I understand that the Merkur Classic has the same head as the HD, but the razor aggressiveness chart shows the Classic as being quite a bit more mild than the HD. Can anyone explain this to me?
Heh, was wondering the same thing myself. I have a Merkur Classic because the HD was out of stock everywhere when I made that order. I have always been tempted to buy the HD for a comparison but given that the heads are supposed to be the same I have never felt that it would be worth the money to do so.
I own both the Classic 33c and the HD. They have the same head sort of. The HD is a two piece razor while the 33c is a three piece razor. From all appearances the head is the same, however, the shave is different. The 33c is milder, while the HD, because of the weight, is more agressive. The HD has a wider handle while the 33c has a narrower handle.
The HD head is removed by twisting the bottom of the handle while the 33c head is removed by twisting the shaft.
Blade gap on the HD is bigger and it is heavier so that should make the classics milder.
At the same time Merkur razors are not very consistant; I have shaved with two 'identical' classics (33) that were very different. But in general the classics are slightly milder than their 2-piece counterparts.