CHAPTER XXIX. THE STUDENTS USE THE SQUARE AND COMPASSES.
Mr. Brookbine stood on one of the timbers intended for the sills of the boat-house. In his hand he held a steel square and a pair of compasses.
"The pair of compasses I hold in my hand," he said, "are of the simplest construction. Those you have in the shop are fitted with a screw-stop so that you can fasten them in any required position. You will complain that it is hard to move the legs of these, but as they must stay in place without any screw, it is necessary that the joint be a tight fit."
"Legs?" said a student.
"You can call them shanks, if you prefer, or arms. There are a great many technical names to parts of apparatus which are not often used because they are not generally known," replied the instructor. "Since I came to Beech Hill I learned that an oar consists of the handle, the loom and the blade. Outside of the navy probably not one in ten ever heard of the loom of an oar, or would know what it meant. In carpentry the technical names used in one part of the country are not known in other parts. Legs is the proper technical name of the two parts of the compasses.
"You notice that the points are more blunt than those you use in the shop. In framing we use one of the legs as a marking-awl. The awl would do just as well, but it is sometimes convenient to have the compasses in your hand so that you can lay off a distance from the square with them. The points are tapered more rapidly so that they will make a mark which can readily be seen by the workman.
"The steel square is one of the most important tools used by the carpenter, and I could use up hours in telling you about it. The parts have technical names, though few make a strict use of them. The corner is called the heel, from which each of the four measures on it start. The long arm is the blade and the short one the tongue. The blade is just two feet long, or twenty-four inches."
"Mine is only twenty-three," suggested one of the boys, all of whom were examining their steel squares.
"Mine is only twenty-two in one place, and twenty-three in another," added another.
"You are altogether too literal, and the letter killeth in carpentry as well as in Scripture," replied Mr. Brookbine. "You must apply common sense to the figures. Now look at the outside measure on the blade: find the figure for one inch. That one means one inch in length, without regard to breadth, as you define a line in geometry. Hold up the square with the tongue down. Now does the inch of length lie on the right or the left of the point marked one."
"On the right," replied a dozen.
"Now look at the point marked twenty-three: is the inch marked with this number on the right or the left of it?"
"On the right."
"But there is another inch on the left of the mark, which is the twenty-fourth inch, though there is no room to mark it uniformly with the other numbers. Now, boys, look the thing over a little before you raise an objection. I repeat that, on the outside, the blade is two feet long. The student who said his blade was marked twenty-two in one place was wrong in his fact, and if he looks again he will see that the inside length of the blade is twenty-two and a half inches, which is the outside width less the width of the tongue.
"In these squares the tongue is sixteen inches long, on the outside, and fourteen on the inside, marked in the same manner as the blade. The inside length is two inches less than the outside, for the blade is two inches wide, while the tongue is only an inch and a half. You must know the square so that you can use it without stopping to study out its meaning.
"The tongue is sixteen inches long in this instance because it furnishes a convenient measure for the placing of studs and furrings. The rule is to put studs and furrings sixteen inches apart; but there is no law which compels any carpenter or architect to follow it. Floor-joists are usually placed at the same distance apart, though the rule is often varied to meet the circumstances."
"I don't know what a furring is," said one of the boys.
"Furring a house is nailing strips of board, usually sawed at the mill three inches wide, to the posts and studs for the sides, and the floor-joist for the ceiling, on a room, at a distance of sixteen inches apart, on which the laths are nailed for the plastering. If they were placed at any other distance from each other, it would make great confusion and waste in lathing. Laths are sawed four feet in length, so as to cover the space from the middle of one furring to the middle of the third one from it. Each lath is nailed to four furrings."
"But every room can not be exactly divided into spaces of sixteen inches in its length or breadth," suggested Harry Franklin.
"Very true; but the sixteen-inch division is used as far as it will go, and the lather must cut his laths for the last one. All the confusion comes in at the end then. If any other division were made he would have to cut every lath he used."
"But I have seen furrings only two inches wide," Lew Shoreham objected.
"No matter whether they are one or six inches wide: the rule is followed. But sixteen inches means from the centre of one furring to the centre of the next one; and the difference in the width comes into the space between them. In some places they lath upon the studs, inside, and clapboard upon them on the outside, without boarding.
"There is no particular reason why the blade of the square should be two feet long, except that it is a convenient length. The width of both the blade and the tongue is important. In mortising the sill for the studs, we shall cut out a square hole of an inch and a half, which is the width of the tongue. We will begin with the timber on which I am standing, which is a foot square. The posts will be eight inches square. Baxter, measure four inches from the end.
"This point will be the centre of the mortise for the post," continued the master carpenter when the students had marked the distance. "Now lay off sixteen inches, and stick the point of the compasses well into the wood so that we can see the mark. This is the centre of the mortise for the first stud. The stuff for the studding is four inches by two. Set the points of your compass one inch apart, and keep them so for the present. Lay off one inch on each side of the point you have made in the sill."
Baxter did as he was told, and the rest of the students watched him.
"The space between the outside points is two inches, just the thickness of the stud," continued Mr. Brookbine. "Put one point of the compasses in either outside hole you have made; rest the tongue of the square against the leg; let the blade hang over the side of the timber just far enough to enable you to square across the upper face of the timber; scratch a line across with the point of the compasses; in other words, scribe it. Do the same with the other outside point. Now you have the length of the mortise marked on the timber.
"Place the tongue of the square against the outer face of the sill, its length just even with the corner, and be accurate about it. Good! Now scribe against the inside of the tongue. Move the square until the outside of the tongue coincides with the line just made, and scribe as before. The result is that you have ruled off the width of the tongue, an inch and a half, at the same distance from the corner of the stick. This gives you the other two sides of the mortise. You must measure, mark, and scribe accurately, or our studs will not come in the right place.
"Now we will take a piece of studding, and finish the subject. The mortise will be an inch and a half deep, and we are to mark off a tenon to fit it. Set the square at the width of the tongue from the end of the stick, scribe all around it. The thickness of the stud fits the mortise, so that we have to cut away none of it. Place the tongue against the face of the stud and scribe it. Do the same on the other side. Place the tongue against the mark made and scribe again. You may scribe in the same manner across the end of the stud. The result is that the tenon of an inch and a half by two inches is marked off at the distance of an inch and a half from the face of the stick. You can see that nothing but the saws are required to do the work."
"We can do all that fast enough," said Ben Ludlow.
"The trouble is that you will do it too fast, and be careless about it," replied the instructor. "It requires sound judgment to do this work well. As I have told you before, one may waste his wages ten times over in cutting up lumber. Before you put the saw into a stick, you should consider what the piece you cut off is good for. Most of the timber is selected for the frame, so as to make the least waste. I shall have a great deal to say to you on this subject as we go along. No matter how much money you have, or who pays the bills, there must be no unnecessary waste. That he cuts stock to good advantage, is one of the best recommendations for a mechanic."
"Don't we have to fit the tenons to the mortises, and number them, or something of that sort?" asked Luke Bennington.
"Some carpenters frame in that way, which answers very well in a small building," replied the instructor. "We shall use in the boat-house between four and five hundred studs, for example, and it would be more work to number and find them than it would be to frame the whole of them. We shall frame by what is sometimes called the square rule. Any long stud will fit any place where a long stud is required. The jack-studs, or short ones, are of different lengths, and we classify them by their size. Of course the short posts cannot be used in the sides or ends, or the side posts at the corners; but all the sticks of the same class are interchangeable."
The master carpenter ended his lecture. The timbers for the sills had been laid out for framing, and under the direction of the instructor, the students proceeded to mark them off for mortising. It would require a whole series of books to follow him in all the details. In what manner he gave his instruction has been shown. Four students were instructed how to mark for the posts, and they proceeded to do it.
Four more were told how to mark for the tenons at the ends of the posts, and as soon as they were fairly at them, four more were selected to prepare the girders. A squad was put upon the braces, another on the plates and a third on the studs. In a short time they were all at work. Mr. Brookbine looked over the marks as fast as his time would admit. Of course there were many mistakes, and these were pointed out.
After an hour's use of the square and compasses, the boys needed a change of work, and the instructor called for the framing-chisels and mallets. All hands were set to mortising where the marks had been made and proved to be correct. The students worked hard, and when night came they did not feel much like skylarking.
The next forenoon, while the pupils were at their studies, the master carpenter went over the marks and measurements on the timbers. He was surprised to find so few errors. Before noon he had arranged everything for the afternoon. The boys worked hard, and the framing was not likely to last long.