there are some oddities I have just dug up in a grammar book and in which you might be interested:
Marginal modal auxiliaries:
used to, ought to, need, dare
used to:
He usedn't to smoke.
He did not use to smoke.
He used to drink, did he not.
Did he use to drink?
ought to:
Ought I to stop smoking? Yes, you ought (to).
You oughtn't to stop smoking.
You do not ought to stop smoking.
dare, need:
may act as modals and full verbs.
The modal usage is restricted to non-assertive contexts, negatives, to if clauses.