LAPIDARY DIGEST
Administered by Hale Sweeny (hale2@mindspring.com)
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This list digest contains the following message subjects:

1. LapDigest News for Issue No. 90 - Fri 12/5/97
2. NEW: Vibratory Lap Machine Motor Life
3. NEW: Diamond Grit on Plexiglas Lap
4. RE: Retensioning & Straightening Saw Blades
5. RE: Retensioning & Straightening Saw Blades
6. SCHOOLS: William Holland School of Lapidary Arts
7. BIO: Steve Walker
8. NOTE: Country of Origin
9. NOTE: Visit our new web page!


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<MSG1>

Subject: LapDigest News for Issue No. 90 - Fri 12/5/97


In Issue 88, Lester Wetherell asked for help in refurbishing
their club's Star Diamond VL-16; in particular, he needs an
Owner's Manual and some information about this model. His
e-address was omitted; it is: <lcwii@austin360.com>. If you
have one of these machines, please write him and tell him so.
He will want to ask you some questions about your machine.Any
help will be appreciated.

Well, we have reached the size limit on the Index, so it will
be broken into two parts; the main part will contain the info
on each thread in the Digest, the BIOs, and the thread files.
The second part will contain the WTB and WTS, NOTES, SHOWS,
and other information. The names of these files will be:
INDEXto89Part1.txt and INDEXto89Part2.txt. (As we get older,
it just gets more complicated!)

Be good, stay safe, and above all, HAVE FUN!! Hug someone you
love tonight!!

hale
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<MSG2>

Subject: NEW: Vibratory Lap Machine Motor Life


I am quite new at vibratory flat lapping, having bought an
old but little used Lortone from someone who tried it once or
twice and didn't like it. Since beginning to use it I have
been hearing from a friend about all the problems he has been
having with a similar machine, make unknown (and he is gone
rock hunting for the winter). First he needed a new mounting
plate for his motor at about one year. He tried to substitute
a good washing machine motor, or some other discarded but
still good motor, but he didn't find anything that would fit.
He built a new mounting plate and remounted the machine.(This
guy designed and built his own 18" slab saw with the best
vise arrangement I've ever seen.) He got another year. The
motor burned out and he replaced with OEM. The new motor had
a 1 year warranty. It burned out after 1 year and two days.
This was actually after only 3 months of use since he is away
from home all summer in Wyoming and all winter in Arizona and
New Mexico. His current situation is that he has no machine
and he is in Arizona.

I have been using my machine heavily for about a month (like
night and day, no Sundays off). My friend's latest problem,
which happened just a week before he was ready to leave for
Arizona, has me worried. I don't want to get into a
situation in which I have something that is always breaking
down.

Frank Fabbiele mentioned a lap machine which I understand
will last a lifetime (if you don't live too long). I'm
wondering if that means with few or no repairs, or that it
will go for a very long time with only routine maintenance.
The motor problems at nearly $100 per seem excessive on a
machine like mine which retails for around $400-$500. If I
have a lot of problems, or a serious one rather soon, I'd
like to opt for a larger, better built machine such he you
described, if it is relatively trouble free.

I'd appreciate any input I could get on this. Thanks.


Herb Luckert
221 Marquette Ave
South Bend, IN 46617
219-282-1354
<Phyllis.Luckert.3@nd.edu>
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Subject: NEW: Diamond Grit on Plexiglas Lap


Hi Folks,

Here's a request for advice. The copper laps on my (used)
Graves Mark IV faceting machine are somewhat worn and not
entirely flat anymore. Moreover, I'm having a scratching
problem with the 600 lap which is quite annoying. To get
these back to flat I'd have to get them turned down, which
would entail getting the diamond out first by dissolving off
a 1/2 mm or so of copper with nitric acid; John Sinkankas
described the procedure in an old issue of the Bead Magazine.
That's a lot of work. Also I don't have any 600 grit diamond
left.

I do, however, have some 1,200 diamond grit and some 350, a
good supply of 1/2" plexiglas with which I've made a number
of laps already for very fine (2,500 and 14,000) diamond
paste and for polishing.

My question is, does anyone have any experience in charging a
plexiglas lap with 1,200 grit dry powder diamond? Will the
diamond stay in the lap long enough to do useful work? Same
for the 350 diamond. I doubt that plexiglas would be a
sufficiently strong substrate to hold such a comparatively
large grain size but have no experience, and don't really
want to waste the diamond on an experiemnt that may not work.

Any advice, comments, experiences would be most welcome -
particularly as regards the 1,200 dry grit diamond on
plexiglas.

Many thanks,
Hans Durstling
sinico@nbnet.nb.ca
Moncton, Canada
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<MSG4>

Subject: RE: Retensioning & Straightening Saw Blades


Hi everyone

I have to insert my 2 cents worth in here concerning
pounding on diamond saw blades once they have been bent by
misuse.

First, it should be understood that reshaping saw blades
is not for the uninitiated, here I am talking about the
larger saw blades, say 10 inches or more in diameter. The
larger the saw the more important this is.

Second, a rotating saw (any kind) has to be dished
slightly in order to work and avoid self destruction. Let me
explain. If the saw were perfectly flat as it approached it's
operating speed (particularly with the thin blades we use) it
would go into an uncontrolled speed wobble because of the
static and dynamic forces generated by imbalances within the
blade. The faster the RPM the worse it would get. In theory I
suppose if it got to a high enough speed the centrifugal
force imparted to the rim would tend to pull the blade
straighter but by that time the blade would have gone into
oscillation and have been ruined. (about the operator
I don't know)

The reason for the slight dish is that as the blade
speeds up it flattens out but is incapable of going into a
wobble because the restrictive tensional force applied to one
side of the blade overcomes the static and dynamic imbalances
inherent in the blade. As the blade slows the slight dish
reforms.

Understand that the dish is minor in a small blade but it
is there. The chap who had his blade returned from the
supplier and could see the dish should be glad it was there,
within reason of course.

I'll wager there is not one among us who could retention
a blade properly. Industry that use rotating blades (any
kind) choose only technically adept employees and even these
take months to learn the art of "pounding" saws into safe and
usable products.

Still have a doubt ? watch the person who balances your
tires apply weights to overcome static and dynamic impalances
and remember that your wheels are stronger and heavier than
the diamond blades we use. Next take a look at the rims your
tires are mounted on, see the dish ?.

......Leo Doucet......Ca.
sg2788@brunnet.net
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<MSG5>

Subject: RE: Retensioning & Straightening Saw Blades


Hans Durstling said:
<< In a dished blade you already have a bowl. The dish shape
alone indicates that the metal at the center has been
stretched. Once stretched, constrained by the less deformed
periphery, it has thrust up into the dish shape. Since you
can't "unthin" the centre....>>

I thought I might offer some input as to a possible solution
to stretched metal. The above is a good general description
as to the problem. It is possible to shrink or unstretch
metal by using heat. This process is/was used extensively in
autobody repair, something that I have experience with though
I haven't tried it on a saw blade. Basically what you need to
do is heat the dished portion of the blade with a torch to a
orange glow and quench it with water. When using this
technique on an autobody the "pooched" portion or dimple is
heated and often tapped against a "dolly" or anvil with a
body hammer. A well soaked sponge is used to quickly quench
the metal. I would try this with a saw blade but skip the
hammering & stay away from the rim with the torch. Several
heatings are usually neccessary to shrink the metal back in
place. I have repaired large 1 sq ft areas of body panels
with this technique by heating & shrinking in 2 inch
increments.

Chuck
ChuckSmy@aol.com
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Subject: SCHOOLS: William Holland School of Lapidary Arts

The school, located in Young Harris, GA., operates from the
last Sunday in April through October of each year. Classes are
one week long, starting on Sunday, and ending on Monday.

Classes are held in almost all of the lapidary arts.

At the current time they are open for 25 weeks of the season
to anyone interested in lapidary, . They lease the school
to the SFMS for the other two weeks a year.

All of the instructors are volunteers. They sell the
supplies needed by students in the class they are teaching,
which helps them meet some of their expenses.

The cost per person per week including room and meals is
$225, for room, meals and tuition. There may be fees for
special supplies. Classes are of one week duration.

The campground has full hookup with a shower room in the
Seabolt building. No pets allowed except in the campground.

Full details of classes and other information, including
application blanks, are given on their web site:
<www.stc.net/~lapidary>.
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Subject: BIO Steve Walker


Hello,

I have been working with metals and jewelry for over 20
years, mostly working with married metals, mokume and Celtic
designs. I have no experience with lapidary but I have been
using stones that I collected in Scotland in my jewelry. A
friend has been cutting them for me.

Lapidary is a logical next step for me since I am currently
paying out quite a bit for cutting. Excellent though it has
been I would like to have greater control over the stones I
use. My apprentice John is also very interested in getting
started. We have no equipment and hope that lurking on the
Digest will help give us some useful information as we get
started. I expect to be buying equipment within a month.

You can see my work and more personal and creative history on
my website at: http://www.underbridge.com/market/walker

Steve Walker
SWalker706@aol.com
Walker Metalsmiths
Andover NY

non-commercial republish permission granted
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<MSG8>

Subject: NOTE: Country of Origin

Leo Doucet wrote:
<<My e-mail address "sg2788@brunnet.net" makes it impossible
to determine from what country I am from...(snip)...>>

There is a really neat program that tells you country of
Origin.You type in the country name or the extention,and it
gives the extention or country name.It is freeware.I think I
got it at www.shareware.com but the link there took me to the
author's web site it is "Country Codes" v1 1.1.0 Jasen
DeCarteret http://www.empire.net/~jason/
Mark Liccini

LICCINI
http:www.LICCINI.com 107C.Columbus Dr.#1A
E-mail:Mark@LICCINI.com Jersey City,N.J.07302
Phone/Fax:201-333-6332
-------------------------------------------------------------
(Ed. Note: The country codes are also easily obtained from
the internet by entering 'country codes' in a search engine
such as Alta Vista, and clicking on the sites. hale)
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Subject: NOTE: Visit our new web page!


Almost too late for the HOLIDAYS, and there's more to come.
Go to:httm://www.couponexpress.com/C/JadeDriveRockShop.html

Thanks BETTY and RUSS
jaderockshop@webtv.net
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