Core drilling - wet or dry?

[G]

Got a marcist core drill setup to make some holes in walls.
The drill 'bit' I've got will do wet or dry.

What are the pros and cons of either?
(Have had a bit of a google, but so far mostly just found stuff trying to sell me the bits I already have .)

[robs321]

Dry is fine, having a dust extractor, or the old womens best dyson will help stop the bit jamming!

[Raffles]

Using water doesn't just clear the debris, it also cools the drill bit and helps to prolong it's life.
____________________
A good loser will always be a loser.

[G]

Got the attachment for water and as it's a 300mm bit, going to be less hassle to use water I reckon.

[Ariel Badger]

water will keep things cool and save your cutter as well as clearing debris and keeping the dust down although it will make a mess and create a shock hazard, make sure you have a breaker in your circuit.
____________________
Bikers make great organ donors, get 115 on your licence today.

[G]

's got a breaker built in... And it's designed for water with a proper attachment, do hopefully should be ok.

[Howling TerrorOutOfOffice]

Drill it straight, anything above shoulder height use some steps.

Earplugs are nice.
____________________
Diabolical homemade music Bandcamp and Soundcloud
Singer songwriter, Artist and allround good bloke Listen to Andrew Susan Johnston here
The Harry Turner Project

[Pete.]

What size holes are you making G?
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[G]

78mm x 500mm. So going to make a pilot hole right the way through, then drill from either side using a guide rod on my 78mm x 300mm core drill bit.

[Pete.]

Okay.

Generally, to distinguish between wet and dry bits you look at the tooth size and spacing. If there is more tooth than gap it's a wet drill. More gap than tooth it's a dry bit. Some are borderline and I could tell right away by looking at it but that's the rule of thumb.

If it's concrete or blocks denser than 7 newton you have to drill wet.

If it's an external brick wall in this weather your you have to do it wet. Dry cutting requires that the bricks are holding no moisture whatsoever. If you try to dry-drill damp bricks, especially that depth, you'll burn out the drill.

At 500 deep, you're pushing it even with bone dry bricks because the dust will wear out the side of the drill tube before the teeth are worn out. The end will go thin and the teeth will fold over.

Wet drill - cut (a lot) faster - longer life - no snagging, need to clean up mess and wash the wall down as you go.

Dry drill - less messy but lots of airborne dust, slower drilling, risk of snagging, harder to get the core out of the bit, faster wear rate and a lot more noise.

For me, and I've been diamond drilling for more than 20yrs, it's a no-brainer - drill it wet unless you can't use water.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Pete.]

Oh, and forget the pilot hole - you won't drill it as level as the diamond and the pilot rods are useless too. Straight through with the diamond is the only way, maks a 300x300 timber setsquare to line it up for the first few inches.

The Marcrist flex handheld is a good enough tool but watch out for bottom gear it's an arm-breaker. Haven't used one for a long time though so the new ones might be better, but they are also very expensive to fix and suffer a weak gear selector mechanism.

I could lend you the proper gear for a couple of days including a 500 long bit if you can get to Kent to collect it.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[G]

No problem doing it wet, so definitely will . The drill bit is a Marcist one that says it will do both wet and dry.

The pilot hole is in the hope that the two sides will meet up if drilled from either side. Otherwise, I could presumably get an extension, but I don't have one at the moment.

Unfortunately Kent is a bit too far from my current location. Ta for the offer, however.

[Pete.]

300mm long sounds like a 3/4bsp thread bit with thin walls. They tend to wear faster because they have softer segments as they are designed for lower-powered machines. I would ask for a longer drill bit as all it is is more tube (the cheapest part of the drill) and not much more to buy. If you get less than 10mm out of line between drilling each side you'll be doing well and half a hole out would be common for a novice.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[G]

1 1/4" thread; walls seems reasonably sized, but obviously far from an expert here! It is the weediest of the range I believe.

It's a Marcrist CCU850X series. (Oh and it's 350mm long, not 300mm, my bad.)

I couldn't find any longer drill bits in the size I wanted. (Probably looking in the wrong place.)

So, would I be better to try and get an appropriate extension (think I've seen such things) as I really could do with it going straight through.
Appreciate I would then have to remove the core bit before continuing.

[Pete.]

Aah 1 1/4" BSP is the better size. Have a look in the directory for a local diamond drilling firm, they might be able to sell you a 500mm long bit or lend you a rod. I could post to you if you get stuck.

What are the holes for?
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Ariel Badger]

At 500mm long I doubt it is for a glory hole in the swimming baths
____________________
Bikers make great organ donors, get 115 on your licence today.

[G]

Cheers all.

Special to pete.

I ended up going for an extension to use on one hole.
I gave up on my plan of steel lining it; it turned out it was going to be troublesome for other reasons too.
This meant the other hole which was way of course, I went through from the other side and managed to make it meet well enough (I was quite suprised, expecting to just have two big holes completely missing each other!)- had to make up a wooden bracket thingy to hold the drill to start that one off as the wall was rougher there and it kept jumping about.

Overall, probably should have just got a company in to do it from the start.