putting a camber on hand plane irons

[Avenida]

I am new to the Tormek, and I really like it. I use for sharpening all my woodworking tools.
As a newbie, I would like to add my 2 cents and perhaps have people comment on my technique.
for the most part, I followed the manual, which to be honest, lacks a bit of detail perhaps because the makers of the tormek rely on the art of sharpening as a skill and not so much as a process.

Long story short, when I first got it, I read the manual and did what it said, or I THOUGHT I did... my blades came out with a very small concave angle, this was not obvious until you bring a square to the blade, and later on, when I tried them, the blade would take deeper cuts on the edge.

That is when I realized that, whatever I was doing, was wrong and needed to review the manual.

I did, and more concave angles resulted but the problem was mostly my technique...

This is how I do it:

I start by marking the blade with a sharpie, I run the blade and the stone by hand and look for a the grinding pattern to be as close to the centre of the blade as possible. for 2+ inches blades I have never been able to get the stone to ground the entire blade, so making sure it starts from the centre, however long that might be, it is key for a straight edge.
Then...
I simply spend more time on the edges. What does that mean? that I take 2/3 of the blade off the stone and grind with light to medium force on the corner for 3 seconds, and then I slide towards the other corner and in the next step is the key to convex edge:
You can't spend 3 seconds in the transition from Left to Right (or the same time you spent on the corner), because if you do, the centre will be grounded at the same rate than the edge but it is exposed the Stone also twice as much when you change directions. In other words, if you spend 3 seconds on the corner, you gotta move fast to the other side, ground that corner and change again fast. If you take 1 second in the centre as you move accross, that accounts for 2 seconds from the time you left the corner to the time you returned to the same corner. The center of the blade gets more time as you travel through it, that is the nature of the process.

A basically count until 4 when I reach the corner, at 4 I transition to the other side not taking more than 1.5 seconds or 1 second.

This might seem very fast at first but this is how I achieved good results and no convex edges!

If someone has a better method please share it.
I will try to perhaps shoot a video of my process if that is allowed in this forum?

[MikeK]

Unlike others, I use the Tormek only for establishing the primary hollow grind on my chisels and plane irons.  I use water stones for the secondary bevel and final honing.  This is a system that works well for me, and I see no reason to change.  My instructor was David Charlesworth, and he posted a video about using the SE-77 for establishing a camber on plane irons, but in practice, he uses the water stones.  I could never get the SE-77 to establish a repeatable or satisfactory camber, so I don't even try now.  However, I use the SE-77 for all of my primary bevels because the small adjustments allow me to accurately dial in the grind across the iron or chisel.

My process for establishing a camber in a fresh plane iron is to grind a uniform 25-degree primary hollow bevel across the width of the iron.  I use a sharpie to monitor progress and ensure I'm still grinding square to the iron.  I'll stop when about 0.5mm of unground iron remains at the edge.  I use the water stones for this last bit.

To aid in keeping the camber even across the iron, I divide the edge into four sections and put an index mark at each quarter of the iron with the sharpie on the side I'm not grinding.  I also use the Lie-Nielsen honing guide during this process.

I use a freshly flattened King 800-grit water stone to establish the secondary bevel camber at 33 degrees (25mm projection on the LN guide).  I work the outer edges of the iron first, and then move into the inner sections when I'm satisfied with the outer edges.  A 1cm wide strip of 0.5mm thick shim stock along the edge of the water stone helps start the camber.  I'll grind one edge of the iron by keeping the other edge on the shim stock.  The water adhesion between the stone and the shim keeps in in place as I work the other side.  As soon as the sharpie mark is removed at the first index mark, I move the shim stock to the other side of the water stone and grind the other side of the iron.  When I'm done, the ground side of the iron will have two narrow wedges of freshly ground edge, with the widest part at the edge of the iron and the point of the wedge at the first index mark in from each side. 

For a new hollow grind, this process takes between 8 and 20 firm strokes on the 800-grit stone, depending on how firm my firm stroke is.  As the iron requires resharpening, this can take more strokes since the secondary bevel area is increasing with successive sharpenings.  After eight or so sharpening sessions, I go back to the Tormek for a new 25-degree hollow grind.  This takes less time than the initial hollow grind since the hollow is already formed.

I then flatten the water stone again, remove the shim stock and start on the inner portions of the iron.   I use firm pressure on one side of the iron, on the inner indes mark, and take four to eight strokes on the 800-grit stone for each side.  I check the progress of the grind to make sure the sharpie mark disappears uniformly and converges on the center index mark.  When I'm satisfied with the grind, I go to the 10,000-grit stone for the final honing bevel.

I use the nagura that came with the 10,000-grit stone to establish a fine slurry of paste on the stone.  I set the angle to 35 degrees (22mm projection on the LN guide) and make four to eight strokes down the stone.  I apply light pressure on the edge of the iron starting on the left and progressing to the right as I complete one stroke.  It doesn't take much effort for this and the rocking motion side to side is barely noticeable; however, it does make a difference on the iron.  I use a 10X loupe to check my progress and ensure the honing bevel is uniform across the iron.

When I'm satisfied with the final bevel, it's time for the Ruler Trick (only for plane irons...never chisels).  I use a 6-inch steel rule along one edge of the 10,000-grit stone and polish the back of the plane iron to establish a microbevel on the back.  You can search for the Ruler Trick to see the details.

As Ken wrote, my bench planes, with the exception of my LN #51 Shooting Plane, have cambered irons.

[Ken S]

Avenida,

I believe the culprit may be the hand pressure you are using. The SE-77 makes camber control possible; it does not make it automatic. Before the SE-77, I used to extend the plane blades further and use "English" (varying hand pressure, heavier near the two edges. Frequently checking with a small square, it was possible to obtain adequate edge camber. Especially with the jack plane for initial rougher work, this rougher method was more than adequate.

Alan Holtham did some excellent videos for Tormek. I love his use of the word "fiddly". The SE-77 can be fiddly. It can be quite versatile, however, obtaining this versatility takes some practice. Having a spare blade and some quiet time help.

Mike, I hold David Charlesworth in very high regard. I was just getting ready to purchase his DVDs when my wife and I became very involved in caring for our grandchildren. That essentially retired my woodworking. I believe following a master is a good way to learn, and David Charlesworth is certainly a very good mentor. Without questioning his methods, I would say that his are not the only good methods. For aa good second opinion, I would recommend Christopher Schwarz. Chris discusses at length the reasons for different amounts of camber, depending on the function of the plane. A jack (or fore) plane, used for the initial heavy planing, would have a lot of camber to lessen the resistance between the plane blade and the wood. The blade should be sharp, but precise shape is not important.
A long jointer plane is used to straighten edges. The amount of camber is considerably less than with the jack plane (about .005"). If it was very slight (.001") like the final smooth plane, creating a straight edge would be a very slow process.

Once you become fluent with the SE-77, you will be able to make very nice cambered edges.

Incidentally, should you want to combine methods, I would reserve David Charlesworth's fine method for your best smooth plane and, if you have one, a panel plane. Try using the traditional Tormek method with your jack and jointer.
You won't be disappointed.

Ken