Newbie question

[IronKnuckles]

Can someone please explain to this poor newb the difference between hardness and toughness and the like? I'm utterly lost because I was under the impression that they were pretty much synonymous

 

[mete]

Hardness is a general measure of edge retention while toughness [opposite of brittleness]is related to how well the blade will take impact use . We look for toughness in blades used for chopping such as a kukri ,machete, axe.Usually the harder the blade the less tough it is so we look for a balance of the two depending on the blades use.

 

[Stacy E. Apelt - Bladesmith]

Diamonds are hard,wood is tough.Hardness is the resistance of the crystal structure to movement ,or interuption, within the latice.Toughness is the ability to deflect the lattice without interupting it.Now that should have cleared it up! On the bladesmiths end this translates to -when you quench a blade you freeze the crystaline structure (grain) of the steel in a certain pattern.The more rigid that pattern is the harder the steel is.However ,if the crystals are deflected (bent) the lattice will shear (deflect) and the blade will break.Tempering ,which is a controlled softening of the steel,helps to ease this.Alloys are added to the steel to make it tougher,thus allowing more deflection (bending) of the edge and blade without the steel crystals separating.A tough blade is one that resists the edge wearing away,bending over,or chipping off,and allows some degree of flexability and impact resistance.A hard blade is one that will retain its edge longer.The best blade has a blend of both.The best combination of hardness and toughness depends on the use of the blade.That is why there is no perfect blade steel.My picks are : Cheap and tough -5160; Cheap and hard - 1095; Tough,hard,and corrosion resistant ATS-34; Best way to combine both -Damascus steel.Try several steels and find the ones that work beat for you.

 

[Stacy E. Apelt - Bladesmith]

Edit: ....shear (deflect)... I ment Shear is the same as interupt. Bend is deflect.

 

[blgoode]

I thought Bend was in Oregon....just kidding

Too hard = broken blade
Too soft = paper weight

 

[IronKnuckles]

Thanks everyone! that really clears alot up.