This ring was cut from a flint pebble I picked up on the beach -
this is the first time I have tried carving rock - and I'm quite pleased with the result.
Music for this video - Inscencer Long (1 hour) by P C III is licensed under a Attribution License. Based on a work at www.pipechoir.com
I set the stone into plaster in a rough wooden mould for a number of reasons:
So that it could be clamped really solidly without moving while I drilled it - I wanted to be able to drill it with a 22mm diamond core cutter, then a larger core cutter on the same centre
I also wanted the plaster to fully support the back of the piece to minimise spalling as the cutter emerged out of the bottom of the rock
Finally, the shape of the plaster and box helps to contain the water with which I lubricated and cooled the diamond cutters
Before I set it in plaster, I marked the centre of the intended drilling site with a pencil X
The diamond core cutters came from BangGood - they seem pretty good and they were not expensive - here's an affiliate product link:
https://www.banggood.com/20Pcs-Diamon...
(If you click and buy from this link, you'll be helping to support this channel financially, just a little, in the form of affiliate commission - if you don't want to do that, no problem - just google up the product and don't use the above link)
The plaster shrank back a little from the wooden mould, so I used hot glue to fill in the crack - mostly just to contain the water I would later add, and prevent unnecessary mess
I used a small random drill bit from my toolbox to ensure the drill was centred on the pencil-marked X - then clamped down the wooden mould frame to the drill platform and swapped out the drill for the smaller of the two holesaws I would use for cutting out the blank
This was a 22mm holesaw, but it actually cuts a hole that is maybe 23.5mm in diameter, as the diamond encrustation adds a little to the actual cutter diameter.
I flooded the top of the plaster form with cold water then began drilling - you'll notice I kept on backing off the drill then pressing in again - this was intentional - to allow both the workpiece and drill to cool down - overheating the holesaw could make it expand and jam - overheating the stone could make it crack.
My drill didn't have enough plunge depth to cut right through in one go (well, technically, it does, but if I had started the table higher, I might not have been able to swap the drillbits - so I ended up cutting about three quarters of the inner circle, then half the outer one - at this point, it was quite safe to remove the mould from the table, as it could be aligned again by dipping the holesaw back into the cut.
Eventually, I broke through and successfully cut the blank - but it got stuck inside the larger holesaw - I freed it by running the cutter under hot water to expand it a little - this, and the flushing out of some stray grit, allowed the blank to be removed from the saw.
It was a little bigger in internal diameter than I originally planned - due to the diamond pieces encrusting the outside of the holesaw - so it's actually too big for most of my fingers, but as this was an experiment, I pressed on.
The blank was quite lovely - a sort of transparent pale golden brown colour, and the white layer did indeed run right through the piece, so was evident as a line around the ring.
There were what appeared to be some small cracks in the flint material, so I dabbed on a little CA superglue, which I hoped would wick inside them and hold the piece together when finishing.
To finish it, I made a push fit chuck out of a piece of steel rod and some electrical tape - just winding the tape around the rod in my drill until it was the right diameter - a little trial and error was necessary.
Then I pushed the blank onto the chuck, secured it with a little more tape and worked on it with my rotary tool (on highest speed) at the same time as spinning it in the drill (at the lowest speed).
I cut off the ends with diamond disc cutters, then finished with diamond burrs and finally with emery paper in ascending grits, up to 400. I could have gone higher and polished the piece to a gloss finish, but I quite like the silky semi-gloss that you get with 400 grit.
Of course, I wore a filter mask while doing all this dry cutting and sanding - the work produced a lot of fine dust that I'm sure would not be great to breathe in.
The end result was a bit on the chunky side, but I dare not take it any thinner, as the flint is really quite fragile - and there are still a couple of cracks visible - it's a little too big to wear as a ring, but it's a lovely object to hold and just turn over in your hands - this was mostly a proof of concept anyway
SLOW TV; Making The 'Stratum' Stone Ring | |
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| How-to & Style | Upload TimePublished on 25 Jan 2018 |
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