Is it possible at all to spam hammers without use of the fury generator throughout the entire fight?
In short yes, but it's very hard to do so in a 1v1.
In a 1v1 fight, this is essentially the formula (based around Hota smash).
(Crit Chance)*(fury per crit)*(.8)(asp)+fury generated > [-hota cost]*(asp)
A simplified version: 103% crit chance, animosity (so 18 fury returned), and assuming 0 fury generated (through other passives or equipment, etc.). In this situation the asp cancels each other out. Another assumption I'm making is that we have 103% crit because 15 higher fury available then needed).
100%*18*.8 = [-hota cost] = 14.4 which means hota cost has to be -14 or lower for us to sustain it indefinitely.
Now if we just had 100% cc (assuming maxed fury), then when we don't proc, we drop down 3% crit - which decreases crit, and will eventually keep us losing cc, and eventually we'll lose all our fury (given enough time)
Now it's hard to calculate a more advanced version, but I'll go speaking from experience.
At 100% crit chance, with animosity and a -15 hota, I cannot sustain hota in a 1v1 situation (ex. a boss or annoying elite). Even though I regen 18 per, the extra 3 doesn't get added until I drop down - which decreases crit chance. And with random chance where I don't proc twice in a row, my cc contianually decreases, and the added fury from the monster atking me is not enough to sustain the loss (at a 2.25 atack speed).
Now if you're at 95% crit, or even 90%, the formula shows how you need to decrease your hota cost or increase fury generation (through passives/equips) to keep permanent hota.
In normal gameplay, this isn't really a concern since I can use nadoes from sprint to make up for the decreasing fury - I don't use a fury generator as a skill, and can keep up perma sprint and perma rend by aiming for groups of 2+ when attacking or when globe has gotten down close to empty (because of using rend/sprint)
As a side note - I have dropped my SOJ and kept up everything permanently, but ONLY in higher mps where my nadoes have a longer duration (at mp 0-3 my nadoes will kill monsters too quickly). I would not be able to keep up a 1v1 battle without SOJ, unless I had perfect proccing on my nadoes to match my unprocs on hota.
I've tried a lot of different combinations (2-hs, differing passives) so if you have questions on sustaining it in other situations, let me know.