October 3-7—JOSHUA TREE, CALIFORNIA: Annual show; Sportsmans Club of Joshua Tree
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 Post subject: pearl drilling advice
PostPosted: Sun Mar 11, 2018 4:49 pm 
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I am thinking of getting my daughter a setup for drilling pearls.

I am leaning toward the joltool to hold the pearl, and a freeform flex unit. (I have a dermal with a flex that she can start with)

I am looking online, and the pearl drills seem to come in spiral and flat types.

They are not inexpensive.

One person uses a sewing needle and breaks the eye off and sharpens it.

In the past I worked on grandfather clocks. We make a lot of "D" drills from drill rod,when making and repairing them. I am very comfortable making them. I am not sure if they would work for pearls.

before I let her start, and break the bits (some are $20 each) can anyone give me some tips and recommendations on both drills and the procedure?

I have made a jig "that lets me sharpen drills on my faceting machine, so the thought of using sewing needels or "D" drills?


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 Post subject: Re: pearl drilling advice
PostPosted: Sun Mar 11, 2018 7:07 pm 
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Hi Ted, you will need a rig that holds the pearl and the drill in the correct orientation. Most drills break because they move out of orientation. Proxxon do an excellent miniature drill press and they supply accessories for it that will fit the bill. I bought, some time ago, a gemstone drilling rig that consisted of a hollow, diamond coated, drill with water feed down the centre of the drill. Really good, fast cool drilling in all stones. I saw, on the Banggood site, a machine for drilling beads. Two hemispherical clamps to clamp the bead with a hole drilled through where an electrically driven drill fits to drill the stone (or pearl). Remember that while it is easy to resharpen a drill bit, getting the broken end out of the pearl can be the devil's own job!


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 Post subject: Re: pearl drilling advice
PostPosted: Mon Mar 12, 2018 3:37 pm 
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Thanks, I will look into the drill you mentioned.

at least pear;s are softer than most gemstones.


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 Post subject: Re: pearl drilling advice
PostPosted: Mon Mar 12, 2018 4:18 pm 
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Yes. pearls are softer than most gems, this can be good, in that you can use steel drill bits, but it can also be bad in that the drilling debris can build up in the drill hole, then if you are not careful the drill bit will bind in the hole, spin the pearl in the holder and scratch it.


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 Post subject: Re: pearl drilling advice
PostPosted: Mon Mar 12, 2018 7:30 pm 
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thanks for that, I know that the L/D ratio is pretty big, which makes it tough to clear the swarf.


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 Post subject: Re: pearl drilling advice
PostPosted: Mon Mar 12, 2018 8:15 pm 
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I looked for the drill press you mentioned.

The ones with the included morot only go to 8000 rpm, not sure if that is enough for the small pearl drills.

I am trying to find a speed chart. So far no luck.

I found instructions for this pearl vice from Rio Grand But they do not seem to stock it anymore. Thbe idntructions do not list the model. I like it, because there are different size cup, and it can be drilled from both ends without changing anything.

Image


If anyone kn ows if this is still made please let me know.


I did find this one, but it has brass cups, in one size.

Image


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 Post subject: Re: pearl drilling advice
PostPosted: Tue Mar 13, 2018 6:16 am 
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Maybe the one with the brass cups, but with a layer of PTFE tape between the pearl and the brass would do the trick. I shouldn't worry about the drill speed, remember that the Arabs, Japanese and Chinese were drilling pearls with a bow drill (maybe 200 rpm if you were lucky) for centuries.


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 Post subject: Re: pearl drilling advice
PostPosted: Tue Mar 13, 2018 8:50 pm 
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sounds good.

The bow drill sounds interesting......


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 Post subject: Re: pearl drilling advice
PostPosted: Wed Mar 14, 2018 3:45 am 
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Yes, it is very interesting to watch someone use a bow drill, but the ability to use one accurately was only acquired after years of practice!


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 Post subject: Re: pearl drilling advice
PostPosted: Fri Mar 23, 2018 9:15 am 
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Hi Ted, I was looking at the website of a dealer I use in Idar Oberstein and noticed that he now does the water fed drill as a standard item. Google "Otto Eigner Idar Oberstein" and look at "Bohrmaschine" and you will see them. The only problem is that the smallest size is 1 mm, a bit big for pearls. Probably best with a 1/2 mm tungsten carbide drill, take it in about 2 or 3 mm at a time, then take the bit out and clean the swarf off with a small, stiff artists brush. Be particularly careful at breakout as the pearl can seriously chip.


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 Post subject: Re: pearl drilling advice
PostPosted: Fri Mar 23, 2018 6:01 pm 
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Alan F. wrote:
Hi Ted, I was looking at the website of a dealer I use in Idar Oberstein and noticed that he now does the water fed drill as a standard item. Google "Otto Eigner Idar Oberstein" and look at "Bohrmaschine" and you will see them. The only problem is that the smallest size is 1 mm, a bit big for pearls. Probably best with a 1/2 mm tungsten carbide drill, take it in about 2 or 3 mm at a time, then take the bit out and clean the swarf off with a small, stiff artists brush. Be particularly careful at breakout as the pearl can seriously chip.


Thanks

One of the fixtures allows drilling from both sides, is it worth doing that to minimize breakout? Or can I just take it slow.


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 Post subject: Re: pearl drilling advice
PostPosted: Sat Mar 24, 2018 12:58 am 
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I would get the simplest setup you can find. I am projecting, but for me, I would want a minimal learning curve.
Pearl in a holder; drill with a guide.


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 Post subject: Re: pearl drilling advice
PostPosted: Sun Mar 25, 2018 11:15 pm 
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Barbra Voltaire wrote:
I would get the simplest setup you can find. I am projecting, but for me, I would want a minimal learning curve.
Pearl in a holder; drill with a guide.



One of the guides only lets you drill from one side. The other lets you drill from both sides, without changing anything.

Neither is that expensive, so I may get them both and let her try them.


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 Post subject: Re: pearl drilling advice
PostPosted: Mon Mar 26, 2018 9:37 am 
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I have drilled many pearls. If you need a drill hole on both sides of the pearI, recommend that you do not drill the pearls from one side. Doing so can crack the nacre as the drill bit penetrates the second side. If you are using a steel twist drill, make sure the pearl and the drill bit are lubricated. I use water for this.


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 Post subject: Re: pearl drilling advice
PostPosted: Tue Mar 27, 2018 12:35 pm 
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Breakout is less of a problem with gemstones than pearls, with pearls, because of the softness and fragility of both the nacre and the mother of pearl bead the slightest bit of excess pressure can crack either or both. So, both side drilling is advisable. The parallelism of the holes can be checked by passing a drill through both sides and seeing if it binds anywhere. Lubrication is also a sound idea, but given the porous nature of the material, pure water is advisable.


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