PDA

View Full Version : Adjusting machi gaps



labor of love
05-29-2013, 05:05 PM
Hopefully this is the right place to start this discussion. I was wondering if machi gaps can be adjusted on certain gyutos? As in, can you simply push the blade further into the handle to close the gap? Suisin inox honyaki, is the knife I have in mind. I used to own one, but the gap was super uncomfortable for me and i always seemed to catch my hand of the gap, even after rounding it. I've been considering repurchasing one soon, just curious if this possible. Thanks.

Pensacola Tiger
05-29-2013, 05:12 PM
Pushing the tang further into the handle to reduce the machi will usually result in a split handle. The solution is to take the handle off, enlarge the hole, and then epoxy the handle in place.

Marko Tsourkan
05-29-2013, 05:15 PM
If the handle is not glued in, the tang can be forced deeper, closing the gap. If it's glued in, you are out of luck.

Whatever J. makers' explanations (aesthetic, regional, functional, balance, etc.) I personally see an open gap as a skipped production step. Squaring machi, once the blade is ground, is not an easy thing to do.

Often top and bottom ends of the machi are uneven and need to be squared. You can file or grind depending whether that portion is hardened or not (monosteel typically hardened and kasumi, not).

Best way to do it is to employ file guide.

M

skiajl6297
05-29-2013, 05:22 PM
Is there any purpose to the gap? I borrowed a knife I would have otherwise loved, but genuinely loathed the feeling of that gap, as described by labor.

Marko Tsourkan
05-29-2013, 05:25 PM
There is no purpose one can logically think of. Wabi Sabi perhaps?

tk59
05-29-2013, 05:32 PM
I doubt it's wabi sabi. Unquestionably top notch makers leave a gap and they are generally squared, too. It is clearly done on purpose and carefully, too. That said, I've never like the gap.

JBroida
05-29-2013, 05:35 PM
there is a purpose... its about finger spacing and handle installation

DevinT
05-29-2013, 05:41 PM
Jon, is it partly to have the ability to tighten the handle over time?

Hoss

JBroida
05-29-2013, 05:44 PM
yes... sometimes handles are removed and replaced (the same handle), and the extra space is very helpful.

Seth
05-29-2013, 06:23 PM
On single bevels it is to allow for sharpening the back side without running into the handle. You can ask the retailer to pick one with a small machi which I find to be aesthetically okay. The large gaps drive me nuts and look like crap. I requested this once and got a yanagi with no machi which looks almost as weird.

orange
06-06-2013, 12:50 PM
yes... sometimes handles are removed and replaced (the same handle), and the extra space is very helpful.

Could you elaborate a bit more?
I have been puzzled about the role of machi ever since and I have not been able to find a satisfying answer yet.
I can't imagine how the extra space is helpful for handle installation.
What is the downside of having a tang without the machi?

Pensacola Tiger
06-06-2013, 02:18 PM
Could you elaborate a bit more?
I have been puzzled about the role of machi ever since and I have not been able to find a satisfying answer yet.
I can't imagine how the extra space is helpful for handle installation.
What is the downside of having a tang without the machi?

First let's get on the same page about what the term "machi" refers to. Gator (in his website ) defines it as:
Machi - Narrow section of metal between the notch at the end of the neck of the blade - L on the Diagram, emoto(K on the Diagram) and the handle, approximately 5mm long. Found on many Japanese knives, never on western knives.

http://zknives.com/images/knives/kitchen/jbladeant.jpg

So, if the emoto is flush with the ferrule, there is no exposed metal, and no machi.

So why are handles installed leaving a machi? The hole in the handle is purposely undersize so the tang is burned in to the handle as tight as possible, and leaving a machi ensures that the tang has been burned in as far as possible. If the emoto is flush to the ferrule, you can't be sure it is burned in properly. And, as Jon said, it makes removing and replacing the handle easier.

Note that this doesn't apply to handles that are glued on to the tang, as is common when a custom handle like those from Stefan Keller or Mike Henry are installed. Nor dosed it apply to some of Marko Tsourkan's handles that are painstakingly fitted to the tang with a friction fit.

Rick

orange
06-06-2013, 10:05 PM
So why are handles installed leaving a machi? The hole in the handle is purposely undersize so the tang is burned in to the handle as tight as possible, and leaving a machi ensures that the tang has been burned in as far as possible. If the emoto is flush to the ferrule, you can't be sure it is burned in properly. And, as Jon said, it makes removing and replacing the handle easier.



Rick, Thanks a lot for your explanation.
Yet, I am still not fully understood why they have the machi; Please bear with my ignorance;
I am just having a hard time to fully appreciate the functional advantage of having the machi.
Basically, I can't understand why the machi makes the removing and replacing of the handle easier.
And why can't they know if a tang is burned in fully without the machi??

I can appreciate if someone says the cut out of metal from the tang making the notch helps weight distribution, thus, balance.
Even so, I think they can achieve the same goal by adjusting the shape/3-d geometry of the tang.
A Shige yanagi that I have does not have the machi. I don't know the shape of the tang inside the handle (if or not it has the notch)
but apparently they do not think that the machi is needed. How come??

I don't mean to sound rude...just try to understand.
If someone says that it's how they had designed the tang area (tradition), I am fine with it. ^^

Karl

Dave Martell
06-06-2013, 10:52 PM
So I have no idea why Japanese makers leave an exposed tang (machi) showing but I can tell you from my own experience burning on handles that if you burn the tang so far into the handle (all the way) flush with the emoto(?) blade notch the handle will be loose, as if the slot gets burned and widened too much. If you stop short of full insertion the handle will be snug, then with a light rap on the bottom of the handle it will be well seated and not easily removed and definitely not loose in anyway. So it's possible that they stop short of driving it home so as to get a secure fit but like I said I have no proof of this, just my own experience.

orange
06-07-2013, 12:17 AM
So I have no idea why Japanese makers leave an exposed tang (machi) showing but I can tell you from my own experience burning on handles that if you burn the tang so far into the handle (all the way) flush with the emoto(?) blade notch the handle will be loose, as if the slot gets burned and widened too much. If you stop short of full insertion the handle will be snug, then with a light rap on the bottom of the handle it will be well seated and not easily removed and definitely not loose in anyway. So it's possible that they stop short of driving it home so as to get a secure fit but like I said I have no proof of this, just my own experience.

Interesting point. Thanks Dave!!
In fact, I read something similar from a different source that when a knife is used its handle may become loose over time. If this happens, one can just tap the bottom of the handle to tightly fit.
But then again, even without the notch (thus, machi), if the tang is tapered, then we would expect the same tight fit, wouldn't we??

JBroida
06-07-2013, 12:57 AM
It's about finger spacing with how your middle finger fits under the neck of the knife and In between the handle

orange
06-07-2013, 02:01 AM
It's about finger spacing with how your middle finger fits under the neck of the knife and In between the handle

Yes Jon, I do understand that part.
The question is why Japanese makers cut out the part of metal from the tang resulting the notched area (machi).
I somehow can not relate the cut out of metal to the ease of handle removal/replacement
So, what is the downside of not cutting out the part, thus, no machi??
A Shigefusa yanagi does not show the machi (maybe it's hidden in the handle?).
They apparently did not think of the need to have the machi (the notch) for the space under the neck of a knife for our middle finger.

JBroida
06-07-2013, 02:24 AM
it is possible to find shigefusa knives with a machi gap fwiw... now days, a lot of stuff for export is made with no machi gap just because they know thats what foreigners like. no machi can present a problem with tang size relative to knife size on certain knives, the wider tang area on knives with no machi can sometimes cause wood to split, the machi helps align the spine of the knife with the handle for comfort, etc.

maxim
06-07-2013, 05:40 AM
Nope, Shig done it long time before with machi but now all he makes is without it. To Japanese too :D

As i understand from him handle is much more prone to crack at the horn when its sits flush without machi. It is nothing to do with export and foreigners
He still sell most single bevels in Japan

Edit:
i just took a look of some oldest Shig that i have one 30 years old and another 40 they are without machi as well. So i dunno maybe you seen Shigs that was rehandled by other ? :O

JBroida
06-07-2013, 02:57 PM
Maybe... there are a number of wholesalers who deal with his stuff, so that might have been it. I've seen more than a few though.