Old Prismatic faceting machine

[johnful]

Hi Debbie,

I have not been to William Holland yet. I have a hard time finding the time due to work. That said, I belong to the Augusta Gem and Mineral Society, which gives out two "scholarships" a year to William Holland. Many of the club members have been there.

J

 

[johnful]

Hi Wally and Whisp,

I tinker a lot. So much so that my wife won't call a handyman but insists I do it. It eats a lot of my time that is not otherwise consumed by my silli-con valley tech company day job. What little time I have left, I focus on hobbies like rock hunting and faceting.

I also like to find my own gem collecting locations instead of the "usual" pay to dig places. Not to knock the pay to dig places like Jackson's crossroads, but I prefer taking a different path. I generally start with www.mindat.org and go from there. If the land is along a body of water in the US, it's generally US army corps of engineers land and easy to get a prospecting permit (for free). That's how I found the amethyst location near my house. In the 50s, when they built the interstate system, it was noted in mindat. A little research with geological survey maps from the period, and I was able to find the spot it in a road cut. The amethyst heart is cut from that material.

Here's another amethyst find, still in the ground ...

Note: in mindat, look for mica. Where there's mica, there's lots of other good stuff. You can narrow from there. The ground where the amethyst came from is covered in flecks of mica. Look for old abandoned mica mines. In Burnsville NC, you find emerald there, among other things.

J

 

[Wally69]

Sounds like a few of us have the same mindset, I am a civil engineer by day but tinkerer at all other times.

Have been chasing sapphires with my brother a couple times a year for the last decade and developed a passion for understanding the geology. I have been hunting for gold and other gemstones locally (within 500km) for the last 4 years and caught the relic bug along the way. Recently unearthed my first pocket of smokey quartz and have learnt to facet, so now I am totally hooked.

Thanks for the insight. :Y:

 

[johnful]

Hi Wally,

You find any good sapphires? I have some sapphires and some rubies from North Carolina. Mostly on the small side. Many are display quality crystals and a few are facet grade.

J

 

[johnful]

Hi Wally,

I also have a lot of old material collected when I was a kid growing up on the west coast of the US. I "inherited" a lot of it when my dad passed away. One summer, when I was 12 I think, we went to Plush Oregon and collected sunstones. I have a few quart jars of them. Here's some of them, yeah that's a dinner plate:

J

 

[Wally69]

Wow - not familiar with sunstone J, looks like it was a great day out.

Travelling for work ATM, will get a few photos together of some of my more interesting sapphires when I get home.

Still after the big clear trophy cutter, although every flash of blue has been a good moment and the odd thumb sized bomb has indicated we should find a good one one day.

 

[Debbie K]

J:

How's the switch install going? I'm delaying starting on machining the new brake and cheater, as I'm going to a metal supply place next week and hope that they have some rod that's closer to the right dimensions. I have a big hunk of aluminum, but no real accurate way to cut it; just a table saw and chop saw which are difficult to get perfectly square. We had icy roads here; a really rare winter storm, Houston practically never gets them but this was the third time this year we had sleet/snow. There's still some ice on things, but the roads are clear, but my trip to MetalSuperstore got delayed.

I have some sunstone, too, that looks like what you showed here. It took a long time and just the right light to see that most of them had some schiller. I've put off faceting any of them until I get better. I messed up a perfectly good anthill garnet yesterday, mostly because of the unreliable brake. I never seem to hit the brake, as it were, and standard brillants are always just a trifle out of round. I seem to take 1 step forward and 2 steps back with every stone I facet; I'm embarrassed to show any of them.

Think I'll take a break from it for a while and go back to carving; it's what I'm good at. I need to get my confidence back!

Debbie

 

[johnful]

Hi Debbie,

The local Grainger had to order the switch. Hope to have it this coming week.

You have to look close at the Sunstone to see the schiller. The darker the color, the more they seem to have. I've cut a few; I'll have to find the pictures. They come out fairly nice. Oddly, when you cut them, they have a sort of slippery feel on the lap that reminds me of soap. It takes some patience. I did a few "Charles Covill" style squares, and an oval or two.

On the brake, the knurled screw is the fine adjustment. Mine was a bit loose. I put a dab of the wife's fingernail polish midway on the threads and let it dry. Now it works like a champ and doesn't slip a bit. It was just enough to "fill in the gaps" and make it a bit tighter after all those years of wear. The polish is softer than any of the metal parts so it shouldn't hurt them.

One thing I noticed on mine is that when you swing the stylus across the lap, the side closer to the operator seems a little "higher" than the side further away. I think the way to adjust that is here, but I haven't tried it yet.

There's a nut you can loosen on the inside toward the stylus, then gradiated markings as you turn the assembly clockwise or counterclockwise. I think I would turn mine slightly counterclockwise (and tighten it again of course) to correct the "swing" problem.

J

 

[Debbie K]

J:

Yes, mine was set at zero, but it wasn't truly zero. I found that it was off about 1/2 -3/4 a degree. I really like this ability to change the orientation; if for any reason the lap gets out of level due to warpage of the base you can adjust out the difference.

The fine tuner on mine is fine; it doesn't slip or move. I marked mine off in 1/10th degrees just for fun. Since I never took shop or had a dad that knew how to do anything, the vernier scale had me mystified. I had to look and look for an explanation for how the thing worked, mostly because I didn't know what it was. If you don't know the name of something, it's hard to find out how it works, but I figured since it had one it must do something.

The brake is the problem; it will not tighten down enough to hold on the axle without using pliers. I think that the aluminum has worn down on the inside of the brake which has made the distance of the gap just a little too large to allow it to be tightened. I have to say, I liked the straight-forward brake on the protractor that the Graves machine has better than this one; it never slipped. But the extra large protractor on the Prismatic along with the fine-tuner gives one the potential for much more accuracy, if only it didn't slip. I've been trying to figure out another approach to a brake that's better than what is on this machine; I'm still thinking...

My cheater was broken in two, which is why I had to make a new one. I plan to make one out of aluminum soon and when I do, this time I'll do a step-by-step and take pictures. I was surprised how easy it was to fabricate the one I made before out of plastic.

Interesting thing; practically the only time I use the cheater is on the table, primarily due to poor dopping transfer. The machine holds all the angles so well with practically no fluctuation that I almost always am hitting the facets in the same place even when I go up and down the mast. On the Graves, I was using it constantly. Which is why I'm trying so hard to get the thing working properly; it could be such a great machine.

Debbie

 

[johnful]

Hi Debbie,

Before you fabricate a new brake, there's a screw on the bottom side that goes into the course adjustment knob which is on the top. Try putting a little thin washer in there and see if it helps. If it does, you can take the screw out, grind it down slightly so its a little shorter, then put it back together. Sounds to me like things loosened up enough that the screw is hitting the end of the hole in the coarse adjustment knob. It's worth a shot.

J

 

[Debbie K]

J:

My coarse adjustment knob is threaded all the way through so this is not the problem. Closing the gap is the issue; as I am tightening the coarse adjustment knob it is unscrewing the bottom screw as I am having to tighten it down really hard to pinch the axle enough to keep the entire brake from rotating on it. I have to hold the bottom screw whilst tightening the knob with pliers to keep it from moving, and even then it seems to loosen as you are cutting a facet. It doesn't seem like that big of deal until you are cutting a stone with many different angles and then it is. I believe this is due to the inside of the brake being abraded over time and becoming too loose to tighten due to extremely close tolerances it was originally engineered to have.

I think before I make a new one, I'll try your fingernail polish approach to either the axle or the inside of the brake. I thought about using shellac or some thinned down metal epoxy, but the fingernail polish sounds easier.

Debbie

 

[johnful]

Hi Debbie,

Got tired of waiting for the switch at Grainger to come in. I found a suitable one at Home Depot. It cost about $6.

I'll try wiring it up this afternoon and post some instructions.

J

 

[johnful]

I think it's I'll need to mount the switch above the speed control. I need to check clearance before I drill a hole

 

[johnful]

Hi Debbie,

More pictures of the hard stop.

Looks like a little lock washer on the bottom where the screw goes in and a rubber washer right below the coarse adjustment knob.

Does yours look like this?

J

 

[johnful]

Hi Debbie,

Given that the screw turns when adjusting, you might be missing the lock washer. You should be able to find one at Lowes or Home Depot for a few cents. It'll stop the screw from turning as you adjust the knob on the other side. The rubber washer under the knob keeps it from vibrating loose. You could find one of those at lowes or Home Depot as well. I had to get one for the lap nut on mine as it was missing. No matter how tight I made the lap nut, it would loosen up in a few minutes. The rubber washer solved that.

J

 

[johnful]

Hi Debbie,

This is a meh Sunstone I was testing with. Weak color and only a tiny bit of Schiller. It's just a 16 sided brilliant so I can test the accuracy of the adjustments to my machine. 600 mesh to rough it out, but you can see the cuts are dead on. I'll try and finish the pavilion today when I get done messing around with the switch.

 

[johnful]

Hi Debbie,

I couldn't figure out where to put the switch. There's not much room. I'll try and find a smaller one.

Here's the sunstone. Excuse the bad iPhone picture. Turns out it had quite a bit of Schiller deeper in. The chiller runs in bands right across the crown It has almost a tiger eye appearance as you tilt it. It winks at you. 8mm SRB unstacked mains.

 

[Debbie K]

Really pretty sunstone! I was looking at mine day before yesterday and saying to myself "and just where did you think you saw a sheen?" I think it would be more accurate to call mine feldspar.

I got so excited after looking at your post because my brake was indeed missing a lock washer. Went and found one, and yes, I put it on the right way so it would dig into the brake if it were trying to loosen. It still slipped when hand-tightened so I used the pliers and it still slips ever so slightly. So I'm back to trying fingernail polish on the inside or making a new one, but am waiting til Wednesday as I need to borrow some spring washer pliers from a friend; the standard one's pins are too large.

I bought some aluminum last week, When I take it apart I'm going to trace the part and get ready to make a new one as I don't have too much confidence that the polish will work. I might just go ahead a make the damn thing as I'll have access to the shop drill press, band saw and belt sanders.

When I had it apart before, the axle was as slick as glass. I thoroughly degreased it before I dimpled it but couldn't help thinking that sometimes rust might be your friend. If I make a new brake, I'm thinking about roughing it up with coarse sandpaper and making the hole in the brake slightly smaller.

Bummer about the switch. What about the real estate in the triangular shaped area in front of the motor? Water might be an issue, though.

I got bored doing nothing and carved this the other day just to keep my hand in. Not my best work, but I'm planning a really elaborate and large carving and have to get back in the habit. Dimensions are about 5/8" wide x 7/8" tall x 1/4" deep.

Debbie

 

[Wally69]

Spare parts on eBay - no idea if this solves your problems

https://www.ebay.com.au/itm/Prismat...634223?hash=item3b0139c72f:g:7MYAAOSw9vlagcGd

 

[Randy2014]

Hi Debbie And Johnful

How did your rebuilds workout on your faceting machines? (Prismatic Accura Flux) I am going to look at the same modal you have this week. I'm told everything is in working order. I have read through all your post the two of you have posted and was wondering if anything else has come up I should look out for?

R