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Posted to uk.d-i-y
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Cutting holes in galvanised steel
wrote:
Cicero wrote:
On Mon, 20 Aug 2007 10:32:44 -0700, teddysnips wrote:
We've had all our plastic guttering and downpipes (rainwater goods, if you
like) replaced with Lindab galvanised steel. Jolly nice it looks too, and
apparently maintenance-free for a good long time.
However, there was a problem with the gutters overflowing so a
representative from Lindab came to take a look, to make sure that the
correct type had been fitted. Apparently the problem was because the
builder had made the hole in the gutter above the "hopper" too small.
Because the builder's now off-site I think I'll have a go.
The Lindab rep said that there are two ways of doing it - drilling a
succession of small holes and then joining them up, or using tin snips to
cut the hole.
Maybe the Incredible Hulk could cut through this stuff with tin snips, but
I can't. I managed to drill round and then cut the joins between the
holes with the tin snips but it was a long and painful job. The main pain
is because the drill bit skitters about when starting the hole.
I don't really want to drill piddling little pilot holes, so do I have any
other options that I haven't considered?
Sorry to go on at length.
Edward
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If this is a case of enlarging an existing hole then a large round file
would do the job. If you don't like manual work you could use a file bit
(can't remember correct name) in your electric drill.
Cic.
Most file bits I've seen have the serrations running the wrong way,
and are thus so slow as to not be worth using. Do you know a supplier
with serrations running along the bit rather than almost across?
NT
My B+D ones aren't too bad, but for significant enlargement of holes in
steel I wouldn't bother.
I'd centre punch (using a nail if I didn't have a centre punch), chain
drill and finish off with a hacksaw blade - wrap one end in a lot of
gaffa tape if you don't want to buy a proper handle.
I reckon in this situation it is quicker overall if you drill pilot
holes: once round with e.g. 4mm on ~10mm centres, then once round with
10mm and there's only a little bit of finishing off to do with the saw.
C
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