Mechanick exercises, or, The doctrine of handy-works by Joseph Moxon.

§ 17. To Frame two Quarters Square into one another.

You must take care in Mortessing and Tennanting, that as near as you can you equallize the strength of the sides of the Mortess to the strength of the Ten∣nant. I do not mean that the stuff should be of an equal Substance, for that is not equallizing strength: But the equallizing strength must be considered with respect to the Quality, Position and Substance of the Stuff: As if you were to make a Tennant upon a piece of Fur, and a Mortess to receive it in a piece of Oak, and the Fur and Oak have both the same size; The Tennant therefore made upon this piece of Fur, must be considerably bigger than a Tennant need be made of Oak, because Fur is much a weaker wood then Oak, and therefore ought to have a greater Substance to equallize the strength of Oak. And for Position, the shorter the stuff that the Tennant is made on, the less Violence the Tennant is subject to. Besides, it is easier to split wood with the grain, than to brake wood cross the grain; and therefore the same wood when posited as a Tennant, is stronger than the same wood of the same size when posited as a Mortess: for the inju∣ry a Mortess is subject to is, splitting with the grain of the wood, which, without good care, it will often

do in working; but the force that must injure a Ten∣nant, must offend it cross the grain of the wood, in which position it will best indure violence.

When two pieces of Wood, of the same quality and substance (as in this our Example) are elected to make on the one a Tennant, and in the other a Mor∣tess. If you make the Mortess too wide, the sides of the Mortess will be weaker than the Tennant; or, if too narrow, the Tennant that must fit the Mor∣tess, will be weaker than the sides that contain the Mortess: And if one be weaker then the other, the weakest will give way to the strongest, when an equal violence is offer'd to both. Therefore you may see a necessity of equallizing the strength of one to the other, as near as you can. But because no Rule is extant to do it by, nor can (for many con∣siderations, I think,) be made, therefore this equalli∣zing of strength, must be referred to the Judgment of the Operator. Now to the work.

The Mortess to be made is in a Quarter four Inches broad. In this case Workmen make the Mortess an Inch wide, so that an Inch and an half Stuff remains on either side it. Therefore your Stuff being squar'd, as was taught in the last Section, set the Oval of the Gage an Inch and an half off the Tooth, and gage with it, on either side your Stuff, a straight line at that distance from the end you intend the Mortess shall be, then open your Compasses to two Inches, and prick off that distance in one of the lines, for the length of the Mortess: then lay the inside of the Han∣dle of the Square to one side of the Stuff, and upon both the pricks successively, and with your Pricker draw straight lines through them by the side of the Tongue, so shall the bounds of your Mortess be struck out on the Quarter. If your Mortess go

through the Quarter, draw the same lines on the op∣posite side of the Quarter, thus, Turn the Quarter, or its edge, and apply the inside of the Handle of the Square, to the ends of the former drawn lines, and by the side of the Tongue draw two lines on the edge of the Quarter; then turn the Quarter again with its other broad side upwards, and apply the inside of the Handle of the Square to the ends of the last lines drawn on the edge, and by the side of the Tongue, draw two lines on this broad side also. These two lines (if your quarter was truly squar'd) shall be exactly opposite to the two lines drawn on the first broad side of the quarter for the length of the Mortess: And for the width of the Mortess Gage this side also, as you did the first; then for the Tennant, Gage on that end of the Quarter you intend the Tennant shall be made, the same lines you did for the Mortess. And because the Quarter is two Inches thick, prick from the end two Inches, and applying the inside of the Handle of the Square to the side of the Quarter, and the Tongue to that Prick, draw by the side of the Tongue a line through that side the Quarter; then turn the other sides of the Quarter suc∣cessively, and draw lines athwart each side the Quar∣ter, as you were taught to draw the opposite lines for the Mortess.

Then place the edge of the Inch-Mortess-Chissel with its Basil from you, and the Helve bearing a lit∣tle towards you, within one half quarter of an Inch of one end of the struck Mortess, and with your Mallet knock hard upon it, till you find the Basil of the Chissel will no longer force the chips out of the Mortess; then remove the Chissel to the other end of the Mortess, and work, as with the first end, till the Chips will void no longer: Then work away

the Stuff betwen the two Ends, and begin again at one of the ends, and then at the other, and work deeper into the Mortess, then again between both; and so work deeper by degrees, till you have wrought the Mortess through, or (if not through) to the intended depht; then with the Mortess-Chis∣sel work nearer the drawn lines at the ends of the Mortess, (for before you were directed to work but within half a quarter of an Inch of the drawn lines,) by laying light blows on it, till you have made it fit to pare smooth with a narrow Paring Chissel, and then pare the ends, as you were taught to work with the Paring-Chissel: then with the broad Paring-Chissel, pare the sides of the Mortess just to the Struck lines; so is the Mortess fini∣shed.

To work the Tennant, lay the other Quarter on edge upon your Work-Bench, and fasten it with the Holdfast, as you were taught Sect. I. Then with the Tennant, Saw a little without the Struck-line towards the end: you must not Saw just upon the Struck-line, because the Saw cuts rough: Besides, you must leave some Stuff to pare away smooth to the Struck-line, that the Stile (that is, the upright Quarter) may make a close Joint with the Rail (that is) the lower Quarter: Saw therefore right down with the Tennant-Saw, just almost to the gaged lines for the thickness of the Tennant, and have a care to keep the Blade of the Saw exactly upright. Then turn the opposite side of the Quarter up∣wards, and work as you were taught to work the first side.

Then with the Paring-Chissel, pare the Work close to the gaged lines for the Tennant. Then try how it fits the Mortess: If it be not pared enough

away, you must Pare it where it Bears, that is, sticks. But if you should chance to have made it too little, you have spoiled your work: Therefore you may see how necessary it is, not to make the Mortess too wide at first, or the Tennant too narrow.

Then with the Piercer pierce two holes through the sides, or cheeks of the Mortess, about half an Inch off either end one. Then knock the Tennant stiff into the Mortess, and set it upright, by apply∣ing the Angle of the outer Square, to the Angle the two Quarters make, and with your Pricker, prick round about the insides of the Pierced holes upon the Tennant. Then take the Tennant out again, and Pierce two holes with the same Bit, about the thickness of a shilling above the Pricked holes on the Tennant, that is, nearer the sholder of the Ten∣nant, that the Pins you are to drive in, may draw the sholder of the Tennant the closer to the flat side of the Quarter the Mortess is made in. Then with the Paring-Chissel make two Pins somewhat Taper∣ing, full big enough, and setting the two Quarters again square, as before, Drive the Pins stiff into the Pierced holes.

If you make another Square, as you did this; and make also a Tennant on each un-Tennanted end of the Stiles, and another Mortess on the top and bottom Rails, you may put them together, and make square Frame of them.