Electroplated Diamond Core Drill Bits

Ideal for trades people, handy people and DIY for cutting glass, china, fibreglass, pottery, marble, porcelain tiles, granite, travertine, blue stone, fibre cement, poly carbonates  and more. Our bits use a finer diamond than the ones you find in big hardware stores, so will cut better.

Supplied with a hex shank, so will fit most drills.
These are to be used in rotary mode only ie not hammer drill.

These bits can be purchased individually (6 - 105mm).
Or we stock the HDEMK8 kit  -  8 Piece kit with drill guide (4, 5, 6, 7, 8, 10 & 12mm bits). 
$87 incl GST

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Part No Diameter Sell Price Part No Diameter Sell Price Part No Diameter Sell Price
HDEM6 6mm $27  HDEM32  32mm  $62  HDEM69  69mm  $144
HDEM7 7mm $27  HDEM35  35mm  $68  HDEM75  75mm  $159
HDEM8 8mm $27  HDEM37  37mm  $72  HDEM77  77mm  $165
HDEM10 10mm $27  HDEM42  42mm  $83  HDEM82  82mm  $178
HDEM12 12mm $28  HDEM44  44mm  $87  HDEM85  85mm  $186
HDEM13 13mm $28  HDEM50  50mm  $100  HDEM86  86mm  $191
HDEM16 16mm $30  HDEM52  52mm  $105  HDEM88  88mm  $198
HDEM19 19mm $37  HDEM60  60mm  $122  HDEM89  89mm  $203
HDEM20 20mm $39  HDEM63  63mm  $129  HDEM90  90mm  $208
HDEM25 25mm $49 HDEM67 67mm $138 HDEM95 95mm  $226


We ship Australia wide using Australia Post airbags.  The Express bags are often overnight (depending on your area), and have a tracking number. You may be able to fit a couple of hole saws in the bags – feel free to call or email for a quote on freight. 
Most of these bits, and the 8 piece kit, fit in a 500gram post bag.

Post  Bags – (3-7  business days)∗

0.5kg      220 x 350mm              $11
1kg         260 x 380mm              $13
3kg         300 x 400mm              $16

Express Bags – (1-2  business days)∗

0.5kg      220 x 350mm              $14
1kg         260 x 380mm              $17
3kg         300 x 400mm              $20

∗Delivery times as indicated by Australia Post, and subject to variation.

Prices correct as of 1/8/19 but subject to change.


Fit the hex shank fully into the drill chuck and tighten.

Use appropriate personal safety equipment - safety glasses, hearing protection etc

Use slow speed drills. A battery drill is much safer with water than an electric one. If using an electric drill, ensure you use an RCD to prevent electrocution.

Check our drill chart below for recommended speed.

Core bit diameter 12mm 25mm 50mm  75mm  90mm 
Fibreglass  1200rpm  700rpm  350rpm  250rpm  175rpm
Glass & china  800rpm  500rpm  250rpm 160rpm  125rpm
Pottery tile & marble 600rpm  450rpm   225rpm  130rpm  100rpm
Porcelain tile  500rpm 375rpm   180rpm  125rpm 90rpm 
Granite  400rpm  300rpm  150rpm  100rpm  75rpm

Clamp the material to be drilled firmly. Never hold the material with one hand while drilling with the other!

Apply plenty of water.  Some objects can be barely immersed in water (beware water in the drill). Or try one of our water suction ring sets - see here

Use only medium drilling pressure. The smaller the diameter, the less pressure is needed (otherwise you will damage the core bit).

Withdraw bit regularly to allow cooling, allow water inside the hole and to clear debris.

A pilot drill bit is provided on larger diameter bits, but a simple template guide is just as fast.

Be aware that porcelain and glass may fracture and these can be very sharp.

Core bit damage will occur if:
 - the drill bit gets too hot to touch
 - drill speed is too high
 - insufficient cooling water
The diamond crown will turn blue and the diamonds will strip off. This is not warranty, so follow these guidelines.

Drill Guides: Drilling holes in stone tiles or other hard, smooth surfaces is often hard to start, especially when working with the lubricants necessary for diamond hole cutters/drill bits. This drilling guide is designed to hold your bit steady so you can start the hole in the right spot without slipping or sliding. Both use a 120mm suction cup

Plastic (red): 8-80mm, with water injection point (for lubrication when drilling) $15

Steel (blue): 8mm to 54 mm $25

(Pictures show two guides in each photo - prices are for 1 each)

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Please see our "Contact Us" page (here) for Australia wide shipping information.

Disclaimer: the information on this website is provided in good faith and believed to be reliable and accurate at this time. However, the information is provided on the basis that the reader will be solely responsible for assessing the information and its veracity and usefulness. UDT shall in no way be liable, in negligence or howsoever, for any loss sustained or incurred by anyone relying on the information, even if such information is or turns out to be wrong, incomplete, out-of-date or misleading.

Dymaxion HDEM6 Sutton Bunnings

United Diamond Tools

Unit 10 / 84 Barberry Way
Bibra Lake
Western Australia 6163

Telephone: (08) 9434 6878
Mobile: 0419 901 533

Email:  sales@udt.com.au