Thank you for visiting my blog, in this series I am preparing a standard hira kanna for conversion into a hikouki kanna. When a new plane is made, in Japan, the parts are created by individual craftsmen who specialize in a portion of the process. The blacksmith’s task is to forge the blade, and sometimes the sub-blade or chip breaker, the blade is then afforded a basic preparation by either the blacksmith himself, one of his staff or a third party. Next the dai-ya makes the plane body to fit that blade and chip breaker. The dai-ya is so named because he cuts the dai, or plane body. Finally it is the job of the end user to complete the task, preparing the plane for use.
The dai-ya, using basic hand tools, quickly and accurately chop out the mortise and fit the blade. Dai-ya differ in their style much the same as blacksmiths and woodworkers each differ in their own style. Having worked with dai from dai-ya such as Inomoto-san and Nimura-san, I can see that each takes different steps to arrive at their result and each chooses how much effort they would like to leave for the end user to accomplish.
I have plans to turn this kanna into a hikouki kanna, or a plane with runners, but first I will be using it at Mokuchi’s annual Kezurou-kai, or planing competition, so I will setup the plane to compete. I will resume the conversion into hikouki in September.
The first step is to fit the blade into the dai mortise, I begin this process by applying graphite to the back of the blade and mixing it with mineral oil.
Then insert into the dai, tapping gently to seat it. The graphite rubs off onto the high spots revealing the contact areas.
This shows that the center of the bed is high, what I want instead is for the blade to be fitted tightly at the sides and at the bottom of the bed, supporting the blade along the bevel and clamping the blade at the sides.
I use a chisel to pare lightly the high spots, then repeat the graphite procedure until the desired fit and pattern are revealed.
This is beginning to look exactly like what I want, with, ideally a little more contact right behind the bevel. At this stage I will insert the blade and determine which side is offering more resistance. I will then lightly pare away that side. The goal I have in mind is to make the two sides equal so that the blade advances forward consistently when tapped forward.
Once good progress is made on that front, I begin adjusting the sides to create a slight clearance the blade to be adjusted side to side.
Once I establish a light clearance on both sides of the blade I can reinstall the blade.
Next I chamfer the leading inside edges of the osae-mizo (the side grooves) to prevent shavings from catching at the corners.
I have found it best to limit this chamfer to only a part of the side groove which extends past the blade’s mimi (ears) and so not to remove contact surface from a critical point.
This dai has been easy work, having a mouth and wear perfectly set right from Inomoto-san. For those unfamiliar, the ‘wear’ is the area of the dia immediately opposite the blade. As a shaving passes through the mouth it has the blade and chip breaker on one side and the wear on the opposing side. If the angle of the wear is too shallow the shaving will bind. If shavings bind rather than pass through the mouth unhindered, the first step is not to open the mouth, but to increase the clearance between the chip breaker and the wear. I do this by paring from the mouth toward the top of the plane, but without affecting the mouth opening.
I did not need to make clearance, but I’ve placed my chisel at the point at which one would need to make clearance.
In a western plane, with a properly set chip breaker, a tight mouth is somewhat unnecessary. In my experience with a kanna, however, I find a tight mouth more critical to the plane’s operation. An open mouth will allow the plane to snipe the end of the board, something that is quite undesirable on a finish plane.
The next step is to begin installing the chip breaker.
It is ideal for the cross pin to contact the chip breaker at the center of the chip breaker, and so I adjust the fit accordingly.
If the chip breaker is not even close I may have to examine the placement of the pin, then plug the current hole and move the pin. Or if the chip breaker doesn’t contact the pin at all, then it’s best to replace the pin with a larger size pin. However if they are both in contact but just too tight then I begin to make clearance.
These were contacting nicely, but initially I was getting contact across the full width of the chip breaker, I really only want contact in the center. I began to file the outside of the pin to create the additional clearance. A caveat being that filing the pin weakens it, however in this case the amount being filed is less than .010″, and Inomoto-san used a steel pin, so it’s quite sturdy.
I now show clearance on the sides and contact in the center.
The chip breaker is able to advanced with light taps from my brass hammer. I like the movement to be easy enough that advancing the chip breaker will not move the main blade, but not so loose that the shaving can push the chip breaker away from the edge.
I withdrawal the blades and move on to prepping the dai’s sole. Ideally a smoothing plane should make contact with the wood at two points, one point immediately ahead of the mouth and the other at the immediate rear of the plane.
The dai, being rift-sawn, has been sitting for a few weeks and has not moved or twisted as it acclimatizes to my environment. This is encouraging, as my usual flat sawn dai move enough with seasonal change that I notice.
Next I set 600 grit sandpaper ( I do actually own sandpaper!) onto the granite surface plate, and draw the plane toward me in one movement. I do not rub back and forth as I want the sandpaper to remain taught and flat to the surface of the plate.
The pattern reveals that the dai is very slightly cupped.
I continue to work the dai in this manner until there is contact across both points fully.
I then check for flatness with my straight edge to ensure that the work has been done properly. The dai is setup nicely from Inomoto-san, having been relieved lightly between the two contact points and between the front of the plane and the blade. However, this is not enough clearance and so I must create the additional clearance by scraping. The process of scraping requires another plane called the dai-naoshi-ganna, or bottom scraper plane.
The dai-naoshi-ganna has a blade which is bedded at about 85 degrees to function as a scraper.
The width of the contact points should be approximately 10mm of contact at the rear, and 6mm contact at the mouth. The dai-naoshi-ganna has 10mm of clearance between the edge of the blade and the side of the plane….perfect!
I scrape in the direction of the rays, as I point out here.
Before I begin scraping I will cut a tiny relief behind the mouth at the sides of the plane to ensure that they do not cause a clearance issue.
First making with a knife, then cutting with a chisel.
Now I can begin scraping, my first step is to clamp a piece of scrap maple at the end of the dai, which will allow the scraper to make a nice crisp line while utilizing the scraper’s built in clearance to create the exact width of contact that I desire.
I do not want a ledge, however, so I have cambered the blade on my scraper so that the cut feathers at the edges.
Ahead of the mouth, I want a smaller contact point. I created a fence which will allow me to adjust the contact point to be exactly what I’m looking for. I hold the fence in place as I scrape.
Now to create the hollow in the center of the plane I work overlapping strokes between these two points until I reach the dimension I am looking for, which is .004″ clearance.
I want the same, or more, at the front of the plane. When the blade is reinstalled, it will apply pressure to the bed, this will bulge the sole outward slightly which can lift the plane off of the work if it is not attended to. Inomoto-san has already taken care to scrape the area hollow.
My next step is to touch up the chamfers at the sides of the plane, they had some light tearout but I made sure to clean them up. I did this with a standard plane, as I do not have a 60 degree chamfer plane.
My final sole preparation is to burnish wax into the contact strips.
Now that the sole is completed, I can seal the end grain exposures on the plane with shellac with exception to the bed.
Finally I touch up the exterior surfaces to remove signs of handling. I use a chamfer plane and smoothing plane to complete this step.
And the result:
Next I set the blade. I find it helpful to sight down the sole of the plane to see how far the blade is extended, initially, and to ensure that the blade protrudes evenly. I’m pointing out here the uneven protrusion, I will tap the blade sideways to even it out.
Next I install the chip breaker, I utilize light coming through the mouth and reflecting off of the main blade to determine how far my chip breaker is from the edge of the blade. I want a fairly tight setting and I will continue to adjust after beginning to cut shavings.
Now to test my result. Proper clearance is visible where needed.
To test the plane I use a wide piece of material, I want to see if any issues will arrive in normal use. The first shaving is a failure, showing that it has caught at the edges of the blade.
Not to worry, however, the reason for this is that I have not cut clearance at the mimi (ears) of the blade. Ideally the chip breaker should be wider than the shaving, but I want as much blade as possible on this plane so I decided to adjust lightly after the fact.
After some grinding at the edges.
And now I can try again. This time it is a success, having cut a full width shavings on Honduran mahogany. I’m aiming for thin shavings that shoot straight out of the plane. I adjust my chip breaker blindly at this point, tapping at the edges until the chip responds properly as it does here.
And most important, the resulting surface created on the wood.
Thank you for following along with this marathon of a post, I hope you have enjoyed. I want to again thank my many mentors. Please comment below!