What is PRECISION CUTTING (vs Hand Cutting and Machine Cutting)?

[@1bwana120]

Justin, Great video. Over the years I have often had to have this very conversation with people about cutting. It has been my position that no matter what type of machine was used to cut, or what pattern (style) a stone was cut in, the important distinction in calling something precision cut lay in what I refer to as the "workmanship". Too many have maintained that precision cut means that the pavilion must come to a pointed culet, or that the term somehow referred to a meet point style of cutting. To me precision "workmanship" refers to a set of tolerances that encompasses proportions, brilliance, symmetry, meet point tolerance, and polish factors. This is very much in alignment with G.I.A.'s colored stone grading criteria. I have cut this way on my Jamb peg, handpiece, and mast machines. Steve

[@JustinKPrim]

Totally agree Steve! 🥲

[@josephgehring6106]

Well said Steve.

[@arvidjohanstusvik8714]

I totally agree with you. I'm faceting on a homemade machine, with one of these cheap Chinese faceting devices. Many people say..no no .. that's some gear that's impossible to use .. But i can make high quality stones on that machine. .of course if i take my time making it 100% .. I have cut 147 facets Portuguese cut stones without missing a single meetpoint. So it's all about getting familiar with your equipment, being self critical, being patient and doing your best.

[@JustinKPrim]

Wow. That’s a feat! I wouldn’t want to cut such a complicated pattern on such a crude machine. But good on you for doing it anyway!!

[@nathanielhartsuff2336]

I know this comment is a year old but I also have one of those cheap chinese machines. Any tips to get better with it? My main issue is precision..

[@raeleenrobinson5749]

I like the orange one! Very nice colour

[@benjamindejonge3624]

Love this ambiguous options , but yes if there’re loupe correct what more do you want? But yes there is a difference between a potato or Swiss cut

[@makenchips]

You did an excellent job in explaining everything! So well done but in your examples I wish you would have had some pointer that would show us what those errors were because all the stones look pretty good in the video maybe you can do another video what does under magnification exactly what you're talking about I understand but I couldn't see it like you could. Also a description of price point per carat based the quality would have been good to understand to, but well done, enjoyed the video very much Columbus Michigan

[@boblakey1359]

Nice video Justin, good explanation, long overdue!

[@CoraleenWaddell]

super informative! thanks for this vid

[@donscott900]

I cut my gems on a flat lap without a manipulator I call that hand cut generally the stone is big enough to fit in your hand and usually not very small at all

[@Liburni]

just like that, it’s more to a good artist than to machines

[@nathanhays1746]

It would be great if you would edit the wiki entry for Faceting Machine. It is clearly biased: "... the mast assembly is what makes a faceting machine a faceting machine". It makes no mention of other mechanisms. To my mind there is nothing "machine" about a mast setup other than the spinning lap. All of the hand lapping devices: peg, hand, or mast, merely restrict the degrees of freedom. Arguably mast and peg "machines" are overly restrictive in that they confine the stone to an arc which forces a particular linear lap rate for various angles of attack. The Sterling style hand piece relaxes that degree of freedom restriction. This allows the cutter to vary the lapping rate, lap coverage, and attack angle very immediately when forming the girdle for example.

[@hamedrahmati3129]

thank you, your videos are excellent, please make video about ground girdles and how to grind a faceted girdle make a round and smooth girdle, specially on oval and pear shapes.

[@JustinKPrim]

For that one you have to pay for the class at facetingapprentice.com. We have a class on hand shaping girdles

[@oddmade7155]

GREAT video - very useful indeed - thank you Justin

[@georgeser3939]

Love those Swiss precision cuts. Are they yellow sapphires? Absolutely gorgeous✨ I remember back in my youth, we used to buy gems like that as an investment to pass on to the next generation as our legacy. Sadly today the majority won't spend money on a beautiful gem but rather buy the next generation iPhone, how plastic can you get?

[@JustinKPrim]

Hey the glass on the camera is part sapphire ! 😂😂😂

[@georgeser3939]

@@JustinKPrim yes but it's not yellow! My Android is made of gorilla Glass. I'll try to facet it 🤣🤣🤣🤣🤣

[@subodhawishwanath2353]

What ever the machine, skill rocks 🤘🤘🤘😉

[@ranvaknin6814]

I love your channel so much. Well done sir.

[@vincesimmons621]

I ALWAYS ENJOY YOUR VIDEOS . On the shelf behind is you a Chinese pink cutting tool. I got one from a friend that brought it from China. Just playing, I have tried to cut a table with no luck. Can you explain to me how they cut and polish tables?

[@JustinKPrim]

I think they use a 45 degree table adapter like mast machines. They put the dop in there and put the adapter in the pink handpiece and then set your height correctly.

[@vincesimmons621]

@@JustinKPrim That makes sense. Thanks for your reply.

[@LapidandoPedraseGemas]

Very good,show

[@Breed2019]

Thank you Justin, Iearning from your videos🙏❤🇹🇭😇

[@mohamedriflan5470]

Well explained.. Thanks👍 Justin K Prim

[@isaacalberda250]

i always take precision cutting to mean that the stone is cut with the specific gems RI into consideration

[@sinceresincere-th4dt]

Justin tell me what kind of a machine should I buy? I am new in this hobby and I bought a machine from the stupid Vevor in canada and parts of the machine were all garbage and they have decided to give half of the money back because it is too expensive to send it back to china and get an other one.

[@JustinKPrim]

Have you seen that angry turtle is now making an upgrade kit for the vevor machine to replace the garbage? You might want to start there. Otherwise I always recommend a sterling Handpiece machine because they’re the most affordable at $2000 and work great. That’s what I use. Here’s the angry turtle upgrade kit video: kzbin.info/www/bejne/o3mkgJ6uj86XjKcsi=4p_O8Wri_jhQpuXO

[@sinceresincere-th4dt]

@@JustinKPrim thanks for your reply. I did watch the video and I have already contacted them and waiting for their reply. One question about your reply. What is sterling handpiece machine? Can you give me an example please before I spend money on the kit or other things. My budget is limited and I am very very new to this hobby and hoping to learn at this age that I am. Thanks Justin.

[@JustinKPrim]

@@sinceresincere-th4dt sterling is the main machine i use. I have a billion videos on my channel showing it but here’s the overview: kzbin.info/www/bejne/qZPCYpV-gLGjn7ssi=YwFx73s9Gx3ZuZzl

[@sinceresincere-th4dt]

@@JustinKPrim Thanks Justin. It is an amazing machine actually and had never seen it before. I will be conducting more search and maybe I will order it. Thanks again my friend. (Tony)

[@sinceresincere-th4dt]

@@JustinKPrim Hello Justin. I got in touch with them and all I realized was a scam. Most probably they are working with Vevor and they are asking for 293 dollars for few screws and magic pen and sand paper. I bought all of those from Nona for only 7 dollars. LOL what a difference.

[@nadabutsi7537]

I have seen gem cutters in Vietnam use this handcrank grinding wheel and then they free hand the dopstick with one hand and spin the wheel with the other, that is what i think people mean by "hand cutting"

[@JustinKPrim]

Yes that’s used in Thailand too but that’s just for the preforming step you make the shape with that and then put it into some kind of faceting device to cut the facets and polish them.

[@nadabutsi7537]

@@JustinKPrim Thanks for the explanation :)

[@azizkhan-ti6jq]

Great explanation

[@lukaszahradnicek7518]

This is very nice video! :) Thanks!

[@superfluity-of-naughtiness777]

Just wondering...at time stamp 6:20 Justin refers to that stone as a "sapphire"??? its pretty clearly a medium red (with a purplish modifier) stone...Unless my TV is way off, isnt that clearly a ruby?

[@JustinKPrim]

Ruby sapphire… it’s a synthetic corundum. Maybe it’s a ruby, maybe it’s too purple. You choose.

[@manatworkhoyeahlovegodmade6373]

Picture very. Great work soldier

[@georgeser3939]

Very correct, brilliant!!!!!

[@aaroningram9741]

They all look good to me but I don't kno anything about gemstone cutting. What is a window? It seems it's bad if it has a window

[@JustinKPrim]

A window means that the cutter didn’t take the material into consideration when they cut the stone. Every gemstone has special angles that they need to be cut at in order to make the light and color reflect everywhere throughout the stone. If you look back at the video at 12:07 you can see that both of those yellow stones have an empty spot in the middle where you can see through the stone. You can see the white background through the stone instead of seeing the yellow reflecting. This is a bad cut stone because the angles are not right and you don’t get the full experience of yellow color throughout the whole stone and it can be improved through better cutting. I hope that’s helpful and makes sense.

[@aaroningram9741]

@@JustinKPrim thank you! I started looking at some faceted amethyst I bought off etsy and they all have a window. I only paid $40 for 4 12×10mm stones so I didn't expect great quality but I'm glad I'm learning about what to look for.

[@tammypriddle7063]

Thank you very informative. I’ve been interested in gems forever.

[@MichaelPhillipsatGreyOwlStudio]

I know this video is 2 years old, but I'm just catching up to it. That orange gemstone on the right as an example of a precision cut stone is magnificent. What kind of gem is it?

[@JustinKPrim]

It's a synthetic sapphire.

[@MichaelPhillipsatGreyOwlStudio]

@@JustinKPrimI don't usually go for synthetics, but it's really beautiful.

[@JustinKPrim]

Thanks. It was cut by my wife Victoria Raynaud@@MichaelPhillipsatGreyOwlStudio

[@MichaelPhillipsatGreyOwlStudio]

@@JustinKPrim She did a great job. The sunny nature of the stone is accented by the solar/floral shapes at the center. Sort of like a sunflower.

[@derrviel]

Is it true that a really well cut sapphire will not darken when it is set in a ring?

[@JustinKPrim]

I’ve never heard of this, but I can imagine that if you have a windowed stone that is getting light from the backside when you look at it in tweezers, then yes it would be darker when set because the setting/finger is obscuring the back of the stone.

[@idonthaveaname42]

I've heard of laser cut before too. Whats that?

[@JustinKPrim]

Laser cut is something now that as far as I known only exists for diamonds. It is exactly what it sounds like. A laser beam is guided by a fine water jet and they can actually cut all the facets on a diamond like this. They still need to polish them by hand though because the laser leaves the diamond’s surface burned.

[@idonthaveaname42]

@@JustinKPrim interesting thanks. Is it mostly used on diamonds because its expensive or for another reason?

[@JustinKPrim]

@@idonthaveaname42 the colored stone industry doesn’t have the same technology at all. Diamond cutting is completely planned by computers and now can be executed digitally with these lasers. Colored stones are planned by human eyes and brains and they don’t use any kind of gem scanner or even much technology. Colored stones are still a traditional art.

[@gamithaa]

tks , precision cutting tolarence 0.05 + and 0.05 _ for watch industry, tka Mr Justin, very good video, thanks again Saman amarasena

[@JustinKPrim]

All the orders I’ve seen are +0/-0.02mm. I’m sure some watch manufacturers have different standards though.

[@raeleenrobinson5749]

What is the best style for a pear shape amethyst, a lady want me to cut one, I have never cut a pear shape before, any hints, besides practice on a piece of glass first. Lol. I don’t want to get it wrong . Trying to arm myself with as much info before I start a trial run on glass .

[@JustinKPrim]

Hmmm. So many visable there but the classic is a mixed cut pear. Brilliant crown, step cut bottom

[@stephenpalummo9367]

the term "hand cutting" for me I've seen a video of cutters literally holding the gem stone in their hand and cutting the stone - no dop no holding jig/peg or the like

[@JustinKPrim]

I’ve only ever seen this done as the preforming step or for cabs. I’d love to see the video because in my experience, no professional cutters facet like this. It would be extremely hard and take a long time with likely poor quality.

[@tallowjewels]

Brilliant

[@Breed2019]

Thanks for the detailed info👌🇹🇭kha-pom🙏

[@jerricklescano8592]

How much price in orange diamond sir thakyou

[@sinceresincere-th4dt]

Thanks my friend for your replies. I really appreciate it. I live in Canada and to be honest with you, there is nothing here and they talk about first world countries. I went to look for a school to teach a little about faceting and lapidary, but that school has closed down. Now I am learning from your KZbin channels. My machine is still awful and I have to look into buying a sterling, but on their web page as soon as I click "buy" it says I have to send money directly to their account, and that is little bit odd to give money to someone that I don't even know. Cheers Justin.

[@JustinKPrim]

What part of canada are you in. I know a bunch of cutters in Montreal, Edmonton, and Vancouver. There is also a new group in Facebook called Canadian faceting. I would join that group. As far as sterling, you need to message them and get a quote with shipping and then do a bank transfer. The website is for info only, not ordering.

[@sinceresincere-th4dt]

@@JustinKPrim Hello Justin. I am in Kingston Ontario . I am more close to Montreal. Thanks for the tip. I will get in touch with them. Lets see what will happen next. Thanks again my friend. Cheers.

[@JustinKPrim]

@@sinceresincere-th4dt go to montreal and meet the cutters at Rippana gems. Super nice people, good cutters, nice stones. Find them on instagram and make an appointment. They can probably help connect you to more local cutters.

[@sinceresincere-th4dt]

@@JustinKPrim Thanks Justin. You are a great help and a perfect teacher my friend. God Bless. Cheers. I will get in touch with you soon after I meet the people in Rippana.

[@altaccout]

Is there a word for cutting using dremels or sandpaper?

[@JustinKPrim]

Cutting using a dremel is getting into the realm of carving but if you mean faceting without a faceting machine, it’s called free hand faceting. I’ve done it for a few stones before I learned to facet. There’s a guy that was in my lapidary club in San Francisco that’s been doing it for over 10 years and is really good at it now.

[@SophieMire-ek1fn]

How much do you sale the second maching?

[@JustinKPrim]

@@SophieMire-ek1fn nothing is for sale.

[@izrysiran8294]

hi justin, could you make an explanation video for gem merchants / buyers to find best cut in the market, step by step thank you

[@JustinKPrim]

Good idea

[@SophieMire-ek1fn]

Do you have industry in Sydney?

[@JustinKPrim]

@@SophieMire-ek1fn sorry. I’ve never been to Australia

[@lilwrongway5190]

❤🧡💛💚💙💜💞💕💞

[@greeneyedguy]

What does he mean by "window"

[@JustinKPrim]

When the bottom of the stone is cut with angles that are too shallow for the material, it doesn't create the mirroring effect, so we call it a Window because light passes through the stone like a window instead of reflecting like a mirror. If the stone has a window you can see what's behind the stone and the stone looks dull and has less color saturation.

[@greeneyedguy]

@@JustinKPrim Thank you very much for the quick reply! 🙏😎🙏. Your videos are exceptionally well received

[@JustinKPrim]

@@greeneyedguy thank you!

[@lancecarcer6876]

What would you consider the oldest and most traditional cutting. Say medieval europe gem era faceting/cutting. Working out ideas for making an as historically accurate as possible opulant cover for a bible.

[@lancecarcer6876]

I've found quite a few ideas and think I know how I'm going to go about it, but I'm curious about your opinion of where this would fit with your definitions.

[@JustinKPrim]

The most traditional old cut is cabochons. You can find lots of example of bibles covered in giant cabs from the medieval period. However if you want it to be faceted, the rose cut is one of the earliest, from 1550ish and would great for a bible cover. This is also from around the time of the reformation so if it’s a Protestant bible, that’s perfect timing!

[@lancecarcer6876]

Thank you kindly for your response. I actually didn't know the correct name them but I was originally planning on cabochons, but it is a protestant Bible and having some rough rose cuts would make it even better. I think I'll try for it. Thank you!

[@babydove]

Sir, Can you send me the Korean auto faceting machine seller website or contact I am interested to buying, thanks

[@JustinKPrim]

Sorry I dont know where you can buy one online. I know that World Jewelry Tools in Bangkok has these types of machines for sale but I don't know if they are of good quality.

[@renanjacob6791]

Free hand is Very apropriated.

[@JustinKPrim]

I’m not sure what this means

[@johnhodgson4216]

The error of the cut, and the accuracy of the cut matters. Hand Cutting is the least accurate cut, Machine cut is the next accurate cut, and precision cutting is cutting with the highest accuracy. the current precision standard is 0.01-degree accuracy. The video is all over the place defining Hand cutting, machine cutting, and precision cutting.

[@JustinKPrim]

Anything I would say in response to your comment is already in the video so I can only conclude that you didn’t really absorb the info in the video. I don’t agree with your statement but it’s ok if we don’t agree. As I say in the video, people use these names and ideas to mean different things in different places.

[@johnhodgson4216]

@@JustinKPrim "pre·ci·sion noun the quality, condition, or fact of being exact and accurate." you would include intelligence in the process. This would define what a "Precision Cut" is. "Machine Cut" could define as no intelligence of the cut being used. "Hand Cut" Hand cutting means cutting components from patterns by hand. In the video you kept referring to the method of cutting, and then the results of cutting, and how hand cutting can achieve precision cutting. In Physics 'which I am taking: Precision is defined as referring to the closeness of two or more measurements to each other." Accuracy ' Accuracy refers to the closeness of a measured value to a standard or known value. this is one of the first lessons the Ph'D professor teaches because it is misunderstood quite often. I do understand that 'Sales People make stuff up, then it becomes something else.

[@JustinKPrim]

@@johnhodgson4216 you’re pulling words out of the dictionary or out of your own imagination. I’m pulling words out of the jewelry trade and discussing how people around the world use those words to mean vastly different things. It doesn’t really matter what the dictionary definition says the word means, if people use it to mean something different. Precision means quality but people use it to mean different things as I said in the video. Americans use it when they really mean meetpoint cutting and faceted girdles. Swiss use it when they’re talking about very precise tolerances on tapered baguettes. Some people say machine cut to mean mast machine, some people say machine cut to mean Korean machine, some people say machine cut to mean automatic machine, a.k.a. robot cutting. As someone who works in the gemcutting trade, runs a gemcutting business, and works with several gemcutting factories, the point of this video was to make people aware of the dramatically different usage of these words around the world. Your comment illustrates this perfectly. What you think those words mean is different what I think those words mean and it’s different than what my customer thinks those words mean. There’s so much to say about this that I could make a whole video. Oh wait… The point is that there’s no standard definition of what any of these words mean for Gemcutting and it’s better to just speak about quality terms. Precision cut is a great term and it’s clear what it should mean, but machine cut, hand cut, native cut, etc. These terms don’t have any clear inherent meaning to someone coming into the jewelry trade. Again, this is the whole point of me making this video.

[@johnhodgson4216]

@@JustinKPrim I don't makeup what words mean, I referred to a dictionary; and the terms of a dictionary. Precision, Accuracy, and Machine are clear definitions. Sales Jargon is just makeup definitions, that's the problem.

[@usmanbacha1114]

Are you odd eyes ???

[@sinceresincere-th4dt]

Justin one more question. Where do you get your Dops? I ordered by Amazon and it was coming from India, which was being delayed and delayed and delayed until I gave up and asked for my money back. Thanks god it was Amazon protecting me all the way. Sorry buddy I am going to bug you many times. LOL god bless.

[@JustinKPrim]

I get mine from the machine manufacturer. In this case, sterling. I’ve never bought third party dops before.

[@mohamadskobide9996]

Do you have Facebook?

[@JustinKPrim]

Yes. Justin K Prim