Discuss am i right in thinking.... in the Electrical Forum area at ElectriciansForums.net

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i=p/u

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have to install a fan tomorrow night and drill through red brick wall, am i right in thinking a when using 4inch core bit on red brick i have to start in reverse to stop the brick breaking ....

think i read it before on the forum.. il take your advice gladly.. ya know me love free stff
 

Archy Styrigg

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have to install a fan tomorrow night and drill through red brick wall, am i right in thinking a when using 4inch core bit on red brick i have to start in reverse to stop the brick breaking ....

think i read it before on the forum.. il take your advice gladly.. ya know me love free stff
You like a free stiff? Steady boy!

Just start slowly so it cuts a neat circle then get stuck in, always worked for me.
 

Des 56

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Slight angle,so that any water/moisture runs out not in
I would also expect running the core bit in reverse would be more chance of throwing you and the bit off the wall,
 
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i=p/u

i=p/u

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cheers , i only ask as ive seen few fans installed when out and about and seen red breaks slightly broken. so ty
 
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i=p/u

i=p/u

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if im putting bit of 4inc pipe in wall the fan wouldnt go on then....
Slight angle,so that any water/moisture runs out not in
I would also expect running the core bit in reverse would be more chance of throwing you and the bit off the wall,
 
G

Guest55

Wouldnt make any difference forward / reverse as the core cutting teeth arent angled.
;-)
 

Des 56

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Wouldnt make any difference forward / reverse as the core cutting teeth arent angled.

Your probably too right there Biff,its more the expectation of where the load usually comes on the wrists I was thinking


if im putting bit of 4inc pipe in wall the fan wouldnt go on then

I can honestly say,I have never had that problem
When I mentioned slight angle,I really meant slight angle,








 
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darkwood

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Nobody seems to have mentioned to drill a long pilot through first so the cutter isn't been held back by the pilot bit then make sure you drill in from the outside brick to stop unsightly blast out, it dont matter too much inside as its covered by plaster.
 

DNS1

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Exactly what I was going to say darkwood!

This thread immediately got me thinking of another a few months ago when I guy was tearing his hair out trying to repair the blast damage that his customer was going mad about!
 
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i=p/u

i=p/u

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well im hoping no need for plaster, nice clean cut... but maybe im dreaming
Nobody seems to have mentioned to drill a long pilot through first so the cutter isn't been held back by the pilot bit then make sure you drill in from the outside brick to stop unsightly blast out, it dont matter too much inside as its covered by plaster.
 

Strima

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My favoured method is to run a pilot through first, then cut in from outside using the core guide about 10mm, then cut from inside all the way through, 99% of the time I've managed to avoid blast out.
 

darkwood

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well im hoping no need for plaster, nice clean cut... but maybe im dreaming
easy way drill from both sides to cavity, but getting it to drill straight is an art form .... running of a mm or 2 could stop your 4" sleeve going through hence its best if possible to pass through all one way.

The customer has the right to sue you if you leave unsightly blast out and she will probably get the costs of rectifying the damage back + legal fees
 
M

MarkieSparkie

Nobody seems to have mentioned to drill a long pilot through first so the cutter isn't been held back by the pilot bit then make sure you drill in from the outside brick to stop unsightly blast out, it dont matter too much inside as its covered by plaster.
The main advantage of dry cutting outside to inside with a diamond core is the majority of the dust and mess is deposited outside rather than inside the property and is easier to clean up. This is often only practical on the ground floor or if scaffolding is erected.
If you are getting 'blast-out' using a diamond core (cutting in either direction), your technique is wrong, you are applying to much forward feed pressure. The forward pressure should be minimal, just enough to keep the core centred and on track, the diamond lands will cut faster, more cleanly and with less heating of the core. Using the correct technique the exit should have no discernible break-out, or minimal break-out if the exit is through loose dry plaster.
Some of my left-handed colleges prefer to core drill with the drill in reverse (anti-clockwise) rotation, they say it's more comfortable, however this technique is not generally recommended as it risks unscrewing the core from the arbor.
Generally, a long pre-drilled pilot hole through the wall is not needed, but may be of advantage when cutting extremely hard materials eg. granite, or you are a novice core drill user and require the greater guidance. All that is required is to start the core with the pilot drill attached, once the core is centred and the diamond lands have cut to at least half the core's full depth, the pilot drill can then be removed, and rest can be cut with just the core, without it deviating significantly from your initial trajectory providing the forward feed pressure is not excessive.
 
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tamz

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Why would any right minded person want to use a core drill in reverse? It will unscrew itself. When you heard that one you were either on the beer or talking to a retard.

If you are doing this stuff regular it is well worth your time (time is money) to spend a few quid on a decent gun and cans instead of using some toy that can go backwards.
 

Geordie Spark

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have to install a fan tomorrow night and drill through red brick wall, am i right in thinking a when using 4inch core bit on red brick i have to start in reverse to stop the brick breaking ....

think i read it before on the forum.. il take your advice gladly.. ya know me love free stff
NOT a good idea as the core bit is screwed onto the arbor with a right hand thread. Running it in reverse will cause it to unscrew & fall off.

I used to make these things back in the '70s when it was a specialist item. I also made bloody big circular saws for cutting holes through reinforced concrete floors for escalators & lift shafts to go through.

We once got a new designer bloke who designed a floor saw with a 36" diameter blade for which he specified a right hand thread for the nut which held the blade on. Problem was, it really should have been a left hand thread as when it was put on test the nut unscrewed itself & the blade running at about 300 RPM flew off & chased a couple of blokes right across the yard!! :74:

I knew exactly what would happen when I first saw his drawings but didn't tell him - after all, he had his HNC and wonderful salary, I only had C&G and a not very good wage.

It wasn't long after that that the new designer left the company .... ;)
 
M

mackers

pilot hole first, then drill from outside into cavity then from inside to the cavity, if your hire the kit i advise to pay for the hover attachment save so much time when cleaning up! red brick dust on growt etc is a nightmare!
some anti-vibration glovestoo, my hands r knackered known after 25 yrs lol
 

Rockingit

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I've always found that the best method for core drilling is to lubricate the entire process with a barrel of patience. You only get it wrong when trying to rush, and it's not something that likes to be hurried.
 
B

BigBreakfast

'originally Posted by Mackers
"pilot hole first, then drill from outside into cavity then from inside to the cavity, if your hire the kit i advise to pay for the hover attachment save so much time when cleaning up! red brick dust on growt etc is a nightmare!
some anti-vibration glovestoo, my hands r knackered known after 25 yrs lol" '



If you can get a hover attachment you can drill it all from outside at any height with ease and no need for scaffolding. :)
 
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M

mackers

If you can get a hover attachment you can drill it all from outside at any height with ease and no need for scaffolding. :)
LOL, now that would be worth the extra cash! hoover!the thought of it is making me chuckle!!!!!!!!!!!!!
 

timbobelfast

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Make sure you measure well because you don't want to pop out behind the soil stack.

Also get yourself a good set of ear defenders because you ears will be ringing all day lol!
 

Fin170

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Best technique I've herd is

"Best not to own a core bit or the right drill, get the builder to do it" :)

Given I've herd some people spend 8 hours drilling through cob before it may be in the customers best interests....and mine. Think I'll pattern a compact dehumidifier that connects to the waste pipe, I'm not keen on spending hours up a ladder playing around with grills and aggressive drills
 
D

drew35

So what do you go through with first to stop the break out from the pilot drill???

Just go straight through with a core bit, why is it causing breakout, its not impacting?

I have never caused breakout with a core bit in any kind of brick- block work?
 

Geordie Spark

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Make sure you measure well because you don't want to pop out behind the soil stack.

Also get yourself a good set of ear defenders because you ears will be ringing all day lol!
It happened to me. I was 4 floors up in an old warehouse that was being converted into luxury apartments & was core drilling a 4" hole for a boiler flue through the two foot thick sandstone wall.

I got all the way through - only to find the core bit hitting the back of a bloody great cast iron plate that was fixed to the end of a tie bar. :angry_smile::mad2:
 

darkwood

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So what do you go through with first to stop the break out from the pilot drill???

Just go straight through with a core bit, why is it causing breakout, its not impacting?

I have never caused breakout with a core bit in any kind of brick- block work?
Your just lucky then and pilot bit will only have minor blast and will be covered by the 4" hole your making, blast out is caused when you are close to breaking through and the pressure and vibration of the cutter can fracture the brick/stone which usually breaks out leaving an unsightly chipped external stone or brick work which isnt covered by the grill, correct drilling manor can reduce this but you cant predict the fractures so always best to avoid putting yourself in that position in the first place.
 
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i=p/u

i=p/u

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well to let you all know, i drilled 10mm hole through wall from inside to out, then drilled with core cutter outside too in, which took ages and not much gain, so got 20mm drill bit out and drilled maybe 10 holes within the the 110mm circle and then took the sds chisel action too it and it was far quicker. and battered the the 4inch pipe in with hammer

core drill was too slow
 

Geordie Spark

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well to let you all know, i drilled 10mm hole through wall from inside to out, then drilled with core cutter outside too in, which took ages and not much gain, so got 20mm drill bit out and drilled maybe 10 holes within the the 110mm circle and then took the sds chisel action too it and it was far quicker. and battered the the 4inch pipe in with hammer

core drill was too slow
Oh ..... you rough ar$e you !!! :disappointed: :wink_smile:
 
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