TCT or diamond core drill?

[Fred]

Hello again,

I would like to add a fan to the downstairs cloakroom. I need to drill a hole in the wall. Is it easier to cut an oblong out and use rectangular ducting or should I use a core drill and take a 110cm circle for round ducting?

I see that the catalogues list TCT core drills and diamond core drills. Is one better than the other? Do I need a special drill to spin them?

Do you think that 10cm fans are any good? Should I upgrade to 15cm?

Thanks.

[Ed Sirett]

Try googling the archives. We had this thread a few weeks ago.

Diamond much better than TCT, both need drill with safety clutch, both much more expensive than by hand.

10cm is good for a bathroom certainly for a small cloakroom. Possibly not good enough for a kitchen.

[John Rumm]

The mount on the wall extractors usually expect to be sited directly over a round hole. If you are ducting then you have more options.

Diamond is better, but as a one off, TCT will probably cope unless you have very hard bricks etc.

You need a powerful drill to spin them. I have managed to drill a 107mm core with my 780W SDS on a number of occasions, but you have to take it nice and gently and try to keep dead straight to avoid snagging the bit. Usually the clutch on a SDS is set to let go a little too soon for cores above 70mm or so. Dedicated core drills usually have a bit more power, and a more aggressive setting on the clutch. (powerful drills without a clutch are a recipe for various injuries when the core snags)

They can be quite effective in the smaller rooms.

[Fred]

Sorry if this is a daft question: how do I know if my drill has a clutch? Does the fact that I don't know mean that it doesn't? Do all sds drills have clutches? What about "traditional" drills?

[Fred]

Thanks. I found the recent TCT core thread and have read that. I think it was the TCT set being discussed that I had seen and thought about using.

How do I search the archives? I didn't even know there were any.

[John Rumm]

groups.google.com archives pretty much all the text based usenet feeds. You can either use the advanced search facility to search a particular group, or include "group:uk.d-i-y" in your search string.

[John Rumm]

Actually a good question - and there is no simple answer to it.

The "quality" SDS machines will have a clutch, as will anything that mentions in its advertising blurb that it has one. However don't assume all SDS machines do. Some of the budget ones are renowned for not having one (google back a few years for accidents with NuTool ones that had a habit of slipping out of chisel only mode into chisel + rotation mode!).

Anything advertised as a "core drill" will also certainly have one.

Most traditional drills and hammer drills won't have one.

[Fred]

I was always taught that google was not the way to read news ;)

Does it obey X-no-archive headers? If so, it may miss a lot of the posts but if it ignores it, that's naughty!

[John Rumm]

Its not. But it is the way to search archives of it! ;-)

It does respect the no archive header - so indeed there are gaps (although it keeps them for a few days). Often enough of the non archived posts are quoted in other replies to let you figure out the gist of it.

[Fred]

Thanks. That's useful to know. It must cost Google in terms of storage. What's in it for them? Do they carry advertisements?

[John Rumm]

I think in the grand scheme of things the whole of usenet (if you ignore the binary groups they don't archive) is almost insignificant in the terms of the storage that google use for other stuff. I have not seen recent stats for a full newsfeed - but it might grow at a few gig a day. It sounds like loads to us, but probably represents 10 seconds worth of consumption used by youtube or similar. The older historical stuff (say up to the late 90's) is only a few gig in total.

As to advertising, yup you get a few sponsored links listed on the right. So that is potential income from their advertisers with every search.

[Fred]

I notice that the Screwfix catalogue has a mixture of 2kg SDS drills some with clutches and some without; the same is true of the 6kg drills. I will have to double check whether mine has a clutch or not.

Thanks again.