US203856A - Improvement in engraving-blocks - Google Patents

Description

G. G. SBTOHBLL. Engraving-Blocks.'

Patented May 21, 1 87'8.,

No. 203,856l

UNTTED STATEs PATENT OEEIGE.

GEORGE C. SETCHELL, OF NORWICH, CONNECTICUT.

IMPROVEMENT IN ENGRAVING-BLOCKS.

Specification forming part of Letters Patent No. 203,856, dated May 21, 1878; application filed March 21, 1877.

sents my mode of constructing blocks, eitherV out of new or old wood, of double thickness, and the lower view represents the nished block, which is produced by splitting the double-thick blocks through the middle ofthe box-wood, as shown by the dotted lines in the drawing, and joining the sections edge to edge.

A represents the box-wood upper portion of my improved block; B, the cheap wood backing, and C the splines which should be used to strengthen the joints between the sections of a finished block.

In utilizing old blocks I first dress off all the engraved portion, and also the back side of the block, until a smooth plane surface is reached on both sides of the box-wood; but in case new box-wood is used, it is first sawed about half the standard thickness of engravers blocks, and dressed off in the same manner.

I next glue firmly upon each -side of this boxwood center a cheap wood backing, of mahogany or other suitable wood, which has been previously dressed, so as to make strong gluejoints. Afterthe glue-joints havebecome thoroughly set, these double-thick blocks are divided through their box-wood central layer, and then their edges are dressed off and grooves cut in the coarse wood backing for the insertion of splines, after which these sections are glued together in the ordinary manner, to form engravers blocks `of any required dimensions,

i, it never before having been practicable to obmainder a comparatively very cheap wood back is used, thus very largely reducing the expense.

Again, my improved blocks are much stronger than the ordinary box-wood blocks now in use, for the glue-joint between the box-wood top and the cheap wood back, owing to the glue entering the end grain of the wood in both, and the large surface thereof, is abundantly strong, and therefore my block is quite as good as a block of solid box-wood; a great increase of strength is derived from the glue adhering more closely to the edge of the coarse wood back than to the edge of the box-wood; and, besides, the splines will adhere much stronger in the grooves of the backing than in the box-wood as ordinarily used. Thus iinished engravers blocks are produced which, besides the great advantage of cheapness, have also the additional advantage of much greater strength in all their joints than the ordinary blocks.

Y I have found it necessary to glue the boxwood face upon the end wood of the backing, because if it is put upon the side of a board the shrinkage of the box-wood face will inevitably spring up the ends of the board, so that it will become warped and wholly unfit for use; consequently this end wood backing becomes the valuable and distinguishing feature of my improvement.

I am aware that it has been a common practice to produce large blocks by joining small blocks edge to edge with glue and bolts, and also that a wood face has been used, secured upon the side of a board with glue or pins, for use in calico printing, and therefore I make no claim of putting a face of wood upon the side of a board, nor for joining blocks edge to edge to produce larger ones 5 but i I do claim as my invention- The blocks herein described, for the purpose of wood-engraving, for letter-press printing, when these blocks are made by gluing a box-wood face upon the end grain of cheap -wood backing, so that the direction of the eEo. c. sETcHELL.l

. Witnesses:

WEBSTER PARK, `H. S. Corr.

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