So as we know, getting the goblin tinkerer can be cancer and extremely boring.
So I will let you in on the fastest method to getting him!
First we need to know the spawn conditions for a goblin army:
It must be daytime (4:30 AM is when it triggers).
The player must be standing near the World Spawn Point (not necessarily the player's spawn point).
At least one evil orb must have been destroyed.
At least one player must have 200 health or more. (If this is not met the Goblin Battle Standard will not work).
So now that we know that, we can exploit it to our benefit!
Now what you need to do is simple, destroy an evil orb with bombs at night (spamming 6-8 sticky bombs above an evil orb should do the trick).
Go to your world spawn point (the point where you first spawn) and save and exit there.
Next what you want to do is wait until day, doing whatever you want while being in that general vacinity.
If the goblin invasion does not occur press alt-f4 and retry until it does since it is a 1/3 so it should happen quickly.
defeat the goblin invasion.
go to a nearby cave formation and go up and down it.
Goblin tinkerer should appear, when he does free him and then proceed to waste all your money on rerolls just to get terrible.
Good luck!
Don't forget to favourite and like thanks!