I’d like to flatten surfaces on some beach pebbles.
With no knowledge of or experince working stone, it seems to me I’m
looking for a flat lap. References in the past have been to cabbing
or facetting, which I don’t intend to do. (At this tme! I know, this
is like opening the door for the devil!)
I hear about the All-you-need, the Genie, Pixie, the Titan. Are any
of these suitable? I’d guess that the largest beach rock I’d be
working with would be about fist size and composition will vary from
sandstone to granite, to basalt. Any advice?
Colleen
(written from her now home / studio by the ocean. Whee! What fun!)
Colleen - The All-you-need units (either 6" or 8") will do exactly
what you want to do, right down to the final polish. There are some
tricks; like it is better not to do a stone which is larger in size
than the radius of the wheel you’re using. It is also a good idea to
keep rotating the stone in your hand as you grind it down: even
though the entire surface of the wheel is moving at the same rpm, the
outer region has more surface area, and grinds more quickly - it’s
easy to get lopsided. Have fun!
Colleen, Probably the best bang for the buck on grinding flats is the
"all-u-need" by High Tech Diamond. On a 6in. machine you can flatten
a stone 2.25 in. diameter. (this is pushing it, limit wise) 8 in.
about 3+ in. If all you want is to flatten, you can get by with 1
coarse diamond lap.(100 grit or so) They also have all the finer
grits for polishing. The three stones you mentioned are not really
very hard as stones go and will have a tendency to grab on a coarse
lap. HANG ON! and use very light pressure until you get the feel of
it. If you can find a gem show where the High Tech guys are doing
demos sometimes you can buy the demo machines “used” at the end of
the show. (I got mine a few years ago this way - 6 in. complete 150
grit to polish … $200.00! and it wasn’t even very dirty.) Tell
them at the begining of the show you are interested in a demo
machine,perhaps they will save one for you. just a satisfied customer,
Mark Thomas Ruby SunSpirit Designs p.s. if I can be of assistance feel
free to contact me @sunspirit
Looks to me like a small flat lap (like a faceting machine) might be
your best bet, if you have a bunch of them to do, and need a really
flat surface. It’s hard to get a really flat surface with a cabbing
machine If you don’t have too many, it might be simpler (and a lot
less expensive), although a bit more time consuming to just go with
the diamond compound on a plate of glass method, and rub them by hand.
If you don’t need a really flat or polished surface, (i.e. you just
want to flatten the back so it will sit well in the bezel) you can
always use a grinding wheel (can get for $30-40 from Harbor Freight)
or something like that.
Do you know about Lapidary Digest? If not, and if you are interested
in working with stone, you might like to subscribe. It’s free; and you
can get just about any kind of question regarding lapidary answered.
Just check www.lapidarydigest.com and it tells you a little about the
Digest; you can see some past issues, and you can subscribe right from
the website.
All the machines list could be used to put a ‘flat’ back on pebbles.
It’s all in the technique.
Depending on the size of the pebbles, they may have to be dopped
(glued on a stick) to provide a handle for holding them while they’re
cut (ground).
Apply the dop to the side opposite the side that is to be flattened.
The G, P & T are all grinders that use the periphery of a round
grinding wheel to remove material from the stone. While the dopped
stone is held against the lower front quadrant of the wheel, it is
moved in a manner that will result in an almost flat back. Depending
on the degree of flatness required, this may be good enough. If you
want it truly flat, the final step should be a flat lap.
The All You Need unit is a flat lap machine. Flat laps up to 8 inches
in diameter can be used.
With either type of machines, you will probably use several different
grit wheels or laps. The different grits are used for gross material
removal (100 grit), to 260, 360, 600 & finer. Which finer ones are
used depends on the material being ground & the smoothness of the
desired finish. If the flat side is just to make the stone easier to
set, a course grind at 100 grit may be sufficient.
To see which works best for your requirements, check with a local
lapidary/rock club. It (or some member) will probably help you find
the equipment to run a short test.
A very simple, effective and economical flat lap machine is the
All-U-Need by Hi Tech. It comes in 6 or 8 inch diameter. I’ve been
using mine for 12 years without any problems. Hi Tech’s number is:
805-522-6211. Bill Navran
Colleen, If all you want is to create a flat side on the relatively
soft stones you mentioned, maybe your best bet would be a slab
saw…probably eight inch, since you want to flatten stones up to
fist size. It is a whole lot quicker and easier to saw the flats than
grind them down.
Jerry in Kodiak
You’ll still need a flat lap to finish/polish the surface although,
if the surface is to act as a base, you might not provided saw marks
are not a problem.
Colleen, I owe you an apology for not getting back to you and telling
you that I had not located a new flat lap as large as the one I bought
several years ago used. I think it was made from a kit. If I
remember right, the “all you need” has a six inch wheel. Perhaps that
would be too small for a fist sized stone. The technique that I was
taught involved working the stone in a figure eight pattern to wear
the surface evenly and move the grit back towards the center of the
wheel. Hopefully someone else can advise you on this point.
Sincerely, Rose Alene McArthur
Mine has no center hole because it uses a magnetic pad to hold down
the steel based diamond laps I use… means I can use the whole
surface for lapping… way cool.
Some of the parts I needed came from Covington Engineering Corp.
715 West Colton Avenue
P.O. Box 35
Redlands, CA 92373
Ph. 909-793-6636
Fax 909-793-7641
no web site so far.
They have finished machines as well as parts & kits for building
lapidary equipment.
I love to design and build machines and mine is working most
excellently.
Another source for discount lapidary products, diamond saw blades,
carving burrs, tools and polishes is Daniel Lopacki Co. www.lopacki.com (I designed this web site and am web master for it www.webmonkdesign.com )
BE FORE WARNED lapidary is addictive… you will discover that
there are not enough hours in the day as the WHOLE WORLD is rocks
just waiting to be finished and set :>) and then of course there is
setting them … hmmmmmmmmmmm
maybe Hanuman should assist us in starting a 12 step meeting for gem
stone and jewelry addicts … hahahahahahaha nah I will never hit
bottom with this stuff it is just too much fun and NO HANGOVER…
all the best in all things,
monk
Source for gem stones, crystals, jewelry
Metaphysical, New Age, Contemporary
Hi, All. It seems to me, from qhat I’ve been seeing lately, that
there are quite a few Orchidians with an interest in Lapidary. So I
would just like to point out to those who have more than a passing
interest that there is an online “magazine”-type site called Lapidary
Digest, which discusses all things lapidary. Free. If you’re
interested, the website is at www.lapidarydigest.com and there you will
find instructions as to how to subscribe, and a complete
library of past issues (which might already have the answers to your
questions).