TCT Core Drills

[The Medway Handyman]

After 2 years of venting tumble dryers, fitting waste pipes etc I finally decided to buy a TCT Core Drill set from Toolstation. Cheap enough @£25 ish so worth a punt and its seems pretty well engineered.

part number 41361.

It came with; 30, 50 and 110mm core. 200mm Hex and SDS arbors. 8mm Taper Guide Drill. 2 x Drift keys.

No instructions however! Since I've never used one before, a few questions;

Do I use the hammer action on my SDS?

I assume the best way is to drill straight through with an 8mm extra long drill, then drill from each side?

The 8mm taper drill guide looks pretty much like an 8mm masonry drill and appears to be a taper fit. I assume the drift keys are to remove it, but why 2?

I have a 620w Wickes SDS with clutch, powerful enough? Failing that I have a Wickes High Torque mains drill, around 85Nm torque - but no clutch, just a large side handle. Don't fancy using that much :-)

I've e-mailed Toolstation asking for instructions, but obviously no reply yet.

[John Rumm]

I believe with the TCT ones you may be able to. With a diamond one definitely not.

Yup, if it is a cavity wall. For solid walls it depends on how deep the core is. Typical diamond ones are a bit longer than the depth of a course of bricks or blocks so it is easy enough to do a course and break out the core if you want to drill from one side only. Usually for non cavity walls I drill from one side only.

For when you lose the first!

It will do the smaller ones. My 780W Makita will just about cope with the 110, but you have to take it carefully and make sure you drill a nice straight core so you don't add to much resistance.

Well 85Nm is going to be the same as about a 20kg weight on the handle

- might be ok if you are expecting it and positioned safely!

(think I would rather have a smooth shank arbour though to allow for some slip!)

Have you tried the screwfix site - they often have downloadable instruction books.

[Andrew Gabriel]

I find it varies enormously with the brick hardness. Old commons go through quite quickly. Drilling a newer house with quite hard bricks took ages. I have a 1050W Metabo and plugged it in through a power meter out of curiosity. With my full weight leaning in to the drill, it was using about 750W at top speed in low gear. On softer bricks, I wouldn't have been able to put such a force behind it. You need to keep an eye on the drill temperature and may need to cool the drill (run at full speed with no load) from time to time.

A friend of mine completely melted his bog standard B&D drill which wasn't man-enough for the job (when it did overheat, he didn't know how to cool it). Then he went and bought a cheap SDS with no clutch, and ended up in A&E having stiches in his chin after the core jammed and the drill spun round and whacked him. On another occasion where the drill couldn't spin round because it hit an ajacent wall, he ended up with a 90 degree twist in the arbour.

That's not reliable. You really have to have a drill with a safety clutch for this job.

[Malcolm Race]

I have drilled one 110mm core with the same drill using a hined diamond bit. I would not dream of trying again without a clutch. The drill coped, but I would not want to do many with that drill, and yes I did work from each side

Malcolm

[shaun]

So you can still get the bit out when you lose the first one?

IMHO: Seriously, don't use one without a clutch. It will snag (especially with the large core). Unless you have forearms like Charles Atlas it will rip out of your hands and you will break your wrist or your nose/cheekbone as my unlucky friend found out when the clutch on his B&Q cheapy failed.

[Martin Bonner]

[snip]

If the 620W isn't enough for larger cores, how about the following approach:

- Drill pilot hole

- Use large core as deep as it will go without jamming on both side (this gives a nice clean edge to the hole)

- Use the largest core the drill can cope with to remove the centre (might be worth getting an ~80mm core).

- Go back to the tried and tested ring-of-holes + SDS-chisel to finish off.

[John]

Someone somewhere is asking where his drift key is.

The pilot drill is a masonary drill. You can leave it in place when drilling a solid wall but it's not needed once the core drill is far enough in to guide itself. If you go though a cavity wall, either go through from one side (without hammer), or drill a pilot hole smaller than 8mm and core drill from both sides. This leaves a neater hole as you break out into the cavity. Remove the pilot drill as soon as the core is self guiding or the pilot bit will fall out and disappear into the cavity.

Use a drill with a clutch or make sure the kick when the drill snags is restrained. A pipe on the side handle and against the floor will do this. A clutch is better though.

John

[Skipweasel]

I must have arms like Charles Atlas then! My B&Q =A330 SDS drill snatched= =20 a few times doing a 110mm hole in hard brick - it wasn't nice but it=20 didn't throw me off the ladder.

What helped was keeping the hole wet. Apart from keeping the dust down=20 the slurry seems to help the drilling process.

--=20 Skipweasel. Never knowingly understood.

[Ed Sirett]

It would have to be very wet, I tried that way but did not get it wet enough. It would have to be jetted into the hole during drilling. Half wet is much much worse than dry.

[Ed Sirett]

Like you I initally bought a TCT unit. The results were noisy dusty and the bits didn't last long. Eventually I had to switch on the hammer to make any progress.

I'm on my second lot of diamond cores now (theft not wear) except for the big ones ( 117 and 127.) They do seem to last a long time.

I'm on my 6th or 7th SDS drill (All bar one due to theft).

The hardest for me is keeping the line absolutely level and square or else the drill jams and the clutch (you better have one) slips.

[The Medway Handyman]

So hammer is OK? Thats what I was unsure of.

I don't think I'd ever get the investment back. Occassional use with me, different if I were a full time plumber.

I simply want to speed up the occassional job & make neater holes.

Thanks, I'll keep an eye on the level & square bit.

You obviously suffer a great deal from theft - are you in an especially bad area?

[John Rumm]

You can get proper wet core drilling systems if you really want to do it this way...

[John Rumm]

How many holes did you get from the big ones out of interest?

I have got a feeling my 107mm Armeg one must be down to its last 20% of tooth depth, and it has probably only done 8 cores so far (most in hard brick mind you).

That could make one want to take someone warmly by the throat! ;-)

[John Rumm]

As long as they are earning you at least £10 per hole, I would have thought a diamond core would pay for itself...

[The Medway Handyman]

In theory yes. In the last year I've vented 2 tumble driers and put about three waste through walls.

Trouble is I could justify so many tools that way!

[John Rumm]

And that is bad because...? ;-)

Tricky I suppose, if customer wants a hole but is paying for the time, then it taking less is not necessarily an advantage (to you). I suppose that sort of job you could quote a fixed price for though.

[Ed Sirett]

Sorry, I put things rather badly (the 117 which is my workhorse is still going well) after about 8 years it's probably done 50 holes! The 127 was bought specifically to install a Baxi Brazilia. The larger core drills live in the store room not the van.

Most of mine are the normal quality from a PM and Some s/fix.

I'm seriously thinking of obtaining an electric fence generator. Yes I know it's illegal. I'd probably get zapped by it more than the scumbags.

I have no off road parking, not that that would help just a better MTBF (Mean time between feft). The average is running at about 1/per year. Never had the van taken outright. Of late the break-ins have been targetted toward the power tools. They used to be a random selection of tools.

Each time it happens I get a nice letter from the police saying ...as yet no one has been arrested...

[Ed Sirett]

I'm not sure on TCT. ON diamonds it's certinaly wrong. When the TCT bits are finished maybe the hammer is the only way to finish both the job in progress and the drill.

once you have the tool you find jobs that otherwise you would not do.

Yes a very great deal. Better of late as this is only the second time in

4.5 years on the new van, 5 attempts with 3 holding out. Each failed attempt takes its toll on the existing locks. For me they always come at night in bad weather. Putting a Kasp on and off all day is impractical. Taking all the tools to the store each night is not on. Maybe just taking the sds,jigsaw and cordless is possible.

every one asks "Can't you insure?" - yes but the premiums will far exceed the claims let alone that they will impose impossible conditions.

London is not really part of the UK. It is part of a set of locations around the globe belonging to "Cosmopolitia". The laws appear to be the same as the surrounding nation but there is too much (far more serious) crime so enforcement is patchy.

At the end of the day I simply budget £600/year for theft. If I started losing more than that then I will consider a new van (which seemed to give me a few years of no thefts).

[The Medway Handyman]

I don't tend to spin jobs out to be honest and yes, mostly that sort of job is an estimated price.

[The Medway Handyman]

Ah. London. That explains things.