Post by metalsmith on Jan 5, 2017 17:52:19 GMT -5
I found this 500g piece of marble fly-tipped on the Canary Island of La Palma. There's no marble naturally occurring there so it must have been imported then, surplus to need, abandoned.
I cut this obelisk today. The obelisk is the apparently featureless longer left edge of the slab. There's still two-thirds more material to work with.
It is tapered from 23mm to 16mm with the opposing faces straight at 20mm; length 103.6mm and coincidentally weight: 103.6g. All the faces are hand cut, except the base. That was the most problematic, because, I think, the length of the 'needle' magnifies the error. Method as below.
Polished up quite nicely but tbh, there are a couple of areas need a rework just to bring the finish up to standard.
Measure and mark with a pen; cut with a diamond blade - mine was a 40mm diameter pendant from my small bench grinder, but a dremel tool would be quite adequate.
On a flat lap, the angles were squared at the obelisk base and the faces slabbed allowing for the taper. The 'peak' was coarsely cut by eye, making sure that the angle across the face kept square.
The edges were bevelled again, by eye, balancing the obelisk on its edge and holding the angles between the faces and the lap equal.
All of the above was repeated at finer 220, 600, 1200 grades
Pre-polishing at 3000 grade and reworking the peak faces until the meet-points were achieved, again double checking the face angle is still square and the rest falls into place.
Polish, here, oil-based diamond #3000 using a felt mop on a dremel pendant
I cut this obelisk today. The obelisk is the apparently featureless longer left edge of the slab. There's still two-thirds more material to work with.
It is tapered from 23mm to 16mm with the opposing faces straight at 20mm; length 103.6mm and coincidentally weight: 103.6g. All the faces are hand cut, except the base. That was the most problematic, because, I think, the length of the 'needle' magnifies the error. Method as below.
Polished up quite nicely but tbh, there are a couple of areas need a rework just to bring the finish up to standard.
Measure and mark with a pen; cut with a diamond blade - mine was a 40mm diameter pendant from my small bench grinder, but a dremel tool would be quite adequate.
On a flat lap, the angles were squared at the obelisk base and the faces slabbed allowing for the taper. The 'peak' was coarsely cut by eye, making sure that the angle across the face kept square.
The edges were bevelled again, by eye, balancing the obelisk on its edge and holding the angles between the faces and the lap equal.
All of the above was repeated at finer 220, 600, 1200 grades
Pre-polishing at 3000 grade and reworking the peak faces until the meet-points were achieved, again double checking the face angle is still square and the rest falls into place.
Polish, here, oil-based diamond #3000 using a felt mop on a dremel pendant
