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When getting dry cutting diamond core bits it is important that the cutting segments are laser welded. The silver brazed ones cannot take the heat, especially at high RPM is using a angle grinder or anything that runs at over 1000 RPM. The dry cutting core bits are designed for soft materials like concrete block and brick. For green or reinforced concrete you need a wet core bit. There is a new brand we have been using from Blue Boar (at www.holepro.com) that includes sizes of 2-5/8" and 3-5/8" and cut to a depth of 10" which works more than 90% of the time. They use a standard 5/8"-11 thread so any angle grinder will work and most adapters for SDS drills. With their low cost I figure a per hole cost of around $3.

Originally Posted by flange

I own both the dry core rig, and a wet core rig. For anything from one to four inch my guys love the dry core rig.

Same here. The guys love the dry core. It makes a much nicer hole than a hammer. Clean and fast.

I use Dynatech dry core drills.

www.dynatech-diamond.com

Very helpful people. I couldn't remember the name of the guy that had helped me, so last time I called I asked if I could talk to an older gentlemen in customer service. Receptionist knew who I was talking about and put me through. Good guy, good products, neat catalog.

size

small makita variable speed ive done 4-5" holes but it goes through fast

how big of a hole with your angle grinder? Is this a big grinder or a small one?

yep

angle grinder and a diamond core bit can be used wet/dry special bit
the fastest for me

I'm not understanding, are you serious?

angle grinder

I pull out my makita angle grinder and make a 5" hole in a wall in less than a minute
*most walls are block so this works most time
sometimes i do need grandpapies long masonry bit
*personal tip
whenever using any diamond bit always keep it cool always dip it in water now and then will make the job go by 10 times faster and your bit will last 15 times longer

Originally Posted by richelli

No theres no hammer action used. We have a Dewalt diamond core drill but there not cheap. We dont buy and particular brand of core but dont buy cheap ones as there arnt as many diamond in the tups so they dont cut as well. I have never used a hammer drill for cutting holes 1" and bigger. The companies I have worked for always use diamond core. Why dont you hire one for your next install and try it and see how it feels before you buy one. We just hold a hover up when were drilling to keep the dust down. I cant imagine the hammer core drill you use doesnt stick in damp walls but for dry solid walls you wont beat a dry core for speed and cleaness of cut.

I've drilled dozens of 5" holes with the hammer. It takes about 30 minutes with an 8" wall.

How long does the dry core take for a 4"?

Originally Posted by flange

I own both the dry core rig, and a wet core rig. For anything from one to four inch my guys love the dry core rig. We have a kit that a local supplier made up consists of one to four inch bits, extensions, drill motor all tucked into a neat canvas carry bag. You need to know that to start a hole, you cannot put the bit flush on the surface, but rather at an angle to starta small spot, then walk it up to hit the entire hole. Have had nothing but good luck in what we use it for. The wet machine can be cumbersome but worthwhile as well.

cool, can I get a name and number for your supplier?

I own both the dry core rig, and a wet core rig. For anything from one to four inch my guys love the dry core rig. We have a kit that a local supplier made up consists of one to four inch bits, extensions, drill motor all tucked into a neat canvas carry bag. You need to know that to start a hole, you cannot put the bit flush on the surface, but rather at an angle to starta small spot, then walk it up to hit the entire hole. Have had nothing but good luck in what we use it for. The wet machine can be cumbersome but worthwhile as well.

No theres no hammer action used. We have a Dewalt diamond core drill but there not cheap. We dont buy and particular brand of core but dont buy cheap ones as there arnt as many diamond in the tups so they dont cut as well. I have never used a hammer drill for cutting holes 1" and bigger. The companies I have worked for always use diamond core. Why dont you hire one for your next install and try it and see how it feels before you buy one. We just hold a hover up when were drilling to keep the dust down. I cant imagine the hammer core drill you use doesnt stick in damp walls but for dry solid walls you wont beat a dry core for speed and cleaness of cut.

tools

So, is it better than my rotary hammer??

There's no 'hammer" on the one you're describing right?

Is there a name brand you like?

gary

We dry core all holes bigger than 22mm. But, and I say but it can be a real pain in the butt. If the wall is dry and the brick is good we have no problem, like a knife through butter. Hit a damp patch and it sticks like mad as the damp dust jams the bit. Cobbles, pebbles, slate or anything loose dont even bother as it just rips the teeth clean off the core and they aint cheap. If its a pain we just hire a wet core drill but only good if you can make a mess. We alse have this red brick which is like cutting a dimond, it just burns the teeth off the core. So basically dry core is olny good for concrete, and good brick. Good thing is if you hit a steel rod or even a metal lintal the dimond core will usually just cut through it too is you hit it right.

Hand held Core drilling

Hey guys and gals,

I have owned a Bosch hammer drill for about 15 years, I have a 5" core that is worn but still drilling, a 4" and a 2", and smaller stuff.

I have a new employee that says he used to work at a company where they used the dry coring system...I believe I saw full page ads in one of the trade mags.

Any how, what is the best way now to drill holes? I guess my biggest needs is 3" plastic, but once in a blue moon I would drill a 4" ABS pipe as well (not so much plumbing anymore).

Does anyone here actually own a 'bolt on' core drilling machine?


Thanks for the help! gary