holes.

I'm told the drill I have is insufficient that I need a hilti style hammer drill. but I don't have a Hilti.

Edited November 19, 20178 yr by Ron Dudelston
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I see they make both drills and drill bits. Can't imagine one type of hammer drill can be that much different than another except maybe for the "horse power". Their bits have carbide brazed tips. Maybe that's the difference. I've drilled some pretty old, hard concrete with Big Box bits. Took a while and wore out the bit. Lots of stone in the mixture. I was using about the same size bits (1/4").

for stone...

use better made bits and coolant...

1 hour ago, Stick486 said:

better made bits and coolan

brand recommendations?

'Way back when, we used 1" star bits and a 3 1/2 lb. hammer to drill into granite. It took about 4 hours to get the hole deep enough, but when the fuse burnt down, it was all worth it!

John

since you didn't say where the rock is or what you were drilling less try cover most everything...

 

FWIW.. I live on one massive rock... granite and more granite... everywhere more granite... the granite has granite..

as for bits, USA, German, Swiss, Austrian, Canadian, New Zealand...

VOE says they cost less than chinese bits..

I think the brazing on the chinese bits leaves a lot to be desired,,

I also think their carbide is too soft and detest being used in a hammer drill and do not take kindly to heat at all...

also make sure the bit is hammer drill/percussion and stone rated...

make  up something like this for flats... works premium for drilling granite counter tops...

 

mold  plumber’s putty around the cap, that will hold it in place AND it will to form a dam around the cap.....
partially fill the bottle cap with oil/coolant/tapping fluid...

drill through the cap...

as you drill cycle the drilling... drill a little bit, raise the bit  for a bit and repeat this cycle as often as required in 5~10 second cycles...

if you are through drilling have something to catch the coolant when the bit breaks through be it a cup or a towel...

towels are cool when the bit grabs it... this is something to think about...

 

for wall drilling...

put a towel under where you are drilling to catch liquids and slurry... have somebody apply your coolant w/ a spray bottle in stream mode...

no need to flood the drilling here just keep up a supply of coolant...

 

inverted drilling....

cycle drill dry....

 

outdoors and a mess isn't an issue...

run a flow of water from a garden hose to the hole...

Edited October 29, 20178 yr by Stick486

7 minutes ago, HARO50 said:

'Way back when, we used 1" star bits and a 3 1/2 lb. hammer to drill into granite. It took about 4 hours to get the hole deep enough, but when the fuse burnt down, it was all worth it!

John

 

core bits and a demo class hammer drill will give you more holes faster which means more fuses...

we gonna do this..

we're gonna make it worth it....

NOTE:

if you use oil you need to clean up like right away...

use brake cleaner and then dish soap w/ a lot of scrubbing action...

you don't want the oil soaking into the stone's pores and staining it....

that just may not be the look you are looking for...

On 10/29/2017 at 7:38 PM, Stick486 said:

since you didn't say where the rock is or what you were drilling less try cover most everything...

Yah   context sometimes is as  important as everything else.  My house foundation is made up of mortared stone about 2 or 3 feet thick.  When a joint isn't convenient as in almost any Cartesian lay out  or the joints are not drillable because they are not flat like a  brick masonry joint I end up faded with less than optimal options.  Drilling into those honkin' hard stones, many the size of my torso would be a nicer option.

 

On 10/29/2017 at 3:47 PM, lew said:

Can't imagine one type of hammer drill can be that much different than another except maybe for the "horse power".

oh they are very  very different. The energy delivered to the impact is   enormously different. That's why a Hilti is so expend-o-licious.   The  cheap hammer drill   hasn't got a genuine  hammering action it's more like a rumple disk.

I learn something new everyday!

1 hour ago, Cliff said:

oh they are very  very different. The energy delivered to the impact is   enormously different. That's why a Hilti is so expend-o-licious.   The  cheap hammer drill   hasn't got a genuine  hammering action it's more like a rumple disk.

 

I'm real partial to the Bosch Bulldog in SDS+, one inch and larger...

I have Hilti... I like the the Bosch way better...

but their (Bosch) pistol grip style is a waste of money..

entry level...

Factory Reconditioned Bosch RH228VC-RT 1 in. SDS-Plus Bulldog Rotary Hammer

now we're getting serious...

Factory Reconditioned Bosch RH432VCQ-RT 1-1/4 in. SDS-Plus Quick-Change Rotary Hammer

Edited November 4, 20178 yr by Stick486

1 hour ago, Cliff said:

Yah   context sometimes is as  important as everything else.  My house foundation is made up of mortared stone about 2 or 3 feet thick.  When a joint isn't convenient as in almost any Cartesian lay out  or the joints are not drillable because they are not flat like a  brick masonry joint I end up faded with less than optimal options.  Drilling into those honkin' hard stones, many the size of my torso would be a nicer option.

 

 

yur in luck...

constant fine low pressure water jet/stream for lube... not spray..

garden sprayer works for this really well...

on horizontal, an easy simple water flow/bath is the ticket...

need mess control... use a wet vac to keep the overflow in check... or use the dam...

we bore/drill 5/32~ 5'' w/ hammer drills... after that to 24'' is serious core or rock drills...

 

1 hour ago, Stick486 said:

actory Reconditioned Bosch RH432VCQ-RT 1-1/4 in. SDS-Plus Quick-Change Rotary Hammer

I may have to get one. 

EDIT: GOT ONE  from that link every one is out of stock but that reseller thanks

And sourcing better drills hasn't fallen in my  lap yet.  It won't be the BORG I can tell ya that.  

 

Edited November 4, 20178 yr by Cliff

57 minutes ago, Cliff said:

And sourcing better drills hasn't fallen in my  lap yet.

 

see Alfa Tools 

Their catalog...

you get what you want from your specified country of manufacture...

another company to talk to...                      this one is finest kind..

you get what you want from your specified country of manufacture too/also and the sales reps really know their stuff and aren't on commission.....

their catalog...

I really like both companies and they get a lot of my business...

Travers has fair prices and outstanding CS/TS... very good place to go to even if you don't have a clue as to what you want/need..

they have a whole department of problem solvers...

 

58 minutes ago, Cliff said:

It won't be the BORG I can tell ya that.  

 

Lowes carries some Bosch bits/tooling made in Europe...

same for HD..

stay away from -

DeWalt..

Hitachi..

Tapcon..

Chinese..

Irwin..

Makita..

Morris.. (iffy)...

 

 

some more to consider...

15GENSec.F.pdf

Driltec_23_2013_catalog.pdf

ROCKHARD.pdf

13 hours ago, Cliff said:

I may have to get one.

 

You can rent one possibly at HD or Lowes and try it.

16 hours ago, Stick486 said:

this one is finest kind..

Thanks,  I ordered a couple of Reltons and the Bosch  from CPO

 

got the bosch today.   Gosh golly that thing  delivers.  holes in hard stone are easy.

which one did you get???

On 11/8/2017 at 8:01 PM, Stick486 said:

which one did you get???

The  RH432VCQ-RT

It's a beast