Improvements in Soft Wood Imitations of Hard Wood and in Apparatus for the Manufacture thereof.
Year: 1892

page_text: [Communicated from abroad by JOHN SHANNON, of Diamond Street, Pittsburg,
Pennsylvania, United States of America, Wood Engraver.]
Improvements in Soft Wood Imitations of Hard Wood and in
Apparatus for the Manufacture thereof.
I JAMES JOHNSON of 4 Clayton Square Liverpool in the County of Lancaster,
Patent Agent do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
The object of my invention is to produce in soft wood an imitation not only of
the surface appearance of hard wood, such as oak, ash, chestnut and the like, but to
impart to the surface the characteristic qualities of hardness, denseness, and
strength which pertain to the hard wood.
When the
In treating wood in accordance with my invention, I take a piece of soft wood,
such as pine, poplar, hemlock, or other woods possessing the peculiar characteristics
appertaining to wood of the class known to the art as soft wood, and by means of
suitable apparatus I produce on its surface series of numerous small indentations or
cuts extending in the line of the grain of the wood and placed near to each other
in such position as to imitate closely the peculiar arrangement of the surface pores
forming the growth or pattern of the wood desired to be simulated. The depth of
these cuts is preferably about one-sixteenth of an inch, more or less.
board has been treated thus, apply to its surface a coating of mineral filler
(hereinafter more fully described), which may be defined as a paste compounded of
oil and a mineral substance, with colour to conform to the colour of the wood to
be imitated. The filler is rubbed or pressed into the artificial surface pores of the
wood so as to fill the same, and the surplus is scraped or rubbed off from the
board's surface as much as possible. The filler is of such composition that it will
harden and set in the artificial pores, producing on the wood's surface a mosaic
composed of a great number of stony plugs, firmly embedded in the wood in close
proximity to each other. This brings out the ornamental pattern clearly and
beautifully, and because of the hard nature imparted to the surface of the wood it
makes it hard and durable, practically as much so as the surface of true hard wood
itself. The wood thus treated may then be polished or otherwise worked to adapt
it to the use to which it is to be put. The advantage which I derive from my
invention is that I get a board which because of the soft nature of its base can be
worked and cut without the labour and expense required in fitting hard wood.
while by reason of the induration of its surface, it affords all the advantages of
denseness, beauty, and susceptibility of high polish appertaining to the best hard
woods.
A suitable mineral filler is made according to the following formula :—

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side view of a machine adapted to the manufacture of my improved
product.
Figure 2 is a vertical section thereof, the section being on the line II-II of
Figure 4.
Figure 3 is a vertical section on the line III-III of Figure 1.
Figure 4 is a plan view of the machine.
Figure 5 is a sectional view of an indenting roller of modified construction.
Figure 6 is a plan view of an indented and filled board.
Figure 7 is a vertical section on the line VII-VII of Figure 6.
Like symbols of reference indicate like parts in each-2 represents the frame of a
machine adapted to indent boards for the manufacture of my improved product;
3 is the indenting roller, journalled in suitable standards 4, and adapted to be
rotated by a belt pulley 5; and 6 is a supporting roller journalled below the
roller 3.
The indenting roller is composed of a cylindrical shell set on a central shaft 7
and provided with a series of encircling thin steel bands or rings 8, formed with
indenting teeth so situate relatively to each other as to impress on a board passed
beneath the roller, indentations arranged in proper order to produce a grain pattern
on the surface thereof.
I shall now describe the manner in which I prefer to form the indenting teeth on
the roller.
more.
The roller is first built up of a series of disks or annular bands 8 of steel made
thin so as to afford sharp edges and set around a central shell or barrel 3¹ and
clamped in place by nuts 9 and end plates 10, which are adapted to be set on the
shaft 7. Annular washers 11 of less diameter than the disks or bands are
interposed between the latter and separate them. The entire surface of the
cylinder thus constituted is then covered with a "resist" preferably of beeswax
applied when melted or other suitable adhesive composition which will resist the
action of the etching acid. Such resist fills the annular spaces between the disks
and covers the edges of the disks, preferably to the thickness of one-eighth inch or
On the surface of the cylinder so coated, I trace the pattern desired to be
produced on the wood, following for this purpose the natural grain appearance of
the wood to be imitated, and then cut off the resist from the surface of the cylinder
in all places not thus marked with the pattern. The surface of the cylinder is
then exposed to the action of strong acid, e.g. nitric acid preferably by revolving
the cylinder when its surface is immersed in such acid bath. The acid eats away
the exposed edge-portions of the metal disks or rings, while the parts which have
been covered with the resist are not affected and constitute the indenting teeth.
The body of the roller and the washers are prevented from corrosion by the acid
by the resist which fills the interstitial spaces, and when the roller has been
washed with water to remove remaining acid, and the resist removed it is ready
for use.
When the board is passed between the rollers 3, and 6, indentations are pressed
on it as shown in Figure 6. In Figure 7 I show these indentations filled with
plugs of mineral filler above described. In this figure, the proportional size and
intervening distance between the indentations are somewhat exaggerated for better
illustration.
In Figure 5 I show an indenting roller of longitudinally curved peripheral outline
adapted to indent mouldings of corresponding shape in cross section.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
First. As a new article of manufacture, wood having a natural soft body, and an

page_text: ndurated surface comprising series of closely adjacent stony plugs
paste set in artificial indentations arranged in proper order to simulate the natural
surface appearance of hard wood; substantially as described.
Second. The method of making wood graining rollers or cylinders, which consists
in building up the cylinder with disks and washers of different diameters, coating
the surface of the cylinder with an acid proof composition which fills the spaces
between the disks and washers, then removing the composition in certain lines
according to the desired design, to expose portions of the cylinder, subjecting that
portion of the cylinder from which the composition has been removed to the action
of acid, and finally removing the composition from the whole surface of the
cylinder; substantially as and for the purposes described.
Third. The method of making wood graining rollers or cylinders, which consists
in building up the cylinder with disks and washers of different diameters, coating
the surface of the cylinder with an acid-proof composition to fill the spaces between
the disks and washers and completely enclose the edges of the disks, removing the
composition according to the desired design of the grain to expose a portion of the
disks, immersing the part of the cylinder containing the design in a bath of acid
and finally removing the composition from the entire surface of the cylinder, for
the purpose described, substantially as set forth.
January 1891.
JOHNSON