How To Set A Stone In A Claw (Prong) Setting

The Bench Blog Episode 3

Claw or Prong Settings (depending on where you live!) are one of the most popular styles of settings, especially for engagement rings but how do successfully set a stone into a claw setting?

Well that is what I am going to show you in this post, but unlike many other guides out there, I am also going to show you the various methods that can be used, because as with everything when it comes to jewellery making, there is always more than one way to do it.

This is because, I am not one of those people who believes my way is the best and that is that! Instead, I prefer to look at all of the different options available, the pros and cons, give them a try and then decide which is the method that I think is the best for me.

Now for this post/tutorial, I am going to be mainly focusing on a 4 claw setting as these are the most common but I will also talk about the advantages/disadvantages of some techniques for settings with more claws.

Step 1: Securely Hold The Piece To Be Set

A very important starting point is to hold the piece you want to set securely as this can make the setting process much easier.

When it comes to options for holding a piece, there are many, such as:

  • Wooden Ring Clamps
  • Ball Vices, such as the GRS Microblock
  • GRS Benchmate

It also depends on the type of piece you are setting and generally there are things like inside ring holders for rings but for more awkward pieces like pendants and earrings, you need to get a little bit creative.

Ball Vice and Ring Clamp

But fortunately, there are things like thermoplastics like GRS Thermoloc or Jett Sett, which just require being heated up and then they become very malleable and this makes it much easier to hold the piece or you can go old school and use shellac. You will need some form of alcohol or acetone to remove the shellac though, which can be problematic for some stones such as oil filled Emeralds.

Step 2: Decide Where You Want The Stone To Sit

One the piece is securely in place, you can then decide where you want the stone to sit in the setting, but this is dependent on a few factors, such as:

  • How deep is the pavilion of the stone? (Coloured gemstones will often have a deeper and in come cases, more rounded pavilion)
  • Is the stone larger or smaller than the setting? (often the case with off the shelf mounts)
  • Where does the customer want the stone to sit?
  • Does the style of setting dictate where the stone is going to sit?

Every setting and stone combination is different and each requires their own consideration but a rule of thumb that I have found helpful (and pretty sure I was taught!) is to have the girdle of the stone sitting about 1mm above the gallery of the setting, if the setting has a gallery!

Diamond vs Sapphire Pavilion

The image above show the difference between the pavilion of a diamond (left), which is very angular as opposed to the pavilion of a Blue Sapphire (right), which is more rounded and this would need to be taken into consideration when planning where the stone is going to sit in the setting.

Once you have decided where you want the stone to sit, mark that point on the claws, so you know exactly where you are going cut the seat.

Step 3: Cut a Seat for the Stone

Now you know where you want your stone to sit, it is time to cut a seat for the stone and there are a couple of options when it comes to doing this and honestly, no method is right or wrong as long as it works for you and gets the job done properly.

Even though I was once told that I was completely wrong in my method and that theirs was 100% the right way to do it! Needless to say, I don’t have much time for people like that but I digress.

Different Types of Burrs
Different Setting Burrs (Right to Left): Setting, Hart, Ball & Cylinder

In the image above are four of the most popular options when it comes to cutting a seat in a claw (these are all mine and used pretty regularly, which is why you can see metal on the burrs!), I call these burrs but they are known by other names.

Below, I am going to break down the methods that use these burrs and the type of seat you can cut with them, the joys of CAD ey!

Method 1: Ball Burr

Arguably the easiest method to get started with, for a couple of reasons:

  1. It is pretty easy to learn
  2. Most jewellers have ball burrs as they are incredibly useful

To cut a seat using a ball burr, hold your flexshaft or micromotor handpiece at at 90 degree angle to to the claw and run the burr horizontally across the claw until you cut a seat and the depth you ideally want your seat to go is between 1/3 and 1/2 of the depth of the claw.

This will create a C shaped channel in the claw, like in the image below, you then want to carefully remove the bottom shoulder of the seat, so that the pavilion of stone sits in nicely.

How to Hold a Ball Burr

This method works great on 4 claw settings and on some larger 6 claw settings but with more claws, it becomes difficult and sometimes impossible to bring the burr in at a 90 degree angle and it does take good handpieces control to use a ball burr to effectively cut a seat at a lesser angle.

This is because it is more difficult to get the seat straight and also the burr can sometimes grab and run around the claw, leaving some unsightly marks that you need to clean up!

Ball Burr Channel

Method 2: Cylinder Burr

I was taught to use the ball burr method above from my first stone setting class and used it until another setter told me about using a cylinder burr for basically doing the same job.

As you can see in the image of the burrs above, a cylinder burr is basically an straight burr in the shape of cylinder (obviously!) and can be used to cut a C shaped seat like a ball burr but the big advantages for is that it is easier to cut a straight seat as you aren’t moving the burr backwards and forwards like you are with a ball burr.

It is also much quicker than a ball burr due to the longer size of the burr and on 4 claw settings, where I can easily get the burr in, this is my preferred method and it is accurate, quick and efficient.

Method 3: Hart Burr or Bearing Cutter

This is one style of burr that is known by a couple of different names and it also comes in two different angles, 70 and 90 degrees and I think most use the 90 degree.

Using the burr can be the most precise and accurate way to cut a seat for a stone and is a popular choice amongst diamond setters but it can also be the most difficult to use properly because each seat has to cut exactly, so that the girdle of the stone sits in the seat perfectly.

To help with this, use a Sharpie or similar to mark a point on the and on the piece, such as the ring shank or bail of a pendant, so that when you are test fitting the stone, you are always placing it back in the same position.

Using a hart burr to cut a seat is different to using either a ball or cylinder burr as you hold the burr parallel to the claw and then proceed to cut the seat, to make this process a little easier, here are a couple of tips:

  1. Use a hart burr that is slightly smaller than the setting but big enough so that it doesn’t fit between the claws, for example a 3-3.5mm hart burr on a 4mm setting this will stop it from grabbing and running around the claw, which trust me is very annoying!
  2. If possible, run your flexshaft or micromotor in reverse, sounds strange right? But you get around 70% of the cutting efficiency of the burr but it is much more controllable.

As with the ball and cylinder burr, you want to cut a seat between 1/3 and 1/2 of the depth of the claw, I prefer to leave a little more metal when using a hart burr as you can create almost a hinge point in the claw that has little to no strength and it is for this reason that if you are brand new to stone setting, I wouldn’t try this method to start with as burr control and precision are hugely important in getting a good finish.

How to Hold a Hart Burr

Method 4: Setting Burr

This one sounds the most logical as you are using a setting burr for setting right? Well this is my least preferred method of cutting a seat into a claw and funnily enough the one I was told was 100% the right way to do it.

The method for using a setting burr is basically the same as a hart burr and other than running your flexshaft or handpiece in reverse, everything I said above applies.

So why don’t I like this method? Simply because it takes too much metal away, which can not only weaken the claw but also can make it difficult to get a nice finish on the claws, especially if you want a simple rounded claw like the image at the top of the page.

Test Fit The Stone!

Whichever method you use, you always want to keep test fitting the stone to make sure that it is:

  • Sitting flat
  • Sitting square
  • The seats are suitable for the stone

I have seen lots of people cut the seats, put the stone in and then tighten the claws, without really checking how the stone is sitting and making adjustments once you have tightened the claws is a headache and can cost you more time than if you had just done some test fitting.

When you are happy with where the stone is sitting, you can then move on to the next step.

Step 4: Clean & Polish The Setting

If you want to get the best finish for your setting, you want to clean and polish the inside of the setting before you set the stone, because you won’t be able to do it once it is set.

This is also the best opportunity to remove any burrs that may be left on the claws after you cut the seat and it is much easier to remove them now and this makes the finish of the setting not only look better but also stops the chances of these burrs catching on clothing etc when the piece is being worn.

To clean and polish the setting, it is best to use attachments for your flexshaft or micromotor, such as:

  • 3M Radial Discs
  • Rubber wheels, cones and pin polishers
  • Bristle, Calico and Wool wheels for polishing

You ideally want the polish within the setting to be to the same standard as the final polish on the rest of the piece.

Step 5: Securing The Stone

Now it is time to set the stone in the setting and once again, there is more than one method for doing this!

Method 1: Pliers

One of the most commonly used methods for tightening claws is to use a pair of pliers, usually chain nose or parallel.

This method isn’t liked be everyone but it is quick and easy, you just need to be careful not to apply too much pressure as you can easily break softer stones, you can also squash the metal as well.

It also works best with round stones but from my experience, doesn’t work that well with Oval, Emerald or any other elongated style of cut.

To tighten the claws using pliers, place one jaw towards the bottom of the setting on one side and one the top of the claw on the opposite side, just like in the picture.

Tighten Stone Pliers

Then gently close the claw over the stone but only bring the claw in slightly as closing it too tightly can push the stone off centre.

Then reverse the position of the pliers and begin to close the opposite claw and then repeat the process for the other two claws. You always want to work opposite claws as this helps keeps the stone centred and the claws positioned evenly around the stone.

Remember to ALWAYS check the fit of the stone to make sure that it is sitting square and level, you will probably have to make minor adjustments to the positioning of the stone as you are tightening the claws.

Method 2: Pusher

The second method is using a pusher and my preferred metal of choice for this is brass as it is not much harder than precious metals such as Silver or Gold, which means it is less likely to damage the metal like a steel pusher.

To tighten the claws using a pusher, begin by pushing the claw in from the side and as with the plier method above, work on opposite corners and bring them in a little at a time.

When you are ready to do your final tightening of the stone, roll the pusher up to around a 45 degree angle so that you are pushing the top of the claw over the stone.

Tighten Stone Pusher

Once again though, proceed carefully and don’t push too hard on the claws as you can damage the stone but gradually work the claws over the stone, still going via opposite claws until the stone is securely held in place.

The great thing about using a pusher to tighten the claws is that it can be used with any shape of stone and you can also put a claw shaped groove into the end of the pusher so that it fits securely around the claw, this helps prevent slipping and can also prevent damaging the claw.

Vector Tightening

One of the main issues you may run into when trying to secure your stone, is that no matter how much you try, you can’t completely secure the stone in the claws.

This is where vector tightening comes into play and is something I do on every claw setting, just as a way of ensuring the stone isn’t going anywhere.

To vector tighten your stone, get your pliers, chain nose or parallel work fine and place the jaws of your pliers on the outer edges of your claws (just like in the picture) and gently close the pliers, which moves the claws together.

You only need to move them a short distance, sometimes a fraction of a mm.

Vector Tightening

You then do the same on the opposite side before bringing the claws back into the correct position by doing the same thing on the two remaining sides.

So using the image above as an example, you would do the two claws on the left, then the two claws on the right, then brings the claws back into shape by doing the claws at the top, then bottom of the picture (hope that makes sense). Visually it shouldn’t look any different but you will find that stone is more secure and if there was some movement of the stone previously, there shouldn’t be any now.

Step 6: Cutting Down The Claws

Now that the stone is in and secure, it is time to move towards finishing the setting and the first step of this is to cut down the claws as they are probably much longer than they need to be.

There are three ways you can do this:

  1. Saw, takes a steady hand but can be very accurate
  2. Snips, quickest but you need to be careful with more fragile stones due to the shock caused by the snip action
  3. Twin Cut Cup burr, for simple round prongs, these burrs are very quick and effective
Saw and Snips

If I am doing something like talon claws, then I will use the saw after I have bent the claws over the stone as I personally find it easier to get a uniform length on the claws.

If I am doing simple rounded claws, like the ones in the image at the top of this page, then I will use the Twin Cut burr.

When using the saw or snips, you want to leave yourself enough metal so that you can shape the claw, if you are just doing simple rounded claws, cut the claws off level with the table of the stone.

Step 7: Shaping The Claws

Once the claws have been cut down to size, it is time to finish them off, so that they look nice and presentable but as always, there is more than one way to do this.

Method 1: Cup Burr

The quickest and arguably easiest way to finish off a claw is to use a cup burr and there are two different types of cup burr:

  1. Traditional Cup Burr, this is the shape of a cup, with teeth on the inside of the cup, like the ones in the picture. These will get the job done but they do clog up quickly.
  2. Twin Cut Burr, these look like the shouldn’t work that well but they are awesome (so much so, that I sold my traditional cup burrs!). They work almost as a mini lathe, so care is required when using these as it is easy to take too much metal away.

To use one of these burrs, just bring them down on the top of claw and use a small circular motion to round off the top of the claw.

While this is a quick and easy method, I often find that the inside edge of the claw is still a little bit catchy when ran across clothing.

That is a good tip actually, to see how smooth the finish of your claws are, run them across a piece of material such as cotton (trousers, top etc) and see if it catches on the material, ideally it shouldn’t and should run smoothly along the surface of the material.

Cup Burr and Files
Safety Tri-Square File, Twin Cut Burr and Knife Edge File

Method 2: Filing Them Into Shape

This is very much the old school method of shaping claws and is still the way to shape talons or square claws but it can also be used for round claws as well.

You want to use a file with a safety edge, which is where there is no teeth on the edge and sometimes face of the file as this reduces that chances of damaging the stone. In many cases, you will need to modify one of your files to have a safety edge, such as the tri-square in the image above, which has one smooth face and two smooth edges.

To shape the claws using a file you want to roll the file 90 degrees during a stroke, this allows you to make a rounded edge on the claw, do this on all 4 sides, then diagonally, so that you round off all the edges of the claw.

To finish off the claw, some setters with then use a large grain tool to create a bright, rounded top to the claw.

My Method

I couldn’t get a finish I was happy with using either of these methods so I made my own hybrid method for round claws, which involves:

  1. Shaping the inside of the claw using a safety edge file, this creates a much nicer edge that a cup burr in my opinion
  2. Use a Twin Cut burr to round off the rest of claw and bring it down to the height that I want

I found that this left a much smoother claw that doesn’t catch on clothing, it took a little bit of trial and error to hone it in but it is now my go to.

Step 8: Finishing The Claws

Now that the claws are shaped, it is time to finish them off before final polish and it is at this stage where you can remove any excess metal, remove any tool marks and soften any sharp edges.

But what metal? You may sometimes get what it called flashing, which is bits of metal that have been squashed against the stone, rather than being removed. The best way to remove this is with a very sharp graver or fine, needle point burnisher but a steady hand is required, so as the not scratch the stone. Simply run the graver or burnisher around the inside edge of the claw and you will see the flashing come away.

The next step is removing any tool marks, this most usually happens when you use pliers on the claws and the tool steel is much harder than the metal and can often leave scratches or nicks in the metal. To remove this, use a fine rubber or pumice wheel and carefully smooth out the metal.

Sometimes but not always, you can end up with sharp edges on the back of your claws, which is something you don’t really want, so carefully use a fine rubber wheel and round of these sharp edges, leaving a nice smooth claw.

Step 9: Final Polish

The stone is set, the claws are finished, now it is time for a the final polish and rightly or possibly wrongly, I am going to assume that you know how to do this.

It will also show you if the are any areas of your claws that could snag on clothing as fibres from your mops will get caught on theses areas and if the amount of fibres caught is significant, then you will need to go back in and fix these areas.

But if there are no fibres caught and the stone is sitting nicely square, level and secure, then you know you have done a good job!

Conclusion

So there it is, my guide to setting a stone in a claw setting and I hope you have found this helpful, especially by seeing some of the different techniques that are out there that can help you achieve the results that you want.

If you are just getting started (as I assume you are if you are reading this post), then be prepared to make quite a few mistakes before you start getting it right as stone setting is very much practice makes perfect, I know my first attempts were abysmal.

But with every one that you do, examine your work under magnification (a 10x loupe will do fine) and look at what you can improve next time and then do that one the next one. This way you are improving on every single one and don’t get discouraged if you mess one up, it happens but make sure you identify what went wrong, so that you don’t do it again next time.

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