Re: Adjusting / sharpening handplanes
Moses Yoder in White Pigeon, MI
>Lee, at the gathering you asked me to tell you what you were doing wrong, and I never really took the time to look at what you were doing and try to give you some pointers. I don't really think that I know much about hand planes, but will post the few things that I have kind of learned and see if anyone can use it. It would be very time consuming to teach someone how to use a hand plane unless you already had a curriculum set up and were organized. So I will try to start at point A and work forward.
1) A number of things work together in a plane, but the main thing is the iron. (The "blade" on a plane is called an iron.) The rest of the plane is simply used to hold the iron in position. Several points on irons; a) the type of steel is important, but the way the iron is hardened and tempered is more important. This is why I buy Hock irons to replace my old Stanley blades. Ron Hock knows a lot about hardening and tempering steel, and I get very consistent and predictable results with his irons. b) The way the iron is sharpened is very important
2)Sharpening; a) It is very important to use a flat surface for honing the iron. If the edges of your honing surface ar worn down slightly more than the center, you will get a very slight (unnoticeable) curve upwards at the center of your iron, so the corners of the iron will be removing more wood than the center of the iron. This is undesirable for a number of reasons. If the center of your honing surface is worn down, you will get unpredictable results from honing, unless you use it as such intentionally (there are exceptions to every rule).
3) The honed surface of the iron should be a flat plane, not curved at all. If the tip of the iron curves upward slightly, the area immediately behind the edge can make contact with the wood before the front of the iron does, which will lead to thick shavings. I am referring to an almost microscopic detail; the very tip of the iron only makes contact when it is extended a small distance from the bottom of the plane, which then pulls it down into the wood, making thicker shavings than a properly honed iron.
4) The back of the iron, up to the tip of the cap iron, needs to be polished to the same degree as the honed front edge of the iron. In my opinion, the first time this is done will take some time to achieve correctly. I think a water stone tends to dish out too fast to actually flatten the back of the iron, so I am using 150 grit drywall screen on plate glass for the inital flattening, then 220 grit sandpaper on glass, then final honing of the back on the water stones.
5) The toe, heel, and area in front of the mouth of the plane needs be on a flat plane (the "sole" of the plane) . In my experience with Stanley planes the problem I have found most often is that the area that is milled out behind the mouth for the front of the frog to contact is bowed down slightly. If you set a straight board on edge in a vice, then retract the iron on the plane, set the plane's toe on the edge of the board and push it forward until the back of the mouth hits the end of the board, just like you were jointing it. Often times you will feel a slight "bump" when the back of the mouth hits the end of the board. This means that the iron has to be extended further than it should be in order for the plane to make continuos contact. It will start to plane a bit, then the area behind the mouth raises it up out of the wood. If the iron is extended slightly further so it protrudes under this slightly raised area, the plane will appear to be working fine but will be unable to take a very thin shaving. This is why it is very imortant to flatten the sole with the frog and iron installed. Again, it is not necessary for the entire sole ot the plane to be flat; just the areas that count.
6) The iron needs to be held securely. If the frog is not bedded correctly, it can bend down slightly from the pressure of the iron biting into the wood. An iron that moves from the pressure of hitting the wood will lead to frustrating results. This will also prevent it from taking thin shavings.
7) Adjusting the plane a) It is beneficial on cast iron bench planes to make sure the area of the frog that the iron contacts is smooth and also waxed. I smooth mine as much as possible without removing the lateral adjust lever, and then wax the frog with paste wax. I will generally wipe a little bit of wax onto the iron when I hone it, so it will adjust smoothly. b) To the point of the original question, I think theoretically it is probably impossible to eliminate "backlash". In both wooden bodied and cast planes it is normal to adjust the plane by extending the iron, not by retracting it. If you retract the iron and then plane, it will almost surely be pushed back into the plane when it first hits the wood. I adjust a plane by first extending the iron until it "feels" close to right by running my thumb front to back over the mouth of the plane. I then run it it over the board at the edge of the iron, checking both sides of the iron to see if either side hits. I then make lateral adjustments until both sides of the iron appear to be taking the same thickness of shaving. If I need a thinner shaving, I can then retract the iron slight into the plane, and then adjust it forward until it is taking the shaving I want at the center of the iron.
This is of course not the final word on planing, and I think the lever and gears used for iron adjustment is one area where planes could be vastly improved if someone thought they could make money by selling a better plane. But in my opinion, modifying the standard cast bench plane to try and eliminate backlash would be an excercise in frustration. Two books I would highly recommend are David Charlesworth's book that has a section on tuning hand planes (I would buy this book over any other) and Garret Hack's book "The Hand Plane Book", which covers a large number of different planes and how to use them.