Fred McKenzie wrote:
In article ,
Ian White GM3SEK wrote:

Any SDS+ drill with the "rotary stop" option will make a very effective
hammer for earth rods.

Ian-

I found SDA+ hammer drills in a couple of the local hardware stores
today. The smallest was around 3 kilograms (6.5 pounds), but I suspect
is the "2 kilogram" class you refer to.

Probably... the "2 kilogram" drills look like a stretched version of a
normal pistol-grip drill, with a horizontal motor. For example:
http://tinyurl.com/33zcrr
http://tinyurl.com/3algeq

(I have no idea why the store calls one of these drills "3/4-inch" and
the other "7/8inch". There is only ONE size of SDS+ chuck and drill
shank.)


The "4 kilogram" drills are "L-shaped" with a vertical motor, and are
much heavier and harder to control. For example:
http://tinyurl.com/37w97w

For most applications the extra power of the 4kg drill is not necessary
- certainly not for hammering or drilling for grounds rods.

One question the sales people couldn't answer, was what you meant by
"rotary stop". The drills I saw all had a linear stop in the form of a
rod that can be adjusted to stop penetration of the drill bit at a
desired depth. Do you mean that kind of stop, or do you mean something
like stopping rotary action, leaving only the hammering action?

That's correct. The rod is usually known as a "depth stop".

Check for the following features:

1. "Rotary stop": ability to stop rotation and use hammer only. On
better drills, this also allows the chuck to be locked in a number of
pre-set positions for use with a chisel bit.

2. "Hammer stop": ability to switch off the hammer action. Very good for
starting holes in exactly the right location.

3. Safety clutch: DON'T BUY a drill that doesn't have one!

4. Very good trigger-operated speed control, that will allow the drill
to be started at a slow crawl. This is something that you can only check
by trying the drill in the store.

More information:
http://www.diyfaq.org.uk/powertools/sds.htm


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek