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Author Topic: Wheels for Cutting Opal  (Read 1009 times)

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Amylynn

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Wheels for Cutting Opal
« on: January 31, 2018, 07:42:43 AM »

Hi!

I need recommendations for wheels specifically for cutting opal. I'm thinking I'll order some Novas... and not sure what metal wheels. I'm considering sintered because I've heard even galaxy wheels aren't lasting long for people.

I've used the standard set up in Paul Downings books- 80/220 galaxy and Novas- 280, 600, 1200, 14000. I liked it well enough, but didn't really use the 80 much.   

I'm contemplating something like:

Metal wheels- 200-300 grit, 600 grit

Novas- 600, 1200, 14000?


I was thinking the hard 600 will give me more wiggle room with thin color bars. Any advice you've got is appreciated. Please recommend brands too, I've been trying to research what brand to buy, but there are opinions and experiences all over the map, so it's hard to rule anything out!

Thank you!
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lithicbeads

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Re: Wheels for Cutting Opal
« Reply #1 on: January 31, 2018, 08:55:24 AM »

200 and 600 hard would be my choice. A hard 600 is a joy to use, it has always been one of my go to wheels as it saves the nova wheels to an extent and does give excellent accuracy as you imagined.
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Pusscat

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Re: Wheels for Cutting Opal
« Reply #2 on: January 31, 2018, 12:04:05 PM »

Hi Amylynn,
I use a 300 and a 600 metal wheel for cutting back and fine shaping. Then onto a soft 600, soft 1200 and then 3000. Then I go onto cerium.

I have a 1400 and 50000 but usually only use them on matrix type stones as I find they can scratch solid opals.

I too love both the 600’s!

Amethyst Rose

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Re: Wheels for Cutting Opal
« Reply #3 on: January 31, 2018, 03:07:46 PM »

If you are mainly cutting opals you will never wear out a sintered wheel.  I cut hundreds to thousands of stones, mostly agates, each year and have never replaced my sintered 80 grit.  Five years and still going strong.  Before the sintered, I was typically replacing the metal bonds every 4-6 months.

I use Linde A on very wet leather for polish on the opal I do cut.

Bob Johannes
The Amethyst Rose
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gemfeller

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Re: Wheels for Cutting Opal
« Reply #4 on: January 31, 2018, 05:38:21 PM »

I've cut hundreds of opals and I wouldn't think of using any wheel coarser than 220 for initial grinding.  I usually jump from that to a 600 Nova and follow that with 1200, 3000 and 8000, sometimes followed by cerium oxide on felt -- leather gets them too hot too fast.  In most cases an 8000 finish is good. 

I've never used a 600 grit hard wheel for opals but it might be nice.  In the past I've sometimes used a 1000 grit hard wheel for final shaping and removal of deep scratches before going back to the 600 Nova to get rid of little flats. 

If all you'll be cutting is opal I see no need for using a sintered wheel.  It'll take a long time to dull a Galaxy 220 cutting opal only but sintered wheels are desirable for their long work life and are desirable despite the initial expense.  It just depends on your pocketbook.
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hummingbirdstones

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Re: Wheels for Cutting Opal
« Reply #5 on: January 31, 2018, 06:04:10 PM »

I do the same as Gemfeller.  I don't see any need to buy a sintered for opal.  It will be years before you'd have to replace it.

I bought a used Genie over 9 years ago and it still has the original 220 on it that came with it.  The wheels were not brand new when I got it.  I just replaced my 80 grit in August 2017.  The 220 needs to be replaced, but it still cuts -- just not as quickly.  Note that I cut a lot of different material, but I cut opal, too.

I wouldn't skip the 3,000 wheel, though.  I'd replace the 14,000 with a 3,000 and maybe get a spin-on pad and 14,000 diamond paste for the side of the machine.



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Robin

Jhon P

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Re: Wheels for Cutting Opal
« Reply #6 on: January 31, 2018, 06:25:39 PM »

I would suggest that you break in any new wheels
With a hard agate or jasper before doing any opal or you
May never get the scratches out of the opal
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gemfeller

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Re: Wheels for Cutting Opal
« Reply #7 on: January 31, 2018, 07:02:16 PM »

I would suggest that you break in any new wheels
With a hard agate or jasper before doing any opal or you
May never get the scratches out of the opal
For sure.  New wheels are aggressive no matter what grit.  They take a bit of taming before doing opal work.
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vitzitziltecpatl

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Re: Wheels for Cutting Opal
« Reply #8 on: February 01, 2018, 06:24:53 AM »

Yes, as the previous posts say, break the new wheels in well with hard stones before cutting opal. On the other hand, however, a good set of "opal wheels" will still cut your opal long after an agate cutter would replace them.

Sometimes you can pick up used wheels from production cutters who don't resurface.

Amylynn

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Re: Wheels for Cutting Opal
« Reply #9 on: February 01, 2018, 07:57:37 AM »

200 and 600 hard would be my choice. A hard 600 is a joy to use, it has always been one of my go to wheels as it saves the nova wheels to an extent and does give excellent accuracy as you imagined.

I'm really glad to hear that. I was afraid people would think this was strange, it sounds great to me. 220 grinds too fast for me!  Thank you!
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Amylynn

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Re: Wheels for Cutting Opal
« Reply #10 on: February 01, 2018, 03:28:29 PM »

Thank you all so much! This is so helpful!

I was thinking sintered because of how long it would last... and it sounds like they're cheaper in the long run. But I didn't really think about how long normal wheels would probably last with opal. I think I'm afraid to buy galaxy wheels because I had some rust within a month... and I've read they aren't lasting people as long anymore.  I don't know how bad rust is on a wheel, but I'm assuming it's not good.. ?

Any brand recommendations? I'll probably go Nova for the soft wheels, but I'm not sure yet about the hard ones.

As far as breaking in, is it easy to tell when they're worn in? I tried breaking in the Novas I had, and I wasn't sure if I was wasting too much diamond or if I needed to grind more agate. Do you need to break in the metal wheels too?

Thank you all again, this is so much better than digging through old books and YouTube videos trying to find answers like this!
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Amylynn

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Re: Wheels for Cutting Opal
« Reply #11 on: February 01, 2018, 03:52:08 PM »

I've cut hundreds of opals and I wouldn't think of using any wheel coarser than 220 for initial grinding.  I usually jump from that to a 600 Nova and follow that with 1200, 3000 and 8000, sometimes followed by cerium oxide on felt -- leather gets them too hot too fast.  In most cases an 8000 finish is good. 

I've never used a 600 grit hard wheel for opals but it might be nice.  In the past I've sometimes used a 1000 grit hard wheel for final shaping and removal of deep scratches before going back to the 600 Nova to get rid of little flats. 

If all you'll be cutting is opal I see no need for using a sintered wheel.  It'll take a long time to dull a Galaxy 220 cutting opal only but sintered wheels are desirable for their long work life and are desirable despite the initial expense.  It just depends on your pocketbook.



I forgot to ask, does this jump from 220 hard to 600 Nova work okay for most material for you? I'm going to get a 600, 1200, and a 3000...  and then a fourth Nova, should I go higher than 3000 or lower than 600... for it?  If that makes sense. I'll also be cutting other random stuff: turquoise, jasper, agate, labradorite, etc... but definitely mostly opal.
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hummingbirdstones

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Re: Wheels for Cutting Opal
« Reply #12 on: February 01, 2018, 04:48:36 PM »

220 galaxy to 600 Nova is not going to get the scratches out of harder material like agate and jasper without wearing your 600 out prematurely.  You will need something in between those two wheels.  There is a 220 Nova that is more aggressive than the 280 and supposedly takes the scratches from the 80 and 220 out better, saving the 600 wheel a lot of work.  I have not tried this one, but I want to.

Does anyone on the board have experience with swapping out the 280 Nova with the 220 Nova?

Regarding breaking in the wheels -- they all need to be broken in.  There will be high spots that need to get tamed so they won't leave gouges the size of the Grand Canyon in your softer stones.  Working them with agate for a while is the best way I know of.  And it does take a awhile.  If you're unsure if they're good to go, use a scrap piece of your softer stone to test them before you put your good opal to one of them.
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Robin

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Re: Wheels for Cutting Opal
« Reply #13 on: February 01, 2018, 07:05:07 PM »

Robin and all, I'm currently playing with a 220 soft wheel.  It's a Johnson Bros. refurb and it's pretty aggressive -- more so than my older 220 sintered.  It's not yet fully broken-in so I still follow with my old 280 when cutting harder stuff.  I wouldn't get near it with an opal at this stage! I'll try to remember to post more about it as the experience curve lengthens.  I don't know how it would compare with a 220 DP Nova which I've not tried.

I think learning which wheel to use when is more of an art than a science.  You get a feel for which wheels cut faster or slower and adapt your cutting style to that as well as the material you're cutting.  New wheels are always more aggressive so you do a work-around.  I use different wheel sequences for different materials as I suspect most cutters do.  And that sequence changes as wheels wear or new ones are added. 

I would add that I think rust on hard wheels is mostly caused by not spinning them dry at the end of a cutting session.  I always let my Genie spin for 2-3 minutes before shutting down for the day.  I've had some metal wheels rust in the past and it was my own fault. 
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hummingbirdstones

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Re: Wheels for Cutting Opal
« Reply #14 on: February 02, 2018, 06:21:36 AM »

I have heard really good things about the 220 Nova, but not from someone I know.  I do know that Diamond Pacific now uses the 220 Galaxy and 220 Nova as standard on their new machines.
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Robin
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