Frequently Asked Questions


Q. Will your drill bits fit my drill?

A. Our drill bits will fit all household rotary type drills as well as hobby drills so long as you have an adjustable collet or chuck which will hold the shank/shaft of our very small drill bits. Sometimes when buying a drill they will come with an adjustable collet but if you find you’re in need of one we supply either a Dremel Multi Chuck or a Dremel Collet Nut Kit. Please see our article ‘12 Things You Should Know About Diamond Drill Bits‘ for more info.

Q. When will my order arrive?

A. We deliver via Royal Mail 1st class and all orders placed before 3pm will be shipped out the same day. Therefore, If you’re based in the UK we aim to have your tools with you the next day or the day after. International orders will take longer. If you have special postage requirements for your order please contact us.

Q. Do you deliver worldwide and what are the shipping costs?

A. We deliver to almost anywhere in the world and the shipping costs are the same wherever you live (£2.75 for orders under £20, £3.95 for orders over £20)

Q. What’s the difference between sintered and electroplated/coated diamonds?

A. Electroplated, or coated diamonds are bonded to the drill bit using nickel in a single layer and although won’t last as long as sintered they are a cheaper alternative. With Sintered, the diamond has been bonded to the matrix at very high temperatures and therefore has several layers of diamonds which by dressing or cleaning with an aluminium oxide stone will help maintain the life of your bur or wheel revealing a new layer of diamonds each time.

Q. I want to extract the core from the core drill, is this possible?

A. Yes, however the diamond core drills are intended for drilling a hole rather than extracting a core so we can’t guarantee the results. That said, we have customers in Universities and research labs who use them for this purpose with success.

Q. The diamonds have come off my drill bits whilst drilling, why is this?

A. Diamond drills are manufactured by electro plating the diamonds onto the drill with nickel. Should you apply too much pressure or not use adequate coolant the Nickel will overheat and subsequently the diamonds will come away. Remember to let the drill do the work. Please see our article ‘12 Things You Should Know About Diamond Drill Bits‘ for more info.

Q. I’d like to cut and smooth some tungsten carbide material, what tools should I use?

A. Our diamond slitting disks would be perfect for the cutting and to smooth you could try our diamond files, 600 grit would be the best grade for this then to polish the tungsten carbide you can use our diamond grinding paste

Q. I’m an amateur horologist and I have a problem drilling an arbour to replace a pivot, which drill do you recommend?

A. We would recommend using our carbide spade drills which are specially designed for re-pivoting

Q.The shank of my drill bits are too small to fit my drill, what can I do?

A. You’ll need an adjustable collet or chuck. We supply a Dremel Collet Nut Kit or a Dremel Multi Chuck if you find your drill didn’t come with the appropriate accessories.

Q. How many holes can a drill bit last?

A. This all depends on how hard your material is, the amount of pressure used, the speed you use your drill at and how cool you keep your material whist drilling. To gain maximum life from your drill bit and to prevent your material from cracking ensure you use little to no pressure, start off with a slow speed and increase and always keep your material and drill bit cool with plenty of water.  If you’r drilling seaglass between 4-5 stones can be guaranteed.

Q. I need to make some holes bigger in some beads I’ve purchased, how can I do this?

A. Our diamond twist drills are perfect for opening up holes. They come in a range of sizes from 0.5mm – 3mm.

Q. With the core drills, does the size indicated refer to the size of the core or the size of the hole you’ll end up with?

A. The size indicated refers to the size of the hole you’ll end up with. Each product page has technical information with shank sizes. The internal diameter of the core drill is roughly about 1mm less than the external diameter.

Q. Do you have something that will arris/bevel around the area of glass where I’ve just drilled my hole?

A. We have a wide range of diamond files perfect for the job and our diamond grinding paste will restore the shine to fused glass edges as well.

Q. Can you advise me on the correct drill bit to drill a hole through bone china and pottery?

A. If the pottery is glazed we would recommend using a diamond core drill bit, if it’s not glazed you can just use a regular drill bit. For further assistance take a look at our online tutorial, How to Drill Glazed Pottery.

Q. Left or right hand clock pivot files?

A. The Left hand clock pivot file is for use on top of the pivot and the right hand is for use underneath the pivot.

Q. How do I stop my core drills from clogging?

A. Core drills won’t clog up so long as plenty of water is used which will wash out the debris as you drill. Try drilling in an up and down motion which will allow more water to flow up inside the core. If they still clog it could be because the material you’re drilling is too soft, they’re designed to drill through hard material such as gemstone and glass. Take a look at our article ’12 Things You Should Know About Diamond Drill Bits’ for further help Using a wire brush or blowing down the shaft of the core drill may also help.

Q. Do I need to use an oil lubricant or will water do?

A. We advise on just using water, it’s cheaper and does the job just as well as an oil lubricant.

Q. Can I use your drill bits to drill through bone?

A. Yes, in fact we have many customers from Universities and research labs using them for just this purpose with great success.

Q. What speed should I use on my drill?

A. It is advisable to start slow then increase the speed.  We advise using your drills lowest setting to begin with. Please see our article ‘12 Things You Should Know About Diamond Drill Bits‘ for more info.

Q. How do I drill seaglass, pebbles, shell, etc

A. Please refer to our Tutorials section where you will find many step by step instructions on how to drill through various materials.

Q. What is the internal diameter of the core drill?

A. About 1mm smaller than the external diameter.

Q. How do I get to receive Eternal Tools’ promotional offers?

A. Our promotion offers are exclusive to customers who sign up for our bi-monthly newsletters.

Q. How do I remove scratches from the surface of glass or gemstones?

A. By using a little diamond polishing paste on a felt bob in your rotary tool.  Work down through the grades of diamond paste starting off with 3 micron (green) then 1 micron (blue) until the desired finish is achieved. Our silicone polishers will also do the same job, again working through from coarse, medium, fine and extra fine until you’ve achieved the polished look you’re after.

Q. How much shank of the diamond drill bit should be in my drill?

A. Roughly about half of the diamond drill bit should be in your chuck of the drill.