Repairing a Japanese Chisel

[Zuye Zheng]

Just got beautiful 3mm Koyamaichi chisel in a dovetail pattern. However went a little hard peening the ends and ended up bending and delaminating the chisel blade...

Any ideas to try to fix it? Do you guys even bother peening such a delicate blade?

333617

[Andrew Hughes]

You must return it to the fires Isengard.
Or it's pretty much done.

[Pat Barry]

I wouldn't call that delaminated

[Brian Holcombe]

Ouch, something went wrong in the peening process. What is your process? Mine involves lightly tapping the edge of the end grain over the hoop after fitting the hoop.

[Kees Heiden]

The elves of Rivendell were into reparing broken blades like that. Otherwise I would write it off.

[Zuye Zheng]

Ya, seems like a loss, good excuse to put in another order though... Giving JB weld a go and seeing if I can at least salvage as a paring chisel.


I wouldn't call that delaminated

Haha ya, the part that bent was the softer steel on top, the harder steel for the blade kinda just separated from the softer.


Ouch, something went wrong in the peening process. What is your process? Mine involves lightly tapping the edge of the end grain over the hoop after fitting the hoop.

I think mine might have been 2 fold, I was pounding decently hard to set the hoop which might have drove the chisel pretty deep into the block and bent it a little. I think peening it off center might have done it in especially with the chisel driven into the block...

On my first set of chisels, I soaked it in water and then peened. I recently read to just go for it instead so tried that which was a little stubborn so probably went with too much force.


The elves of Rivendell were into reparing broken blades like that. Otherwise I would write it off.

How's shipping costs there?

[Allan Speers]

Wow.


Maybe silver solder? JB Weld?

I'd try anything, before tossing a nice piece like that.


If all fails, maybe you could grind a new bevel, and turn it into a mini router plane. :)

[Mel Fulks]

I think Allan has it right. I recently broke a 1/4 inch beginner priced Japanese chisel. No good for demolition work!

[Jebediah Eckert]

You must return it to the fires Isengard.
Or it's pretty much done.

That is the best solution, but USPS won't ship to Mordor, too many problems with the Orks.

[David Wong]

I think mine might have been 2 fold, I was pounding decently hard to set the hoop which might have drove the chisel pretty deep into the block and bent it a little. I think peening it off center might have done it in especially with the chisel driven into the block...

On my first set of chisels, I soaked it in water and then peened. I recently read to just go for it instead so tried that which was a little stubborn so probably went with too much force.

I use to wet the ends of the chisel before setting the hoops, but after some internet "discussions", I decided that setting the hoops dry would work just fine. I do not set the chisel on a block when I set the hoops. I simply hold it in the air with my left hand, and hit the edge of the protruding wood with a hammer in my right. I try to have between 1 and 2mm of wood proud of the hoops. I lightly hammer the handle on an anvil to compress the wood before placing the hoop. Hoops generally have a thick and thin end. The thin end goes in first. If there are any burrs or rough edges inside the hoop, file them smooth. I use a hoop setting tool to pound the hoop onto the handle before preening.

[Brian Holcombe]

The hard steel is ahead of the break, so there is no way a bevel is going to hold on that stub.

Peening from the side with the chisel knocked into a block of wood is definetly what did it.

I don't hammer them into a block, I fit the hoop so that about 1-2mm of handle is exposed than I just peen around the edge of the wood to lock it in.

I have a cone shaped tool for knocking the hoops on.

File the inside of the hoop to remove any burrs that may prevent the hoop from installing smoothly. The shape of the hoop is made so that it compresses the wood as it sinks down onto the handle and naturally the wood should partially return to size after it exits the handle. If it won't drive onto the handle, some wood must be removed. I do this very carefully, takin slight shavings and testing the hoop as I go.


edit, looks like David beat me to the punch with near identical advice, hah.

[Chris Fournier]

As mentioned silver solder or brazing, I'd even consider TIG in my shop. Then of course you need to reharden and temper. Plenty of work...

[Stanley Covington]

Defective chisel. Return to retailer for replacement.

[Matthew Hills]

Defective chisel. Return to retailer for replacement.
Not sure that this was "defective".
When I got my Koyamaichi chisels some years ago, I set the hoops following the instructions on TFWW site.
https://www.toolsforworkingwood.com/store/know/setting_hoop_guide.html


They explicitly cautioned about the risk of cracking the chisel on 1.5 and 3mm chisels when setting the hoop. (they recommended holding in hand or making a hole in wood and supporting the bolster, rather than putting the blade into a block and whacking away. They also recommended against putting the handle into a vise (potentially knocking the blade off and onto the floor)

I will say that the Witchhazel handles on my chisels did not mush very well at all.

Matt

[Kees Heiden]

I always wondered if my Koyamaichi chisels were made with wrought iron or not. Well, this break certainly looks like wrought iron, the grainy structure is visible as far as I can see.

[Stanley Covington]

Not sure that this was "defective".
When I got my Koyamaichi chisels some years ago, I set the hoops following the instructions on TFWW site.
https://www.toolsforworkingwood.com/store/know/setting_hoop_guide.html They explicitly cautioned about the risk of cracking the chisel on 1.5 and 3mm chisels when setting the hoop. (they recommended holding in hand or making a hole in wood and supporting the bolster, rather than putting the blade into a block and whacking away. They also recommended against putting the handle into a vise (potentially knocking the blade off and onto the floor)Matt

The OP did not describe how he set the hoop, but judging from the picture only, and assuming he used a regular hammer and not a sledge, the failure appears to be due to a forging defect. It obviously cannot be repaired by welding or brazing without damaging the temper of a significant portion of the blade, ergo, the brand new blade is trash, and the OP has not received value for his money. The retailer should replace it if he cares about his brand reputation. Perhaps the trolls will come out now...

The Retailer will return it to the wholesaler in Osaka, who will return it to the blacksmith in Miki. This is SOP; All 3 parties are accustomed to dealing with such problems, and should not complain, even if it is the customer's failure. The retailer will not be out any money, but will have lost some time dealing with the return. Don't feel sorry for him unless he sold it to you at cost. Dealing directly with retail customer's problems is his yob, and how he justifies his markup. If the retailer won't replace it, then the OP is a dissatisfied customer that has learned something about the retailer.

Quality problems are not something to be tolerated, but corrected. Japanese quality of manufactured goods, including chisels, is high because, unlike consumers in many other countries, Japanese consumers do not excuse poor quality, but are offended and demand refunds or replacement.

[Frederick Skelly]

Quality problems are not something to be tolerated, but corrected. Japanese quality of manufactured goods, including chisels, is high because, unlike consumers in many other countries, Japanese consumers do not excuse poor quality, but are offended and demand refunds or replacement.

I'd definitely return it based on Stan's advice. He lives among the Japanese and understands their cultural values better than many of us ever will.

[george wilson]

JB Weld isn't going to even approach holding that chisel together. Do as Stanley says. It is a goner.

[Zuye Zheng]

Thanks for the feedback guys! First off, just want to be clear that the muck up is completely mine and 100% sure the chisel was not defective and looking back at it, I'm surprised something so delicate (3mm and shinogi profile) took so much errant abuse from me in the first place (I was using a 300g Japanese hammer, but going pretty hard).

And to Stanley's advice, much appreciated insight. In fact, the awesome vendor (who I will not name since I am unsure if they want the attention or not, but is easy to guess) actually proactively offered a replacement from seeing this thread and even knowing it was most likely my inexperience that caused it. Now that's service and commitment to your customers! However, knowing the screw up was mine and response from the vendor, I don't think I can in good conscience accept a replacement and have them eat the cost, but it is good to know there are companies out there who would do so.

Anyways, I had already decided when posting to take it as my own learning experience to never repeat so I attempted my own fix. Lacking any metal working experience or tooling, I JB welded it with a extra piece of metal at the split (you can stop laughing now, thanks), probably no where near its initial strength, but hopefully usable as a parer.

Also tried the whole hold and peen method and realized light taps will do the trick. At least one end of my chisel looks good (well maybe not to Stanley's or Brian's standards) now.

333721

P.S. I think I might have also been driving my hoop too deep, Brian mentioned 1-2mm, I've read 3-4 as well. Also from some eBay purchases of older chisels, I've seen peening that covers the entire hoop which would seem to require a deeper set, but maybe all that is required is enough to hold the hoop in place.

[Brian Holcombe]

That looks good.

Discard the damaged chisel, if it breaks in use (and it will) you stand a chance at very badly injuring yourself.

[Stanley Covington]

And to Stanley's advice, much appreciated insight. In fact, the awesome vendor (who I will not name since I am unsure if they want the attention or not, but is easy to guess) actually proactively offered a replacement from seeing this thread and even knowing it was most likely my inexperience that caused it. Now that's service and commitment to your customers! However, knowing the screw up was mine and response from the vendor, I don't think I can in good conscience accept a replacement and have them eat the cost, but it is good to know there are companies out there who would do so.

Anyways, I had already decided when posting to take it as my own learning experience to never repeat so I attempted my own fix. Lacking any metal working experience or tooling, I JB welded it with a extra piece of metal at the split (you can stop laughing now, thanks), probably no where near its initial strength, but hopefully usable as a parer.

Very impressive indeed! Both your forthrightness and the Retailer's response.

That is the sort of Retailer we should all do business with. He should be given all possible credit. If you reveal his name, it can only help (since you have already named the chisel manufacturer, don't forget).

BTW, anything but a full-pen weld (which would ruin the blade's temper) would not have adequate strength.

Despite the crazy things people claim, JB Weld is just epoxy with powdered metal filler. It can fill gaps and cracks, but it is not a structural repair material. I strongly agree with Brian: If you try to fix it yourself, you are highly likely to get a nasty cut on your hand when the chisel fails again. If the Retailer does not want the damaged chisel returned, then save handle, hoop and ferrule and toss the blade.

On second thought, instead of tossing the blade, you might want to grind it down to make a couple of marking gauge blades or splitting gauge blades. When you grind, keep dipping the blade in water to keep it constantly wet. When the surface water evaporates quickly, you know the blade is getting too hot and the temper is at risk, so let it cool. Also, keep the tip of your finger near the metal being ground. If it gets too hot to hold, the temper is at great risk and you should cool the blade. A pain, but temper is damaged long before you can see it as a color change.

Stan