Well I've been playing with yet another grinder- a kitchen 'Herb and Nut Mill' this time;
http://www.ebay.co.uk/itm/260863922511
Inexpensive at £4.75, and with a bit of modification it works well!
It's a bit like one of the old style 'Mullamatic' grinders, but with a catching container built in underneath. The unit also fixes to the worksurface with suckers on the bottom, which is quite handy but doesn't change my life. It does mean it has a 'home' place.
Unfortunately out of the box the bottom part of the grinding mechanism (the flat strips) doesn't meet closely with the shaft of the cutting wheel, and as a result the bud just gets jammed up in there. With bone dry material it might work OK, though I doubt it, and for certain modification is needed to effectively grind buds. As you can see I simply caved in the strips at the bottom, pressing with a screwdriver to remove the gap between them and the shaft. Hard to explain verbally, but I hope you get what I mean.
(the coin is a tiny UK 5p. No idea on the international size equivalent)
Ugly modification done and this actually produces a really good fine and uniform grind. Better results wise than many hand held grinders. I've got it fixed to my shelf with it's suckers next to my ssv and it's actually OK overall. I like that it's kind of a 'fixed installation' and grinding it into the little drawer. It's also bigger than disc grinders and handy for grinding several grams at a time.
On the negatives, firstly it's clearly nowhere near as nice to handle or use as a metal CNC built grinder. secondly I'm not too sure about the attachment of the grinding spindle- of course there's no bearing and it's just the spindle resting in the plastic holes (square spindle in round plastic holes!
) - over time there's bound to be some wear on the plastic, and who knows where that will end up. No sign of wear yet though after a few uses, and it's not likely to be any meaningful amount of plastic IMO, but I know that it will be a big negative potential in the eyes of many.
Overall it doesn't do a bad job for under £5. With a little redesign it could be perfect as a home grinder. However, it's clearly not a design for everybody and has no stealth or portability aspects to triumph, so I won't bother redesigning it and bringing it to market.