I meant it only for the nitride balls long term, not for the impact zone of creating the dent.
But thinking about it it would also probably turn into a nasty gluey mess after a few years.
The manufacturing process sounds a bit more tricky than I thought.
How about drilling a hole in a circle of wood of suitable thickness and diameter to fit into the brass cup - then giving it a good whack with a hammer?
Would that tend to deform the flat base so as to render it wobbly/unstable?
That should work, but to ensure centring you need to make sure the hammer strikes completely perpendicular and with the face of the hammer parallel to the surface on which the brass rests.
Yes it will deform the base enough to make it rattle; but grinding it flat again is easy (320 or 600 grade wet or dry paper used wet, supported on a flat glass plate).
Easy, get a sheet of 'Wet or Dry" paper - i.e. a silicon carbide abrasive paper ( ‘grey sandpaper’ ) designed to be used either wet or dry. Cut a piece about 75mm wide by about 100mm length, wet it and hold it on top of the glass plate. Take the brass cup in the other hand and, pressing in the middle of the brass cup, using circular movements, rub its bottom on the wet or dry paper until it’s flat again. Rinse the abrasive paper in water and repeat for the next brass cup.
Make sure it’s its bottom you rub on the abrasive paper, not your own!
There’s a problem with those. The base thickness is just 1.15mm, that doesn’t allow much room for forming an indent on the bottom. The type of brass stop end for water fittings that I used are probably better.than core plugs as they are about 3mm thick at the base.
For a 14.3mm silicon nitride ball, I’d suggest using a 20mm to 25mm ball bearing (steel) to form the indent.
To decide where to position the 3 balls under each glass, did you hold the Naim box underneath and tilt it to test where the weight is distributed within it, then put the points in a configuration that is likley to stabilize that?
And perhaps look at a photo of what’s in the box too, to see where the heavy components are?
e.g. if a transformer is in one corner, put a ball close by or directly under it?
If anyone has any experience of vendors of any of the following items, please let us know.
(e.g. specific sellers within t’bay, as one can get lost trying to work out which one is best):
brass stop end for water fittings
10mm toughened glass sheets cut to size
silicon nitride balls
steel ball bearing
This is common practice on the forum on some other threads, so it seems to be within the rules.
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