He is also very careful that when he is to File upon the Face of the Matrice, to Screw the Face of it Horizontally flat in the Vice: And that in Filing upon it, he keeps his File directly Horizontal, as was shewed, Numb. 1. Fol. 15, 16. Vol. 1. For if he let his right or left hand dip, the File will in its Natural Progress take too much off the side it dips upon, and consequently the Face of the Letter on that side will lie shallower from the Face of the Matrice then it will on the opposite side. The like caution he makes, in Filing between the Top and Bottom of the Matrice on the Face. For if he Files away too much Copper toward the Top or Bottom, the Face of the Letter on its Top or Bottom-Line, will lie on that end shallower from the Face of the Matrice.
Then he considers by his Proof-Letters how much too thick the right or left side of the Matrice is.
I told you in §. 11. ¶. 4. that the Angle the Sholder made with the Face of the Letter, is about 100 Degrees, which is 10 Degrees more then a right Angle or Square. So that if a Letter be Cast and Rub’d just so thick that the Liner when applied to the Shanck of the Letter reaches just to the Sholder, there will be an Angle of 10 Degrees, contained between the edge of the Liner and the Straight Line that proceeds from the Sholder at the Shanck, to the outer-edge of the Face of the Letter. And if two Letters be thus Cast and Rub’d and Set together, the Angle contained between their Shancks, and the outer-edge of the Face of the Letter will be 20 Degrees, which is too wide by half for the Faces of two Letters to stand assunder. Therefore the sides of the Matrice must be so Justified, that when the Shancks of two Letters stand close together, the Angle between both the Shancks, and the adjacent outer-edges of the Faces of the Letters may both make an Angle of about 10 Degrees as aforesaid, which is a convenient distance for two Letters to stand assunder at the Face. But to do which, If the right-side be too thick, the Register of the under-half of the Mold, being (as I said) hard screw’d, so as to stand about an n off the edge of the Body towards the right hand; He places the Foot of the Matrice on the Stool, and the right-side of the Matrice close against the Register, and observes how much too thick that side of the Matrice is: For so much as the right-hand edge of the Orifice of the Matrice stands on the left-hand side of the Body, so much is the Right-side of the Matrice too thick, and must by several offers be Filed away with a Bastard-Cut-File, not all at once, least (ere he be aware) he makes that side of the Matrice too thin, which will be a great dammage to the Matrice, and cannot be mended but with a Botch, as shall in proper place be shewed.
Having by several proffers wrought the right-side of the Matrice thus near its thickness, he proceeds to Justifie the left side also. But this side must be Justified by the upper half of the Mold; By turning the top of the Matrice downwards, and placing the left side of it (now the right-side) against the Register, and works away the left side in all respects as he did the right-side; still being very cautious he takes not to much Copper away at once.
To Justifie the Letter in Line he examins the Proof-Letter (yet standing in the Lining-Stick) and applies the Liner to the Foot-line: And if the Liner touch all the way upon the Foot-line of the Proof-Letter and the Foot-Line of all the old m’s, that Matrice is Justified in Line. But this also very rarely happens at first, for by design it is generally made to stand too low in Line: Because the Bottom of the Matrice may by several proffers be Filed away till the Letter stand exactly in Line. But should he take too much off the Bottom of the Matrice, it cannot be made to stand lower without another Botch.
Nor does he reckon that this first Operation, or perhaps several more such, shall Justifie the Matrice in Line. But after bringing both the sides of the Matrice thus near, and also bringing the Matrice thus near the Line. He Casts another Proof-Letter or two, and Rubbing all the sides of their Shancks, as before was shew’d, he tries by Rubbing the Letters how near he has brought the thickness of both the sides: For when the sides of the Matrice are brought just to such a thickness, that the Shanck of the Letter (Cast in the Mold) Rubs flat half way up beyond the Beard towards the Face of the Letter, the Matrice is of a convenient thickness, and there the Angle from the Beard of the Shanck, to the outer-edge of two Letters set together, will make an Angle of about 10 degrees as aforesaid, which being about one third part of a thin Space is a convenient distance for the adjacent edges of two Letters to stand assunder: But yet Founders sometimes to Get in or drive-out, Cast the Letters thinner or thicker, and consequently their Faces stand closer or wider assunder, which is unseemly when the Letter comes to be Printed.
Then he sets the Proof-Letters in the Lining-Stick, between four or five old m’s as before, and with the Liner examins again how well these Proof-Letters stand in Line with the old m’s, which if they do not, he Reiterates the former Operations so oft, till the sides and Line of the Matrice is Justified, and at every Operation Casts new Proof-Letters to examine the thickness of both the Sides, and how well the Matrice is Justified to Stand in Line.
The Matrice being now Justified, he Files a Leather-Groove round about it, viz. a Notch (made properest with a three square File) within about a thick Scaboard of the top of the Matrice, to tie the Leather fast to.
He also Files another Notch in the back-side of the Matrice athwart it, to rest the point of the Wyer or Spring in. But this Notch must by no means be made before the Matrice be Justified to its true Height against Paper: Because when this Notch is made, the Punch cannot again be struck in the Matrice; For that the Matrice will not lie solid on the Stake in that place.