Translation:A hammer is an object that one uses to hit with.
Omitting "til" here would change the meaning:
"bruke til å" = to use to/for/in order to (in the sense of utilizing)
"bruke å" = to tend to, to use to (in the sense of usually/habitually doing something). It can often be translated with the adverb 'usually'.
Here's a sentence using both expressions:
"Han bruker å bruke hammeren til å slå ting med."
"He tends to use the hammer to hit things with."
"Jeg var vant til å..." = "I was used to..." (I was accustomed to X)
"Jeg brukte å..." = "I used to..." (I habitually/usually did X)
As you can see there's a difference in nuance, but often they amount to the same, as one becomes accustomed to doing what one usually does. They can be used both in the past and the present tense.
"Vi bruker å gjøre det på denne måten, så det er det jeg er vant til."
"We [usually do/tend to do] it in this manner, so that's what I'm used to."
No, 'which' would sound unnatural here. The problem here is that 'hit' is being used intransitively, so there's no direct object for 'which' to refer to. You could write 'with which' if you wanted to sound formal, but I'd personally either omit the relative pronoun here or use 'that'.
Ok, thx. I'm sure you're correct, but I'm a little confused. In the sentence: 'A hammer is an object that one uses to hit with' I thought that 'which' referred to 'object' (it's been a while since my last grammar lesson). Also, how would the sentence look like when using 'with which'?
'Which' and 'that' are interchangeable in this context in British English, but 'that' is preferred in US English
The suggested translation is a very literal one and sounds a bit unnatural to me anyway.
I would prefer 'A hammer is an object that/which one uses to hit' or 'A hammer is an object that/which one hits with'.
I think talideon is referring to an alternative to the previous sentence - 'A hammer is an object with which one hits'. You definitely can't say 'A hammer is an object with which one uses to hit.'