Pertruabo:
Hello guys
so for the skullcracker,does it need a base? or should I just roll unbased?
Bloodbeard:
Warmachines don’t need bases.
But I’ve put bases under all my warmachines - just for the looks of it.
The last ETC base size you could choose (option because base is not required) for a skullcracker was 80*100 mm as I recall.
Malorndk:
Since the Iron Daemon and Skullcracker are actually Unique Unittype and not warmachines they should actually have a base i guess?
And Bloodbeard is right about the ECT base size:
Skullcracker: 80100
Iron Daemon: 60100
Thommy H:
There aren’t any rules that relate unit type to base size (except that war machines don’t need one) - you just whatever base it’s sold with. Since the Skullcracker doesn’t come with one, it doesn’t have one. However, since it’s treated as a chariot for most of its rules, it probably ought to be on a chariot base.
Odatria:
Forgeworld said the Iron Daemon should go on a 100x60 (screaming bell) base.
If you ask me a skullcracker is still an iron daemon, so I’d base it on that.
Pertruabo:
Aight,so do you recommend adding a base or not?
Malorndk:
I will base mine on a 80*100 following the ETC since it is a unique unit and not a warmachine, but no where is this required either by RAW or RAI, so you can choose to do whatever you want
Admiral:
It’s not necessary, but for aesthetic reasons more than rules I recommend you to put Iron Daemons and Skullcrackers on Screaming Bell bases.
Bitterman:
Do they even fit? The Skullcracker in particular looks (from memory) to be much, much longer than 100mm.
Malorndk:
They fit better than the 6th edition wyvern on its 50*50 base if you remember that monstrosity 
The skullcracker might have some hammers extending from the base but the core of the model should fit