DanG wrote in :

On 1/29/2012 10:59 PM, Harry K wrote:
On Jan 29, 7:09 pm, wrote:
Often on Holmes Inspection and This Old House, the workers use what
appear to be hammer drills as electric screwdrivers, particularly
for lag bolts or long screws. Are they really using hammer drills,
or does it just sound like a hammer drill?

There are two different animals:

Hammer drill - was an option but it may be standard now on electric
drills from 3/8" on up. The "hammer" action can be turned on/off at
will.

Impact driver - hammer only, no choice and is usually a heavier and
more robust tool.

Harry K


Just not so. My full sized DeWalt impact gun is lighter and smaller
than my DeWalt drill. The newer lighter weight impacts are almost
half the size and weight and hit as hard or harder. I've not invested
in the newer light weights because I'm waiting to wear out something I
already own or develop a specific need.


an impact driver does not "hammer",it strikes in a ROTATIONAL direction.
It has more torque than a drill-driver.
a hammer drill strikes in the axial direction,while rotating the bit.

--
Jim Yanik
jyanik
at
localnet
dot com