Diamond core drill - this is getting ridiculous - which brand?

[David]

I'm almost through my first brick but my rate of progress seems to have almost stalled. I am now wondering if this sodding extra hard brick has worn down the diamond core.

I have

at £25.

Other options are:

also from Mexco at £33.32

at £26.49

at £38.99

at £44.99

The two most expensive Screwfix ones don't have a slotted body. Not sure why, may have something to do with dust extraction.

Any experience of any of these drills?

The way this is going, with the benefit of hindsight I would probably have been better off hiring something to do this job.

However I had no idea the brick in this area was so hard.

Time to review if hiring a core drill is now the way to go, or if I jjust need one drill per brick!

Cheers

Dave R

[tabbypurr]

On Thursday, 23 August 2018 16:03:32 UTC+1, David WE Roberts (Google) wrot e:

Hiring someone is seldom the solution.

I would not pick diamond any time unless genuinely needed - it's far more m oney than TC so you get a lot less of it. TC is the practical option. I've too much experience of diamond tools that either contain very little diamon d or lose it all quickly.

If it's going that bad why not drill in half an inch from each side then SD S the remainder out with a pointed chisel.

NT

[David]

bit-52mm/3489r

Thanks for the reminder about TC.

Unfortunately I can only drill from one side because of a hanging wall outside, so it has to be all done under the sink.

Nothing reasonable to hire at the moment.

I may buy a TC bit and see how that goes.

Cheers

Dave R

[David]

Hum - slightly different sizes.

50mm instead of 52mm.

I wonder if they fit on the same arbor?

[tabbypurr]

take it with you.

NT

[Chris Hogg]

Has the drill become 'blunt'? My experience of diamond cutting tools is limited to diamond saws of about thirty years ago, but over time and with a lot of use they would become 'blunt'. That is to say, the metal in which the diamonds were embedded would get smeared over the diamonds and they lost their cutting action. The solution was to cut into a silicon carbide whetstone to abrade off the surface metal and re-expose the diamonds. Things may be different today with modern drills, of course.

[FMurtz]

You need those blokes that bored that hole into the bank.

[Yendor]

What sort of Drill are you using, as opposed to Drill Bits.

SDS Plus or SDS Max or Hammer Drill?

[David]

bit-52mm/3489r

SDS Plus.

However the core bit isn't designed to be used with hammer action, so as far as I can tell all this does is match the drill shank on the arbor.

Cheers

Dave R

[Yendor]

I work in Aberdeen, and regularly drill through granite. Best thing is to hire a Core drilling kit from the likes of Brandon Hire.

Something like this goes

[John Rumm]

Have the teeth visibly shortened?

What rotational speed are you drilling at? (you should be ok with

1000rpm on a smallish core like that.

Not those specifically - but I have used TS own brand in the past, also Armeg. Marcrist are usually rated as good.

Even in hard stuff you ought to get at least two or three holes per core bit. You may find dipping in water from time to time helps. (lubricates and cools it a bit)

[John Rumm]

Cutting into a bit of sandstone also works for a "glazed" drilling surface...

[GB]

Or measure them. I guess the 10mm shown on the side is the tooth length?

I notice it says "Not to be used on hammer action." Wouldn't it be an awful lot quicker to have a drill bit that you can use on hammer? (I've never had to do this job, so please excuse the foolish questions.)

[David]

I rubbed the diamond area to see if there was any diamond left and after that it seemed to cut a bit better. So I started cleaning it regularly with a wire brush which seemed to help.

I also made an effort to vacuum out the brick dust very often.

These two things seemed to improve things, and I am finally through the first brick.

Going to try SDS drill and chisel on the second (outside) brick from the inside to see if that speeds things up.

Cheers

Dave R

[John Rumm]

If you don't mind a huge "exit wound"!

[John Rumm]

Diamond cores don't have teeth as such - just wide areas of abrasive, with some gaps to clear the dust. They cut the masonry with an abrasive action, so the hammer action will not help - since you want constant contact and pressure.

The TCT core drills with little carbide teeth, can be used with hammer, since that helps drive the teeth into the masonry, while the rotation excavates the spoil.

[Fredxx]

That is why I would attack this from both sides

I would use a long drill the same nominal size as the pilot through the whole wall.

Even a small drill can create a large exit wound!

[David]

Normally I would do that but I can't get directly at the outside because of a retaining wall which keeps the patio away from the house.

I managed by drilling with a long drill from the inside to establish where the hole is, then attacking the outside at an angle with SDS drill and SDS chisels.

Fortunately I had managed to drill at one end of a brick so three sides of the hole were mortar, which made things easier. I just cut the end of the brick off. It will take a bit of filling in but I plan to use expanding foam finished off with mortar. Also for filling the old hole.

Cheers

Dave R