Stone Wear

[robincbailey]

I get through a lot of stones, I do sharpen a lot of knives though as I run it as a business. But I would have thought that 60 knives taking off 5mm is excessive. I use both the std stone and the blackstone on a T7.
Is this normal?

[Herman Trivilino]

Yeah, that seems excessive to me, too.  It took me several years to put 50 mm of wear on my first stone.  I'm not a commercial user, but I sharpened all kinds of stuff with that stone, from shovels to lawn mower blades and of course lots and lots of knives.

Have you by any chance been using the truing tool a lot?  That'll wear your stone down quick because, well, that's what it's designed to do.

[robincbailey]

I only true the stone when I have planer blades to do.
Perhaps I am applying too much pressure when sharpening

[Herman Trivilino]

I don't think you could possibly wear a stone that fast by pushing down too hard.  Do you leave the stone soaking in the water tray overnight?  Are you adding something to the water that might be softening the stone?

[robincbailey]

I do not add anything to the water.
I don't leave it soaking either.
I have this problem with both the SG-250 and SB-250, although I think the blackstone is slightly better as I don't have to use so much downwards pressure.

[Herman Trivilino]

Just for the heck of it, have you ever tried sharpening a cheap kitchen knife on the Tormek?  If you're pushing down too hard, that cheap knife would wear away quickly.

[robincbailey]

I sharpen all sorts of knives, including cheap ones, and you are right in as much that two passes on a cheap knife raises a burr as oppossed to six to ten passess each side on a Global.
Not sure what this maens though, apart from cheap knives have softer steel?
I guess I was shocked that when I bought the T7 as everyone was saying the stones would last for years, but this is just not the case if you are actually using it daily.
I think I will keep the T7 for knives only, and invest in a TAS (Twice as Sharp) for the scissors and heavier shears that might be taking too much off the stone. Shame though, as I have just had a hairdresser say that their scissors were so sharp after I did them that they cut through a clients gold chain without noticing, and then had to pay for it!

[Herman Trivilino]

Ok, so when you see the burr form, you know to stop grinding.  As a beginner, I wore away several cheap knives by grinding to long -- obviously, that's not happening to you -- so maybe it's like you say, the stone's just getting a lot of use.

I'm just a do-it-yourselfer so my stone doesn't see as much steel as yours. 

Did you sharpen the hairdresser's scissors on the Tormek?!  My daughter-in-law won't let me touch hers.  And I don't blame her, they're very expensive scissors.

[robincbailey]

Yes I did, but the very small blade of hairdressing scissors does not lend itself to the scissor jig very easily, hence I have ordered a TAS.
Really, unless they are really blunt you can touch them up on the leather wheel and that normally will suffice.