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Hammer drill vs. impact driver - Pros / Cons

Posted: Wed Nov 17, 2010 3:38 pm
by mickyd
Curious to see comments on the decision to buy either a hammer drill vs. an impact driver, primarily for driving screws.

All I can see is.......
  • Hammer drill has adjustable max torque setting.
  • Hammer drill allows chucking of straight shank drill bits (without the 1/4" hex drive)
  • Impact driver will have more torque?????
  • Impact driver more compact

Posted: Wed Nov 17, 2010 4:34 pm
by holsgo
I bought a cordless from Harbor Freight many years ago. It was shot within a year. I stay away from their cordles tools altogether now. As far as what to get, I would go with the impact driver for screws. The hammer drill isn't suited for driving screws.
If you really want something well above what you need but would be a great buy is a Rotary hammer. Love the tool.

Posted: Wed Nov 17, 2010 5:49 pm
by mickyd
holsgo wrote:..........The hammer drill isn't suited for driving screws.
If you really want something well above what you need but would be a great buy is a Rotary hammer. Love the tool.
But, but, Mr. Wikisays hammer drill, also known as a rotary hammer. :eek:

Posted: Wed Nov 17, 2010 6:26 pm
by mickyd
This article at woodwhisperer.com discusses the differences. I'm going for the impact driver to add to my collection vs. a hammer drill.

Posted: Wed Nov 17, 2010 6:32 pm
by mbcabinetmaker
Impact driver Mike. If you ever need a hammer drill buy a corded model Bosch with the SDS quick change bits. http://www.boschtools.com/Products/Tool ... d=11258VSR

Back to the impact driver. I have Bosch 18 volt drivers and Milwaukee 12 volts. The Milwaukee's work great for most things and are now around 125.00 at HD but look for sales to start soon for the Holidays.

Posted: Wed Nov 17, 2010 6:32 pm
by holsgo
OK, Ok. Wiki. A Rotary hammer is a big boy. It takes only a certain type of bit that has a slot which the rotary hammer receives. It can't take standard bits. It a beast of a tool that you can use with chisels on hammer mode to bring up tile, chip brick, concrete etc. The hammer drilling mode is very much like a hammer drill.
My buddy got into this with me when he bought his hammer drill. Depending on the size of the tools there is probably no difference but up into the 1 inch range and above (bit size) there certainly is. It's the hammer action that's different.

Posted: Wed Nov 17, 2010 6:52 pm
by burkhome
I can't make up my mind. Ace will have a milwaukee set of a 12v cordless drill and a 12v impact driver on their day after Thanksgiving day sale. I'll do that....Easier than making decisions.

Driving Screws

Posted: Wed Nov 17, 2010 10:02 pm
by cincinnati10
mickyd wrote:... primarily for driving screws.

All I can see is.......
  • Hammer drill has adjustable max torque setting.
    Hammer drill allows chucking of straight shank drill bits (without the 1/4" hex drive)
    Impact driver will have more torque?????
    Impact driver more compact
Hammer Drills are used for drilling into hard materials like concrete and rock. If you need holes in these kinds of material , get a hammer Drill. GO with a corded drill. I haven't found a cordless hammer drill worth its salt. Makita is my personal preference in a hammer drill.

If you are driving screws, the questions become "how many?" and "into what?" IMHO, for most hobby WW shops, a good quality cordless drill is adequate. Both DeWalt and Festool have adjustable torque clutches so you can set the point of max torque. I prefer Festool. I have the older design C12 drill which came with two batteries. One charges in about 20 minutes. It takes more than 20 minutes to drain the other. So I can work all day in my shop without needing more batteries.

I used 12V and 18V Cordless DeWalt drill/drivers for years, and consider them very adequate as well. I want the portability of cordless tools for a drill / screw driver. I repair our privacy fence, do repairs at our shooting range, and help others with their repair projects where having a corded tool is not only unnecessary, but often impossible to use b/c of no electrical source.

Finally, the new generation of drivers use Li-ion battery technology. Buy this over NiMH or NiCad.

Posted: Wed Dec 01, 2010 9:21 pm
by larrys
Definitely an impact, there is not much difference on screws less than 2" but an impact will bury a hammer drill on screws over this length.

I have both and hardly use my hammer/drill anymore. And have now bought all my drill bits with 1/4 hex, or buy a chuck adaptor for a 1/4 hex.

Larry

Posted: Thu Dec 02, 2010 1:14 am
by Ed in Tampa
Impact drills are for turning things that are difficult to turn.
Hammer drills are for drilling holes into masonary and stone.

Two different purposes. A hammer drill makes a lousey screw driver when it is in hammer drill mode (most can shift from hammer drill to straight drill). In straight drill mode most do any excellent job of driving screws/bolts.

Impact drills are usually used to loosen stuck nuts or bolts. I know many people use them to drive screws and it usually works. However many screws are harden in such a way that the impact can and sometimes does snap the shank.

The problem most people have with power drills is they can't hold the drill in alignment with the screw and the bit cams out of the screw head and strips the head. The can be overcome with practice, if you screw enough screws you will eventually learn to keep the screw and drill in alignment. I have also found that square head screws are more forgiving in the alignment area.
I'm prone to strip a screw head so I try to use square head slot screws. Can't remember the last time I had the bit cam out and strip the screw head.

I love having an hammer drill, very useful here in Florida where most houses are concrete block construction. I also love my impact drill when I need to drive 1/4 or bigger lag bolts home after I have used the hammer drill to drill the hole.