[meteorite-list] Re: Cutting irons?

From: Jamie Stephens <J.Stephens_at_meteoritecentral.com>
Date: Thu Apr 22 10:23:43 2004
Message-ID: <3E616A2A.E324A290_at_morphism.com>

List Members:

Here's a summary of what I've learned. Thanks to the list members for
their generous advice.

Though I haven't tried it myself, I've heard that the best way to cut
large irons is with a large metal-cutting band saw with oil coolant.
Maybe something like

  http://www.tsmachine.com/quotes/6x10hs.html

?

My experience is with a 12" lapidary slab saw. I made two changes to
my saw. First, I added enough oil to use a 10" blade, which is
sufficient and less wasteful. Second, I added a gravity feed system.
The power feed system, which is not adjustable, is too fast for this
hard stuff.

I orient the meteorite in plaster. Sometimes I'll first do a test cut
and etch to check the orientation of the crystals. In the plaster (and
vise), I like to have the leading edge of the meteorite close to
perpendicular to the blade. Then I start the cut with the power feed.
Once I'm into the iron, I switch to gravity feed. I can move weights
long a beam to adjust the weight.

The 10" "meteorite CBN" blade is thin, which certainly reduces waste.
However, the blade does tend to wander when it hits hard spots. The
resulting blade marks require serious sanding, which creates its own
waste. If I reduce the force to reduce blade wandering, the cuts are
very slow. Wandering can lead to bending, and that situation creates
various problems. So I went back to a standard 10" diamond blade.
It's worked out pretty well. I set the gravity feed for a very slow
cut. Maybe 1.5"/hour for a slice 7cm tall. Sloooow, but the cut is
pretty clean.

Occasionally I dress the blade with a dressing stick. This dressing
does seem to improve the cuts a bit.

Warning: I haven't made very many cuts with this blade, so it's hard
to tell how well it's holding up. I haven't noticed serious
degradation after about 30cm x 7cm of cuts.

Of course, the previously-offered advice ("leave it to the
professionals") still stands. The orient-cut-sand-etch-dry process
takes lots of time (and money) to perfect.

Thanks again to members who sent me suggestions.

--Jamie

Jamie Stephens wrote:
>
> List Members,
>
> Here's a classic question: What's the best technique for
> cutting iron meteorites, including irons with schreibersite,
> cohenite, and other hard stuff?
>
> I've looked in the list archives, and the best advice I've
> found was "leave it to the professionals". I've taken that
> advice (thanks, Jim), and I'll continue to. But I'd also
> like to see what I can learn first-hand. (Yet another way
> to spend lots of time and money on meteorites.)
>
> What blades are best? I have a 12" slab saw that can
> accomodate 10" blades. Oil only. Are the "meteorite CBN"
> blades better than good-quality, traditional diamond blades?
> I'd like to use 10" blades to minimize kerf/waste, but blade
> strength might be an issue.
>
> Power feed or gravity feed? I like the idea of constant
> force gravity feed into hard minerals.
>
> I'd appreciate any suggestions.
>
> --Jamie Stephens
> IMCA 2828
Received on Sat 01 Mar 2003 09:19:22 PM PST