A GREAT MANY men who use as common a tool as a plane cannot do a good job in keeping the tool in order. It is quite a knack to sharpen a plane in good shape, especially to set an edge on the plane iron with an oil stone. Figs. 1 and 2 show how to do it, and how not to do it. Supposing the plane iron has just been ground: it is placed upon the oil stone in the position shown in Fig. 1. The bevel of the tool is brought to bear flat upon top of the stone, then the back of the bevel is slightly raised, perhaps two or three one-hundredths of an inch, and while in that position the plane iron is carefully moved along the stone from end to end. The required pressure is applied by the finger, care being taken not to give the plane iron too rocking a motion.
Some mechanics fall into the habit of moving the tool as shown in Fig. 3. This motion is fatal to good work, and makes the bevel of the tool as shown in Fig. 4. The bevel is supposed to commence at a and should run nearly flat to b. Instead of this it is rounded, and as a good mechanic would term it, “is as crooked as a dog’s hind leg.” Fig. 5 shows a tool that has been whetted many times upon an oil stone and is ready for grinding. The bevel proper extends from a to c. The effect of the oil stone is shown from b to c, where the secondary bevel has been formed. This is the correct way to whet a plane iron. It should not be done as shown in Fig. 6, which represents the type of plane iron known too commonly among careless workmen.
Fig. 7 shows a plane iron that has just been ground, the bevel being sharp and clean from c to d. When the tool is placed on an oil stone it should be held in the position shown in Fig. 1, and in larger view in Fig 8. In the latter cut a represents the plane iron and b the stone. It will be seen that there is very little difference between the heel of the plane iron c and the stone. As the tool is used and the sharpening must be repeated it is necessary to raise the heel of the bevel more and more each time the whetting is repeated. After the tool has been sharpened a dozen times it will occupy a position on the stone shown in Fig. 9. Here it is seen the actual cutting bevel of the tool has become more stunt and the heel e is raised considerably further from the stone. When a tool gets whetted down as stunt as shown in Fig. 9, it should be taken to the grindstone and given a dose. Fig. 10 gives a view of a plane iron that needs grinding. It will be seen that the oil stone has extended only one-third of the way up the grinding bevel. Trying to whet a tool like this on an oil stone is a mere waste of time and elbow grease. A tool should be ground until it looks like Fig. 11. It will be seen that there is the least possible bevel to be distinguished. In fact it is impossible to draw a picture of the slight bevel left after the tool is ground; it is less than the width of one of the lines used in the drawing. When looked at with the eye it appears to be a mere line extending along the edge of the tool. It is so narrow that one or two rubs on the oil stone will remove it entirely and give a keen edge to the tool. The careless grinder is apt to grind a tool more than this, and raise what is called feather edge. This is somewhat imperfectly represented by Fig. 12, where what should be the cutting edge of the tool looks like a mess of iron filings stuck in a row on the cutting edge. It is to avoid such an occurrence that the slight bevel shown in Fig. 11 is left after grinding.
When the edge shown in Fig. 12 appears, either from carelessness—and that is the cause nine times out of ten—or otherwise, the edge of the tool should be drawn over one corner of a board. Usually the grindstone suffers from this business, and the writer has seen several frames which looked as if the rats had gnawed them. Fig. 13 shows how a feather edge is removed; indeed, it is about as well when such an edge appears to touch the tool square upon the face of the stone for an instant, as shown in Fig. 14, thus removing the edge entirely and leaving the end of the tool blunt, as shown in Fig. 15.
The bevel must now be carried up to the dotted lines a b, making it necessary to remove enough of the metal to have lasted many weeks with careful use. This shows how careless grinding will wear out a tool much more than ordinary use. Sometimes the apprentice boy has had luck with a plane, running it on to a bench hook or a nail, and giving the tool the appearance shown in Fig. 16. This means a grind right off. If a tool in this condition is to be ground the metal must be removed to the letters c d of Fig. 17. In doing this nine times out of ten the man who grinds will place the tool on the stone in the usual way, and the first thing he knows one corner of the iron is ground off too much, as shown in Fig. 18 at c. The only remedy is to keep grinding, but it is much better before attempting to carry the bevel up to the line c d in Fig. 17 to square off the front end of the plane iron, as shown in Fig. 14. Grind boldly the whole edge of the tool up the line a of Fig. 19, which will remove all the nicks and broken places, and goes about up to the line c x, shown in Fig. 16.
With the tool in the condition shown by Fig. 20 it can be ground to an edge very quickly without the possibility of grinding off the corners, as shown in Fig. 18. A man who uses planes a great deal finds that he must grind them differently for different kinds of wood. For pine he will grind them about as shown in Fig. 21, leaving a long, thin bevel. If oak or walnut is to be cut the bevel is more like Fig. 22. The latter would not cut pine worth a cent. The one shown in Fig. 21 would cut hard wood all right as long as it remained sharp, but the edge would be gone by the time the first shaving had been made. For soft straight-grained wood the plane iron may lay very flat, as shown in Fig. 23; but for cross-grained and hard wood it should stand at a greater angle, as shown in Fig. 24, and also have a cap fastened to the upper side of the plane iron, as represented by a in this cut. The action of the cap is to break off the chip and prevent slivering up the wood that is being planed. For finishing curly maple and other very cross grained wood the iron should be very stunt, as shown in Fig. 25; while for planing the ends of wood for fitting the ends of clapboards, for example, the iron lays very flat and is turned upside down, as shown in Fig. 26.
These last few engravings will be a useful guide to the man who has planes to grind. He will in all cases adjust the angle of bevel so that it will just clear the work after the tool has been whetted several times. This is shown more particularly in Figs. 28 and 24. They also show that if he whets a plane too stunt or lets it get too round, the false bevel given by the oil stone will strike the work before the edge of the tool touches it, and the poor planer man will make more “cuss words ” than shavings.
There is one thing that should not be done when whetting the plane iron, and that is rubbing the face of the iron over the stone as shown in Fig. 27. This is often done by mechanics and some good ones at that, but if a good mechanic will do it, he is sure to lay the iron perfectly flat upon the stone, not raising the back end a particle. By doing this he brightens up the edge close to the end and greatly assists in sharpening the tool. A plane iron, however, can be sharpened without it, but it is a great test of proficiency in setting an edge on a plane iron to be able to whet up a cap plane iron in the manner shown in Fig. 28, and to stop whetting when an edge has been brought up sharp, so that it will not be necessary to remove the cap and rub the feather edge off the plane iron.
This trick is done by a number of first-class mechanics of the writer’s acquaintance, but there are not more than three in a hundred carpenters who can do it. It requires an accurate eye and a steady hand, and the man who can successfully perform the operation is a first-class mechanic.
Carpentry and Building – August 1891
- Jeff Burks