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Small Diamond Core Drills


Bulk Discounts

Quantity Purchased Price
1 - 4 £5.95
5 - 9 £4.95
10 - 24 £3.85
25 + £3.45

Sizes Available: 1.00mm, 1.25mm, 1.50mm, 2.00mm, 2.50mm, 3.00mm

Similar to our small solid diamond drill bits but with a hole through the middle, these drill bits are hollow, allowing water to circulate inside the core. They are ideal for drilling holes in glass, tile, ceramic and porcelain, glazed pottery, beads, pebbles, stone, slate, petrified wood, fossilized bone, optical material, composites and rock. For those tough pieces of sea glass, they work like a dream! For very hard stone such as quartz try our small diamond drill bits

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You may need a collet or chuck to hold these small diamond core drills. Have you tried the Dremel Multi Chuck? This allows you to change drill bit sizes really easily.

What is a Core Drill?

Our diamond core drills are designed to drill holes in very hard materials and they do this by removing a cylinder of the material. The core allows drilling with water or a lubricant to swirl up inside the core whilst drilling, preventing overheating. Overheating can cause your material to crack or break and will shorten the life of the drill bit.

Many of our customers use our core drill bits to achieve a core rather than to drill a hole. We can't guarantee the precision with which you might achieve the perfect core but many have done so with success.

From time to time the debris may become stuck in the core of the drill bit. If this happens it will often become dislodged when you begin drilling your next hole. Alternatively use a wire brush to clean out the core of the drill bit. To prevent this from happening, drill in and out/up and down as you drill to dislodge the debris. This will prevent the debris from being pushed up the core of the drill bit.

If you're new to these drill bits then our Infographic 'How to Drill Through Glass' has easy to follow steps.

Tip: use with plenty of cold water, slow speed, low pressure

Disclaimer. Using rotary tools near water has never been, to the best of our knowledge, endorsed by any of the rotary tool manufacturers. If you do choose to drill near water or with attachments under water connected to your drill then you do so at your own risk. Please be aware that mixing electricity and water can be very dangerous.


Diamond grit is precisely electroplated onto a steel shank

1.00mm Diameter

  • Overall length: 35mm
  • Diamond working length: 3.00mm
  • Shank: 0.75mm

1.25mm Diameter

  • Overall length: 35mm
  • Diamond working length: 3mm
  • Shank: 1.00mm

1.50mm Diameter

  • Overall length: 35mm
  • Diamond working length: 3.00mm
  • Shank: 1.15mm

2.00mm Diameter

  • Overall length: 35mm
  • Diamond working length: 4.00mm
  • Shank: 1.75mm

2.50mm Diameter

  • Overall length: 35mm
  • Diamond working length: 4.00mm
  • Shank: 2.15mm

3.00mm Diameter

  • Overall length: 50mm
  • Diamond working length: 3.50mm
  • Shank: 2.35mm

Customer Reviews

The product is great and goes through my seaglass like a knife through butter! However after about 4 or 5 pieces of glass being drilled, it gets quite blunt, and is time to change the drillbit, so it would be amazing if the product lasted a bit longer and were more durable. Although, i do understand that it is quite hard to achieve this as cutting through glass is bound to make the drillbit blunt! Would use again!!
job well done thanks will buy againg
great tools fantastic service and advice
Nice products. Exactly as described. 100%
Good quality drill bits which I used for drilling sea glass.
There wasn't any diamond on them
Product arrived quickly and purchasing was easy on their website
Best product out there for drilling stones and glass
drills look ok but as yet I have not used them
Easy to use and great quality.
very quick delivery. The diamond drills were good value for money
the best, nothing works like these drill bits, i ordered once from somewhere else and the quality comes nowhere near these.
Does exactly what they are meant to.
The quality of the drill bits I've purchased seems very good. The smaller diameter (1mm) drills bits seem to have a longevity/durability issue but that's probably my fault!
Right Tool for the delicate and precise Job
Drill lasted for only 2 broadbean sized Quartz pebbles.I have drilled stones[hard ones]before with other types of drills which have lasted longer
drilled hole in pebble. RESULT!
They make drilling glass a doddle :)
Works really well. The shaft is a bit soft and got crushed by the bit holder but didn't affect the use
As Above
As Above
Perfect, exactly what I needed
Very good service! Will shop again
Very happy with the product.
3mm drill bits are great, not so sure about 2 mm they broke fairly quickly.
As Above
Product does what I need, will be back for more. Have not used long enough to test thoroughly.
Excellent cutting .............
Excellent. Did the job of drilling holes in beach pebbles.
I only need to use these types of drills occasionally for making fishing weights so have not had a chance to try the core drill bits yet but if they perform as well as the other types of small diamond drill bits I have brought from them in the passed they will be very useful for my hobby
Great tools. Will be back for more!
expensive core drills but last a lot longer than the cheaper ones from other DIY stores They are probably better value for money as well
my husband seems to have adopt these drills for his work on stones

Questions & Answers

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Other questions and our answers

Will your drill bits fit my drill?


Hi Clare, Our drill bits will fit all rotary drills so long as you have an adjustable collet or chuck with which to hold the shank of our very small drill bits. Sometimes when buying a drill they will come with an adjustable collet but if you find you are in need of one then we supply either a Dremel Multi Chuck (DMC4486) or a Dremel Collet Nut Kit (DCNK4485).

Will the small diamond drill bits work in a drill press ?


Hello Ann, Yes they work perfectly well in a drill press.  They will work in any drill so long as there is an adjustable chuck to hold the shank of the drill bits. 

Hi, I want to order diamond bits to drill 1mm holes in 500um thick borosilicate glass wafer. Could you please tell me if 0.75mm diameter drill bit would be perfect for that or not. Also, what other items I would need to drill hole along with drilling machine. Besides, could you suggest me which drilling machine would be sufficient for this job. Thank you. Best Regards Deepika Sharma

Deepika Sharma

Hi Deepika,

Good to hear from you. We recommend using a Dremel 3000 drill with a Dremel Multi Chuck and use either the small diamond drill bits or the small diamond core drills. If you are new to drilling holes in glass we recommend trying the core drills first. The size of the core drill indicates the size of the hole you will achieve, so if you need a 1mm hole, you will need to purchase the 1mm diamond core drills. All the best with the project.

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