A NEW METHOD OF PLAINING WOOD
Year: 1791

page_text: BENTHAM'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, 1,
SAMUEL BENTHAM, of Dover Street, in the County of Middlesex,.
Esquire, send greeting.
WHEREAS His most Excellent Majesty King George the Third
did, by His Letters Patent under the Great Seal of Great Britain,
bearing date at Westminster, the Twenty-sixth day of November, in
the twenty-third year of His reign, give and grant unto me, the
said Samuel Bentham, His especial licence that I, the said Samuel
Bentham, during the term of years therein mentioned, should and law-
fully might use, exercise, and vend, within England, Wales, and the
Town of Berwick-upon-Tweed, my Invention of A NEW METHOD OF
PLAINING WOOD;" in which said Letters Patent there is contained a
proviso obliging me, the said Samuel Bentham, by an instrument in
writing under my hand and scal, to cause a particular description of
the nature of my said Invention, and in what manner the same is to
be performed, to be inrolled in His Majesty's High Court of Chancery
within four calendar months after the date of the said recited Letters
Patent.
NOW KNOW YE, that in compliance with the said proviso I, the
said Samuel Bentham, do hereby declare that my said Invention is
described in manner following, that is to say:

page_text: The essence of the present. Invention respecting the plaining of wood
cousists in the having divested that operation of the quantity of skill
and attention at present necessary, in such sort that brute force may
be employed in it. By brute forco 1 mean not only the strength of
animals, but the force of inanimate agents, such as wind, water, steam,
&c., and even that of men, when employed in such a way as requires
nothing of skill or dexterity on the part of the person who exerts it.
By this means machinery may take place of human skill in this opera-
tion to as perfect a degree as in any of the manufactures on which
invention has been employed, so much to the honour and advantage of
this country. Hence arise three capital advantages; first, the quantity
of force employed, and thence the quantity of work done at a time,
may be encreas'd at pleasure; second, even the force of men may be
exerted in this way to a greater advantage than while confined, as in
the present practice, to a particular mode by the necessity of care and
dexterity: third, the labour, not only of the aukward and unpracticed,
but of the blind and the lame, may be called in, and a value given to it
little if at all short of that which the most skilful and experienced artist
bears at present. The Invention, as thus stated, is, properly speaking.
the Invention not of a mode, but of a principle. The modes in which
that principle may be employed, and the species of work to the per-
formance of which it may be applied in different circumstances, with
different degrees of advantage, are innumerable. To fulfil the condi-
tions prescribed by law the best and indeed only course I can pursue
is, therefore, to give such a general and in a manner exhaustive-view
of the extent of the principle, of the manner of applying it, and of the
sorts of work to which it may be applied, as to enable the public at
large, upon the expiration of my term, to reap the benefit of the
Invention in its fullest extent, by such directions and instructions of a
general nature as in each of the many different sorts of work in which
it may be employed may put an intelligent workman in the way of
making use of the principle to the most advantage. Drawings are not
given, as they would tend rather to confine the direction to a particular
mode: whereas words may serve to convoy the instruction in the
most general way, and with a latitude that will adapt itself to whatever

page_text: variety of circumstances may present themselves, and the better enable
the artist to pursue the Invention through all its branches. In the
common mode of plaining a straight board. for example, the workman,
besides exerting the force necessary to move the instrument along and
overcome the resistance he finds opposed to it, has a number of other
points to attend to; first, he has to adjust his tool to the board in a
proper manner for beginning the stroke; second, he has to employ
exertion to keep the instrument down, so as to prevent its passing over
without cutting; third, he has exertion to employ again to raise it
upon its return in order to save the cutting edge from being injured;
fourth, he has to guide it sideways to prevent its slipping off'; fifth, 'as
the board is broader than his plane, he has to examine from time to
time if the middle of the board corresponds with the edges, and to take
as much care not to cut away too much froin such parts as to cut away
enough from others; sixth, in many cases having had to mark it at the
edges, he has now from, time to time to observe these marks; and to 'take
care that his strokes conform to them. Upon my principle all these
points are accomplislied by machinery in manner following:-To begin
with the simplest case, viz', when the board to be planed is already of
the form required, and nothing more is wanted than that degree
of smoothing which a plane will give when drawn over the board
with the sole resting thereon; here the board may be laid on the
bench in the usual way, but the plane for this purpose must be mado in
the first place as broad at least as the board, that is, it must be capable
of cutting the whole breadth of the board at once. Secondly, the sides
of the plane, which I call the checks, and which are necessarily of a
substance sufficient for the strength of the plane, may extend below the
sole sufficiently to serve as guides to the plane on each side in its course
along the board, and should cover so much of the breadth of the iron;
if there be any, as does not cut, so that shavings may be taken from
cheek to check in such manner as not to be impeded by their breadth
in their passage out at the mouth. For making the stroke the plain
may be kept down by its own weight, or by being loaded as required;
the force necessary for this purpose being greater or less, according to
the breadth of the board and other circumstances. But though mere

page_text: weight may serve to insure the continuation of its cutting, when once it
has been. properly applied, yet for guiding it upon the first applica
tion to the end of the board at the commencement of the stroke, and
upon the quitting the board at the conclusion of the stroke, particular
precautions or contrivances are necessary. The bench, it is evident,
must be at each end as much longer than the board as to afford a
resting place for the plane, at which places it will rest upon its checks.
From this situation it will have to rise at the commencement of the
stroke for the sole to mount upon the board, and it will fall down again
in the same manner upon these checks at the conclusion of the stroke.
The nearer, therefore, the depth of these checks is to the thickness of
the board, the less the plane will have to rise and fall; but as there
must always be some difference between the two levels, or the iron
would not take hold, the sole of the plane at each end must be rounded
off or sloped up to enable it to slide on and off the board; but this
would not do without some further contrivance. Whatever were the
pressure employed, for keeping the plane to its work during the continu-
ance of the stroke, that same degree of pressure would not do at the
commencement or conclusion of it; at the commencement the fore
end must be pressed down hardest, that in rising it may be made to
assume the direction in which it is to cut; so at the conclusion of the
stroke the pressure must be augmented at the hinder end, lest by the
dropping or tilting down of the fore end the iron should be raised from
the board before it had reached the end of it. This variation in the
pressure may be insured by a weight resting upon the plane, but made
capable of traversing from end to end, and shaped in such a manner as
not to disturb the passage of the shavings. An obstacle connected with
the bench in such manner as for the moveable weight to be carried
against it by the plane, while the plane itself passes clear of it, will, by
causing the weight to slide, accordingly secure the preponderancy of the
part required at each of these points. While the plane is off the board,
fillets or batteus may guide it, or secure it from lateral deviation. If tho
board, being finished at one stroke, is thereupon removed, the plane may
be thereupon drawn back without obstacle or difficulty; but if a fresh
stroke is to be given, a contrivance is necessary to save the cutting edge

page_text: from being injured in dragging back on the board. For this purpose the
sole of the plane must be lifted up, so as to be clear of the board, and
the plane in its passage back must find sonic other support. Amongst
the variety of means by any of which this effect may be produced, as
simple a one, perhaps, as any, is as follows:-From the upper surface of
the plane project a bar of wood or metal, answering the purpose of a
handle, to which the moving force is to be applied. Let this bandle be
connected with the plane by a pin passing through it in a direction
transverse to the plane, so as to form an axis round which the handle
may play in a manner of a lever for a small and determinate distance
in a direction parellel to the length of the plane. The upper (which it
may be convenient to make the longer) end of this handle being shaped
in the manner the most convenient for its connection with the moving
power, the lower end is forked, or otherwise adapted to receive one or
more rollers, which, when the handle is erect, extend before the sole of
the plane, and thereby clear it of the wood. In this way, when the
moving force draws the plane forward, the handle, by the play it was
allowed to have round its axis, is made to incline forward, whereby the
rollers attached to it are raised in such manner as to leave the sole of
the plane free to drop down upon the work. As soon as the moving
force acts upon the handle in a manner to draw the plane back again it
becomes erect, and the rollers are thereby pressed down below the sole
of the plane, so as to receive the weight of it during its return, leaving
the sole and the iron clear of the work. It is true if there be but one
handle of this sort, then, according as the rollers are nearer to the one
or the other end of the planes the opposite end will still bear a part of the
weight; but the edge of the sole being of course smooth and rounded off,
this slight bearing will not be productive of any inconvenience; and if you
fix another. roller at this end, just even with the sole, this second roller
will take off so much of the weight as was left by the first. These rollers
will of course be so contrived and disposed as not to damage the work,
especially where it is of any of the nicer kinds herein-after spoken of.
So much for the most simple case; but in others further contrivances
will be necessary. The accuracy of planing depends, even in the present
mode, in some measure upon the bench. In this new mo:le an attention

page_text: to the construction of that implement is particularly essential. For the
case when the board winds so as to afford no surface on which it would
lio firm on an ordinary bench, a compound bench may be employed.
consisting of a middle part and two sides; the middle part serves for
the support of the board or piece to be planed, and is capable of being
lowered or raised at pleasure; the sides are made to seperate and close
borizontally, so as to receive between them, and keep steady, a picco of
any breadth; for this purpose they are furnished with one or moro rows
of flat teeth, which, without being long enough to damage the board,
are numerous enough (in conjunction with a common stop or bench
hook) to keep it to its position in spite of the weight of the plane, and
the tendency which the action of the stroke will sometimes have to
draw the plane and board together. The piece being thus fixed with
such part as you think proper to cutt off projecting above the sides of
the bench, the plane being set to work will cut away till its checks
come down so as to touch these bench sides. which, being out of
winding, in respect of each other, will insure the same regularity to the
surface of the piece between them. When one surface has been thus
planed out of winding so as to lie flat on the bench the piece may
easily be planed to a parallel thickness on an ordinary bench, viz, by
only making the cheeks of the plane to rise and fall, and adjusting them
to the thickness which is to be taken off. But here it is necessary to
observe, that in planing of boards not very thick, even after the plane
iron has been stopped by the checks from getting down to this board,
the board may at one part of it spring up to the iron, and the iron having
thus once got hold of it may not part with it till it has reduced it below
the intended thickness to which the checks were adapted. To obviate
this accident recourse must be had in such a case to the sort of
compound or compressing bench above mentioned; and in case of very
thin boards, where, though you keep down the edges in manner above
mentioned, the middle may, notwithstanding, be apt to rise, there may
be heavy rollers, or rollers loaded with weights, let through the sides of
the plane, as near the iron as may be, and on one or both sides of it.
In this manner, without any great additional consumption of moving
force, the board, however thin, may be effectually kept down flat upon

page_text: the bench. When the two sides of a board are brought into parel-
lelism, as before, in order to bring either of the edges to a square with
them, all you have to do is to steady it by compression between the
sides of the beneb, as in the former case, leaving as much above them
as you see occasion to cut away; only here, as the sides of the boards
are finished, to save them from being indented, you must give the tooth
of the bench sides something by way of a sheath to bite upon, and one
edge of the board being thus squared and smoothed will, as before,
serve as a basis which, by resting on the middle part of the bench, will
insure parrellelisni to the opposite edge. The same sort of bench-affords
an easy means of tapering the piece to any degree of taper, and that as
well lengthways as crossways, in the manner of weather boarding. Raise
one end of the middle part of the bench, you taper the piece at that
end; raise one of the sides of the bench, you taper the piece at that side.
Having raised the middle part of the bench at one end, raise the two
sides to any one and the same angle, but one of them higher than the
other, you may thus taper the board in both ways at once; so instead of
letting the plane bring itself down as it works to the piece to be planed,
viz, by rising less and less after each shaving has been taken off, you
may make the piece bring itself to the plane. To do this, rise the
middle part of the bench on which the piece rests, leaving the position
of the sides unaltered. But where the sides are employed to keep the
piece fast, as in the case of thin stuff before mentioned, false sides
without them must be added for the plane to run upon, which false sides
remain fixed while all the rest of the bench is raised up, or, what will be
easier, letting the rest of the bench remain fixed, lower these false sides.
This manner of working will admit of the planes being perfectly confined
in all directions, except that of the horizontal or other line in which it
is worked, in such manner that all the above-mentioned contrivances for
setting and keeping the plane to its work, and saving the edge from injury,
are superceded. A yet remaining way of producing the same effect is by
making the plane so as to drop after each shaving between its checks.
Any of these parallel risings and droppings may be effected by two or
more screws so connected as to be all turned at once. By a proper con-
figuration of the bench the surface of the work may be made to receive

page_text: curved forms, and those of a very complex nature. In a transverse
direction such forms are already given to the work in the ordinary
way of plaining, for instance. by moulding planes. In longitudinal
-direction also the work may now be curved by giving a correspondent
curvature to the bench sides, and by a combination of these two sources
of curvature it is easy to see that enrves of a very complex and seem-
ingly irregular nature may be produced. By means of a double motion
another more complicated, but, perhaps, for some cases a useful plane
may be made, very much extended in breadth, and of different curvatures
at different parts of that breadth, and thus, by being made to move
transversely at the same time that it is drawn along longitudinally,
it may present to different parts of the work dillerent curvatures
at different periods of its course. Barrel staves, blades of oars, and
Several other articles may be worked, and perhaps with advantage, in this
manner. So much with regard to the plaining a single surface at a time.
But where your board or other piece is of substance enough to admit
of your confining it in such manner as to come at more than one surface.
you may easily connect planes together, or compound your plane, so ns
for it to apply itself to either or both edges at the same time as to one
side. In the case of a single edge, one means of confining to its work
the plane belonging to that edge is by giving to the plane iron of the
plane belonging to the side a diagonal direction, as is sometimes done
in rabbit planes, or you may confine the plane at the edge, or a plane
at each edge, by springs or guides. In this manner edges of boards
may receive any moulding, or be rabbitted or tongued and grooved, at
the same time that the side is planed. Hitherto I have spoken only
if taking a single shaving at a time from each surface, though it be the
whole breadth of the piece. But irons may be so disposed in the plane,
ne behind and lower than another, as to take off as many shavings in
thickness as you please, and the piece being fixed, and the last and
Towermost iron adjusted to the checks of the plane at the proper height
to carry off the whole thickness required, and so finish the planing. In
this way, if before the last iron you have provided irons enough, to
take off the thickness, the plane, if it has compleated its course, cannot
but have done its business. In this manner, so you apply force enough,

page_text: your may perform almost any planing work at one stroke, though it
embrace several surfaces at once. You may dispose irons enough
one after the other to cut the picco through, and if you make them
narrow enough, slitting or plowing may in this manner take the place
of sawing. But here it is evident the difficulty of attaining sufficient
accuracy will encrease with the depth; the thinner too the irons,
that is, the narrower the slit, the weaker they will be, and the more
liable to bend or break; the thicker the irons the greater will be the
resistance to be overcome, and the greater the waste of wood, which in
some instances may be a material object. Minute instructions and
dimensions cannot here be given, since these must be adapted to the
nature of the wood. The above inconveniencies may be obviated in
some degree by applying a slitting plane of this sort to each of the two
opposite sides, so as for the two planes to meet in the middle at the
conclusion of the stroke, by which means cach will have but half the
depth to cut which a single one would have. But in making of such
many ironed planes a great deal of accuracy is necessary in making
them, and if any one of the irons is damaged or choaks the operation
fails. A better may be to employ a number of seperate planes con-
nected so as to follow one another, but so that each may be pressed
down to the work seperately by its own weight or otherwise. In this
way, though choaking were to take place, the bad effect of it may be
avoided, for if any one of such a chain of planes gets choaked it will
only rise and pass over without eflect. A depth of shaving correspon-
dent to this choaked plane will indeed fail of having been taken, and a
correspondent failure will of course take place in the whole depth
carried away, in comparison of what was intended to be carried away,
so that so much of the work will remain undone requiring a fresh stroke.
But against this inconvenience sufficient security may be provided by
only adding a few supernumerary planes over and above the number.
which in the event of their not any of them choaking would be sufficient.
In this case if none of the planes which come before the supernumerary
ones choak, the supernumerary ones will pass over without effect. As
to the mode of connection between the links of such a chain of planes,
as simple a one as any may be by an oblong frame, the sides of it fur-

page_text: nished with perpendicular slits to receive pins projecting from the
sides of each of the planes, the length of the slit sufficient to leave the
pins at liberty to play up and down to the extent of the whole thick
ness which the whole chain of planes is intended to plane away. In the
thickness of shaving which these different planes are set to take of
there may be some difference; the foremost ones being set the rankes
for the sake of riddance, the hinder ones the less rank for the sak
of smoothness, but each of them prevented by its checks from cut-
ting below the total depth intended. To save the length of planc
otherwise necessary to take off the whole thickness at a time, the
whole breadth of a board may be planed into grooves and ridges, and
those ridges immediately taken off in the following manner :-Divide
the breadth of your plane iron into teeth. say about one eightli of an
inch wide, with intervals equal in width to the width of the teeth;
this makes a set of channels of that width, with ridges between them
of equal width; to bring these channels to the depth required, say a
quarter of an inch, I put four such irons, one behind and below the
other, cach taking a shaving of a sixteenth of an inch. To cut away the
intermediate ridges behind the last of these toothed irons I use a set
of square pins running in and reaching to the bottom of these channels,
a pin following each tooth, and the whole of them fitted into an iron
frame placed underneath the sole of the plane. Each pin at it's base
where it runs along the bottom of the channel terminated in and stood
as it were on a horizontal cutter or tooth, shaped like the blade of a
bricklayer's trowel. Being broader than the channel by a full sixteenth
of an inch on each side. cach of these trowels cuts through half the
adjacent ridge on each side, so that between the trowel on the left hand
of it and that on the right hand each ridge is cut away as it were at its
root. This sort of plane, however, can hardly be made to such nicety
but that a shaving or two of an ordinary plane iron will be necessary
to smooth the work. The use of this sort of plane is most conspicuous in
the case of cross-grained wood, to which it would otherwise be necessary
to use double irons, becauso double irons taking so much thinner shaving
than single irons must be in proportionably greater number to do the
business, a uumber which, where the. thickness to be taken away is

page_text: considerable, may be so great as to render the length of the plane not
only expensive but cumbersome and inconvenient. Hitherto I have
considered the plane alone as moving, the piece of wood to be planed
remaining fixed;, but planing may equally be performed by moving the
piece, the plane remaining fixed, or even were both to move. The
expedient of making the piece move, while the plane is fixed may,
besides being applicable in cases where the piece is very small or short.
be particularly useful where the plane is so constructed as to embrace
the piece on all sides, whether it have cutters on all sides or not.
In this mode, which seems to bear resemblance to wire drawing in
metal, several sorts of work, such as the plaining tree-nails for ships.
the fluting of pillars, and the forming of rails and bannisters, might
be performed, and perhaps to some advantage; but there are other
configurations given to wood, in the instance. of which the plane
is at present either not used at all or used in such a way as to
perform the business but imperfectly, in spite of all the skill and dex-
terity which can be applied to it. Tenons are sometimes, for example,
plained mortises are not, but are made in a manner in which accuracy
depends altogether upon skill and dexterity. Both these, as also all
other forms which wood is made to receive for the purpose of junction
and commenction, may be produced in this way of planing upon this same
principle. As to tenons, at the end of a bench let a plane, with checks,
but no wood before the cutting iron, be so disposed as to move in a
channel longitudinally straight and lying flat on the bench, the depth
of the checks determining the height at which it moves. Then, if any
straight piece to which a tenon is to be formed at the end (a door rail.
for example) be confined straight and flat on the bench, the depth of
the shoulder being already cut by a saw or other tool, such a plane
may be made to cut off shaving after shaving the whole, depth of the
shoulder quite home to the saw kerf. When the tenon is thus
worked down to the proper depth on one side, the other may be
turned and treated in the same manner. If the tenon was already
roughed out by sawing or otherwise, so as not to require more than one
stroke of the plane, no rising or lowering of either plane or piece
would be necessary at each shaving. By putting two cutters, one for

page_text: .
the upper, the other for the lower side, and, if wanted, one for each
edge, the whole tenon may be finished at a stroke, and by an alteration
in the breadth of and distances between these cutters tenons of
different sizes may be finished. It is scarce necessary to observe that
* against cross-grained wood double irons and other precautions against
the tearing up of the grain may be employed here as in other cases;
neither, in cases where the extent of the motion required is thus short.
is it necessary that there should be checks running upon the liench, if
the stock or part usually made of wood be made to move in the
required direction, by being confined within a piece projecting upwards
from the end of the bench to the same stock. Instead of these cutters,"
which are calenlated to embrace the outside of tenons, other irons may
be adapted proper to finish the inside of mortises, and that either at all
the sides or at any lesser number of the sides at a time. For this
purpose the greater part of the wood must already have been got out
of the mortise, either by boring, for instance, or otherwise. The piece
in which the mortise is to be cut will be laid horizontally across the
bench, confined by proper stops. to receive in the requisite parts the
action of the tool. The cutting out scores and dovetails may of course
be performed in the same manner, the former being only a species of
right angled, the other of acute angled mortise, each wanting one of
the four sides. To these operations 1 give the name of planing 'as
well as to any of the above: the entting instrument being employed
and governed by guides, as well in respect of the depth to which it is
set to cut as in point of direction. With respect to thic choice of the
moving power for all these several operations, and the manner of apply-
ing it, nothing need here be said. The choice as between wind, water,
steam, animal strength, and so forth is a consideration of œconomy
depending upon particular circumstances. In the production of the
alternate motion, like that of ordinary planing, if the strength of man
is employed in what I have termed a brute way, it may be assisted by
declivity or by adventitious weight; by a man's having to push down-
hill as he makes the stroke, and consequently draw up-hill as the
plane is brought back free, or by drawing up over a pully, on the
return of the plane, a weight, which being fastened to the plane, assists

page_text: him as it works; or further force may be produced by a man or men
drawing in any manner a rope fastened to the plane, for instance,
winding it over a barrel by a winch.
Having shown that channels in the bench may be made to guide the
plane, and the planes so guided will do the work, the determining the
plane to move along the guides, whatever be the direction of them,
is a business within the competency of any intelligent mechanic, who, I
think, cannot now be much at a loss for means of executing the details
of any of the species of work above mentioned. In point of ceconomy
how far machines thus complicated may, in particular instances and
under particular circumstances, give an advantage in comparison of
cach other, or of the present mode of working by hand, is a matter of
calculation foreign to the present purpose.
In witness whereof, I, the said Samuel Bentham, have hereunto
set my hand and seal, this Twenty-sixth day of March, in the
Lol One thousand sovou hundred and ninety-two.
SAM BENTHAM. (L.S.)
AND BE IT REMEMBERED, that on the same Twenty-sixth day
of March, in the year above mentioned, the said Samuel Beuthani
came before our Lord the King, in His Chancery, and acknowledged
the Specification aforesaid, and all and every thing therein contained, in
form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute in that case made and provided.
Inrolled the same Twenty-sixth day of March, in the year above
written.