My take on sharpening

[Martin Loesing]

Hello everyone,
I'm new to SMC so first of all I would like to thank everyone who contributes to this forum for sharing their knowledge.

There are obviously many ways to successfully sharpen edge tools and I'm not claiming to hold any ultimate truth. So this post is simply meant as some input to those who struggle with sharpening or those who like to experiment.

A few month ago I've discovered the blog https://scienceofsharp.wordpress.com/ where (mainly) straight razors honed on different media are examined via electron microscopy. One of the conclusions of the resulting images is that edge trailing strokes on sharpening stones create a keen, chip free edge but also a burr which is quite difficult to remove and which when ripped off leaves a rough/heterogeneous edge apex. Edge leading strokes on the other hand create a micro-chipped but burr free edge, with the size of the micro-chips being correlated to the coarseness of the sharpening medium.

Based on these conclusions I've adapted my sharpening technique and now do only edge-leading strokes on my sharpening stones (which is facilitated by using a honing guide where you can lift the edge on the return stroke). After honing on my final stone I do very few (still experimenting here, but around 5) edge- trailing strokes on the same stone to refine the keenness of the edge without creating a burr.

I get great results using a two stone setup consisting of a worn in EZE-LAP 1200 and a Shapton 6k, with finer stones being completely unnecessary I think. A note of caution this technique seems to work quite quickly and with a low stroke count but will not polish the bevel very well. I've only tested this on simple carbon steels, so it might be different for more tenacious steels.

Kind regards,
Martin

[Mike Cherry]

Welcome to the creek Martin! Interesting thoughts on edge leading strokes. I have always trailed the edge but true sharpness was never realized until I made very sure to remove the wire edge completely. I do this with a strop. There's a couple or three ways to get to sharp, I'm glad you found yours!

[Phil Mueller]

Martin, welcome to SMC! Thank you for posting your sharpening technique. I think you'll find a zillion opinions on sharpening, but it comes with a great appreciation for everyone's trials and successes. I have believed in the past, there is a bit of over obsession in sharpening, relying on sandpaper and plate glass myself. But i must admit recent projects requiring a lot of end grain paring has highlighted some shortcomings in my sharpening technique.
All input is helpful in our quest for sharp.

[Jim Koepke]

Howdy Martin and welcome to the Creek.

I am always curious to the spot on earth others call home. Where is your home spot?

There is more ways to sharpen than most of us care to imagine. Some strong opinions can be found in most discussions about sharpening.

My sharpening used to stop at a 4,000 stone. It did pretty good. Then along came an 8,000 stone and things were a bit better.

I know a bit more sharpness and a higher polish could be coaxed onto my blades with a finer stone, but it seems to be a diminishing return compared to the added cost.

jtk

[Frederick Skelly]

Welcome Martin! Glad you've joined us. Thanks for the input on technique - I plan to give that a try and see if it works better for me.

Fred

[Brian Holcombe]

Martin, do you inspect your work with a microscope? Curious if your findings follow closely to those linked. The chisel edge is a few degrees steeper than a straight razor, which I wonder if it minimizes the effect of trailing strokes.

[Tom M King]

I sharpened on oil stones for at least the first 20 years, and only ever went forward. No reason other than that's the way I taught myself to do it. It works just fine. It's still ingrained in my wrists, and I have no reason to do otherwise, except on the diamond lapping film I use to finish with. It's easy to slice that film with a sharp iron going forward, and I haven't used any yet that I haven't sliced by thinking about something else while doing it. Fortunately, it still works just fine with a slice in it, but you should only go backwards on that stuff.

[Warren Mickley]

Martin, do you inspect your work with a microscope? Curious if your findings follow closely to those linked. The chisel edge is a few degrees steeper than a straight razor, which I wonder if it minimizes the effect of trailing strokes.

My razor is 17 degrees (8 1/2 on each side) my chisels are 30 degrees. There are some differences in technique sharpening the two.

[Brian Holcombe]

I'm playing devil's advocate a bit, but I tend to bias all of the work to the bevel edge on my chisels, but flip the razor every stroke.

[Derek Cohen]

A few month ago I've discovered the blog https://scienceofsharp.wordpress.com/ where (mainly) straight razors honed on different media are examined via electron microscopy. One of the conclusions of the resulting images is that edge trailing strokes on sharpening stones create a keen, chip free edge but also a burr which is quite difficult to remove and which when ripped off leaves a rough/heterogeneous edge apex. Edge leading strokes on the other hand create a micro-chipped but burr free edge, with the size of the micro-chips being correlated to the coarseness of the sharpening medium.

Hi Martin

Welcome to the forum!

That is an interesting observation and, intuitively, it makes sense.

My preference is side-to-side sharpening, and I recall reading an article (by Harrelson Stanley) that claimed it created less "chipping" at the edge and, thus, a stronger edge.

However there are occasions when other directions are used owing to circumstances. For example, I would hone a 1/8" chisel on a hollow and drag it back over the waterstone - since pushing it forward might gouge the stone. Similarly, high angle (50 degree) micro secondary bevels for BU plane blades are best done using a honing guide. At that angle, one is forced to drag the blade. It would also gouge the stone if pushed forward.

Regards from Perth

Derek

[Pat Barry]

I've also seen, and tried, a figure eight technique that gives you the best of both worlds. In the end, its really whatever works best for you isn't it?

[Nicholas Lawrence]

Well, now we have some competition for the imperial versus metric thread....I'm not sure this will make 9 pages though.

[Mike Cherry]

Well, now we have some competition for the imperial versus metric thread....I'm not sure this will make 9 pages though.

Hehe yea this is definitely one of those topics that can go on for days!

[Brian Holcombe]

Practicality weighs in as well. I'm working on those long handles Tsuki's and I dont remove the handles to sharpen (some people do on carpentry slicks and such). To maintain the bevel by hand I generally make short strokes with the blade on a diagonal so that I have the longest possible reference surface in the direction I'm pushing the chisel.

Shorter handles make the work a little easier and I can get closer to side-to-side sharpening.

[Ian Moone]

Plasma sharpening!

https://www.youtube.com/watch?v=PNq4Oa1GwwE

I thought everyone already used this?