In article ,
The Medway Handyman wrote:
Just received some 10 x 100mm Turbo Coach Screws from Screwfix.

The catalogue description reads: "Make any job faster with Zinc-plated,
Yellow-passivated Coach Screws, combining the unique design of the
Turbo Screw along with a self-cutting point. (May require pilot holes
in harder substrates.) Unique Rifled Shank for Easier Driving &
Reduced Splitting, Self-Drilling Point".

You simply cannot drive these into softwood without a large pilot
hole!!!! Let alone 'harder substrates'.

I tried with my 14.4v driver (loads of torque), a 350w mains driver and
a 500w variable speed drill. No chance at all, they go in for about
an inch and thats it.

I'm not surprised at 10mm diameter. Most drills will struggle with screws
half that size without a pilot.

--
*Black holes are where God divided by zero *

Dave Plowman London SW
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