Working with gemstones is becoming a very popular hobby nowadays. The first thing you need to do is cutting the stone into a reasonable size; after that, you’ll have to do some grinding to get the desired shape. Finally, the most satisfying part, the polishing, which brings out the beauty of the gemstone.
What tool to use for cutting gemstones? The most obvious choice would be a lapidary saw. It’s a stationary saw that comes with a diamond-coated wheel. It also has a water-based cooling system. Sounds pretty expensive, right? If you are looking for a cheaper alternative, then a rotary tool like a Dremel might do the trick for you.
In this article, we’ll primarily focus on discussing how to cut stones with a Dremel. In short, the following steps are involved:
- Choose the right bit. A diamond-coated wheel such as the EZ545 is ideal for this type of activity;
- Prepare for the cutting phase. Wear safety gear; mark the cutting line; convert your Dremel into a stationary tool by clamping the Flex Shaft or by using a Dremel Multi-Vise;
- Finally, do the cutting. Keep the stone wet for dust control and tool protection; stay between 12.000 and 24.000 RPM. Always work against the rotation direction.
Then, we’ll briefly talk about the next phases required to obtain a finished gemstone: shaping and polishing. That way, you’ll have a complete idea of the topic. I’ll give you some ideas on how to use a Dremel do to that.
How to Cut Gemstones With a Dremel – Step by Step Guide
1) Choose the Correct Attachment
Dremels come with a wide choice of bits to choose from, which suit many activities such as grinding, carving, cutting. When it comes to cutting, it’s key to choose the right attachment depending on the material you need to work on. If you use the wrong bit, one or more of the following will happen: the attachment will break/become dull very quickly; the cut will end up looking rough/ugly; you won’t be able to cut through the material or it will require much more time than what is actually due.
So what’s the best Dremel bit to cut gemstones? The answer is a diamond-coated wheel. That’s the only type of bit which can cut through hard materials such as stones, tiles, marble in a decent way. A good choice is the EZ545 1-1/2-Inch Diamond Wheel.
2) Prepare for the Cutting
Before we get to the cutting, we need to get ready for it. Make sure to follow these indications:
- First, let’s talk about safety. You absolutely need to take all the safety precautions needed, such as wearing earplugs (Dremels get very loud when working) and glasses to protect your eyes from flying debris. There shouldn’t be that much dust flying around, since we’ll be using water to keep it down. Decide if a face mask is needed in your case.
- As I mentioned before, we’ll use water for dust control and to keep the diamond wheel cool. This will prevent it from going dull very fast. Basically, what you need to do is get a bowl of water and frequently dip the stone in it, between a pass and the other. This will also remove any dust, making it easier to check the progress you’ve made.
- When cutting a gemstone, deciding the line to take is key. The goal here is to highlight the strong points of the stone and remove any flaws, such as cleavages. That’s why you need to draw the line you want to cut along. Use a permanent marker for it, since you’ll put the stone in water.
3) Transform the Dremel into a Stationary Tool for Better Results
What about holding the stone in place? This is very important to get a clean cut. You don’t want the stone to move around when working on it. There are a few approaches to this:
- The most common way of cutting I see is holding the stone with one hand while using the Dremel with the other. This is quite dangerous since your fingers will end up really close to the spinning wheel. Plus, keeping the Dremel steady with one hand is no easy task. If you decide to do this, at least use a Flex Shaft to make things more controllable.
- In my opinion, the best way to cut gemstones is by converting the Dremel into a stationary tool. Two ways to do this. First, you could use a bench wise. The main downside of this approach is that you don’t want to clamp the Dremel too hard, to avoid cracking the plastic case. To avoid doing any damage, you could attach the Flex Shaft to the Dremel and clamp the latter. Alternatively, you could get the Dremel Multi-Vise, which is specifically designed to turn the Dremel stationary. Plus it can also be used as a common clamp, which always comes in handy.
- Maybe you are not confident with the earlier methods, since you’ll end up with your fingers very close to the cutting wheel anyways. If the stone shape allows it, use a pair of pliers to hold it. Alternatively, you could directly clamp it. This will get things a little messier since you’ll have to pour water on it instead of dipping the stone directly.
In my opinion, using the Multi-vise is the best way to do it. It will give you the best results, plus it’s the safest way. Use it either to keep the stone in place or to clamp your stone.
3) Cutting
Now that it’s all set, we can get to the fun part, cutting. Make sure to follow these steps:
- Always work against the rotation direction. Otherwise, the wheel (or the stone) will try to “run off”, making things difficult to control and quite dangerous.
- Use a speed rate between 12.000 and 24.000 RPM. The best speed will depend on the material and hand. Use a trial and error approach to determine it. Start on the lower hand and move up until you can’t keep things under control anymore, or you start to feel more resistance.
- To complete the cut, you’ll need multiple passes. Make sure to dip the stone in water between each one of them to keep things cool and to remove any dust.
- If you are working with a stationary Dremel, make sure to hold the stone with both hands and try to keep your fingers as far from the spinning wheel as possible. Use a pair of pliers to hold the stone for additional safety.
That’s pretty much all there is to say when it comes to cutting gemstones with a Dremel. For the next phases, check out the following two paragraphs.
How to Grind/Sand Gemstones With A Dremel
The next thing to do after cutting is getting the gemstone into the desired shape. You might want to get the stone into a more symmetrical shape. Or you may want to simply remove any sharp edge and/or clean up the cutting surface. If your stone is big and you needed to rotate the stone to cut in its entirety, then this is certainly the case. You’ll need to move by steps here: start with a more aggressive grinding accessory, then move onto higher grit stuff until you get the desired smoothness.
- Start by removing the higher amount of material with a grinding stone. A silicon carbide-based one is ideal for hard materials like gemstones. A good starting point might be the 83142 Dremel Grinding Stone. Other shapes are available, choose accordingly to your rock shape. Aluminum oxide-based stones like the 952 could also work fine. The same principles as before apply here. Start at around 10.000 RPM and move up as needed, up to 15.000 RPM; keep the stone wet for dust control and tool safeguarding.
- After that, it’s time to move on to a sanding pad with a higher grit. Use the same approach as with the grinding stone. Continue dipping the gemstone into water when dust starts flying around.
- For the final touches, use higher grit sandpaper. Start at 220 and move up to 1000, until you reach the desired look. For even finer results, go up to 2000 grit sandpaper. Remember to keep the sandpaper wet.
How to Polish Gemstones With a Dremel
If you are satisfied with the gemstone look after the earlier step, then your job is finished. However, if you want to give it an even more glossy look, then it’s time to apply some polish to it.
- Get yourself some polishing compound and a buffing wheel that goes with the Dremel, such as these ones.
- Apply the polish onto the wheel, then turn the Dremel on.
- Assuming you are still using the stationary setup, gently move the stone around to get it polished. Make sure you move always in the same direction to get better results. Keep on working on it until you get the desired look.
As always, keep your safety glasses on when doing this.
Final Thoughts
So there you have it, a complete guide on how to cut gemstone using a Dremel. I hope you also appreciated the additional suggestions on how to shape and polish a stone with a Dremel.
As you can see, cutting gemstones with a Dremel is quite simple, and also safe with the correct setup and attachments. Just remember to keep things wet to keep your tools from getting dull in no time. If it’s the first time doing this, it will be a pleasure discovering all the hidden facets of your stone as you go.
One final suggestion: consider getting a lapidary saw if you need to cut bigger stones like geodes. It’s always a good idea to match the tool to the application at hand. Use Dremels only on small stones, don’t ask too much from a handheld rotary tool.
What Dremel size and model is a minimum for stone slicing?