# Best drill bit for old concrete



## princelake

A rotary hammer drill is key to drilling that old concrete and if the hole just isn't drilling start a new one because your hitting something that will just burn out your bit. If you don't have a rotary hammer drill cause the rotary hammer drill bits in your regular hammer drill. Also buy a good brand drill bit like hilti or dewalt.


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## Just Bill

Old concrete with lots of agregate can be hard on bits, and a good hammer drill is a must. Carbide tipped bits specifically labeled for hammer/percussion drills. Avoid anything made in china.


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## johnjack11

Just Bill said:


> Old concrete with lots of agregate can be hard on bits, and a good hammer drill is a must. Carbide tipped bits specifically labeled for hammer/percussion drills. Avoid anything made in china.


I have a hammer drill, I think I must be just hitting something really hard in certain spots. I will just stop drilling those wholes and try again close by I guess.

Is there a brand that is much better than others? I will make sure to get carbide tipped ones. Anyway to resharpen those after they get dull, or do you just throw them out?

Thanks for the replies,
Jack


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## robs660

Hammer drill is drill is different then rotary hammer. A rotery hammer spins slower and hits harder with each impact. They will drill through very hard material quite quickly. 
Here is a link to a good quality Bosch at a good price. 
http://www.cpotools.com/bosch-11224...11224vsr,default,pd.html?ref=cdi_bshn11224vsr

Hammer drills are known for burning up bits. They spin too fast and create too much heat


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## princelake

I've found the hilti ones to be the best. And there's no the carbide tip either wears or falls off. Regular bits you can sharpen them with a grinder and put it up to 2 nuts together giving you the correct angle or buy a bit doctor


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## jomama45

As stated above, a normal hammer drill relies on speed to get the job done, sometimes as fast as 3000 rpm. They have very little hammering/impact though.

A rotary hammer is quite the opposite, with far lower speed and far greater impact. As well, the SDS+ bits tend to last far longer than any generic smooth shank pecussion drill bit. Even though the SDS+ have a unique shank drive, they can still be placed into a standard chuck (as long as it's 1/2" cappacity) with a little trial & error, and will perform much better on both the speed of drilling & the lifespan of the bit. Wouldn't be surprised to drill all 400 holes with one bit.


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## oh'mike

I seem to get the longest life from Bosch bits---Hilti are top of the line also,but not available easily--Mike--


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## johnjack11

Great, thanks for all the replies.

Jack


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## johnjack11

Anyone ever use the Chicago rotary hammer drill at harbor Freight?

It would be about $60 for me after a coupon, I am not sure that I will use a rotary drill that much after completing this project.

I have had some chicago tools in the past, their multitool has been pretty good for me.

Thanks for the help,
Jack


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## robs660

I have the Bosch and I have used it more then expected. I would assume the Chicago would work well. Make sure it takes the sds max bits


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## joecaption

Chicago Tools are trash. I use a Bosch Bull Dog with SDS bits and can do a whole room with one bit. You can rent a Bull dog or a Hilti at Home Depot.
http://www.expresstools.com/Bosch-11224VSR-SDS-plus-Bulldog-Rotary-Hammer.aspx

Use Tap Con brand screws and an Impact driver to insert the screws.
I use a Ryobi driver and Dewault impact ready bits.


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## PaliBob

robs660 said:


> …. Make sure it takes the sds max bits


 The OP is using Ultracon Concrete Screws (very similar to Tapcons) which come in a maximum diameter of 5/16”. For his application the SDS-Max is overkill. The cheapest Bosch SDS-Max hammer drill that I see is the Bosch 11240.
http://www.amazon.com/Bosch-11240-16-Inch-SDS-Max-Combination/dp/B0000695HG

Most of the Bosch SDS Hammer Drills use just regular SDS bits which are also called SDS-Plus. 
E.g. all five of the Bosch ‘Bulldog’ Rotary Hammer Drills are SDS-Plus


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## johnjack11

*Drill*

I found some good Bosch bits, and drilling the holes is no longer an issue with my hammer drill.

The ultra cons can be a pain though, and I wondered if the cheaper rotary drill would help with those. Quite a few screws have gone in just about all the way but will then not go far enough to sit just under/flush with the osb.

When I take them out, drill some more and then vacuum the hole again I can usually get them in. I have had to use 3 screws in some areas though. Not sure if it is a technique problem on my part or the hammer drill.

As much as I love good tools, I would prefer not to spend a lot on a rotary hammer, I just won't need it that much. I have a large list of materials to frame out the basement. Heck the xps foam and osb was $800.

I would buy the cheaper Chicago tool if people thought it might help with the screws, any advice on technique driving the screws would also be welcome.

Once again thanks for all the replies, this is a great sounding bouts for me.

Jack


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## PaliBob

johnjack11 said:


> .... Not sure if it is a technique problem on my part......


 Ultracon screws are almost the same as the more commonly known Tapcons but they have an impressive history.
http://www.tannerbolt.com/default.a...er/tabonu/customerpages/tap-con-ultra-con.htm

It sounds to me that you are not drilling the holes deep enough, or the holes are not being cleaned enough.
From the TapCon Site:


> The hole drilled with the bit should be 1/4" deeper than the Tapcon®	depth at which the screw will be installed into the base material.


Ref http://www.concretescrews.com/tapcon-questions.aspx


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## johnjack11

Thanks PaliBob,

initially depth was a problem, but a new longer bit took care of that. I think it might be a "cleaning" problem. I am using a shop vac to get the dust out, I might just need to work a bit harder on it.

The shop vac might just be pulling dust up the hole, and not all the way out. I will something thinner, and push it down the hole to make sure it is clear.

Thanks again,
Jack



PaliBob said:


> Ultracon screws are almost the same as the more commonly known Tapcons but they have an impressive history.
> http://www.tannerbolt.com/default.a...er/tabonu/customerpages/tap-con-ultra-con.htm
> 
> It sounds to me that you are not drilling the holes deep enough, or the holes are not being cleaned enough.
> From the TapCon Site: Ref http://www.concretescrews.com/tapcon-questions.aspx


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## PaliBob

johnjack11 said:


> ....I think it might be a "cleaning" problem....


 Make a depth gauge with an unsharpened pencil with a blue masking tape marker to indicate hole depth.
Any powder residue should show up on the depth gauge.
Another thing you can do is use a small diameter funnel taped to the end of the vacuum hose.


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## johnjack11

Funnel is a great idea.

I picked up the Chicago rotary hammer tonight, will give it a try tomorrow. Too late now and the kids are in bed.

I was hoping to find an sds driver bit to drive the ultracons too, but did not see one at lowes or online.

Has anyone seen another manufacturer that makes these:
http://www.toolstop.co.uk/makita-p-63725-maklok-quick-change-chuck-sds-plus-adapter-p14735

Thanks,
Jack


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## stadry

nobody's house conc is that hard because no contractor or homeowner would spend the $ necessary to make it so,,, more than likely you're running into superhard coarse aggregate & it may be a dense mix of aggregate/cement paste - that's all conc is - cement, water, fine aggregate ( sand ), & coarse aggregate ( crushed rock ).

let me echo the ' chicago ' brand from whereever - its junk however it may last long enough to finish your work. IF it has the jacobs chuck, don't expect much - either spline, sds, or sds improved are necessary for your work - smooth bits are impossible to tighten in the chuck when subjected to the hammer vibration.

have you considered _sinusoidal anchors_ instead ? much faster


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## johnjack11

The Chicago drill seems to be much better, goes through the concrete like wood. I did snap a bit after 20 or so holes though. It has an SDS plus chuck, which is so much easier to work with, I was tightening drill bits every five minutes with the hammer drill.

I agree that you get what you pay for with power tools, but budget was a priority on this one. K just won't use it much after this part of the project. It was cheaper than renting.

I am concerned with the broken bit, it was around $5, I might try another brand at lowes. Hopefully it was just a problem with that particular bit.

Jack


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## johnjack11

itsreallyconc said:


> nobody's house conc is that hard because no contractor or homeowner would spend the $ necessary to make it so,,, more than likely you're running into superhard coarse aggregate & it may be a dense mix of aggregate/cement paste - that's all conc is - cement, water, fine aggregate ( sand ), & coarse aggregate ( crushed rock ).
> 
> let me echo the ' chicago ' brand from whereever - its junk however it may last long enough to finish your work. IF it has the jacobs chuck, don't expect much - either spline, sds, or sds improved are necessary for your work - smooth bits are impossible to tighten in the chuck when subjected to the hammer vibration.
> 
> have you considered sinusoidal anchors instead ? much faster


I will have to research the anchors, but I have 400 ultra cons now. The drill makes it much more doable. I got a full 4 by 8 screwed down last night in half the time it took to fasten 2 screws previously.

Jack


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## PaliBob

I did not understand that reference to "sinusoidal anchors" in post #19
Nor did Google point me to any suppliers that would help in your application.

In my location I had not seen the Ultracon brand masonry screws but their web site shows an impressive history:
http://www.tannerbolt.com/default.a...er/tabonu/customerpages/tap-con-ultra-con.htm
.


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## johnjack11

Same here on the anchors.

As for ultracons, there seem to be the same quality level as tapcons and they are a lot cheaper.

Jack



PaliBob said:


> I did not understand that reference to "sinusoidal anchors" in post #19
> Nor did Google point me to any suppliers that would help in your application.
> 
> In my location I had not seen the Ultracon brand masonry screws but their web site shows an impressive history:
> http://www.tannerbolt.com/default.a...er/tabonu/customerpages/tap-con-ultra-con.htm
> .


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