Roadblock, 85 kilograms of malevolence on wheels, is set to fight it out with five other remote-controlled warriors on the BBC2's Robot Wars next Friday.
The show's presenter, Jeremy Clarkson, described the forthcoming final battle as "a six-way orgy of death and destruction".
Hender, aged 18, helped design and build the machine as part of his A-level in technology at Bodmin Community College. He worked with fellow student Chris Kinsey and his father Peter Kinsey who is head of technology at the Cornish college.
They used machinery and parts given by local firms, friends and relatives, and the result is a remote-controlled machine with a circular saw on its back so that it can corner its enemies, then turn and rip them to pieces.
Hender, who could get up to 30 per cent of his A-level marks for the project, used pictures of Roadblock to win a place on a mechanical engineering degree course at London's Imperial College.
Roadblock - its body is made of old road signs - is now on display in the school's foyer and is being used in Mr Kinsey's technology lessons to illustrate automation, electronics and design. The BBC programme does not pick up the semantic challenge of defining a robot, simply requesting that the machines are remote controlled.
Roadblock has battled with Barry, built by pupils from Hagley High School in the Midlands and Mortis, created by students from the University of East London. An aeronautics company in Ireland entered a robot called Killotron.
"It's a pretty scary machine and there were times when I feared for my kneecaps," Hender said. "It will go for anything and it sounds terrible with its motor screaming as it lunges about. It's evil. It's sole purpose is to destroy."
Teammate Chris, 17, who is in the lower sixth at the school, said: "We had to do a lot of problem-solving to make sure it would work properly. But I've learned that if you put the hours in you get the results. It's so powerful it can pull a car and its driver. It can take on anything."
The team used an old electric wheelchair as the basis for the robot, altering the electronics to make it react faster and installing remote control. The circular saw on its back is also remote controlled.
The robots were put through heats including an assault course and a mechanical maze before heading into battle.
Mr Kinsey, who was a mechanical engineer designing mining equipment before becoming a teacher, said: "It's been a tremendous talking point in the school. People like making things and this helps bring technology to life. I bring Roadblock into many of my lessons now because people want to know how it works."