Ok - question about core drilling masonry.

[kctyphoon]

I have plenty of experience with rotary hammers, but not with really big holes for conduit and sleeves.. watched a few vids and can't really find a definite answer.

Obviously with BIG core drills and those bits, like wet drilling, there is no hammer function being used. My question is for say, drilling a 2 or 3 inch hole with an sds plus dry core bit, from say Bosch or Milwaukee. Once the hole is started and say you want to, or remove the pilot bit from the core bit - are you or are you not suppose to use the hammer function drilling through say an 8" thick brick wall? Seems like people are doing both, and I'd like to know if using the hammer function on the dry core bit is a bad thing for the bit?

 

[manwithtools]

Hammer drilling with an SDS with a 2" diameter bit works fine for me. The hard part is keeping it straight thru a CMU. They have limited depth capability, so remember to withdraw and clean the SDS hole saw if you are going through a solid wall.

 

[Al Borland]

Do not hammer a core bit. it has diamond grit in the edge for cutting. The teeth will break off and it can not core thru one of it's own broken off teeth trapped in the hole.

 

[signcrafter]

You DO NOT hammer drill with a core bit. Rotation only. They have teeth on them to do the cutting and hammering can damage them.

A couple years back I bought a cheap core drill off ebay and love it. It has the bigger 1 1/4" screw on bits and is water cooled. I've used it a bunch drilling up to 4.5" cores and it does great. I can't justify a hilti or other nice core drill for the couple times I use it a year. I didn't want to do dry core bits with SDS because it's harder and also they can only drill in a couple inches before you have to take the bit out and break the core off and pull it out and keep going. I needed to drill through 8" slab and didn't want to deal with that.

So not sure what you're using it for but it's another option to look into.

https://www.ebay.com/itm/4-Z-1-CORE...161510&hash=item284cad19b8:g:HQEAAMXQ4uJSDTJn

 

[manwithtools]

Do not hammer a core bit. it has diamond grit in the edge for cutting. The teeth will break off and it can not core thru one of it's own broken off teeth trapped in the hole.

Disagree, SDS rated core bits don't have diamond grit, they have carbide teeth and designed to be used with a SDS hammer drill.

 

[KnurledNut]

Carbide core bits are designed for concrete with the use of a rotary hammer drill SDS-Plus, SDS-Max or Spline.
Unlike diamond core bits which require a special core drill, carbide core bits are meant to be used in hammer mode which hit and breaks up concrete while it drills.
Carbide bits can be a little more aggressive because of this hammer action so blow out on the back side can be more common. Carbide bits can be run dry unlike diamond core bits which are best used with a flow of water.
Some metal or rebar can be handled with carbide bits but will dull the bits much faster so best to avoid any metal if possible.

 

[Rc_Guy]

There are other dry core bits that we drill through an 8" or 10" concrete block and you don't have to stop and empty the bit I til you are done.

They run of what looks kinda like a right angle drill except no chuck, probably a grinder or buffer motor.

I have wet cored holes so thick I have needed a couple 10" or 12" extensions, as big as a 10" hole you don't have to stop and empty the bit I til you are done.

The job I'm on now we will wet core four 5" holes, and about a dozen 4" holes.

Here is a pic of a dry core bit like we have used, we don't dry core much anymore because of the dust.

 

[dutchgray]

We have dry diamond cored through a 3' stone wall before at work, took the best part of a day per hole, not something you would want to do often. Your normal block wall is easy with dry diamond and a hand drill up to about 6" provided you have the right rpm and clear the dust often. If its something you do all the time you would have a proper wet core rig, but since we are only drilling out for fan vents and pipes its not worth the cost.

 

[kctyphoon]

The bits I just picked up are Bosch and Milwaukee 2 9/16" dry core bits with carbide teeth. The Milwaukee pilot extensions have a removable pilot bit, the Bosch does not. The bits are very shallow, not a long sleeve like you'd use on a true core drill with a water set up.

I mean - it LOOKS as if using the hammer function would be fine with the aggressive teeth, but honestly I can't find info on that where I've looked. Also drilling an 8" wall would require a few passes. So I'm figuring I'd have to drill as far as the bit, break off the core stuck in the wall, and then continue.

I had to drill a 2.5" hole through 8" of brick the other day with a 3/8" bit. Obviously I don't wanna do that again, so I picked up a few core bits (wasn't even aware they were made for sds plus) so I'd like to not damage the bits or look like an idiot using them the wrong way.

For clarity, these are the type of bits
https://www.homedepot.com/p/Milwauk...DS-Plus-Masonry-Core-Bit-48-20-5230/300728278

 

[Rc_Guy]

Finally got around to core drilling the holes on the job I’m on. We drilled a 5” and a 3” hole on the landing of each floor 1st through 4th floor and the landing on the roof access for fire standpipe and drain pipe.

Then we drilled eight 5” holes for a test header and fire department connection (4 holes for each one) and a 3” hope for the 2” drain.

 

[Dagny]

Rebar is not your friend.

 

[Al Borland]

Wet cut with a core drill setup will go thru rebar and barely slow down. It will merrily go thru buried conduit and try to kill you. (Know where those are before you drill)
It will even cut thru I-Beams that are inside the concrete. Only thing that I ever cored that really messed up the bits fast was lead sheets inside the floors. It kinda melts to the bit and clogs the teeth.

 

[Rc_Guy]

Wet cut with a core drill setup will go thru rebar and barely slow down. It will merrily go thru buried conduit and try to kill you. (Know where those are before you drill)
It will even cut thru I-Beams that are inside the concrete. Only thing that I ever cored that really messed up the bits fast was lead sheets inside the floors. It kinda melts to the bit and clogs the teeth.

Correct, the eight 5" holes all had rebar crossing them as well as running the same way the core bit was going.

The eight 5" holes and one 3" hole took about 10-11 hours to drill but we could not and did not get any water on the floor, it was all caught in a bucket, the wall was covered in mineral wool insulation other than where the insulator cut out so I could core drill

 

[cdoublejj]

so there is impactive core drives and rotational core drills but, when i google and search they are all almost always a sds max shank. the largest sds plus BIT (hammer) i have is 1-1/8"

 

[danski0224]

I have plenty of experience with rotary hammers, but not with really big holes for conduit and sleeves.. watched a few vids and can't really find a definite answer.

Obviously with BIG core drills and those bits, like wet drilling, there is no hammer function being used. My question is for say, drilling a 2 or 3 inch hole with an sds plus dry core bit, from say Bosch or Milwaukee. Once the hole is started and say you want to, or remove the pilot bit from the core bit - are you or are you not suppose to use the hammer function drilling through say an 8" thick brick wall? Seems like people are doing both, and I'd like to know if using the hammer function on the dry core bit is a bad thing for the bit?

Sometimes, the pilot bit is just held in place with pressure, it needs to be removed once the hole is started.

Percussion core bits will blow out the other side of the wall, and it is exceedingly difficult to maintain a level drilling path. stuff in the masonry/concrete will push the bit around some.

In my area, there are several companies that do concrete cutting and coring, and the price isn't too bad when you consider buying tools and your time.

 

[PCustoms]

so there is impactive core drives and rotational core drills but, when i google and search they are all almost always a sds max shank. the largest sds plus BIT i have is 1-1/8"

hey everybody, let's reply to a dead thread started by a now banned user 7 years ago because of this random post!

 

[KnurledNut]

so there is impactive core drives and rotational core drills but, when i google and search they are all almost always a sds max shank. the largest sds plus BIT (hammer) i have is 1-1/8"

Is there a size you're looking for?
Bosch offers a pretty good range in SDS+.
https://www.boschtools.com/us/en/sds-plus®-speedcore-thin-wall-core-bits-43546-ocs-ac/
https://www.amazon.com/Bosch-T3919SC-SDS-plus-SPEEDCORE-Thin-wall/dp/B00EMFONL6?tag=atomicindus08-20

 

[cdoublejj]

hey everybody, let's reply to a dead thread started by a now banned user 7 years ago because of this random post!

Hey man yah gotta stop being so smart that certain subjects bump your forum to the top google results for being the only place left on the net with the collective smarts ;-)

Is there a size you're looking for?
Bosch offers a pretty good range in SDS+.
https://www.boschtools.com/us/en/sds-plus®-speedcore-thin-wall-core-bits-43546-ocs-ac/
https://www.amazon.com/Bosch-T3919SC-SDS-plus-SPEEDCORE-Thin-wall/dp/B00EMFONL6?tag=atomicindus08-20

Heeellll yeah it is!!! Amazon search *****! Next I'll skip amazon searching up on KnurlNet!


Its true though precussive pops and leavs poc marksmy hammer has drill only so I ought to look for drill/diamond cut type as well but for the price I seen so a 2"-3" range ones that look perfect for conduit. Thanks guys!!