I wonder if anyone can help. I need to fix 15 x 2 metre long metal rails
("T" section) vertically to a concrete wall. I'll be using those 'self
tapping' bolts that require a 6mm hammerdrill bit. I will need to drill 8
holes in each rail.

Q.1. How much larger will the rail holes need to be 6.5, 7.00, 7.5mm Etc?

Q.2. Nowadays, which drill bit manufacturer is considered high quality?

Q.3. Is there a good, reliable on-line source to the above? Many thanks.

Nathaniel.

Natty Takeup wrote:
I wonder if anyone can help. I need to fix 15 x 2 metre long metal rails
("T" section) vertically to a concrete wall. I'll be using those 'self
tapping' bolts that require a 6mm hammerdrill bit. I will need to drill
8 holes in each rail.

Q.1. How much larger will the rail holes need to be 6.5, 7.00, 7.5mm Etc?

Sounds like seven should be ample - do the fixings not specify a
clearance hole?

Q.2. Nowadays, which drill bit manufacturer is considered high quality?

What sort of drill? For a SDS bit then most makes will be fine as long
as you avoid the 3 for a quid range from a pound shop.

For conventional masonry drills, then the Bosch multimaterial bits are
very good.

Q.3. Is there a good, reliable on-line source to the above? Many thanks.

Take your pick: Screwfix, Toolstation, Axminster etc.

--
Cheers,

John.

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"John Rumm" wrote in message
o.uk...
Natty Takeup wrote:

Thanks John my virgin.net newserver hung onto this post for a couple of
days, so I repeated it on news.individual (above) under "drill bits info
please".