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#1

Dihusky
Member
From: Gold Coast, QLD
Joined: 16 June 2017
Posts: 710
Member
28 January 2019 07:48 pm

Picked this up today, anyone know them or have a user manual? Needs a full rebuild, but once done, this can do so much.1548665307_gemmmasta-gem-grinder.jpg

6 users like this post: Jackthehound, Jaros, LoneWolf, Wishfull, Rockhound, Mackka

#2

LoneWolf
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From: Gold Coast, QLD
Joined: 12 April 2016
Posts: 2,956
Member
28 January 2019 10:10 pm

Well I think its an old Gemmasta wink .. a very early Faceting Machine..... I think its around 1960ish or even earlier but could be a multi-purpose Machine... going by the Dops and the way the machine moves. Instead of tilting the stone as you do on a modern machine, with this one you move the lap back and forth...and swing the other half into the lap to give you your angles....
How to use? My guess is :
You put your dopped stone in the 'Head' on the right side and you can swing it into the Lap or saw blade on the left, well maybe not a saw blade but it could also Cut with a saw blade..... I think you would use a lap tho and the handle on the right would move the lap in and out so you are not working the same spot on the lap... And can be used as a Flat lapping Machine in a vertical stance, instead of a Horizontal Flat Lap too...
I will have a look through my old books... There could be something in there that will give you a definite answer...

LW....
1548674434_1548665307_gemmmasta-gem-grinder.jpg

Last edited by LoneWolf (28 January 2019 10:25 pm)


Growing Old is Inevitable.... Growing Up is Optional.... Prospectors United Will Never Be Defeated

#3

Dihusky
Member
From: Gold Coast, QLD
Joined: 16 June 2017
Posts: 710
Member
28 January 2019 10:42 pm

Hey LW, it's called a Gem Grinder and was patented by Roy Arthur Gaerth back in 1970. It is for grinding rounds and Cabochons to very specific sizes so they can be set in standard sized findings.

Beautifully engineered gearing system so the length-width ratio can be varied.

Your markings are just about spot-on, the lap isn't flat though it's a sintered diamond edged wheel, guarantee is't going to be difficult finding replacements.

Back swing to the screw in stop is for the bevel edge, then the machine swings forward to create the dome.

There are a couple of bits I'm not sure about so hoping someone else has one and maybe a users manual to fill in the gaps.

Going to make an interesting winter project.

Picked it up from an Opal miner who was given it by an Opal cutter who passed a couple of years back.

1 user likes this post: LoneWolf

#4

LoneWolf
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From: Gold Coast, QLD
Joined: 12 April 2016
Posts: 2,956
Member
28 January 2019 10:54 pm

Shows how much I know about Lapidary.... kiss yikes sad Glad you found that out...

Looking closer you can see a Cab still on the dopping stem roll ... Few too many Bourbons today... Yeh Ha... Best I close the computer before I get into Trouble... angel

LW...


Growing Old is Inevitable.... Growing Up is Optional.... Prospectors United Will Never Be Defeated

1 user likes this post: goody2shoes

#5

LoneWolf
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From: Gold Coast, QLD
Joined: 12 April 2016
Posts: 2,956
Member
29 January 2019 12:32 am

We need to catch up as I have a heap of thin grinding wheels here that I got off an old fellow that I bought gear off a few years ago and don't know what you would use them for in Lapidary... So may-be?? they are what you need, im not sure...

LW.....


Growing Old is Inevitable.... Growing Up is Optional.... Prospectors United Will Never Be Defeated

#6

Dihusky
Member
From: Gold Coast, QLD
Joined: 16 June 2017
Posts: 710
Member
29 January 2019 05:27 pm

Going to pull the wheel out so I can really see what it is, then start the hunt for different grits. Could be interesting to compare with what you've got

1 user likes this post: LoneWolf

#7

Dihusky
Member
From: Gold Coast, QLD
Joined: 16 June 2017
Posts: 710
Member
29 January 2019 06:42 pm

Wheel's off and cleaned:

1548747171_grinding-wheel.jpg
151mm diameter with a 1" bore, made by Universal Corundum Aus

1548747200_wheel-id.jpg
Looks as though this is 120 grit, so very much a cutting wheel. Runs at 2850rpm

1548747219_wheel-edge.jpg
10mm wide edge, around 2.5mm thick

3 users like this post: Jaros, goody2shoes, Mackka

#8

Jaros
Moderator
From: S.E.Qld., QLD
Joined: 11 August 2013
Posts: 10,919
Moderator
29 January 2019 07:00 pm

Waddaya reckon-happy??


F1A4M2, Exterra 705 Gold, Ace 250, Goldrat 8" Dreammat River Sluice.

#9

Dihusky
Member
From: Gold Coast, QLD
Joined: 16 June 2017
Posts: 710
Member
29 January 2019 07:32 pm

Jaros wrote:

Waddaya reckon-happy??

Youbetcha, lot more work to be done yet before I'll be happy to run the machine. Hopefully someone might come up with some more info as there are a couple of areas are not making sense. One is a cam, a secondary profiling cam which looks as though it creates the shape of the cab dome:
1548750537_dome-cam.jpg I'm thinking there could be different profiles for different domes.
The other is an adjustable stop which doesn't seem to to touch anything.
1548750574_adjustable_stop.jpg
Looks like the knurled end un-screws and there is something that goes behind it and locks onto the flat sided piece beside the bearing.

Big question is what?

2 users like this post: goody2shoes, Mackka

#10

Jaros
Moderator
From: S.E.Qld., QLD
Joined: 11 August 2013
Posts: 10,919
Moderator
29 January 2019 07:40 pm

Someone will know something - good luck.


F1A4M2, Exterra 705 Gold, Ace 250, Goldrat 8" Dreammat River Sluice.

#11

LoneWolf
Member
From: Gold Coast, QLD
Joined: 12 April 2016
Posts: 2,956
Member
29 January 2019 10:22 pm

Oh I thought it was a Stone grinding wheel.. That's what I have here. 15 stone wheels of various sizes and grits... Didn't realise it has a 'lip' on the edge...
But I do have a brass one here that could be simular.(no lipped edge tho).. Never been used I think as there is no marks on it at all... I was going to use it as a base plate for my small flat lap that needs a re-build....

LW....

Last edited by LoneWolf (29 January 2019 10:27 pm)


Growing Old is Inevitable.... Growing Up is Optional.... Prospectors United Will Never Be Defeated

#12

mrjunkalot
Newbie
Joined: 29 March 2019
Posts: 2
Newbie
29 March 2019 11:05 pm

Dihusky wrote:

Picked this up today, anyone know them or have a user manual? Needs a full rebuild, but once done, this can do so much.https://www.prospectingaustralia.com.au/forum/img/member-images/10304/1548665307_gemmmasta-gem-grinder.jpg

Hi,
I have one of these cab cutting machines I bought in 1978 awesome for calibrated cabs...... from memory there was no manual .If you find one I'd love to get a copy....I lent my machine to my Dad and only got it back three years ago and I suspect I'm missing a few things....., my enquires led to Shell lap Adelaide who now make Gemmasta machines ( but not these ) but they still have some spares for these smile . cheers

1 user likes this post: Mackka

#13

Dihusky
Member
From: Gold Coast, QLD
Joined: 16 June 2017
Posts: 710
Member
30 March 2019 10:13 am

mrjunkalot wrote:
Dihusky wrote:

Picked this up today, anyone know them or have a user manual? Needs a full rebuild, but once done, this can do so much.https://www.prospectingaustralia.com.au/forum/img/member-images/10304/1548665307_gemmmasta-gem-grinder.jpg

Hi,
I have one of these cab cutting machines I bought in 1978 awesome for calibrated cabs...... from memory there was no manual .If you find one I'd love to get a copy....I lent my machine to my Dad and only got it back three years ago and I suspect I'm missing a few things....., my enquires led to Shell lap Adelaide who now make Gemmasta machines ( but not these ) but they still have some spares for these smile . cheers

Wow, amazing.... kind of hoped something would appear eventually as there had to be someone out there who has or had come across these machines. They are an engineering marvel, hate to think what they cost back in the 70's

I am not sure if a manual is truly necessary, but would certainly be handy, I do have an old typed up chart detailing sizes, cams, hand wheel setting, roller number, 'back', thickness and 'crts', this is then divided into size for I assume round cabs, plus ovals with either high or low domes.

Happy to share this if you're interested.

What I'm chasing is the cams as I only have a #4
1553900127_4-cam.jpg

I'd love to get hold of the other 3 to make the set, if I can get the patterns then I can make them, likewise I don't have any of the rollers that fit the spindle on the rhs of the main drive. Having one cam gives me a starting point for making some more, but it will take a massive mount of experimentation to get them right. The rollers are a different matter though.

1553900284_roller-shaft.jpg

As I don't have one I have no starting point for making one, or a set. Based on the printed info I have, there are at least 3 different versions of the roller.

I haven't been in touch with Shell Lap as their website is now Gemcuts in Ballina who took over all the Gemmasta material, will have to give them a ring and see what they have.

Be great to share info if the info I have can be of help in any way.

Last edited by Dihusky (30 March 2019 10:14 am)

#14

mrjunkalot
Newbie
Joined: 29 March 2019
Posts: 2
Newbie
30 March 2019 10:59 am

I'm going to pull this out of storage in the next two weeks and I'll check those bits you're looking for and send you photos or cut templates for you if i can. Could you send me the chart you've got and any patent reference info to me at mrjunkalot@gmail.com
I use to have a jade and opal cutting factory , the grinder cut ovals, rds, cushion and with special cupped dop stick you could make beads by reversing 50% domes.
You can also make oval and round cylinders by cutting a hole in the otherside of the grind wheel face so you can then use it like a gem lathe. The machine also champhers a back bezel on cabs.
From memory the original cost in 1977 was $3,995 plus we had additional keyed brass dop sticks made. Have you got dops ?
Have you investigated if the inventor is still alive ? He was in Mile End area (?) Adelaide I think.
I did speak with Shell Lap three years ago and they inherited a lot of spares when they bought Gemmasta from the origin owner inc for our machine.
Look forward to collaborating .
Cheers,
Mike

#15

Dihusky
Member
From: Gold Coast, QLD
Joined: 16 June 2017
Posts: 710
Member
30 March 2019 11:43 am

Thanks Mike, sent you an email. Shell Lap is no longer in business sad so I am hoping Gemcuts might have got the bits and pieces without realising what they are.


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