Just a followup on brianhw's excellent Homemade Tool of the Week winning Damaged Thread Chamfering Tool.
Like most of us, if I see a why-didn't-I-think-of-that type of homemade tool, I'll often search around to see who else has built something similar, or if there are equivalent commercial tools on the market. I'll usually find something; it's practically impossible to have an original idea these days, and the similar concepts floating around on the net provide multiple additional building ideas, plus good grist for the mill.
The technical term for this is multiple discovery - it holds that most inventions are made independently and simultaneously by different inventors. This is thought to have occurred numerous times, from the discovery of the fact that our solar system revolves around the sun in 300 BC, through the more famous multiple discovery invention of the jet engine, and even right up to modern times. In fact, the 2015 Nobel Prize in Physics was shared between Takaaki Kajita of Japan and Arthur B. McDonald of Canada. Although the two physicists knew each other, they weren't working together - they each separately discovered that neutrinos have mass, in two different experiments, on two different continents. The $1 million Nobel prize award was even split evenly between them both.
I know we've been looking at a lot of Kickstarters for tools lately. There was a successful Kickstarter for a similar tool called a "Uniburr". Here's the product video, patent drawings, plus links to the Kickstarter and the website selling the product.
This one is sold in two different options, a $45 Standard model for mild steel and $65 Plus model for harder steel.
Looks like the milder model has attracted some Amazon criticism, and of course there is a funny exchange between a 1-star rater who claims that the tool could not fix the threads on a "cold hot dog", and a rep from the manufacturing company who kindly explains that the hot dog may have had "a hardness rating that exceeded Grade 2".
The patent is here, and here are some drawings:
Uniburr on Kickstarter
UNIBURR deburring chamfer tool bit for fast bolt repair
Uniburr on Amazon