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Dry-Cutting Petrographic Specimens

Hello List,

I have a 6 inch rock trim saw with a very thin-kerf blade (a rock blade type used by jeweler makers).  I have cut soluble specimens without water, unscented mineral spirits or special cutting oils.  I chuck the specimen into the saw's cutting guide (a simple thumb-screw vise on a track parallel to the blade cut).  The key is feeding the cut very slowing by hand with many, many long pauses between very short, quick cuts to let the blade stay cool -- and not using a mechanical-feed or a gravity-feed (weight hanging on a string).  I use my shop compressor and with an attachment to blow dust out of the kerf and off the blade between cuts (I suppose a good vacuum cleaner might also work for this purpose).  The enemy is heat build-up that dulls the diamonds by coating them with metal material from the saw blade matrix.  By hand feeding short, quick cuts and letting the blade cool, you can avoid the heat build up.  Eventually, the diamond blade dulls from build-up and must be cleaned and sharpened by running the blade wet and making short cuts into an ordinary sharpening grind stone (this re-exposes the diamonds).  Yes, your saw blade will have a shorter useful life and it will take much, much more time than wet cutting.  I pay about $25 per new blade, which is a lot less than I pay for meteorites and some other specimens.  The key is patience to avoid heat build-up.

(I suppose someone will suggest using a clean vacuum cleaner bag and hose so the dust specks can be sold encased in Plexiglas cubes.  That's a little too "micro" for my collecting tastes.)

Regards,
Steve

********************************
Steven Excell
Seattle, WA 98102 USA
E-Mail: excell@concentric.net
********************************


-----Original Message-----
From:	Robert S Verish [SMTP:Robert.S.Verish@jpl.nasa.gov]
Sent:	Thursday, June 11, 1998 2:22 PM
To:	IPM Return requested
Subject:	Re[2]: THE BATTLE FOR MONAHANS - may be lost to water.


     Polling the List for non-aqueous rock cutting methods....
     
     I was refraining from asking this question - thought it might be 
     considered a "newbie" question - but after reading posts about hammers and 
     thinking out loud comments like, "Oh yeah! Water and salt, good point!", 
     I'm getting a little nervous.
     
     Question - how do rare, one-of-a-kind stonies get cut?
     
     Let's continue this discussion about waterless rock cutting - 
     Anybody out there have any suggestions?
     How did NASA/JSC Houston cut/make their tests?
     
     Water, OUT - hammer, OUT - rock trimmer?
     My experience with rock trimmers is that, how a rock breaks, is 
     dependent upon the matrix.  Makes a difference whether the break goes 
     through or around chondrules and crystals.
     
     My turn to think out loud - 
     Since cutting fluids are used to primarily cool the blade, the problem 
     is to find an appropriate replacement fluid.  If an air tight 
     enclosure could be placed around the saw/blade, and the oxygen was 
     replaced by another inert gas, would it be safe enough to use alcohol 
     as a coolant?
     
     Educate me,
     Bob V.
______________________________ Reply Separator _________________________________
Subject: Re: THE BATTLE FOR MONAHANS - may be lost to water.
Author:  bernd.pauli@lehrer1.rz.uni-karlsruhe.de at Internet 
Date:    6/11/98 1:13 PM
     
     
Matt Morgan schrieb:
     
> I have to agree, cutting may be out of the question. Michael, better 
> get a hammer...Matt
     
A hammer probably would not be a good solution either if I think of all 
those quartz and amethyst crystals I destroyed while trying to remove as 
much of the surrounding rock as possible when finding a druse in a 
quarry.
     
Best wishes fom Germany, Bernd