[Rockhounds] Color of Minerals (now: need saw blade recommendation)

[jb]

Kris Rowe wrote:
> jb, thanks for the great info! This is a great start for a basic primer,
> something to work on for one of the Rockhounds @ drizzle' new websites.
> Perhaps a primer section for various tasks & equipment?
>
> Thankfully, I've had a little experience with smaller saws, and the 18"
> arrived in my hands through the time honored tradition of "Get that UGLY
> thing out of the garage!" by a friends wife. I've experienced the 'cutting
> edge' breaking, due to allowing a new lapidary (also known as a "friend with
> a rock") practice their slicing skills with my 6" trim saw. Amazingly,
> suppliers don't want to replace a brand new blade in such a situation.
> Imagine that!
>
>   
Hmmm.... Well, saws usually don't "break" their cutting edge; they bend 
it. Your biggest enemy is a blade that is turning at 2K to 3K 
surface-feet per minute and is ever so slightly not uniform or out of 
balance. You are cutting hard dense materials and that takes a lot of 
force. One doesn't usually just let the saw passively cut through 
through a rock as if nothing is there. Force is involved, and that force 
is released violently if the rock gets away or, if  not, as a great 
excess of heat. The heat will quickly degrade and destroy what ever 
ability the blade had to maintain its integrity. It will do this no 
matter what the lubricant, and it will have a quicker and greater effect 
the thinner the blade.
> Strangely enough, my friend ended up bartering some of his thundereggs (One
> word or two? Opinions? I've heard that the Oregon legislature says it's one
> word ... and they're the experts, right?) to get the rest sliced open. I may
> freehand trimming preforms, but eggs always get clamped securely, since they
> always seem to twist when a void opens up. And yes, I know that it's silly
> to open eggs with a 6", but ya' works with what you gots!
>
> So, perhaps rule #1 of the primer could be: Be careful *who* uses your saw!
>
>   
My Rule #1 would be: Understand the purpose and limits of each piece of 
equipment you have before you use it.

Know that a thin kerf 4" or 6" saw is for cutting thin expensive 
materials with minimal waste. That is always a delicate operation that 
takes time and patience. Slabs are not cut on small saws. Understand 
that a circular saw can effectively cut only about 45% of its diameter. 
A 10" saw gets very cranky when forced to cut a 6" slab, and so on. If 
you want to cut boulders or blocks of granite out of a mountain, use a 
drag saw or grit cable; don't consider using a "large" circular saw.  In 
other words, use the tool to fit the job at hand. Understand that 
different materials cause different effects on saw blades. If one cuts 
very hard materials too long , especially with a sintered saw, the 
nickel carrier sloughs over and covers the diamond. The saw is not 
ruined but requires routine maintenance to restore the original cutting 
surface ( usually by cutting a considerable amount of softer material; 
use American bricks or other well-fired material; the Mexican bricks, 
e.g., are usually too soft and not too uniform.) Understand that the 
lapidary saw really is a precision piece of equipment. The more 
attention one pays to keeping it like new, the less trouble it will give 
the user. For example, it takes very little effort to spray the entire 
machine with something like WD-40 after cleaning it up, and that helps 
preserve everything from worn metal to screw threads.  The prime enemy 
of the saw (and grinder) is not necessarily moisture ( at least in the 
short run). It is mud, the stuff left over after one has retrieved the 
slab and removed the stock. Mud gets into everything and it must be 
thoroughly removed each and every time the saw is cleaned. (It makes an 
excellent addition to the compost heap, by the way, if the oil is 
minimized and made degradable, and there are not too many heavy metals 
in it.) And so on --- you get the picture.
> Then there's the 4" thin kerf "Crystal Blade" that I use as an ash tray, one
> of many sacrificed to experience. Ah, the things we nonchalantly "forget" to
> mention when showing our skills to others, like the heap of dollars each box
> of "dished" blades represents! "The dog broke my blade! HONEST!"
>
>   
You are always going to create some ashtrays or coasters as the case may 
be. But why have 36 when only 3 or 4 will do? Thinking about the tool 
you have and its use is the best practice. Bad maintenance and not using 
a tool for what it was intended are the major glees of the people who 
like to sell replacement parts and newer equipment. The truly skilled 
craftsmen, like my brother who was a tool and die maker,  understand 
this very well.
> So, if I can sweet talk my "Queen of Receipts" into unchaining the Royal
> Exchequer (I've learned to duck *quickly*), the MK - 303 will adorn the 18",
> and a converted '60's vintage Craftsman arbor will host a Chinese blade in a
> homemade tank. Ain't it fun to fabricate? Mechanically speaking, of course.
> };)
>
>   
Good luck, friend. Lapidary is not the cheapest of hobbies even if the 
material is "free". And things like saw blades and diamond grinding 
wheels are expendables, after all. It takes some thinking about the best 
way to proceed. Then there's the creative part...but that is another 
world altogether. Ah, just collecting specimens is so much easier!
> Thanks for the great input, my friends!
>                                                             Kris
>   

john