View Full Version : Usuba refurb / sharpening
11-16-2012, 12:13 PM
I recently got a 40 - 50 yr. old Usuba from a fellow in Hawaii. Not the greatest packing job - the blade was best a little and it's seen its fair share of abuse. I got the blade straightened out and am in the process of thinning and reestablishing the secondary bevel. How far up the blade is normal? Pictures of new ones are not a big help as this blade has been sharpened down some - it's 1-9/16" wide.
I struck a line 3/4" up from the edge and am using it for a reference as I thin.
Advice is always appreciated.
11-16-2012, 02:28 PM
I'd increase the height of the shinogi line by the same amount of what you believe to be lost in edge height. So if you think that the knife has been sharpened/shortened by 3mm then increase the height of the shinogi line by 3mm. It's a guessing game really.
11-16-2012, 02:35 PM
not quite as much of a guessing game... 180mm usuba are generally around a 6-6.5 degree angle if the edge were flat from edge to shinogi line. This is just a guideline, not a hard and fast rule, but its a place to start at least.
11-16-2012, 04:21 PM
Thank you Dave and Jon - I've raised it some and since the front was quite rounded I sanded it square and out a less extreme bevel on that. I ought to post some WIP pics so you see where I'm at.
11-18-2012, 05:23 PM
Here's a few pics of it - the right side looked like the back, but is coming along. I'm bringing the shinogi line straight across slowly. I don't want to narrow the blade anymore than it is, but I want to widen the secondary bevel. How much primary bevel do these take? 2-3mm like gyuto or is the secondary bevel it? All I have to go by is web pictures so any advice on progress is appreciated.
11-18-2012, 09:06 PM
I dont know why this one isnt showing up right, but it should be this: https://www.youtube.com/watch?feature=player_detailpage&v=kA0vdeDDSJI&list=PLEBF55079F53216AB
11-19-2012, 07:44 PM
Thanks for the links Jon - this is proving to be a frustrating refurb. Hell of a learning curve having been bent and all, but it's slowly coming along.
11-19-2012, 07:52 PM
That's a major refurb, I have to give you credit for diving in Mike. :hatsoff:
11-19-2012, 08:21 PM
i hope you're packing an XXC DMT!
11-19-2012, 08:49 PM
oh... make sure the blade is straight before you begin anything ;)
and, yes, kudos to you for doing this
11-19-2012, 10:35 PM
Thanks for the encouragement fellas. Jon - Between my vise and a block of soft end grain pine and a mallet this blade is a straight as it's going to get.
Yeah - diamond is my new best friend followed closely by my Gesshin 400 :lol2:
11-24-2012, 12:50 PM
Keep us posted on your progress. This is quite an overhaul.
11-24-2012, 02:28 PM
Well this is as good as it gets for this poor thing. Nice and comfortable now and very sharp. The handle is ebony and ironwood.
12-12-2012, 06:09 PM
Good job Mike At least when you use it you have the satisfaction that you brought it back fr. the dead.There are alot of rusty old single bevels laying around in Hawaii,because of 3&4 generations of Japanese here.I picked up a couple dirt cheap,there is still some pretty good steel under all that rust:)
12-12-2012, 09:05 PM
Thanks - I used it tonight and the Nakiri that he sent to make up the bent blade. Both turned out to be excellent knives.
12-12-2012, 09:29 PM
12-12-2012, 09:36 PM
that's an interesting looking knife.
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