But not basalt and granite.

/Ruben


> Alabaster is a lot closer to plaster than concrete. (I think
> some of it is calcined plaster.) It doesn't take much to
> drill.
>=20
> Allen
>=20
> > -----Original Message-----
> > From: piclist-bounces@mit.edu [mailto:piclist-
> > bounces@mit.edu] On Behalf Of Ruben J=F6nsson
> > Sent: Tuesday, August 20, 2013 9:28 AM
> > To: Microcontroller discussion list - Public.
> > Subject: Re: [OT]:: "Drilling" concrete - ideas sought
> >=20
> >=20
> > > Short:
> > >
> > > Ideas sought for low cost low effort way of cutting a
> say
> > 4"/100 mm dia
> > > hole (or larger) through 6" / 150mm concrete.
> > > Aggregate but no steel.
> > > Can take some days if effective and wholly hands-off.
> > >
> > > Note: 20mm tungsten carbide tipped drill bit + hammer-
> > drill is low cost
> > > (but costly on me) but far far from low effort.
> > >
> > > _________________________
> >=20
> > Too bad we can't ask the ancient egyptians how they did
> (or
> > other people all
> > around the globe a couple of thousand years ago).
> >=20
> > An example (of many) in figure 3 to 7 here:
> > <http://www.gizapyramid.com/mehler%20new%20article.h
> > tm>
> >=20
> > Note the spiral grooves, indicating a feedrate of the
> drill of
> > about 0.1 inch
> > per revolution.
> >=20
> >=20
> > /Ruben
> >=20
> >=20
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> > Ruben J=F6nsson
> > AB Liros Electronic
> > Box 9124
> > 200 39 Malm=F6 Sweden
> > www.liros.se
> > Tel +46 40142078
> > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
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> >=20
> > --
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=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
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Ruben J=F6nsson
AB Liros Electronic
Box 9124
200 39 Malm=F6 Sweden
Tel +46 40142078
ruben@rjjournal.net
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