Silverline 406549 Diamond Core Drill Bit 152 x 150 mm, Blue

Had to put in some 100mm extractor fans, which needed holes cut through 12 inch thick brick and cinder block cavity walls. Got this 107 mm diameter by 150mm long core drill, as it was cheaper that getting someone in to do the job. I was lent a 110mm TCT Core Drill Bit, but that was too shallow to get through a course of brick in one go, so it needed a lot of extra chiselling. With this I was able to cut straight through the wall from one side in one go, occasionally stopping to remove debris, from inside the warm house, on a cold day. My SDS drill is not the best quality and struggled a bit with such a large cutter, sometimes causing the safety clutch to slip, but with care it worked ok. I bought this together with the "Silverline 124518 SDS Plus Core Drill Arbour 200mm" and "Silverline 769992 Morse Tapered Guide Drill Bit 8mm x 200mm". The instructions were in the tiniest writing I have ever seen, or could hardly see, part of which read as follows; Important notes * NEVER use hammer or impact action with diamond core drill bits; * this will damage the cutting edges, increase the risk of jamming and possibly bend longer arbours and arbour extensions * Core drill bits should only be used with drills with safety clutches, with the possible exception of small core drills * Core drills, arbours and extensions are heavy, and core drilling creates a large load for the motor of the power tool, even at low rpm. It is important to consider this when selecting a suitable power drill for the diameter and depth of the hole you wish to drill. It may be necessary to use the `stitch' drilling technique first and then finish with the core drill to make the final cut for the hole So it was not until I finished and then scanned, enlarged and transcribed the instructions I able to read them and then realised I should not have used any hammer action with the SDS drill. However the cutter still seems in pretty good condition. The guide drill was a bit prone to falling out, particularly with the hammer action, so was firmly tapped into place and stayed in long enough for the core drill to get deep enough to guide itself. Otherwise it all worked ok for me and achieved what was needed at an acceptable cost.

If you need to drill a hole up to say 16mm then there are perfectly good conventional masonry bits available in a variety of lengths. If you want to go from 38mm upwards then there are some really good diamond core drilling sets. In this middle ground there is not much to choose from, which as I needed to drill holes through 9 inch brickwork to run cable conduit was a problem for me. This bit did the job. I used it slowly and it drilled cleanly on the outside, but did give some breakout on the inside. The only slight problem was clearing bits of the core which stuck in the bit and took some careful wiggling to remove them. I see another reviewer has not recommended this as up to the job for concrete which is a shame as it is listed for this. The listing does though say this is only suitable for DIY use, and I think that is fair - it is worth the cost if you will only need it once in a while; if you need to drill these size cores everyday then look elsewhere (and be prepared to pay a lot more). One correction on the listing - it says this goes with the silverline pilot drill and arbour; it does not - neither are needed as this is a standalone item. Despite the lack of a guide drill it was not difficult to get a clean start to the holes.

width 107 and depth 47

Perfect. Did the job of making a hole through a cavity brick wall. Did a nice tidy job, took an hour or 2 to get through but used it quite slowly to create less dust. Looks like it's got plenty of wear in it still, should be good for a few jobs. But I'm glad to say I am never going to do something like this again as holding an SDS drill for this amount of time is a killer boring job

I bought this through amazon warehouse deals. It was described and priced as second hand but the one I received was immaculate. Either unused or very well reconditioned. Used it to cut two holes through kitchen wall to fit extractor fan. Its a bit difficult to hold the core drill in the right place to start the hole due to the vibrations, but that has to be expected. It was within 10mm from where I wanted it. The core cutter performed faultlessly. The cores of brick it cut are perfect cylinders. Very very impressed. You MUST use a sds with a clutch with this cutter. Saved my arms a few times.

Solid piece of kit, didn’t know I needed the arbour and guide drill but that’s my fault! Got through the wall with relative ease using a 600w SDS+ drill :) Perfect for 40mm waste pipe from a sink!

Poor quality product — one of the four cutting edges snapped off on first use drilling into a 1930s brick wall. Total waste of money. This is basically a disposable drill bit — use it once and throw it away. Don’t bother.

As an electrician, this is a very common size I use. In the past I have always bought the expensive core bits, but this time as money was tight I thought I would try the budget range. To be honest, I was thinking I would use this core for the job we are on the either have it re tipped or bin it, as every other bit of Silverline kit has lasted 5 minutes if I was lucky. Any way, we cored 2 holes through breeze block and common building brick, 2 holes through concrete block and sandstone and 1 hole through a single leaf sandstone wall. Amazingly, this core bit still has 5 mm of the tips left and will do at least another 6 or so holes in similar materials. As for the cutting performance, I couldn't honestly tell any difference between this bit and my previous more expensive Faithful Tools bit. It probably helps with the fact that we use a proper core drill Dewalt D21580K 1705W 1/2-inch Male BSP 2-Speed Dry Diamond Drill 240V and not the useless SDS arbors they sell for use with these cores. One last thing, as the manufacturer or Amazon don't bother listing it, the thread size on the core bit is 1/2 inch BSP, so will fit the same arbors as other more respected makes of core bit.