Filarmonica Sub Cero

Anyone know anything about the "sub cero" line of fillies? Is it sort of like INOX, deep freeze stiffness and all?

It just means sub-zero, so I'm assuming it's ice-hardened. I own a doble temple (double-tempered) half hollow which gives me amazing shaves.

I didn't even know Filarmonica made half-hollows. Is it the "12" you bought on that ebay clearance sale last month?

Even though CS describes razors of this configuration as fully hollowed, this one feels stiffer and doesn't look bi-concave. Generally when I refer to full hollows I refer to biconcave grinds.

I see. I have a "14" from that lot and just assumed it was a full hollow. But this isn't the first time you've had to set me straight on grinds.

I still don't know exactly how a bi-concave differs from single concave...

I am actually a bit unclear on this because a blade can be fully hollowed out without being bi-concave, but maybe that would not be a stable configuration and would create too much flex if it reached the delicacy of a biconcave.
When you look at a single concave blade from the front, it just has a single smooth curve from the spine to the edge. A binconcave grind has one concave surface going from the spine to 1/2-2/3 of the way down, then a little belly appears and from that belly there is a smaller concave curve going down to the edge. A quick and easy way to know is to look at a blade with the toe facing toward you and to see if it's a smooth curve or it has that belly.

Here's some interesting info coming from Arthur E. Boon:

http://www.en.nassrasur.com/razorcentral/grind.html
This will give you an idea of the belly that I was talking about.

http://www.en.nassrasur.com/razorcentral/identify.html
And this is a quick and dirty way to identify without looking for a miniscule belly.

Read the whole document, it's very informative. I still read it for entertainment purposes.

What Razor Central doesn't show is what would be referred to as 0/4 (simple hollow ground) if we wanted to be consistent. That is a single concave from spine to edge. This really shouldn't be called a wedge, because a real wedge has flat sides, as Boon shows.

Thanks Joe. That was one instance I was iffy about when it comes to nomenclature.