Wanted: an 1/8 inch or so hole in the porcelain of a bog cistern. I've used this tile-hole cutter drill-bit on tiles before with no problems. But on cistern porcelain got through the glaze ok but no further in than about 1/8 inch deep. I've not tried sharpening as it doesn't seem blunt and I've tried oil, then, water as cutting medium but no further in. Anyone been here before ? Correct drill speed ?
Seemed a neat idea for making a 2-level flush from an old simple flush mechanism. Pass a brass rod through the cuistern lid , located onto the ball of the float valve. Then add a weight to the brass to depress the float more, for more water, until the excess weight is balanced off. Remove the weight for cheap-skate flush.