My prefix is an H bent outwards minus end three

Part 1 is here (not important to solving this one)

My prefix is an H bent outwards minus end three;

My infix weighs fourteen pounds, minus the letters in me;

My suffix is an uncle's brother's grandsons, minus the first one;

All together, I'm in machines, but don't get me stuck to you when you're done.

P.S. (not really a hint but still)

You can assume the uncle in question has only one brother.

My prefix is an H bent outwards minus end three;

pisces (- last 3 letters) = PIS
Thanks to Tom for finding this!

My infix weighs fourteen pounds, minus the letters in me;

stone (-m -e) = STON

My suffix is an uncle's brother's grandsons, minus the first one;

sons (- first letter) = ONS

All together, I'm in machines, but don't get me stuck to you when you're done.

PISTONS

• Word is right, reasoning for the infix and suffix is right, reasoning for the prefix is not. Keep looking! Jan 1, 2019 at 15:01
• Prefix looks like rot13 cvfprf
– Tom
Jan 1, 2019 at 17:05
• @Tom looks good! Jan 1, 2019 at 17:09