Advice for a drill capable to drill a 100mm hole

by **ruinunes** » Thu Aug 30, 2012 7:41 am

Hi all

I'm new here at the forum.

I'm looking for some advice from you guys for a drill capable to drill a 100mm diameter for my extractor fan ducting.

I been checking for some drills and I came across to some makita kits like 4 or 6 tools with three batteries 18volts 3.0ah lithium. Apparently form what I read on the internet these batteries are really good and powerful.

I was really keen to buy one of these kits as I can use these batteries in any of tools in this kit. I won't be using the tools every day but once in a while as I started doing some DIY in my flat.

In this kit there is a drill which is a Makita BHR202Z sds plus rotary hammer and I wonder if it will be capable of drilling a large hole with a diamond core bit as I said earlier, another thing is that on the drill specs is not saying anything about safety clutch.

Please guys let me know what you think. All the advice will be appreciated.

by **welsh brickie** » Thu Aug 30, 2012 8:04 pm

I have the same kit, makita LXT 18v 3.0ah battery sds cordless hammer drill, is more than capable for your needs.

by **ruinunes** » Thu Aug 30, 2012 10:44 pm

welsh brickie wrote:I have the same kit, makita LXT 18v 3.0ah battery sds cordless hammer drill, is more than capable for your needs.

Thanks for your help. you are the first person who says that this drill is good enough to do this job. I asked a few people, friends and 2 builders and they all said that a 18 volts batery will struggle pretty much and I should go for something more professional, corded

by **plumbbob** » Sat Sep 01, 2012 2:42 pm

Sorry, but I can't agree with Welsh Brickie in this instance, maybe he has misread your post.

To drill a 4" core for an extractor, a mains corded drill will be required. No battery powered drill will have anywhere near the power required to drive such a bit through 9 or 11" of brick. Sure, I use an 18volt drill to drive ordinary sds bits (up to 28mm) through a wall, but not of that diameter.

Even normal high power drills won't cut the mustard. Coincidentally, I burnt out my Bosch Pro drill yesterday trying to drill a 125mm diamond core bit through a wall for a toilet waste. That is £200+ up the spout!!! You need a specialist core drill. It will need a clutch too to prevent a trip to casualty with a dislocated thumb or wrist.

IF you only have one hole to cut, hire a drill - it is cheaper.

by **ruinunes** » Sat Sep 01, 2012 9:16 pm

Hi again. Thanks for the comments.

I know that with £50 I can hire a drill but the thing is, after the hole is made I need to take back the drill, £50 gone and I have no drill. That's why I thought some cordless drills could be up to the job. If I buy a drill I know I will spend more than £50 but at least I still have the drill for further use.

In a quick search I found a corded drill, It is a "hitachi dh24pc3" Please guys have a look and tell me what you think.

by **plumbbob** » Sun Sep 02, 2012 4:36 pm

I think you may be underestimating what you are trying to do. I assume you want to cut a 100mm hole in a brick wall using a diamond core bit? The drill you mention would be fine for ordinary drilling, but it doesn't even mention being suitable for core drilling.

For one thing, core bits eat drill watts. Anything less than 1000 watts or preferably 1300 - 1500 watts will result in the drill burning out possibly before you have even completed a single hole.

Core drills are specialist bits of kit and are different to ordinary electric drills. Core bits work best when driven at between 1100 and 1500 rpm a speed that most normal drills won't work efficiently at.

Navigate to Screwfix and examine their range of core drills. Read the reviews for the most expensive then notice how customer's who bought the cheaper models want their money back.

I bought a Titan 5kg sds drill from them (product 55660) a while ago and had to use it for finishing off a 125mm hole last week because my core drill had gone up in a puff of smoke. It is man enough for the job, but only runs at 750 rpm so the going was slow. It did the job, but given its size and weight, it isn't the piece of kit you would be wanting to hold at shoulder height on a pair of steps for any length of time either.