Help with a diamond core bit

[rpfn140378]

Hi guys.

I need to drill a 100mm diameter hole in my kitchen for the extractor fan ducting. After googling a bit I found a reasonable price on one website. I don't need anything too professional because I'm a DIY person and I'm not doing this sort of holes everyday. Instead of hiring it for £50 I can buy one and keep it to use in any other property that I can move to. 

I always like to buy professional tools to do my bits and pieces but in this situation I don't think I need something too expensive. 
Please check the link below and tell me what you guys think: 

http://www.bamfordtrading.com/products/ ... drill.html

 

[AndyT]

Not really a woodworking or hand tool question but never mind...

Silverline is the 'house brand' of Toolstation who are in the same group of companies as Wickes and Travis Perkins; the tools are also sold by many other outlets. It's a budget range, mainly made in China. So it's probably the ideal grade for a one-off use such as yours.

You will need to have an SDS drill to use it - it won't fit in an ordinary three-jaw chuck and even a decent corded diy drill would not be beefy enough.

The alternative approach is to buy a long masonry bit of about 12- 18 mm diameter and drill a ring of small holes which you then connect with a cold chisel and lump hammer - but this is a lot more practical if you are drilling through a solid wall, not a cavity one.

 

[rpfn140378]

Not really a woodworking or hand tool question but never mind...

Silverline is the 'house brand' of Toolstation who are in the same group of companies as Wickes and Travis Perkins; the tools are also sold by many other outlets. It's a budget range, mainly made in China. So it's probably the ideal grade for a one-off use such as yours.

You will need to have an SDS drill to use it - it won't fit in an ordinary three-jaw chuck and even a decent corded diy drill would not be beefy enough.

The alternative approach is to buy a long masonry bit of about 12- 18 mm diameter and drill a ring of small holes which you then connect with a cold chisel and lump hammer - but this is a lot more practical if you are drilling through a solid wall, not a cavity one.

Thanks for your reply. 
The hole is to be drilled in a cavity wall and I've got the decent sds drill. Anything you can recommend that doesn't cost a lot for a person like me to drill a hole with a diamond core once in a blue moon?  

 

[AndyT]

Anything you can recommend that doesn't cost a lot for a person like me to drill a hole with a diamond core once in a blue moon?  

Not really - I don't think you'll find anything cheaper that would do the job.

 

[GazPal]

Not really a woodworking or hand tool question but never mind...

The alternative approach is to buy a long masonry bit of about 12- 18 mm diameter and drill a ring of small holes which you then connect with a cold chisel and lump hammer - but this is a lot more practical if you are drilling through a solid wall, not a cavity one.

I agree it's not a woodworking question, but it does fall within the realms of hand tool work if considering ye olde worlde method involving hand drilling (Hammer & star point chisel). As a one-off project I'd struggle to justify buying a core bit when the straight forward method Andy's mentioned is certainly fit for purpose and a darned sight less expensive financially. If your wallet is capable of carrying the investment in a core bit, by all means go for it.

The following is suitable for use on most masonry/brick wall types;

Drill the perimeter of the target hole (Any opening shape) using a 12mm-13mm bit at 25mm-38mm between centres, BUT also drill several holes at the centre of the intended opening. This effectively relieves the centre of the proposed opening and helps release the walling material. This makes excavation easier, as you create the hole from the centre outwards and a surprisingly clean sided opening when using cold and bolster chisels.

 

[Jacob]

I'm faced with this task soon - 8no 5" holes through 2' of limestone rubble walls. So that'd be about 15no 12mm holes per 5" hole.
By the time this is done and the centre knocked out I can't help feeling the core drill is going to be not much slower - but it will do a much neater hole with less disturbance to the surrounding masonry, no hammering etc etc.
Limestone around here is very hard - would the small drill approach still be best?

 

[GazPal]

I'm faced with this task soon - 8no 5" holes through 2' of limestone rubble walls. So that'd be about 15no 12mm holes per 5" hole.
By the time this is done and the centre knocked out I can't help feeling the core drill is going to be not much slower - but it will do a much neater hole with less disturbance to the surrounding masonry, no hammering etc etc.
Limestone around here is very hard - would the small drill approach still be best?

I'd opt for diamond core every single time with random rubble or dressed stone walling.....Especially in terms or preserving both sanity and the existing facing on the stone work if the lime mortar isn't already dead. We had to punch quite a number of holes through random rubble (Wyn Flint) walling during a farm re-build/revamp project before the advent of readily available diamond core bits and pretty well had to re-build the 18"-24" thick stonework around the fitted vents, windows, etc..

The small drill approach is still tenable if the rubble size isn't too fine, but random rubble walling has a habit of being bedded in lime mortar (Sometimes reinforced using horsehair) with larger stone as facing work and rubble fill within the two outer stone leaves. I'd opt to drill a test hole before deciding on the best approach, plus plan for the worst in terms of remedial work.

 

[Lons]

Gary is spot on if it's a random rubble wall. I've done a couple and in both cases (600mm thick walls) the centre was just filled up with loose cr*p which falls down as you drill.

I regularly drill 100mm holes for kitchen extraction and I have a decent DeWalt SDS drill and several cheap tungsten tipped core drills and a couple of screw on extensions. I buy these from cheapo wholesaler JTF but have seen identical drills in some of the cheapie shops, (Yorkshire Trading and one of the bigger chains though can't remember the name at the minute. Core drill costs less than £10 and 150mm extension under £5. they will go (carefully) through all but the hardest brick without problems and initially I bought 2 each at 100mm and 50mm but after dozens of holes, I haven't used the back ups yet.

If they didn't work I'd have thrown them away as it's my business and time is money etc.

Shame you aren't in the North east or you could borrow mine.

Bob

 

[Jacob]

Thanks for that.
I've done one 5" hole here with a core drill and some hire kit. Seemed to take half a day, but nice clean hole with no breakout through the old render.
I might buy the stuff instead and sell it on if not knacked. Don't want to finally destroy my Bosch SDS it's too small for the job anyway.

 

[rpfn140378]

Here it goes another set:
http://www.ebay.co.uk/itm/160822901748?redirect=mobile

Let me know what you guys think

 

[Peter T]

My son had a new central heating boiler fitted a while ago and the plumber had a large set of core drills plus a huge SDS drill for cutting the hole for the flue.

Maybe you could talk to your friendly neighborhood plumber??

Good luck,

 

[dickm]

Shouldn't really continue this thread in a hand tool section, but......

In the box with my £25 Kango 950 (thanks to SWMBO who realised what the advert for a Cango meant!) was what looks like a TCT toothed 4" core drill. BUT, there didn't appear to be an arbor to take it. It has a taper in the centre, no other means of retention. Question - does anyone know what arbor this needs?

 

[Dusty]

If it is a Diamond tipped as in the link , I would switch the hammer off as it relies in just coring plus you will mess the diamond up , you only want to use the hammer on the SDS is if it is a TCT ..Take a look on you tube .

cheers

 

[Lons]

I really don't see the problem for a one off hole :? Sledge hammer to crack a nut is what comes to mind.

Easy to check how hard your brick / stone is. Just test drill with a standard masonary bit on hammer setting. The core drills as in picks are my cheapies as mentioned and have drilled dozens of holes and good for dozens more. Last drilled were 3 of the 100mm + through my own extension which is build of very hard Bradstone concrete blocks outer / 7 n conc blocks inner - no probs!
Largest has the extension shaft fitted which just screws on (can be a pipper to get off again tho :lol: )

.

Bob

 

[rpfn140378]

My son had a new central heating boiler fitted a while ago and the plumber had a large set of core drills plus a huge SDS drill for cutting the hole for the flue.

Maybe you could talk to your friendly neighborhood plumber??

Good luck,

Thanks for your advice. When I had my boiler fitted last June the plumber told me that if I needed to make a hole for the ducting he was very pleased to lend the drill and core bit to me. The thing is, a few weeks ago I called him up and he said that he couldn't help because he was using it to make a hole for the boiler flue in someone's house and the arbor snapped. So, was he telling me the truth? I know that a professional dry core set is very expensive, so if he wasn't keen in lending it to me he shouldn't have offered to lend it to me in the first instance. 

 

[Phil Pascoe]

Maybe truth reared it's ugly head?..............

 

[GazPal]

My son had a new central heating boiler fitted a while ago and the plumber had a large set of core drills plus a huge SDS drill for cutting the hole for the flue.

Maybe you could talk to your friendly neighborhood plumber??

Good luck,

Thanks for your advice. When I had my boiler fitted last June the plumber told me that if I needed to make a hole for the ducting he was very pleased to lend the drill and core bit to me. The thing is, a few weeks ago I called him up and he said that he couldn't help because he was using it to make a hole for the boiler flue in someone's house and the arbor snapped. So, was he telling me the truth? I know that a professional dry core set is very expensive, so if he wasn't keen in lending it to me he shouldn't have offered to lend it to me in the first instance. 

Perhaps an opportunity to offer to repay his kindness by replacing the arbor as a means of payment? Such a simple offer/act could pay dividends if you consider the risk to your own equipment, because an under powered drill can easily burn out during such heavy use. The fact of the matter is circumstances quite often change like the wind in terms of construction work and activities and losing a specific piece of kit to breakage/wear and tear is a prime example of such spanners in the works. Having been in similar situations on a number of occasions, I'd tend to give your plumber the benefit of the doubt, offer to replace the arbor (If it's not too expensive) and see how things go from there.

 

[rpfn140378]

My son had a new central heating boiler fitted a while ago and the plumber had a large set of core drills plus a huge SDS drill for cutting the hole for the flue.

Maybe you could talk to your friendly neighborhood plumber??

Good luck,

Thanks for your advice. When I had my boiler fitted last June the plumber told me that if I needed to make a hole for the ducting he was very pleased to lend the drill and core bit to me. The thing is, a few weeks ago I called him up and he said that he couldn't help because he was using it to make a hole for the boiler flue in someone's house and the arbor snapped. So, was he telling me the truth? I know that a professional dry core set is very expensive, so if he wasn't keen in lending it to me he shouldn't have offered to lend it to me in the first instance. 

Perhaps an opportunity to offer to repay his kindness by replacing the arbor as a means of payment? Such a simple offer/act could pay dividends if you consider the risk to your own equipment, because an under powered drill can easily burn out during such heavy use. The fact of the matter is circumstances quite often change like the wind in terms of construction work and activities and losing a specific piece of kit to breakage/wear and tear is a prime example of such spanners in the works. Having been in similar situations on a number of occasions, I'd tend to give your plumber the benefit of the doubt, offer to replace the arbor (If it's not too expensive) and see how things go from there.

Good point...

 

[davem62]

hi when using these large core bits make sure the sds drill you are using has a clutch on it as you can seriously hurt your wrists if the bit locks up.If its a one off hole you could always mark out the hole and drill several 5mm holes around the circumference and brake out with a hammer and chisel,just drill from both sides to avoid break out,hth
regards dave

 

[rpfn140378]

hi when using these large core bits make sure the sds drill you are using has a clutch on it as you can seriously hurt your wrists if the bit locks up.If its a one off hole you could always mark out the hole and drill several 5mm holes around the circumference and brake out with a hammer and chisel,just drill from both sides to avoid break out,hth
regards dave

Thanks. My sds has a clutch. I know it is rated at 50mm max core drill but if I drill it slowly I think I will be fine.