Name For a Japanese Wheel

Stacy E. Apelt - Bladesmith

Stacy E. Apelt - Bladesmith

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I have had a senior moment, and can not recall the name for the large wheel used to grind Japanese knives. The only name that I can think of is ashi-hormono....or something like that.

The wheel is about 36-48" round and 4" wide. It revolves fairly slow and is water cooled. They are dressed with a special tool. An apprentice has to spend years learning to grind on one, and then more years learning to dress one. They are really hard to get, outside Japan.

I asked Dave Martell, and he said he has never known the name either.

Anyone know the proper name?
 
Kaiten Toshi - That's It!!! - Thanks Salem.
I'm not very good at Japanese, but kaiten means revolving and Toshi can mean anything from a part of town, to a year, to a reflection. I always took the term to mean "rotating sharpening stone".....AKA grinding wheel.

I was starting an ideas file for my project to build a belt grinder version of a kaiten toshi and could not pull the name out of my head. I must have seen a video from Ashi Hamano and that was why I remembered that name.
I thought of Murray, but asked Dave first.

The machine will be a water cooled 4X160" belt running on a 36" contact wheel, plus a 12" idler and a 12"drive wheel.
If I go to 48" wheel, the belt will be 4X200". I should be able to get high quality belts made up by Klingspor for about $30 each. A belt run at slow speed and water cooled should last a very long time. I am thinking 100, 220, and 400 grit.
Power will be a VFD driven 3HP 3Ph motor.
It will be heavily geared down ( 5:1) to turn the wheel about 300RPM max, and probably will get run at 100RPM for most grinding. That is a ballpark range of about 300 to 1000 SFPM.

Using the right name, I was able to re-find this build link:
http://forums.dfoggknives.com/index.php?showtopic=15046
 
Cool!!! that is really sweet. however, that sounds like a pretty expensive contact wheel.
 
That's funny Stacy, the same link Salem posted above.


I've seen that build wip & even though I don't do anything in that style, I really want to build one of those.
 
here this might help as i been wantign to build one too on the 36 x3 inch wheel size since the 48 would just be too massive to build right now (and the belt size as you listed)


ops re read and saw you foind the link
 
Yeah I've been keen on a project like this myself for a while.. Stacy how are you sourcing the contact wheel? You planning to make it yourself or have someone that's doing it for you? I ask because I'm in-capable of producing one myself, but would love to get one made if the price could land in the realm of reasonable. ;\


I've got a 3 horser and a KBAC 29 waiting for some fun.
 
Here's the wheels from Watanabe Blade. You can see his wet belt grinder too.
 

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The fellow in the Bladesmith's Forum Board thread made his own contact wheel. He fabbed it out of aluminum plate, set it in a ring mold, and poured a 2-part polyurethane tire around it. He turned it to size, spinning on it's own arbor. Apparently it runs very smooth.

I want one too... it's just sick. 48" hollow grinds? Are you kidding me? I know it's mainly for roughing scale and flats in, but still...
 
Ahh-so, Dave-san....... to-ishi, that makes more sense - water stone...thus kaiten toishi = revolving water stone.
An old proverb ( I believe it was even used by Po in Kung-Fu) - "Sometimes one looks so hard for what is hidden that they can't see what is in front of them."

I plan on making the wheel. I have several options. One is to laminate the wheel from some material and turn it to shape on its bearings, then cover it with a rubber tire. Another is to use a truck/bus wheel and tire,and its axle. I would sand the tread surface flat while turning the wheel. This would make a pretty good 30" or so contact wheel.
 
This sounds like a multi-year project. Just when we thought we'd see more of you because you have 30% better bandwidth, now you're planning to disappear into the shop to immerse yourself into kaiten toishi lore. :)
 
When I first saw that build, I wondered why he would try to bend a ring and weld it to a disc to make up a wheel instead of just turning one from solid aluminium.

Doing it that way created more difficulty in making it round and balanced.

Then I did a calculation to determine the volume and weight of a full aluminium wheel.

48” round by 4 inch width.
Radius squared x pi x width of the wheel
24x24 x 3.14
x4
=7235 cubic inches
X the density of al
x.098
=709 pounds
x the price of aluminium
x $4/ pound I pay here

$2,836 just for aluminium.
More if you start with flat stock and cut out the diameter.

I guess that's why.

If you know some backyard casters, you could cast up a nice wheel from scrap barbeques and small engines, then outsource the cleanup turning.

Aluminium would allow you to get it coated by a proper contact wheel vulcanization
(if they had the capability for that size)
and that would be $$$ too.
That would be the nicest though.


The slow speed of the wheel allows much more variety of materials in building it like MDF, but then the need to run it wet takes that away again.

I wonder if it could be made from MDF and then coated with fibreglass as waterproofing.
$200 in MDF, much more reasonable.


UHMW would allow you to rough shape it with woodworking tools like a bandsaw and router with circle jig.

Even UHMW would be about $1,000 for a piece that size.

There are surplus shops that sell cutoffs of plastics, but a piece that size is not likely to be there.
You could laminate it from smaller bits I suppose.


Using a truck axle and wheel seems like it would be really heavy & the frame would have to handle that too.
That weight would be really smooth and solve the tire issue of the contact wheel too.
It won't give you the full wheel size, or a sharp contact wheel edge either.

Do you have a farm equipment scrap yard close?

Spoked wheels from old equipment may work too.
Heck, peoople have those wheels sitting in their yards for decoration.
2-1.jpg

i2398.jpg


It has become popular for skid steers to use metal rims and solid tires.
8007-2.jpg
 
Or you could maybe fab a wheel from iron plate for less cost... it would be heavy, though.

I agree that this a sourcing problem most likely to be solved by a keen eye for rusty stuff and recyclable items. Fortunately, I've been cultivating that for years.

It also turns my mind to thoughts of whether I could possibly fab an iron rimmed and spoked wheel or not. If the water could be removed when not in use, and the wheel was painted well with even zinc spray over primer, it could last a long time.
 
The difference between steel and al surprises me too.

Steel weighs 3 x more
but al costs 4 x more

The difference isn't that much al is 4/3 the cost of steel

The big difference is outsourcing the AL welding.
 
Another possibility is DIY micarta, you could easily source the scrap materials for cheap, if you do the layup yourself. You'd spend a fair bit in epoxy, but if you buy bulk fiberglass resin you can get it for about $100 for 5 gallons or so. Although I have no idea how much you'd need.
 
That's thinking outside the box. About like building a surfboard in terms of goop factor....
Count, good point. Happily, I have the use of a nice Miller MIG welder with a spool gun so the Al welding wouldn't be a prob for me.
I need to quit thinking about this hypothetical build, and go make some knives and rebuild my forge instead.
 
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