Using a digger as weapon to secure poor-quality residence (10)

'using' is the definition.
The definition and answer can be both to do with contact as well as being present participle verbs.
Perhaps you can see a link between them that I can't see?

'a digger as weapon to secure poor-quality residence' is the wordplay.
I cannot quite understand how this works, but
'digger' could be 'shovel' (synonyms) and 'shovel' is found in the answer.
'as' could be 'in' (I've seen this in other clues) and 'in' is located in the answer.
This explanation may well be incorrect...

Can you help me to learn more?