How do you properly measure ring size on a mandrel?

[beaujolais]

How do you properly measure ring size on a mandrel?

I have the $3 plastic one from e-bay. Do you put the ring on & let it stop on its own or do you push it down a bit?

Thanks.

 

[Michael_E]

Push it down a bit and look all around the upper end to make sure that the ring is truly round and touches the mandrel all around. If not then you have to make a guess about how much bigger it really is. You also want to be aware that lots of mandrels are different sizes than they should be. I would suggest marking the mandrel with a black line on the upper side and then measuring the diameter of the mandrel at that point. Include the ring size AND that diameter measurement when communicating with a jeweler and they will have a much better idea of what size you really are.

 

[beaujolais]

Thanks so Mike! I was hoping you'd answer, actually. Will do, much appreciated!

 

[minousbijoux]

Push it down a bit and look all around the upper end to make sure that the ring is truly round and touches the mandrel all around. If not then you have to make a guess about how much bigger it really is. You also want to be aware that lots of mandrels are different sizes than they should be. I would suggest marking the mandrel with a black line on the upper side and then measuring the diameter of the mandrel at that point. Include the ring size AND that diameter measurement when communicating with a jeweler and they will have a much better idea of what size you really are.

So I'm trying to imagine what you are saying Michael. Is this correct? You are holding the mandrel straight up and down, with the thickest part (biggest sizes) on the bottom. You drop the ring on, making sure its round enough to really have an accurate reading. So where the bottom of the ring hits is the first size or measurement you note, and then note where the upper end of the ring ends on the mandrel and measure that point too? TIA

 

[Michael_E]

So I'm trying to imagine what you are saying Michael. Is this correct? You are holding the mandrel straight up and down, with the thickest part (biggest sizes) on the bottom. You drop the ring on, making sure its round enough to really have an accurate reading. So where the bottom of the ring hits is the first size or measurement you note, and then note where the upper end of the ring ends on the mandrel and measure that point too? TIA

Almost correct minousbijoux. Where the ring hit on the widest part of the mandrel give the size of the ring. In the US that's a numeric size like 6 or 7. To do the second part requires that the person doing the sizing have some calipers or other method of measuring the diameter of the mandrel. You then measure the mandrel at the size of the your ring and give that measurement to the jeweler so that they can calibrate the mandrel they will be using to the mandrel you are using. For instance, your mandrel might show a size 7 and the same size on the jewelers mandrel could be a 7 1/2...yes they can be that far off. Giving them the diameter at that size lets them get the size of your ring just right.

Here's what the diameters of the mandrels should be at various sizes: http://www.onlineconversion.com/ring_size.htm Oh calipers are fairly cheap and are a good way to measure stones, (if you're careful with them). Look on Amazon and you can find cheap digital calipers for $12 or so. They show three decimal places, but are probably only accurate to two...plenty for what we're doing.

 

[minousbijoux]

So I'm trying to imagine what you are saying Michael. Is this correct? You are holding the mandrel straight up and down, with the thickest part (biggest sizes) on the bottom. You drop the ring on, making sure its round enough to really have an accurate reading. So where the bottom of the ring hits is the first size or measurement you note, and then note where the upper end of the ring ends on the mandrel and measure that point too? TIA

Almost correct minousbijoux. Where the ring hit on the widest part of the mandrel give the size of the ring. In the US that's a numeric size like 6 or 7. To do the second part requires that the person doing the sizing have some calipers or other method of measuring the diameter of the mandrel. You then measure the mandrel at the size of the your ring and give that measurement to the jeweler so that they can calibrate the mandrel they will be using to the mandrel you are using. For instance, your mandrel might show a size 7 and the same size on the jewelers mandrel could be a 7 1/2...yes they can be that far off. Giving them the diameter at that size lets them get the size of your ring just right.

Here's what the diameters of the mandrels should be at various sizes: http://www.onlineconversion.com/ring_size.htm Oh calipers are fairly cheap and are a good way to measure stones, (if you're careful with them). Look on Amazon and you can find cheap digital calipers for $12 or so. They show three decimal places, but are probably only accurate to two...plenty for what we're doing.

Thank you - this is very helpful to know.

 

[Mico]

Very helpful! thanks!

 

[Lee Little]

You should flip the ring over and check it from both directions then average the two readings as they will likely be different.
I had three mandrels and they did not agree with one another. One is steel, it reads a bit larger than the Aluminum one which I believe to be the most accurate. The 3rd was made of plastic and I threw it away shortly after it arrived in the mail. Best regards, Lee

 

[chrono]

I think the plastic ones aren't accurate and from what I've been reading in RT, even mandrel sizes varies from jeweller to jeweller.