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Black_Moons
09-27-2010, 05:11 PM
How do carbide burrs last so long at die grinder SFPM? most die grinders spec 20,000+ RPM free speed, Lets say its only 10,000rpm under load, using a 3/8" burr (Not too big, but not very small either), thats 981SFPM

Isent that a wee bit high for uncoated carbide vs mild steel? And thats after it slows down.. initialy it will be at 20,000rpm, or twice that, nearly 2000sfm.

Not to mention its also very often used on welds that are harder then mild steel.

Seems to me these burrs should wear out a lot faster.. Especialy considering they are not even mounted to a rigid machine, but a flabby human arm insted. So far I have never worn out a burr.. but I have snaped a few accidently... (usally using them on small holes where they start doing laps and somehow my die grinder wanders off axis too much..)

becksmachine
09-27-2010, 05:47 PM
Yes, I have a collection of broken ones myself. Don't know why I collect them, it's not like I would be able to re-braze them close enough to run at 20,000 rpm. ;)

I very rarely (never?) use them on steel, would rather use a stone for that.

Usually on cast iron or one of the softer metals like brass or aluminum, which helps lead to a longer life.

Dave

Black_Moons
09-27-2010, 08:00 PM
I shoulda kept mine (broken burrs).. Iv been thinking of making a carbide tiped scriber outta one, but don't have any... Tempted to snap one of those micro endmills that are sold in 10's for $5 at HF/princess auto. Or just yaknow, attempt to use it and watch it snap accidently.