Choosing Diamond Bits to Drill Beach Stones with a Dremel

Jewelers, beading and lapidary enthusiasts, and those that work with sea glass have a common problem:  How to make a hole in their material, be it stone, precious or semiprecious gems, or glass.

Drilled beach stone

Drilled Beach Stone with Silver Inlay

I have worked with beach stones for about 12 years.  They come in different hardness measured on a 1-10 Mohs’ scale.  The quarzites are hard (7 on the Mohs scale) and the sedimentary or sand stones are much softer (about 3-5 on the Mohs scale) and therefore easier to drill.  We use a Dremel drill.  Take a look at the comments to this post about different models of Dremel drills.  We use cylinder drill bits that are coated with diamond dust (simply called diamond drill bits).  I buy them in bulk because we use so many.  I am out of bits again and I just scoured the web for suppliers.  This post is about how to choose a supplier!  Drill bits come in very different quality, so you want to choose carefully.

First, lets consider the different types of bits.  There are  1) cylinder bits, 2) twisted bits, 3) shank bits, 4) core bits, 5) crinkled core bits, 6) cintered core bits. If you are not sure what this means you can check out pictures of these bits at Dad’s Rock Shop.  I have tried choices 1-4.  Considering the cost, I still prefer the simple cylinder bits or the twisted bits. They are much cheaper.  Most sources have a variety of sizes to offer.  And you can buy in bulk.  They work for really hard stones and they work with glass.   In terms of how long they last before they are totally dulled up, it’s your technique which is most important: drill slowly, under water to keep everything cool and with a relatively slow rpm (<2000).   Drill even more carefully and without exerting much pressure if you are making a hole in glass.

So, once again I have decided to go with cylinder bits and I want diameters of 1-2 mm.  I usually order large quantities, say 300 – 1000 bits.  I did a google search for  ‘1 mm diamond drill bits’.  Here is what I got.  The prices are per drill bit.

Dad’s Rock Shop  $3.50 (no discount for large quantities)

Lasco Diamond Products $1.75 (1.5mm Diamond drill bits only)

By The Bay Treasures  $2.30  (min 50 bits)

Delta One Lapidary  $1.85 (min 12 bits)

Twisted bits on Ebay $0.35 (20 bits)

Thunderbird Supply Co.  $1.32 (min 30 bits)

Covington Engineering  $1.00 (min 50 bits)

Daniel Lopacki  $0.95 (min 100 bits)

I read every web site in detail and looked at the “about” section.  That tells me whether the seller has first hand experience with drilling stones.   I have previously bought drill bits (and other stuff) from Dad’s Rock Shop.  They are good quality, but their current prices are not competitive.  I have bought poor quality bits too, but not from any of the suppliers mentioned above.  I was somewhat interested in the drill bits from Bay Treasures because these are clearly lapidary enthusiasts and concerned with quality products.  However, I think I am going to go with Daniel Lopacki.  His prices are very competitive if you buy in bulk.  And the website includes great tips for drillers.  They know how to do it and have done it themselves and quality bits are a concern for this seller too.  As you can see, you can get bargains on Ebay.  I have had variable success with these bits depending on the vendor.  But check out the comments below, because Seth from fans4pc managed to change my mind on his diamond bits which are both well priced and good quality.

Drilled Beach Stone – Sterling Silver

Drilled Beach Stone – Sterling Silver

Drilled Beach Stones – Deer Skin Leather

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33 Responses to Choosing Diamond Bits to Drill Beach Stones with a Dremel

  1. A very informative post not only for those making jewelry, but also for anyone interested in how it’s done. As usual, you’ve included wonderful accompanying pictures and I must say–your Drilled Beach Stone with Silver Inlay is quite lovely!

  2. Thanks John. And thanks for the idea!

  3. Someone asked what Dremel model to buy for drilling stones. There are 4 corded rotary Dremel models described on the Dremel website: http://www.dremel.com/en-us/Tools/Pages/CategoryProducts.aspx?catid=2013
    I have used the 200 series and it lasted about 10 years. I don’t like the chuck system for attaching the bits, but that has been redesigned in both the 3000 and 4000 series (the latter with more power or “high performance”). Variable speed is important. More power is not important, because you want to use the lowest rpm you can and you need to drill slowly with little pressure on the drill press. So my next Dremel is going to be the 3000 series.

  4. Thanks for being here!

  5. Hi Robin, I love your stone sculptures! Great work. David

  6. Mike Styga (Jacksonville FL)

    Hello, I’m a woodturner and came upon your site searching for small diamond drills. Info is great. I want to incorporate semi-precious stones in my bowls. Question: In the first “beach stone SS” photo, there is a loop that runs through the stone. Is that a technique with wire or a set piece that can be purchase in quantity? It looks very cool.
    Thanks, Mike (TurnStyles Etc)

  7. It is a handmade SS wire loop soldered to a SS tube – have to solder AFTER you put the SS wire through the holes in the stone, which makes it a bit tricky because you need a heat shield to protect the stone from cracking. Also tricky to drill 2 small holes that close to one another in the stone. But one hole, with both wires going thru it, works too. In this piece the neck wire needed to have a slender clasp that would fit thru the tube.

    If you drill a larger hole (3-4mm) through the stone, you could use prefab SS wire loops with attached tubes and these could be made in large quantities and sold for about $5 per piece. The measurements could be custom to suit your needs! Thanks for the question (and the idea).

  8. I found your site by looking for information on beach shell types, I’ve been collecting shells in my yard and making wind chimes and jewelry for friends and I had no idea what those shiny little yellow and orange shells were, Till now! Thank you! mystery solved! :)
    I’m so glad I found your site! great info and attention to detail, love your work! I hope to be as good someday!

  9. We are a supplier of diamond coated drill bits for both cylindrical and twist design.
    We sell 30 pack of 1mm Diamond Drill Bits for $19.99, FREE shipping.
    We also sell other sizes such as 1.5mm, 2mm, 2.5mm.
    An assorted pack of 20 pcs. costs $19.99, FREE shipping.
    stores.ebay.com/FanDepot

  10. hello David,
    Would you be interested in trying our diamond drill bits and review them on your blog?We’ll be more than happy to send you a free sample pack.
    Thanks
    fans4pc@yahoo.com
    stores.ebay.com/FanDepot

  11. Seth from fans4pc sent me some drill bits to test (thanks). I took a piece of granite 4.5 mm thick and drilled it with my standard 1mm cylinder bits (about $1/bit) and then I changed bits and used a 1mm twisted diamond drill bit from Seth (about 0.66 $/bit) to drill the same stone at the same thickness of 4.5mm. Drilling was done under cold water and I timed the two drills. Results:
    standard bit – 17 sec
    Seth’s bit – 15 sec

    Then I used Seth’s twisted 1mm bit to drill 10 more stones (about 72mm of total drilling). On the 11th stone the drill bit broke.

    That is a pretty awesome result. Its rare that I can use one of these bits to drill that many stones.

    I also tested his other bits, including cylinder bits and core bits of different sizes. They were very good quality, even when drilling glass.

    Bottom line I am ordering his bits today!
    fans4pc@yahoo.com
    stores.ebay.com/FanDepot

    David

  12. Thanks very much for all this information. Based on your review of fans4pc, I’ve just ordered a new set of 1mm diamond coated twist drill bits from him. I have a battery operated Dremel which I feel better about putting in water… However, perhaps I’ll have to use my Foredom TX. I want to drill small holes in small, flat stones picked up on a sand bar/and sea glass.

  13. Lela, let us know what your experience is. I found another vendor on Ebay who charges $0.45 per bit for 1mm twisted diamond drill bits….

  14. Update: I received the 1mm diamond coated twist drill bits from fans4pc on ebay. Shipping was SPEEDY and Free. Can’t beat that! In addition, I offered $15.99 (instead of the asking price of $19.99) for the set and it was accepted. Thanks for that, too, Seth.

    I have tried the bits today in my hand held Dremel. The first two bits I used broke after a couple of drills. HOWEVER, I decided it might be because I did not have them all the way in the Dremel – So on the third bit, I put it all the way in. The GOOD news is that I have drilled 24 beach stones, 9 pieces of beach glass and 20 shell fragments and the bit is still going strong. I had to stop only because the battery on the Dremel was getting weak.

    I was drilling under water. I did notice that the beach glass is opening out a larger area in the under side when drilled. Any hints to avoid that?

    If the rest of these bits work as well as the current one, I’ll be ordering more.

  15. Thanks for this useful info

  16. @Lela: regarding the large area opening on the under side, this is a common problem with stones and glass. A few comments: 1) go very slowly and with out pressure at the end of the drill just before you crack through, 2) use a solid wood surface as a support on the under side, 3) drill from both sides by turning over the stone and guessing where the holes will meet up!! The last trick really works best, but it requires a bit of practice so that your 2 holes from either side are well aligned.

  17. Just starting – great to knows about you and your work. THANKS

  18. Thank you for allthe info.I have become interested in cat-eye shell and want to mount on a necklace to show both sides(not at once!)I have a dremel type drill and am about to buy 1mm diamond twist drill.Any advice on thetype of mount would be much appreciated.As woodturner I made a number of wooden cups(shallow)but that only gives you one side when glueing the shell in. With Thanks.R.Payne

  19. Just one comment about shells. I find diamond drills are not so good for shells. A regular steel bit often works better for me. Be careful about not exerting too much pressure or you will crack the shell. Keep every thing cool with cold water. Also, be sure to wear a mask. The ground shell dust gets in to your lungs and can not be good for you!

  20. Have tried and failed at drilling sea glass until reading this – thanks so much! I was forcing and using too much pressure. Ready to buy bits in bulk now that I have improved my technique. Any particular recomendation on size of bit? I will mostly be using jump rings to add to the drilled glass. Any other tips you may not have covered – although you seem to have hit them all.

  21. Any size bit will work. Choose according to your needs. Consider making a smaller hole first and then enlargening. Consider “core bits” (hollowed) for the larger holes, 3mm and larger. But core bits can be expensive. Thanks for your comments. David

  22. Hi. I want to drill a fossilized druzy shell. It looks like a regular shell,but the inside is druzy crystal formations, and the back has formed into solid rock. The actual ‘shell’ is now very hard and solid. Any tips a?

  23. I want to drill across the top. Appx 1/2 ” across. A very small hole for wire

    • That will be difficult Jennifer, 1/2 inch tiny hole thru a druzy (hard) – all I can say is go slowly and count on using several drill bits.

      • I am not drilling though the crystal formations. I am drilling across the top of a shell. I am going to try and send you an email. The inside of the shell is basically hard rock. I have seen thm drilled before.

  24. hello – thankyou, I’ve really enjoyed you work, and thanks for really useful advice on drilling stones, I’ve started drilling beach stones for a sculptural piece. I am using a dremel 4000 successfully with a 3mm diamond core drill bit, but now I need the holes to be 4mm. I have just ordered some 4mm diamond core bits – but they are too big in shaft size to go into the dremel (I’m new to the tool!!). I can’t find any adapters for fitting 4mm shafts into the dremel… – so i wondered if you had any tips on the following- should i drill 3mm with the dremel, then enlarge the hole to 4mm with the large hollow diamond bits using a regular power drill? – or do you think a twisted bit is better for enlarging the hole. I’m based in UK and there seem to be less suppliers here. I used the very expensive dremel bits for the first few tests (pricey mistakes!!) – and now – the cheapest place I have found is here, but i’ve yet to put them fully to the test… (4mm shaft issue) – i hope you might be able to advise. thanks

    • It looks like you have a problem if your bit does not fit in to the Dremel and you can’t get a suitable adapter. However, it’s not difficult to me make a 4mm hole with a 3mm bit using a constant circular motion. If you are careful you can get a pretty accurate circle. That is what I would do. I would not use a regular power drill. They are heavy and clumsy tools and the rpms are insufficient.

  25. so much great information – thank you! I have been collecting rocks and sea glass for 40+ years and have them everywhere! Even put in marinace verde granite counter tops which look like imbedded rocks. I have been making jewelry with wire wrapping and want to try drilling. What should i practice on before endangering my little lovelies? Would a dishpan full of water with a piece of wood at the bottom be a good work set up? Love your work thanks again Karen

    • Thanks Karen. Yes, I agree with your plan. I use a Tupperware shallow plastic container with water and a piece of wood in it. Try drilling a few stones. Sand stones are very soft and easy to drill.

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