How It Works
This 23-pound drill bores six-inch-wide holes in brick and smashes concrete, without destroying your arms
By Chuck Cage Posted 03.19.2009 at 11:51 am 11 Comments

Double Trouble A switch deactivates the drill’s rotation, so you can attach a chisel bit and use the DH50MRY like a jackhammer John B. Carnett (See how it works)

Standard drills will barely make a chip in concrete or brick. That’s why contractors drilling holes in a home’s foundation use rotary hammer drills like this new Hitachi DH50MRY. In addition to the standard spinning bit, it slams a weight—the hammer—forward to create a sort of jackhammer effect to crush masonry as it drills. But all that pounding beats the heck out of your hands and arms. The Hitachi is one of the first to integrate a counterweight to absorb recoil. The result is a safer and easier-to-control drill that’s still concrete’s worst nightmare.

Piston

Sliding back and forth inside a cylinder, the piston compresses air to create a pneumatic effect that drives the hammer forward.

Counterweight

Two thin metal strips support the counterweight, which can sway just enough to absorb up to 25 percent of the recoil from each hammer strike, sparing your hands.

Gearbox

A set of gears transfers the motor’s rotation to two places: a 90-degree cam that turns the bit, and another gear that drives the piston back and forth.

Electric Motor

A variable-speed motor spins the drive shaft.

Drill Bit

The grooves on the bit remove debris from the hole, clearing the way for more destruction.

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11 Comments

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lbukys
03/21/09 at 1:37 pm

I think you mean six-inch-deep holes, not six-inch-wide holes?

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LiNERROR
03/22/09 at 2:14 am

Six inch deep holes? really? i don't think so, as the bit in the picture is longer than 6 inches...

i don't see how that Hitachi get's the Meanest Drill award... look at the Hilti TE70... it's not even top of the line and can do 6 inch WIDE holes and weighs less... and won't kill your arms.

www.us.hilti.com/holus/modules/editorial/edit_singlepage.jsp?edtid=-21476_000001

and even then... i'd have to say this kicks it's ass... www.carrierconcretecutting.com/concrete-cutting-coring-services/poolekent27bit020.jpg

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electrodynamic
03/26/09 at 1:04 am

I've used the hilti many times,and I never saw a six inch bit,but I bet they make them.Would be very expensive.usually people grab a self feeding drill that looks like a coring tool when the holes get that size.there are companies out there that do that and not much else.I have used a 3 inch diam. bit myself,and have seen 4 foot long bits.If your not a man when you pick up one of these monsters you will be by the end of the day.It is amazing though what you can put a hole through.

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electrodynamic
03/26/09 at 1:08 am

I was actually expecting some kind of massive industrial drill press or something.Slightly let down yeah.

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buddyred
04/02/09 at 11:38 am

It seems a little bulky, it better come with a case, or i wouldn't bother lugging it around at work, how nice would it be if it were cordless.

Buddyred

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smack5446
01/12/10 at 4:30 am

I have sold and used Hitachi Rotary Hammers for years. They make a great tool. A few tools on the market can drill a 6" wide hole in concrete, Hitachi just happens to make one of the better ones. The drill bit pictured is 1/2" diameter. Drill bit length has nothing to do with the size of hole a drill can handle.
It sells for about $600 to $800 (market pending) and comes with a case. Cordless tools are great but could not handle 6" capacity, just not enough electricty.
I'm no contractor but if I needed a quality tool of this nature I would buy Hitachi of Hilti.

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smack5446
01/12/10 at 4:31 am

Hitachi or Hilti

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nylife
06/08/11 at 3:47 pm

I've never seen a 6 inch wide masonry bit, and I don't even want to imagine trying to drill through any significant concrete with one. Any contractor making holes that big in concrete is using a core driller with a hollow diamond bit. Good luck getting through re-enforcing bar with a mason bit. It can't be done.

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doitbetternow
06/14/11 at 1:20 am

nylife, a two flute masonry bits weakest point is, well, the point Where a two flute bit usually snaps off the carbide inserts if it hits rebar, a 4 fluted masonry bit is more likely to just bounce off the rebar and not damage the inserts aside from dulling the cutting faces. A two fluted bit roPenetrating a rebar with a 4 flute bit can be done, but the question is how much time you want to spend cutting through the rebar.

There's always time to do it better NOW.

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biology_geek
12/05/11 at 10:32 am

I agree with you all
Biology_Geek

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leo922
02/12/12 at 10:41 am

Great, but first I must have to check for rebars to let the 6-inch diameter drill through which will make a nice smooth cut?



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