Frank Kuzma is releasing a new arm!

Let’s spare ourselves the obvious jokes about its cost. The elephant in the room is that this tonearm is an elephant. At 60g effective mass, not many if any cartridges will qualify, if you base tonearm matching upon the equation for resonant frequency or even bring it into the buying decision? And yet its mass will be ignored by the well healed cognoscenti, because it is so expensive. In the minds of many with big bucks, cost can overcome the constraints of the physical universe. Even Fremer, who mentioned this product, its cost and its effective mass, in his most recent newsletter, didn’t bat an eyelash over that last specification. We shall see how it is ultimately viewed.

Just read Mijostyn’s last post after having posted this. I don’t see how you can divorce effective mass from inertia.

Aesthetics are important for some. Me included. To me it looks like an Orca whale (fitting giving it’s mass) and I would not want it if it were free. My Reed 3P’s not only sound great but to my eyes are beautiful. Same with my decks. I want both performance and beauty. If an Edsel could outrun a Lambo, would you want to be caught dead in it?

I'm into aesthetics as well and think this arm on a Kuzma Stabi R in black would look awesome. Beauty is in the eyes of the beholder. 

@lewm , no, you can't entirely divorce inertia from mass but it does matter where the mass is. 

@fsonicsmith , stiffness of the arm tube is a very important characteristic for a tonearm and many of the best arms use wider diameter arm tubes. Certainly, the days of arms like the Infinity Black Widow are over. It does seem to me that if you are using a very stiff substance like sapphire you should be able to get away with a thinner lighter arm tube but there may be a problem manufacturing a smaller tapered sapphire tube. Frank Kuzma is no dummy. If he could have made it lighter he would have. He obviously had to compromise by making the arm a bit shorter. I think it is a good looking arm for what it is worth. Does it offer any advantages over arms like the regular 4 points or the Reed 2G, Schroder CB and Tri Planar? Set up correctly I would probably not be able to tell the difference and I would have to notice a difference to spend that kind of money. But, nobody has made a sapphire tonearm before so, this is another Kuzma first.

Frank Kuzma is no dummy, I totally agree.  I greatly admire his turntables, and based on the kudos accorded to them, I also admire his tonearms, until now, possibly. But sometimes even smart guys over reach.  We shall see. You wrote,  "no, you can't entirely divorce inertia from mass but it does matter where the mass is."  But in fact the equation for "effective mass" (not mass alone) already takes into account the distribution of mass in a tonearm, as I am sure you realize. Ergo "effective mass" is closely related to inertia. Perhaps Kuzma ameliorates the problem by using a variable damper counterweight, a la the Technics EPA100.

I also was wondering before this discussion ever came up, after having read Fremer's reveal of the sapphire tonearm, is sapphire really so much stiffer than other stiff but not so dense materials of which tonearms are conventionally made? For example, the Technics EPA100 arm wand, titanium nitride. And the Mk2 version which was made of boron something. Or even steel?