# Core bit help



## Josue (Apr 25, 2010)

I would like to convince my dad to buy a core bit, or even buy one for him. 
We have a bosch 11247 hammerdrill.:thumbup:

Would this be a good option?
http://www.toolbarn.com/bosch-HC8035.html


Any suggestions or comments would be appreciated.

Thanks!:thumbsup:


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## 480sparky (Sep 20, 2007)

I've never had any interest in getting into core drilling. If I need to do it, I call a company that specializes in it.


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## electricalwiz (Mar 12, 2011)

i bought my core drill and my core bits for my bosch rotary hammer on ebay, I would check there first


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## Southeast Power (Jan 18, 2009)

The bigger hole the greater chance that you will hit rebar. I would invest in a core drilling machine or just rent one. If you have enough work to pay for that tool or any tool in one or two jobs and you will be using it often then its a good investment.
Too many guys buy bucket trucks, ditchwitch machines, lifts and bobcats just to have them sit and rot. I would rent them and not worry about repairs, storage or maintenance. There are lots of good rental deals now that work in slow.


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## Josue (Apr 25, 2010)

480sparky said:


> I've never had any interest in getting into core drilling. If I need to do it, I call a company that specializes in it.


Why are you not interested? In Mexico almost every house is made out of brick and concrete, so we have to get across masonry everyday. Whenever we need to make a big hole we make several smaller holes and then chisel the rest of it. I did that today. It took me about 10 minutes. A core bit would make the job easier............and would be a lot more fun.:laughing:


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## Josue (Apr 25, 2010)

electricalwiz said:


> i bought my core drill and my core bits for my bosch rotary hammer on ebay, I would check there first


OK, will do. Thanks.:thumbsup:

Were they used?



jrannis said:


> The bigger hole the greater chance that you will hit rebar. I would invest in a core drilling machine or just rent one. If you have enough work to pay for that tool or any tool in one or two jobs and you will be using it often then its a good investment.
> Too many guys buy bucket trucks, ditchwitch machines, lifts and bobcats just to have them sit and rot. I would rent them and not worry about repairs, storage or maintenance. There are lots of good rental deals now that work in slow.


We don't drill where we know there is rebar. We normally find a brick wall where there is no concrete with rebar enclosed and drill there.:thumbsup:


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## 480sparky (Sep 20, 2007)

Josue said:


> Why are you not interested? In Mexico almost every house is made out of brick and concrete, so we have to get across masonry everyday. Whenever we need to make a big hole we make several smaller holes and then chisel the rest of it. I did that today. It took me about 10 minutes. A core bit would make the job easier............and would be a lot more fun.:laughing:


I don't need to core drill every day. Maybe once every 2-3 weeks at best.


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## Josue (Apr 25, 2010)

480sparky said:


> I don't need to core drill every day. Maybe once every 2-3 weeks at best.


OK.

There are no companies that do that in Mexico. One would normally chisel into the wall and make the hole. We have many tools other electricians in Mexico don't have. 
An average Mexican electrician would carry one tiny tool box with all his tools, the tool box might be 14" long. They might have a so so hammerdrill.

We carry 6 tool boxes, (that includes my bucket). We have an excellent hammerdrill, a normal electrician wouldn't have such a good hammerdrill, not even cordless tools! We carry 3, 18v cordless tools. You can't even find 18v tools in the city I live in! You have to order them by catalog.


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## B4T (Feb 10, 2009)

Josue said:


> Why are you not interested? In Mexico almost every house is made out of brick and concrete, so we have to get across masonry everyday. Whenever we need to make a big hole we make several smaller holes and then chisel the rest of it. I did that today. It took me about 10 minutes. A core bit would make the job easier............and would be a lot more fun.:laughing:


You are talking to a guy who has to take pics (50) feet up in the air from a tri-pod..

IF he was interested in core drilling.. he would have every bit up to 6".. and a selection of rotary drills to use them with.. :laughing:


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## electricalwiz (Mar 12, 2011)

Josue said:


> OK, will do. Thanks.:thumbsup:
> 
> Were they used
> 
> ...


The core drill was used, the rotary hammer and the core bits were new
Do you have a spline or sds max drill


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## chewy (May 9, 2010)

How do you guys find those core bits for the rotary hammers? I assume you have to hammer drill a pilot then swap over to just drilling? 

I was thinking about getting a core drill and I can get a 1500w core drill and stand for a little over $700 and was wondering if it was worth getting it to use once in a while or if those SDS core bits would do the job, primarily it will be for doing penetrations through poured block walls and from floor to floor on new construction.


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## 480sparky (Sep 20, 2007)

B4T said:


> You are talking to a guy who has to take pics (50) feet up in the air from a tri-pod..



Damn straight. At least you can _see_ the tripod. :whistling2:




B4T said:


> IF he was interested in core drilling.. he would have every bit up to 6".. and a selection of rotary drills to use them with.. :laughing:


And therein lies the problem. One or two bits wouldn't suffice. You keep having to buy yet another high-$ bit because the ones you have aren't the right size.


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## electricalwiz (Mar 12, 2011)

chewy said:


> How do you guys find those core bits for the rotary hammers? I assume you have to hammer drill a pilot then swap over to just drilling?
> 
> I was thinking about getting a core drill and I can get a 1500w core drill and stand for a little over $700 and was wondering if it was worth getting it to use once in a while or if those SDS core bits would do the job, primarily it will be for doing penetrations through poured block walls and from floor to floor on new construction.


the core bits for the rotary hammers work great on block and brick, concrete is a little harder depending on the thickness and psi of the concrete and amount of rebar. you do not have to drill a pilot bit.
i have a core drill with a rig i would sell you but shipping to NZ would be pretty pricey


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## Speedy Petey (Jan 10, 2007)

I can't see how anyone would thing drilling a 2-1/2" hole in concrete or block is a "specialized" task. :blink:

I have only one core bit, and the 2-1/2" is it, for getting 2" conduit through concrete. I use it only every few months, and would not think of being without it. 
Guys I used to work for would have me drill a bunch of small holes and then know out the center. How caveman is that???

IMO a bit for 3/4"-1" and 2" conduit should be standard issue for most electricians. 
Most all of us already have rotary hammers and while the bits are not cheap, if taken care of will last nearly forever.


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## wcord (Jan 23, 2011)

Josue said:


> I would like to convince my dad to buy a core bit, or even buy one for him.
> We have a bosch 11247 hammerdrill.:thumbup:
> 
> Would this be a good option?
> ...


Go for it!
We have both Bosch and Dewalt core bits.
I really cant say that I can notice any difference in performance.
We use the 2" capacity Bosch and it will blow a 3 1/2 hole thru a basement wall very quickly (way less than 5 minutes)
When I had a smaller hammer, we would drill a circle of small holes than chisel it out. Not any more
We also bought a ground rod bit for it. Less than a minute to drive a rod in!


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## electricalwiz (Mar 12, 2011)

Speedy Petey said:


> I can't see how anyone would thing drilling a 2-1/2" hole in concrete or block is a "specialized" task. :blink:
> 
> I have only one core bit, and the 2-1/2" is it, for getting 2" conduit through concrete. I use it only every few months, and would not think of being without it.
> Guys I used to work for would have me drill a bunch of small holes and then know out the center. How caveman is that???
> ...


That is how i look at it, what kind of drill you have, I have a bosch spline


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## chewy (May 9, 2010)

electricalwiz said:


> the core bits for the rotary hammers work great on block and brick, concrete is a little harder depending on the thickness and psi of the concrete and amount of rebar. you do not have to drill a pilot bit.
> i have a core drill with a rig i would sell you but shipping to NZ would be pretty pricey


 
True, the concrete differs quite a bit over here, probally easier just to get a core drill and not have the problems. We usually have a contractor that comes in to cut concrete or core drilling but sometimes you either cant wait or your working out in the wopwops. 

Cheers for the offer but if I bought your rig I'd have to weld a shelf on it to carry the 230v to 110v stepdown transformer I'd have to lug around with it :laughing: We had some American contractors come over to do some work inhouse and they bought 5 pelican cases full of tools.... We run 230v and we are also Metric, so not alot in those cases got used. I would bet it would have been cheaper to buy tools locally than to ship those huge cases.


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## Speedy Petey (Jan 10, 2007)

I have a Makita SDS Max. I have several smaller long standard bits for 3/4" and 1", and a dry core bit for 2".


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## amptech (Sep 21, 2007)

I have a 1-1/2, 2, 2-1/2 thin wall cores that fit on the same 12" arbor. The cores are 4" deep. I have had thick wall cores and find the thin wall cores cut faster through concrete and cut through rebar easier. All you do is drill a starter hole with a 3/8" masonry bit about 1/2" deep. Each core comes with a centering point that you use until the core has started a grove. Then you remove the centering point and have at it. I have cored 14" concrete walls. Just drill until you bottom out the core then use a bull point to remove the plug then core some more. For a neat hole on both sides of the wall I use my 22" long 3/8" bit and drill clear through the wall and core at least 3" deep on the finish side before starting on the other side.


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## farlsincharge (Dec 31, 2010)

Would you guys recommend the core bits or a core cutter like the milwaukee turbo tunnel?
Will a tct core actually cut through rebar?


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## captkirk (Nov 21, 2007)

Jose those bits are good as long as you dont hit any rebar...I have the one you pictured and its good for most stuff. If you work with walls that have a tons of rebar you should save up for a diamond core drill. I have used the Hitli DD130 for years and that is a really really nice tool. It cuts through rebar like butter. Its not cheap though alomost 2500 just for the drill no including bits, stand/press, or vacume pump if you want to stick it to walls.


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## Steve Shephard (Jun 25, 2011)

Josue said:


> Why are you not interested? In Mexico almost every house is made out of brick and concrete, so we have to get across masonry everyday. Whenever we need to make a big hole we make several smaller holes and then chisel the rest of it. I did that today. It took me about 10 minutes. A core bit would make the job easier............and would be a lot more fun.:laughing:


 Get a real core drill machine. The kind you bolt to the wall and hook a water hose up to.


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## macmikeman (Jan 23, 2007)

Steve Shephard said:


> Get a real core drill machine. The kind you bolt to the wall and hook a water hose up to.


Mine, we used a hose or we also rigged up a hand pump cannister to the core drill for jobs where there was no hose nearby to use. I still have mine buried away in a gang box in my shop, but it hasn't seen any use in twenty years..... 1 have the bits up to 6" in various lengths.


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## Josue (Apr 25, 2010)

electricalwiz said:


> The core drill was used, the rotary hammer and the core bits were new
> Do you have a spline or sds max drill


spline:thumbsup:


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## Josue (Apr 25, 2010)

Speedy Petey said:


> I can't see how anyone would thing drilling a 2-1/2" hole in concrete or block is a "specialized" task. :blink:
> 
> I have only one core bit, and the 2-1/2" is it, for getting 2" conduit through concrete. I use it only every few months, and would not think of being without it.
> Guys I used to work for would have me drill a bunch of small holes and then know out the center. How caveman is that???
> ...



You are right.

The biggest drill bit we have is 1'' x 22''


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## Josue (Apr 25, 2010)

wcord said:


> Go for it!
> We have both Bosch and Dewalt core bits.
> I really cant say that I can notice any difference in performance.
> We use the 2" capacity Bosch and it will blow a 3 1/2 hole thru a basement wall very quickly (way less than 5 minutes)
> ...



Thanks!

I'll see of getting one for my dad!


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## Josue (Apr 25, 2010)

captkirk said:


> Jose those bits are good as long as you dont hit any rebar...I have the one you pictured and its good for most stuff. If you work with walls that have a tons of rebar you should save up for a diamond core drill. I have used the Hitli DD130 for years and that is a really really nice tool. It cuts through rebar like butter. Its not cheap though alomost 2500 just for the drill no including bits, stand/press, or vacume pump if you want to stick it to walls.



If I get a core bit, I won't be drilling where I know there is rebar. I'd core through brick.


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## pwregan (Apr 13, 2011)

*core bits*

If you can look into dry core bits
they are used with a 7 inch or 10 inch angle grinder and are much quicker and cleaner than a core bit and a hammer drill
for multiple holes in same location we make a template out of 3/4 plywood and hole saws then fasten template to wall to align dry cores, also a template can be made for single holes as well- safer for starting the dry core
I never liked trying to core with a hammer drill- not really made to do that job, longer to do, loud as hell, and tough on the equipment-just my 2 cents


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## Josue (Apr 25, 2010)

pwregan said:


> If you can look into dry core bits
> they are used with a 7 inch or 10 inch angle grinder and are much quicker and cleaner than a core bit and a hammer drill
> for multiple holes in same location we make a template out of 3/4 plywood and hole saws then fasten template to wall to align dry cores, also a template can be made for single holes as well- safer for starting the dry core
> I never liked trying to core with a hammer drill- not really made to do that job, longer to do, loud as hell, and tough on the equipment-just my 2 cents


Thanks:thumbsup:


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## Marcus (Mar 30, 2010)

I use one of these in my Hilti TE-40.








The bit I have is 68mm in diameter, which I use for penetrations for A/C pipework, drain & wires. Anything bigger I'll call someone in with a diamond corer.


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## Josue (Apr 25, 2010)

Marcus said:


> I use one of these in my Hilti TE-40.
> 
> 
> 
> ...


Ok.

That kind is the one I want.:thumbsup:


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## jhall.sparky (Jun 14, 2011)

Josue said:


> Ok.
> 
> That kind is the one I want.:thumbsup:


I have three types of coring tools and about 26 different bits. 

I don't always use them ,however , being the money hungry scrooge I am I
Have charged for drilling holes for everyone. I recently used 
A 6" core drill to help the plumbers out. Also I have charged for 
Using my bobcat and ditchwitch. If you buy it they'll pay YOU. 
Sounds like jose would be the Go-To guy in his neck of the
Woods , errr .... Desert. 

Anyone who ever told me not to buy a certain tool told me thanks also. 

One tip / you don't have to buy new every time just look around and be 
Patient. 
J. Hall.


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## Josue (Apr 25, 2010)

RedLiz75 said:


> You can find the answer to your question at electricians job talk dot com!


I think your post is double.:laughing: 

You posted this at the hardest job ever thread too.:laughing:


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## Josue (Apr 25, 2010)

jhall.sparky said:


> I have three types of coring tools and about 26 different bits.
> 
> I don't always use them ,however , being the money hungry scrooge I am I
> Have charged for drilling holes for everyone. I recently used
> ...


WOW those are a lot of bits!!!

Glad you're getting your $$$ back:laughing:

The part of Mexico I live in is not desert, it is mostly woods.:laughing:


Thanks for the input.


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## chewy (May 9, 2010)

jhall.sparky said:


> I have three types of coring tools and about 26 different bits.
> 
> I don't always use them ,however , being the money hungry scrooge I am I
> Have charged for drilling holes for everyone. I recently used
> ...


Thats why I was planning on buying a core drill, a bit of cash work for other trades after hours sounds alright to me. :whistling2:


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## Josue (Apr 25, 2010)

chewy said:


> Thats why I was planning on buying a core drill, a bit of cash work for other trades after hours sounds alright to me. :whistling2:


:laughing:


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