# What is the "sharpest" cutting tool? **URL:** \ **Category:** Factual Questions\ **Created:** [November 3, 2005, 6:10pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325 "2005-11-03T18:10:41Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\ **Post date:** [November 3, 2005, 6:10pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/1 "2005-11-03T18:10:41Z")
By that I mean what is capable of cutting through the greatest variety of materials? Is it surgical steel? A Samurai sword? Obsidan? Some kind of laser? A roll of oven-melted-than cooled plastic wrap? ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [November 3, 2005, 6:15pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/2 "2005-11-03T18:15:17Z")
Water. > **[How can water cut through steel?](https://science.howstuffworks.com/environmental/energy/question553.htm)** > > How can water cut through steel? A device called a waterjet uses extreme force to cut through all sorts of things. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [November 3, 2005, 6:22pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/3 "2005-11-03T18:22:36Z")
Or hydrogen. Bonds with a great many things to form variations on the theme of acid. ---
**Author:** ![CynicalGabe](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@CynicalGabe](https://boards.straightdope.com/u/CynicalGabe)\ **Post date:** [November 3, 2005, 6:44pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/4 "2005-11-03T18:44:06Z")
Probably doesn’t count, but maybe thermite? ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [November 3, 2005, 9:02pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/5 "2005-11-03T21:02:36Z")
In a three way showdown I think I could take the guy with the vial of acid, 😃 but would hesitate approaching the guy with the soild rocket booster. :eek: ---
**Author:** ![kidchameleon](https://avatars.discourse-cdn.com/v4/letter/k/898d66/32.png) [@kidchameleon](https://boards.straightdope.com/u/kidchameleon)\ **Post date:** [November 3, 2005, 9:11pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/6 "2005-11-03T21:11:15Z")
Nothing is sharper and colder than when a woman really rejects you. 😛 ---
**Author:** ![Ike\_Witt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ike_witt/32/283_2.png) [@Ike\_Witt](https://boards.straightdope.com/u/Ike_Witt)\ **Post date:** [November 3, 2005, 9:24pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/7 "2005-11-03T21:24:28Z")
Obsidian. Keeps its edge to a thickness of one molecule. It is sharper than any metal blade could be made to be. ---
**Author:** ![av8rmike](https://avatars.discourse-cdn.com/v4/letter/a/edb3f5/32.png) [@av8rmike](https://boards.straightdope.com/u/av8rmike)\ **Post date:** [November 3, 2005, 9:47pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/8 "2005-11-03T21:47:19Z")
A laser, since it can cut diamond, the hardest mineral? Or, maybe, a thankless child? ---
**Author:** ![Meaty\_Beaty\_Big\_and\_Bouncy](https://avatars.discourse-cdn.com/v4/letter/m/c57346/32.png) [@Meaty\_Beaty\_Big\_and\_Bouncy](https://boards.straightdope.com/u/Meaty_Beaty_Big_and_Bouncy)\ **Post date:** [November 3, 2005, 9:54pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/9 "2005-11-03T21:54:24Z")
I’ve had some diamond-cutter erections. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [November 3, 2005, 10:35pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/10 "2005-11-03T22:35:40Z")
The metal tip on a scanning probe microscope, which is often a single metal atom like the final cannonball on one of those pyramid piles. They do use these tips to move bits of sample around - it’s as much “cutting” as anything else you could call it. Why can’t metal blades have single-atom tips? ---
**Author:** ![Ike\_Witt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ike_witt/32/283_2.png) [@Ike\_Witt](https://boards.straightdope.com/u/Ike_Witt)\ **Post date:** [November 3, 2005, 10:40pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/11 "2005-11-03T22:40:40Z")
> [@Napier](#): > > Why can’t metal blades have single-atom tips? IIRC, it is because of the way that the molecules are arranged, you might be able to make one that thin, but the edge wouldn’t keep after use. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [November 3, 2005, 10:43pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/12 "2005-11-03T22:43:38Z")
This is General Questions. I would go with the water for its ability to cut the largest selections of material. Other runners up would be lasers, and ultrasonics. ---
**Author:** ![RandomLetters](https://avatars.discourse-cdn.com/v4/letter/r/8edcca/32.png) [@RandomLetters](https://boards.straightdope.com/u/RandomLetters)\ **Post date:** [November 4, 2005, 2:35am UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/13 "2005-11-04T02:35:32Z")
> [@CynicalGabe](#): > > Probably doesn’t count, but maybe thermite? Well, if you are going in include that, why stop at puny chemical explosions? 😉 IRRC one of the Operation Plowshare plans involved using a series of nuclear bombs to cut a sea level canal between the Atlantic and Pacific oceans. 😃 ---
**Author:** ![AHunter3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ahunter3/32/368_2.png) [@AHunter3](https://boards.straightdope.com/u/AHunter3)\ **Post date:** [November 4, 2005, 4:22am UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/14 "2005-11-04T04:22:53Z")
Boron carbide. The most abrasive substance known, and damn near as hard as diamond. A cutting wheel surfaced with boron carbide will cut through damn near anything. You might need to replace the wheel a few times to cut through a diamond. The dust at the bottom will be about 46% diamond dust and 54% boron carbide dust. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [November 4, 2005, 5:13pm UTC](https://boards.straightdope.com/t/what-is-the-sharpest-cutting-tool/329325/15 "2005-11-04T17:13:53Z")
> [@AHunter3](#): > > Boron carbide.The most abrasive substance known, and damn near as hard as diamond. A cutting wheel surfaced with boron carbide will cut through damn near anything. You might need to replace the wheel a few times to cut through a diamond.The dust at the bottom will be about 46% diamond dust and 54% boron carbide dust. Diamond are split if large and small diamonds may be cut with a wet diamond saw. Diamonds are finished wet with diamond dust on a metal lap wheel. Re: OP IMHO there is NO one general purpose cutting agent/tool for the wide range of material existing today. What works well for one may be very poor with another.