Help turning a forgie chef into a forgie sujihiki??

[gic]

So I bought a forgie at a thrift shop knowing it had been really badly sharpened over the years as the pictures I am attaching indicate. It has that typical "too wide heel" caused by poor sharpening over many many years, i.e. the contact with a cutting board is just not there any more.

But I bought it because it was cheap and I was thinking if I could only learn how to reshape it, while keeping the temper on the steel, I would have one awesome sujihicki!

So I am hoping someone would point me to a thread or to a video or just tell me: how do you fix a knife that looks like this - assuming it is even possible.

(Reshaping on stones is clearly hopeless as it would just take too long, but a friend of mine has a bench grinder if that is the key - but would that ruin the temper?)

Anyway, any advice would be appreciated.

 

[ecchef]

Suji would be tough. You'd probably have to narrow the tang as well to keep the proportions legit. Might be easier going the honesuke/garasuki route if you have a need for one.

 

[gic]

Well it is 10" blade so that would be pretty long for a honsuki?

Would it be possible to turn it into a fairly narrow chef, sort of a suji/guyto hybrid?

But, basically I just am wondering how you rehab a badly sharpened knife like this so it can make reasonable contact with a board, and whatever profile I'd end up with would be OK...

...

 

[Geo87]

Your first step is to decide on a new profile and mark out where you need to remove metal with a sharpie . You could either remove metal from the heel and go the suji route or remove metal from the front and make a shorter gyuto with a French style flatter heel profile. Perhaps someone with better computer skills could draw potential profiles on those pictures

I would use a belt sander for this not a bench grinder if you have access to one? (Less potential to ruin heat treat) Basically you hold the knife with the edge trailing the belt (or it will dig it and potentially fling right at you) and make passes starting from heal moving towards the tip. You need a bucket of water to dunk the knife in to cool it down after every pass over the belt, then wipe the blade dry. as long as you do that you shouldn't ruin the heat treat. Be very careful with power tools... They eat metal fast and you can't put it back

Your first job would be to shape the new profile once that's done you'd need to thin the blade ALOT! As it will be much thicker as you move up the blade face. Make sure you thin the blade evenly so it doesn't steer or wedge. If you choose a suji profile your balance may be handle heavy as your removing a lot of weight from the blade . That's not really ideal. If you can rehandle you could reshape the tang and put a wa handle on to restore the balance. Or you might like a handle heavy slicer? See how it feels first I guess

After all that you'll need to hand sand the entire blade with wet and dry starting from a very low grit working your way up slowly through the grits. Then the final step is sharpen on stones

You have one hell of a project ahead of you.

 

[daveb]

I'll admit up front that I'm lazy and don't find grinding metal a satisfying pastime. I would list it on the bay as is or just take the hit on it. Search the bay for a Forgecraft slicer. I picked one up with a boning knife for under $20. Some thinning, maybe a handle project and you're on your way to a decent slicer.

 

[gic]

Thanks Geo87, I guess the question I have to ask myself is would I learn enough to make the time worthwhile doing what you describe. I mostly buy thrift shop, abused knives as ways to learn more about sharpening, but I didn't realize what would be involved in this one! I'm tempted to get a belt sander because I want to learn how to make handles and for that a belt sander is better than a grinder anyway and I need "abused" knives to learn belt sanding skills just like I needed them to learn how to freehand! (Admittedly, I didn't know how much was involved in this case...)

But now I am curious, exactly how does a knife get like this, it's a sif the knife was only sharpened at the front!

 

[Pensacola Tiger]

But now I am curious, exactly how does a knife get like this, it's a sif the knife was only sharpened at the front!

It's likely that it has only been steeled, never taken to a stone. Poor steeling techinique will leave the heel and tip untouched, and over time the edge develops that "frown".

 

[cheflivengood]

It's likely that it has only been steeled, never taken to a stone. Poor steeling techinique will leave the heel and tip untouched, and over time the edge develops that "frown".

+1, especially those that use really aggressive diamond steels from say global.

 

[Geo87]

Gic : I think if you took on this project you would definitely learn a lot ! Jumping right in and giving it a go is a great way to learn. I say just do it! I will warn you that knife would take a serious amount of hours to convert to a wa sujihiki though.
I'm not sure about the US but I picked up a cheap grinder/ belt sander and a drill press from the hardware store for $AU 160 they've been great for learning on and I can upgrade them if I pursue this hobby further. 3 year warranty too

If you decide this is too much work send the knife here, I'll do a WIP and put the knife on pay it forward I love forgies.

 

[gic]

Yep just bought one for $119 belt sander a Ryobi from home depot, seems to get reasonable reviews. I'm looking forward to learning how to use it!

https://www.ryobitools.com/products/details/506

Also just for the heck of it, I took it to the stones, it may be ruined profile wise but the steel is that good forgie stuff, took an amazingly sharp edge really easily

 

[shownomarci]

Got the knife and got the tools, so that means a WIP thread.
Lookin' at the knife i can see 10'' sujihiki or an 8'' gyuto/santoku.
As it has been mentioned before draw the desired shape with a marker pen and get to work.

 

[Kippington]

Lookin' at the knife i can see 10'' sujihiki or an 8'' gyuto/santoku.

For sure there are other options too, but I agree these ones are the most obvious.

 

[gic]

I agree,im going the suji route!

 

[Kippington]

Good luck! If you want a bit more of a challenge you can also consider ecchef's quote:

Suji would be tough. You'd probably have to narrow the tang as well to keep the proportions legit.

There'd be a few other ways of doing it too, but it's just for your consideration.

 

[gic]

We will call it a sugi/gyuto hybrid and then I can leave the tang alone

 

[chinacats]

But you're going to have to do some serious thinning because the blade is going to be nasty thick where you're removing all the edge (heel area)...

 

[Geo87]

Agreed. There will be a crazy amount of thinning needed after reprofiling. Almost from the spine down. Post lots of pictures please as you go

 

[gic]

Yep, I am counting on that , cause I want to learn how to use the belt grinder to thin! If I wasn't viewing this as a learning experience on a belt grinder, it would clearly be insane!

I bought an 80 and 120 grit belt for the ryobi should I get some higher grit belts as well?

 

[CPD]

Yep, I am counting on that , cause I want to learn how to use the belt grinder to thin! If I wasn't viewing this as a learning experience on a belt grinder, it would clearly be insane!

I bought an 80 and 120 grit belt for the ryobi should I get some higher grit belts as well?

I re-did a Forgie 8" chef a while back and converted it to a WA. I did the tang on the bench grinder but the rest on a 1x30. It's been a while and don't recall details well, but if memory serves, it was slow going on the grind. Pretty sure I used an even coarser grit - maybe 50 - to get me close to desired profile.... then used grits on the belts from 80 up to near 400 at different parts of the process.

 

[ecchef]

For sure there are other options too, but I agree these ones are the most obvious.

Actually, that don't look half bad. :thumbsup:

Liking the bottom version a lot!

 

[Geo87]

Gic: I agree with CPD I would go coarser for the reprofiling say 40 grit.
I did a wa conversion on a 240 forgie I used grinder to reshape tang, rotary tool to reshape choil and 40-120 grit belts for thinning the blade from spine down. After the 120 belt I hand sanded up to 1200 wet and dry.

 

[gic]

Just ordered some 40 grit belts, I have never used such a low grit before, sort of a cinder block on a belt :- )

 

[Geo87]

I agree it's very coarse... But you've got a whole lot of metal to remove !

 

[CPD]

I agree it's very coarse... But you've got a whole lot of metal to remove !

+1, and it's already hardened/heat treated.

 

[kostantinos]

The suji will require some work.But it will look awesome . Take your time

I would suggest you removing the scales and working closer to the tang and the heel of the knife. That will also allow you to see what you want to do with the handle in terms of shaping or making new or refurbishing existent ones also will uncover any potential small problems hide in the tang with rust.

Also maybe it would be wise to take measurements of the original and measure a profile you are happy with from a sufi so that you have reference points of what you are shooting for? That way you can make measurements as you go and adjust as you go.

I have never use a belt grinder i am not sure if you have in the past but maybe play with a couple of drawer knifes before you do a go with this one, just to have an elevated understanding of the tool

Either way i feel it will be a great project with great learning curve.

I would love to see a WIP thread or updates as you go