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Small Diamond Core Drills


Bulk Discounts

Quantity Purchased Price
1 - 4 $8.01
5 - 9 $7.00
10 - 24 $5.52
25 + $4.98

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, sea glass,  tile, ceramic and porcelain, glazed pottery, beach pottery, beads, pebbles, stone, slate, petrified wood, fossilized bone, optical material, composites and rock. For those tough pieces of seaglass, they work like a dream! For very hard stone such as quartz try our small diamond drill bits. 

Please read on for further information

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You may need an adjustable chuck  or collet to hold these small diamond core drills, take a look under the 'Technical' tab below to find out the shank sizes of these drill bits. . If you have a Dremel rotary tool, we recommend the Dremel Multi Chuck. This allows you to change drill bit sizes easily.

Tip: use with plenty of cold water, slow speed, low pressure.  These three crucial elements when drilling will prevent the diamond grit wearing off or burning off,  will prevent the drill bit from snapping (too much pressure applied), and prevent your material from cracking. 

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. If you would like to drill holes in pebbles, see our article:  'How To Drill Holes in Pebbles'

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 hardened 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

Tools are ****, the cheapest drill bits i've ever worked with.
Always good quality, well packed.
great tools to work with, super quality
These are awesome, perfect for drilling seaglass. I buy a range of sizes for different thicknesses of glass, but mostly use the 0.5. They last for about 30 pieces depending on the thickness and toughness of the glass, then when they get a bit worn I use them for driftwood or pebbles, which they cut through easily. If I am impatient and use more pressure when drilling they dont last quite as long!
Excellent product, very happy
Amazing core drills. It did exactly what I needed.
Quality bits at a great price.
Didn't last very long I thought but haven't used them before
Good product - speedily delivered
Price of tool is very good, but price of shiping, for me (from BiH) - high...
bought diamond tip drills which were used for drilling sea glass. the quality was good and advise good
great service and quality as always
Good quality items, packaged well
Over priced, same quality as China, but quicker delivery.
El paquete llegó en perfectas rápido y en perfectas condiciones
many thanks.good well

Questions & Answers

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Other questions and our answers

Can these bits (small diamond core drills) be used with a Dremel rotary tool? Thank you in advance. Best regards, Silvio Berra

Silvio Berra

Hi Silvio, 

Thanks for your enquiry. Yes the small diamond core drills bits are ideal to use in a Dremel rotary tool, but you will need the Dremel Multi Chuck to hold the very small shanks of these 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.

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. 

Will your drill bits fit my drill?


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).

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