A polishing thread

To no-one’s surprise, I think any sharpening forum needs a polishing thread. Some may view them as different disciplines, but I like the Japanese approach of viewing everything from geometry work, to aesthetic finishing, to the final apex as part of the “sharpeners” job.

Let’s use this thread to discuss everything polishing. Not just for showing off your fancy kasumi results, let’s talk about the geometry work that has to come first, the tedious surface prep that happens, natural stones, polishing powders, diamond emulsions, finger stones, etc. Progress pics, questions, and flashy polish results all welcome.

 

This is a area that I really don't have a good grasp of, but would really like to develop.

 

im of no value in knowledge, but I'm here for the learning. Still cant get a simple even polish to save my life

 

So, is there a Cheater’s Shortcut to polishing? I know the One True Way is to stone polish bevels that are true convex hulls…

but if, say, I’m an innately degenerate individual with no hope for redemption in this lifetime

can I use sandpaper? What are the details of dealing with the devil?

 

While I’m also curious about what Mengwong mentioned above, I’ve been loving the experience of rubbing steel on natural rocks. However, what EThompson mentions about the base geometry work seems to be evading me - I really want to maintain (or even accentuate) convexity, but it seems like sometimes that is impossible without a loss in height if there are low spots / hollows in the bevel as ground?

I know from a performance standpoint I should just be happy with a knife that cuts well and on which I can erase with bench stones 95% of the sharp sharpie grid I drew on the bevel - but if I want to chase that last 5%, am I looking at grinding down the rest of the bevel to be in line with that one low spot? Are finger stones just the answer here?

Also, I’m guessing that without pics and and specific examples this is tough to answer, but just wanted to throw it out here in case anyone else is having a similar experience!

 

Sandpaper+autosol is the way of the devil.

 

I really need to add a diagram, but if you thin and raise the effective shinogi line slightly, can you retain height, convexity and remove low spots?

This is actually something I've always wanted to know, not really an answer haha. Really just an additional question for someone in the know.

 

Well… the answer when it comes to shinogi / heel heights, convexity, and removing low spots is “it depends.” Not a very satisfying answer, but the truth. Sometimes there are spots, usually right T the heel or tip, that just aren’t worth chasing out. Sometimes you can loose 0.5mm or less and that’ll give you the wiggle room to even everything out while keeping convexity. Sometimes you should raise the shinogi. And most of the time you need to do a mixture of both.

And as for polishing without going through a bench stone progression - not only is it possible, in some instances it’s the better choice! Sand paper, diamond pastes, and then finger-stones can give really crazy finishes.

 

Pictures are key, if anyone has questions about a specific project I’m more than happy to offer my amateur opinion on it. As I said, each case is different

 

It is a helpful point to hear and to try to remember for sure. That the approach should be informed by analysis of the characteristics of each individual knife, rather than trying to start with certain “proper” approach and trying to apply that to every knife. It sounds super obvious when I write it down, but in practice I almost certainly don’t spend enough time on assessing geometry and other prep.

Will try to get some pictures up in the near future - and having seen the beautiful work you do, I think you’re being pretty modest about how not-amateur your opinion is!