reeddemarco wrote: ↑
Tue Jul 09, 2019 9:16 pm
I am caught in the midst of the toothy v. polished debate. The knife in question is a Mercer Renaissance paring knife. Felt really toothy out of the box and cut like a dream. Hand sharpened on medium and fine spyderco bench stones with some stropping and it is hair shaving sharp but won’t cut through a tomato with ease (or at least no where near the push cutting ease that I hear about on the forums). What am I doing wrong? I consider myself a decent hand sharpener but have never been able to get the ceramic stones to cut in the kitchen like, say, my chosera 800. Anyone else have this experience? Please help a guy out.
They don't have the finishing polish power of a 800 Naniwa but have other benefits.
The bonding of the Naniwa contributes more to polishing the bevel, the higher hardness bonding on the spyderco ceramic will help produce more cut than polish in some cases which can be desired.
It's less an issue about the stones and more about the user. That Mercer knife is soft and doesn't want to release the burr so one has to double check that burr is removed and not just straightened out into a false foil edge that will crumple over in use. I'm confused but the statement of "it had a toothy edge that cut like a dream" and that "it will not push cut a tomato"
A push cut is when the edge is not drawn across what is being cut but pushed straight downward and displacing materials and relys on a polished edge.
A toothy edge doesn't push cut but is drawn across material for aggressive Slicing like a saw blade/microserration.
A tomato seems like something simple to cut but most are eluded by why there sharp knife is not cutting the tomato very well and it has to do with both edge finish and cutting style.
A tomato has a tough outer skin that most polished edges will slide on if being DRAWN across lightly yet has a delicate flesh that a toothy edge can crush if PUSHED directly down through to displace. The best edge is a burr free, flat crispy, 15dps, medium finish 800-1500 with a slight draw and push mixed in the cut.
That finish gives the optimal balance for push and draw, precision and endurance, with a variety of foods in the kitchen.
The spyderco capable with that soft Mercer steel just different than the Naniwa. I think you just need to go back and do it again. Step it up. Rule out angle inconsistency, burr formation and removal.
They have less feed back compared to the Naniwa so it's easier to let angle inconsistency sneak up on you if your relying on stone feedback for tactile feel. Also keep those stone unglazed and clean so they cut good.
Any of the softy stainless like that is pointless to polish past 800-1500 and seems to work better in the 600-800 range due to the low yield Strength of the material however most attempt to go higher in grit to help mitigate the horrendous stubborn burr due to lack of understanding of how to remove burr at lower grit.