Mike Whittome wrote:

In message , Andrew Mawson
writes

"David Littlewood" wrote in message
...
In article , Tom Miller
writes


I tend to use sheet metal drills for hole
starting. They are very short and are double
ended. you can break twice as many for the same
price!


Sheet metal drills?

David
--
David Littlewood

They are ground to a sort of a cusp - centre point and also cutting
edge at the periphery of the flutes

AWEM




Perhaps look at .............

http://www.centerdrills.com/CNCspot.htm

After reading this thread I bought some spotting drills to try (from ebay),
and I have only one comment - wonderful!!

Centre drills are good for drilling centers where you need a pilot hole and
a 60 degree "countersink" for the center, but for getting a hole in the
right place without hassles or the drill bit wandering all over, spotting
drills are unbeatable.

I just drilled a cross hole in a bit of hard shiny 8mm round stainless with
a rickety old pillar drill, and I didn't even use a centre pop to mark it -
nae fuss nor bother, and it just started in the right place!

I don't know how they work, because they don't look too different, but I am
convinced - apart from centers, I'll never use a centre drill to start a
hole again.



OT, how does one spell the word? Is it optional, or another case of two
countries divided by a common language?

--
Peter Fairbrother