Freehand sharpening Yoshikane 180mm SKD-11 (D2) 64 Hrc Petty

[BluntCut MetalWorks]

After 4 months of usage/abuse, there were a few micro-chips on my Yoshikane 180mm/7" Petty (guyto). Time to sharpen this knife & enjoy some humble-pie.

Yoshikane 180mm Petty Hammer Finished, SKD-11 (D2) steel, 64 Hrc
King 800/4000 Grit waterstone 2.5x7.25x1.0 inches
DMT diafold E & EE (9 & 3 micron)

Thanks for watching & appreciate any feedbacks.

[video=youtube_share;nhjNUH3B-ks]http://youtu.be/nhjNUH3B-ks[/video]

 

[BluntCut MetalWorks]

Yoshikane vs Spyderco Stretch CF on pushcut newsprint across grain.

3 minutes follow up video
[video=youtube_share;q6ebeHs94rs]http://youtu.be/q6ebeHs94rs[/video]

Comments anyone?

 

[Jason B.]

I sharpened one of their gyutos, used a Naniwa green brick and Nubatama Han-Han stone to finish, probably the sharpest blade I have ever held.

I would just use the waterstone, the DMT is coarser than the waterstone you have.

Also, draw the knife through wood don't scrap it. By scraping the edge you can cause lateral stress which could include chipping on a high hardness blade.

 

[BluntCut MetalWorks]

Thanks Knifenut1013. I'll re-examine my burr removal technique by fold & file the bent-over-burr off. I definitely watch for lateral stress chippage on my 240mm V2 64hrc blade.

Indeed Yoshikane knives are really nice and can take abuse fairly well - yep micro chips on a few yrs crusty pizza, until 4 months ago, I made a 14.5" gyuto pizza knife.

I've this Yoshi for almost 7yrs now. It was mostly sharpened on an EP for 5 yrs, usually finised on 1K tape. Well, once I dropped the angle to around 12*/side, the resulted edge was never clean. Then upgraded to 1K(no-name)+6K(king-s2)+8K(kitayama) waterstones, got better edge but still lack of durability. Next was spyderco ceramic stones + 8K, same thing. Went diamond crazy + fold&file burr removal, quite happy with the result.

I re-measured this knife bevel with a caliper, it's between 8 or 9 degree/side. Just like D2 with super thin apex, the burr consists of spread-out dots (probably around 5 dots/inch) on the apex. I think those are parts of vanadium carbide, light draw on wood won't do anything, hard draw end up with carbide pull out (or maybe just fracture or chip).

For the pushcut video, I sharpened the edge from previous video through progression: fold & filed with dmt EE to ensure a burr free edge, next edge-leading on diamond surface stones 3um -> 1um -> 0.5um -> 0.25um -> 0.1um, finished with 3 minutes stropping on bare leather. Edit: These steps were applied to a micro-bevel ~ +3*/side.

Again thanks for the feedbacks and pointers.

 

[HeavyHanded]

Thanks for posting - I have no experience with this metal, so cannot comment much except a "what would I do?" I agree with Knifenut, you should be able to remove burr on 4K instead of the diamond - if it can grind/abrade well, can deburr too. I have noticed problems using my Kings on certain steels, so perhaps D2 doesn't respond well to the King binder abrasive mix?
Your hands aren't nearly as wobbly as you claim, technique looks sound and better results with diamond. When using my Kings I always attempt to completely remove the burr before moving to 4/6k polishing, even off the 800 stone should be possible or nearly so. On very acute bevels becomes very tricky at all stages as I'm sure you know.

Good stuff!

 

[BluntCut MetalWorks]

Thanks for posting - I have no experience with this metal, so cannot comment much except a "what would I do?" I agree with Knifenut, you should be able to remove burr on 4K instead of the diamond - if it can grind/abrade well, can deburr too. I have noticed problems using my Kings on certain steels, so perhaps D2 doesn't respond well to the King binder abrasive mix?
Your hands aren't nearly as wobbly as you claim, technique looks sound and better results with diamond. When using my Kings I always attempt to completely remove the burr before moving to 4/6k polishing, even off the 800 stone should be possible or nearly so. On very acute bevels becomes very tricky at all stages as I'm sure you know.

Good stuff!

Thanks for watching & comments, HeavyHanded!

Removing burr at every low grit stones is a good practice; however my laziness + for kitchen knives sharpen on waterstones, the mud will keeps the burr reasonably short. So moving to a higher grit stone will just shorten the burr further - again need some mud <- which clearly I didn't generated much.

You are spot on about King binder + abrasive mix, it can polishs (lots of lapping actions) the steel matrix well but doesn't abrade alloyed grains very well. I didn't get good result with ceramic either, so yep, you're right diamond is a good fits for my sharpening technique. I like deterministic/predicability rather than the 'art' of sharpening, which might explain why of late, I am using fold & file burr removal and edge-leading stroke.