Using a Kanaban and a 1-2-3 Block to tune a plane

This is a 1-2-3 block on a kanaban.

A 1-2-3 block is a very stable tool used by machinists to make sure things are square and precise and all sorts of other things.  It measures 1″ by 2″ by 3″ and is great for testing, setup and even measuring.

The Kanaban is a nice thick slab of precision ground steel.  With these two tools, things can be fairly quickly and cheaply made flat and square.  Mine is a 10″ by 18″ by 7/16″  slab of O1 steel.   I plan to cut it into three approximately 6″ by 8″ slabs.  They will be more than large enough for most of my work.   With three of them, I will be able to true them to flatness by grinding them against each other.

First you want to make the primary surface flat.  Here is a block plane body being ground with 80 grit Aluminum Oxide grit.

Here I am checking the Body and the mouth in the middle of the process.

This suction pattern that forms when you lift the plane can give clues about how flat you have gotten the sole of the plane.  Here I am using water as a lubricant.

One good way to test is to clean the plane, and then mark it.   In this case I used High-Spot.

High Spot is good for testing large surfaces, but it is a mess, always.

After some grinding, it lets you easily see where the low spots are.

For a small subject like this plane, a permanent magic marker works as well, and is much cleaner.  I had the high-spot out and handy from testing the flatness of my kanaban, or I would not have used it on the plane.

Once you have the sole and mouth bottom flat, you can then use the 1-2-3 block to make things square.

Here is the mouth held against the side of the 1-2-3 block to make sure the mouth is square, side to side.

See the spots of blue on my fingers, High Spot does not come off easily either.

Here it is with the sole of the mouth against the 1-2-3 block making the mouth square across the depth of the mouth.  By sliding the mouth over grit on the kanaban and keeping the 1-2-3 block still, the block is not altered while the plane mouth is precision ground.

Here is how the side of a plane can be made square to the bottom.

Again the block is not moved, while the plane body is.

Here is the plane sole being polished on Linde B.  Note the flaw in the kanaban.  This was caused by me when I was parkerizing the O1 steel plate to make it a bit more weather resistant.  The line is where the five gallon bucket was not deep enough to totally immerse the kanaban in phosphoric acid.  Since the line is etched into the surface, and the surface is still flat, it does no harm at all.  In fact, it seems to help.

I did something rather odd, when I ground this particular plane.  I went from 80 grit aluminum oxide straight to 0.05 micron aluminum oxide.  This means the sole of the plane, while being quite smooth running on a the surface it is planing, will not appear to be polished at all.  On a blade surface, this would be a bad idea.  The irregularities would lead to an inconsistent edge.  On a plane sole, it may actually be a superior.  A plane will lift more easily if a vacuum is not formed while it is slid along a smooth surface.

Flattening a blade on a kanaban is fairly fast, easy and precise, but you still have to run through the grits and polish it.  Here I am using baby oil as a lubricant.

The bed, I had to file carefully by feel and eye, testing with high point and a flattened and squared blade.  I still haven’t figured out a perfect way to hand grind that angle.


11 comments to Using a Kanaban and a 1-2-3 Block to tune a plane

  • Skip J.

    Hmmmnnn… diamond paste on a steel lapping plate… sounds familiar, maybe I need to get my camera out????


  • In this case I am using aluminum oxide instead of diamond. It is a lot slower, but I am still deciding if I want to bed diamond grit in the big kanaban. The problem with diamond is that the largest grit you bed into a plate sets the grit for the plate. Aluminum oxide grit on a kanaban still works pretty well.

    What you have and use is faster and ideal for sharpening, but not really large enough for tuning a plane.


  • Skip J.

    Thanks Bob;

    You got that right. Mine is just right for blades though.

    So this is the same grit lapping idea, but on a larger scale and not diamond “intensive”. I have some large soft steel plate I could cut up, but it’s not quite flat…. I will say scary sharp sure does roll loose grit under a metal plane sole and cause problems; it makes rehabbing a woodie a lot more attractive than metal planes….


  • Cast iron griddles and pans can be flipped over and ground flat to do a great job. However the grinding takes an amazing amount of time.

    I just bought the precision ground O1 plates from Victor Machine so that I could skip the process.

    Multiple large plates with different diamond grits might be nice someday.


  • Skip J.

    Quote:”Multiple large plates with different diamond grits might be nice someday. Bob”

    Oh my,….. now you’re talking bigger plates than DMT’s for large planes – and a larger selection of grit sizes, down to very small grit – that’ll last a long, long time – for considerably less money. You mite need to work up a business plan on this one…. well, it had to happen someday I guess… congrats!


  • incanopy

    Where do you get your AlOX 80 grit powder from?

    I ask because I haven’t had great luck doing my course blade shaping using 325 micron diamond paste on a steel kannaban. The diamond does cut very quickly at first, but it also goes away fairly quickly, even if I rub the diamond into the kannaban using the flat side of an old O1 blade. That makes the process not cost-effective.

    In any event, I’m in the hunt for a cheaper abrasive powder to try for course grinding. The classic choice is silicon carbide, but since it breaks down so quickly, I would like to try AlOx as well.


  • Lapidary supplies are good sources for a lot of different grits., are a few that I turned up with a web search.
    An important note on grits. Pressure destroys grit faster. Often a lighter pressure will slow you down in the short run, but the retention of grit will speed you up over the long run.
    There are two types of abrasive diamond crystals normally sold. The most common one sold these days is the friable diamond grit. It fragments easily. As a result it gives constant sharp edges, but it reduces in size quickly. Pressure will speed this process. The other crystal is more like a diamond ring. Not as sharp generally, it dulls instead of breaking. It still processes quickly, and it still lasts a very long time. It still dulls eventually. Here is a bit more data on this sort of thing.

    I prefer a good aluminum oxide to silicon dioxide grit for most things, it is more economical. Another good place to search for grits would be blast media used for sand blasting.


  • MarkL

    I have to mention, you’re using an abrasive on a flat steel surface plate to grind true another steel surface. Over time low spots will develop and the surface plate will become dished and will no longer be truly flat.

  • Bob Strawn

    You are correct. That is why I keep three plates to grind against each other. With three plates, you can remain flat.


  • Bernadette

    Thanks for this post, I have loose grit on hand from Lee Valley and after having worn out a plate of glass I got to start with, I was looking for a more permanent solution- I dislike disposables! Can you detail the three plate method of keeping everything flat?

  • Bob Strawn

    with two plates you can grind a matching surface which can be like a ball and socket. One concave and one convex. If you don’t rotate a few degrees every so often, you can get convex on one axis and concave in another. Whatever is the path of the least resistance is what happens. If you rotate among three surfaces and rotate in the directions ground, you will end up with concave grinding concave and convex grinding convex so that flattening occurs.
    If you take a ruler with a straight edge and check across a plate you can see where light is allowed under the ruler and determine the shape. When using grit, you can also see where the fine grit is left alone and figure that that is shallow. If you match grinding high against high, with three plates, you will end up with flat faster.


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