on one of the shopping channels they were flogging sets of these
drills,they used a grinding wheel to test a drill and it made no
impression on the drill,then they used the sane drill to drill through
concrete,brick and finally a car disc brake plate,anyone used these
and what did you think as i have tins full of blunt drills and they
are never the same re sharpened,tia
sounds like a universal or multi-material bit with sharp TC tip.
Masonry use will blunt the tip, leading to loss of function with wood,
steel etc, but will still work fine on masonry. Useful for combination
material workpieces, but regular or preferably titanium twist drills
are best for metal, dowel bits or aggressively reground twist drils
are best for wood, and standard masonry bits a fair bit better for
According to the Ideal World web site, they are simply cobalt drills.
Cobalt drills are intended for drilling hard and difficult maaterials,
but are more brittle than HSS, so you could end up with a box of broken
drills, rather than blunt ones.
Nothing simple about cobalt drills.
If they're cheap (or on TV) and they're "cobalt", then they'll be a
cobalt _coating_ and probably a bluish rainbow colour. These aren't
Decent ones are solid M42 alloy. These are good, but keep them in the
workshop "for best". They also work in a drill press, but not well in
a hand drill. Try Axminster for a supply.
It's also very easy to drill concrete, brick, brake disks and files.
The concrete needs to be a mix with little, or a very soft aggregate
in it. The bricks shouldn't be blue or over-fired. Brake disks are
soft cast iron. Even files are only hard on their skins, even before
you annealed them off-stage beforehand.
For a really good multi-material DIY drill, try the Bosch Constructor
series. I've just built a fireproof workbench for the glass kiln,
which involved a bunch of drilling through stacked asbestos cement
board and Dexion. These are carbide tipped and don't bunt in an
abrasive board, but they're ground sharp enough to drill steel with
hand drill pressure. They're also efficient enough to work with the
cordless drill and clear dust well enough to cope with cloying wet
On Mon, 22 Nov 2010 07:49:59 -0800 (PST), Andy Dingley
I think I saw this show as I was channel hopping. They were very, very
shiny almost like chrome vanadium sockets but who knows, may be they
had been polished and had several kilowatts of light shining at them.
The presenter was hilarious: "the man who fitted our bathroom had his
van broken into and his tools stolen. He had another job the next day
and didn't want to let the customer down, so he asked if he could
borrow my tools. I lent him these..."
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