My first Dai

[thumbsucker]

I managed to get my first ever Dai. It was a cheap ebay score, I am told the Dai dates from the 1950. The Kanna is superb. It took a little bit of cleaning up the back and the bevel. It took an amazing sharp edge, much finer, then any of my O1, D2 or M2 blades. Its edge retention seems to be marginally better then O1.

The dai however is not in such great shape. It has a two cracks at the back edge of the mouth. I will have to make another dai asap.

I however have a few problems. My dai is ones without the wedge. It is an amazingly interesting design.

I have the following problems:

My blade was lose in the dai. Which caused my blade to project to far out of the mouth, before it would secure/wedge tightly into place. It could be that the two cracks are opening up causing the blade to project to far down the throat. So I used some paper tape on the bed of the plane body. This tightened up the throat and the blade now is a tight fit. Is this problem a common problem with this style of Japanese planes, and how is it usually fixed?

My second problem is that the bed is at about 40º. I used some assorted Australian hardwoods, and the plane tore the living daylights out of the wood, huge chunks. I then used the plane on some Douglas Fur scarp which was the only softwood that I had on hand and the plane did a nice job, giving me a polished waxy surface. I known the Japanese mostly work softwoods, am I just asking the plane to do to much using it on Australian Hardwoods. I suspect that this problem will resolve itself if I made a new dai with a 60º bed.

The third problem is that I am having trouble setting the blade projection for a supper fine cut. I can get a course cut, and a medium cut. However when I set the blade for a supper fine cut, all I get is dust, at best. What am I doing wrong? I have a full set of HNT Gordon's and I am used to taking fine cuts with wooden hand planes. But I am having some trouble with this plane.

Some questions:


Is it sacriliguis to hollow grind a Japanese plane blade?
When pulling the plane, I found that placing two fingers in the breast I was able to control and pull the plane better. IS this good form?
I had a short piece of scrap, shorter then the space between the two high spots of the sole. This causes the toe to drop of the front edge before the second bump. Would this not cause the face being planed to become convex, matching the concavity on the sole of the plane. Is this a problem and I how do I plane short stock with a Japanese plane? outside of using a smaller dai.
Do the Japanese add a crown to their plane blades to avoid the train tracks on the wood?

[BobL]

Pics?

[thumbsucker]

I do not have a camera at the moment.

[Sheets]

Hi Thumbsucker,

Well, you are off to a typical start for someone using a Japanese kanna for the first time. Rest assured, your questions are quite answerable.

First, having a blade loosen over time is common. After all, the dai gets worn and the kanna does too as it gets sharpened, so having the right amount of material to keep it tight (right at the point the edge meets the throat opening) over its life time isn't likely. So using a shim (usually of paper as layers can be added to increase the thickness as needed) is the usual fix. Having cracks in the dai can also cause the wedging effect to become less effective.

Second, a shallow bed angle vs some types of hardwood is a known problem, so you will not have any success with some types of wood.

Third, there are a couple of things likely causing your inability to get a nice thin shaving. First is the sole of the dai not letting the blade project at the right distance and still meet the wood surface for a fine cut. If you check the various sources on tuning a dai, you should be able to discover if that is a fault. The other likely problem is the throat opening is too big (due to the worn state of the sole). Even with a correctly tuned dai, the throat opening has to be very narrow to achieve a fine shaving (especially without use of an osae-gane [chip breaker or sub-blade]). As the dai sole gets conditioned, wood is removed, so it follows that the throat will widen. Sometimes, it is closed up by adding some wood across the sole in front of the throat (a temporary fix, as this wood will also get worn away as the sole continues to get conditioned) or by using a sliding dovetail key (kuchi-ire) in the slope opposite the blade bed. As the sole gets worn, the key is just tapped down to make the throat narrow again. I've attached a pic of a dai with kuchi-ire (courtesy of Japan Woodworker.com).
Here's a link for conditioning: http://www.japanwoodworker.com/newswire.asp?month=3/2004

As for making a new dai, that will solve many problems: you can get the kanna tight without a shim, make a nice tight throat and you can increase the blade angle to be of more use on you usual woods. You can also make it with an osae-gane (chip breaker) if you wish. Contact So at Japan-Tool.com (not all that expensive). He can get you one the correct size for your kanna if you wish.
There are lots of pics of dai making here: http://www.daikudojo.org/
There aren't any specialty tools required (chisels, saws) and while fairly straight forward, obviously, accurate measurement and precision work are necessary (like most things).

While I'm not an employer of hollow grind myself, some people do it on Japanese tools (just be careful of heat).
As to planing form, do what feels best for you (try different positions - said the parson to the young man). Usually, it is finding the correct balance between pressure ahead of the blade and behind it as well as laterally.
Planing short stock is better with a short dai, but it can be done with a large one being conscious to pull the plane straight out when finishing the cut (you almost have to think of lifting the nose, which you do, just to keep it horizontal coming off the piece, while putting pressure on the dai behind the blade at that point). The hollow in the sole should not be so large anyway, as to make any concavity or convexity if you are pulling straight.

What do you mean by your last question about a crown and train tracks? I don't understand.

Steve

[thumbsucker]

Hi Steve

Thanks for the link on conditioning a plane. It will come in handy when I make a new dai. Which seems to be the way to go.

I had a look at the opening of the mouth. It is almost 2 mm wide. I think this maybe the cause of the fine shavings problem.

A crown is when you add a very subtle and imperceptible curve or camber to the leading cutting edge of the blade. See this article (http://www3.telus.net/BrentBeach/Sharpen/scrubsharp.html) and video (http://www.taunton.com/finewoodworking/SkillsAndTechniques/SkillsAndTechniquesArticle.aspx?id=29711).

[Sheets]

Ok, now I see. Yes, they add a very slight "crown" to avoid leaving marks from the corners of the blade.

Also, 2 mm isn't all that big, so I suspect the fault will be with the condition of the sole mostly.

What size is your kanna? (at the cutting edge). I ask because if you make a new dai and steepen the blade angle, if its a wide kanna, it will be more difficult (power-wise) to pull. Not so much a problem for finish planing, but if you intend to remove a fair amount of wood, it is easier with a smaller kanna.

Steve

[thumbsucker]

Ok, now I see. Yes, they add a very slight "crown" to avoid leaving marks from the corners of the blade.

Also, 2 mm isn't all that big, so I suspect the fault will be with the condition of the sole mostly.

What size is your kanna? (at the cutting edge). I ask because if you make a new dai and steepen the blade angle, if its a wide kanna, it will be more difficult (power-wise) to pull. Not so much a problem for finish planing, but if you intend to remove a fair amount of wood, it is easier with a smaller kanna.

Steve

Steve, Thanks for the help.

I want to make a super smoother from the kanna that is why, I want a 60º bed. Its only a 50 mm blade.

I will post back when I a ready to make the dai. Then we can fine tune the dai as I go.