Retired Friends of mine and I myself have a $20 per hour shop rate for
people we know and about double that for strangers.
At even the $40 we aren't recovering our shop costs and we know it.
The thing is, if you give things away, then they aren't valued anyway.

I saw a sign:

$20 per hour
$40 if you watch
$60 if you help

Setting a cost on these things is difficult. I do not do machine work, but
rather welding. Price can vary a lot. The final call is up to what you
value your work at, the friend/person involved, attitude, what may come back
to you in the future from the job, lots of things.

Steve