A Tube Cutter for Boiler Tubes and other Fixed Tubes.
Year: 1897

page_text: Date of Application, 30th Dec., 1897-Accepted, 12th Feb., 1898
COMPLETE SPECIFICATION.
A Tube Cutter for Boiler Tubes and other Fixed Tubes.
I, ELLAS STEPHENSON DIXON, of 43, Northcote. Street, South Shields, Durham,
Marine Engineer, 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:
My invention is a tool for cutting, in a cheap and expeditious manner, metal
tubes and particularly tubes which are fixed in boilers and other steam generators.
The chief features of the tool are that the tubes are cut transversely from the inside:
at the same time that part of the tube which would otherwise remain in the boiler
plate is also cut longitudinally in order that it may be easily removed: a few
strokes of a hammer will effect the operation.
I take a suitable piece of metal, preferably solid round steel bar a little less than
the diameter of the inside of the tube to be cut and several times the length of such
diameter or of any other suitable metal and I forge one end of it to form a flange
flattened at the top and bottom, at right angles all round it sufficiently to hold the
set screws or adjusting screws hereinafter mentioned; or I use a piece of steel rod
of larger diameter and turn it down to suit leaving the aforesaid flange at one end;
in either case the other end of the bar is left quite true and flat to allow an addition
to be fixed to it.
The addition consists of another shorter piece of similar bar metal of the same
diameter with a small cutter or flange at one end which is carefully turned so as
to form a kinife like projection or cutter all the way round the bar; this cutter
however need not be of the same piece as this secondly described bar but it can be
of a separate piece of metal and would then be a disc with a sharp edge. These
two pieces or disc only as the case may be are fixed on the flat end of the first
named bar by screw studs; the outside diameter of the cutter when fixed fitting
the internal diameter of the tube to be cut so that the tool can be easily pushed
into the tube. I do not make the cutter a true circle but I flatten the top and
bottom to a small extent. The cutter must also be made of a particular section:
that is one side of it is shaped at an angle and the other side (next to the flange)
perpendicular: the angle is designed so that the tube end which is cut is turned up
or flanged and so shortened and when the tool is withdrawn the tube drops and the
other side is made vertical so as to give a clean shear cut past the tube plat in a
perpendicular or vertical direction.
In addition to the above method I can also make the tool entirely of one piece of
metal.
I also make the first named piece (that is the one with the flange) a little longer
and cut a slot round it to take the cutter; whichever plan is adopted the cutter
would be flattened as before mentioned.
The aforesaid pieces of metal forming one complete tool when screwed together
(or the one piece of metal if made solid) are then cut into two longitudinal pieces

page_text: of semi circular section. The flat faces of each half of the tool must be cut away
sufficiently to leave a tapering space smaller towards the inner end (that is the
end which goes first in the tube) to admit of a wedge being introduced between
them when they are adjusted in the tube: a feather is also left on each flat face to
keep the wedge in position.
The wedge is made of similar metal as broad as and a little longer than the tool,
with a slot way cut along on both sides to carry the aforesaid feather left in the
inner sides of the tool: the angle of the tapering will be such that when the tool
is in the tube the wedge can be pushed in between the halves without using any
force as far as the other ends of the tool.
The wedge and the corresponding taper in the tool must be so arranged that the
pressure is distributed along the whole surface of the tool when the wedge is
driven in.
The flange of the tool has holes drilled through and tapped: two in each half, to
take set screws screwing parallel with the tool; the screws must be pitched at
such a radius that they clear the outside edge of the tube to be cut, I mean that
part of the boiler tube projecting outside the boiler or tube plate; and at the same
time do not foul any neighbouring tubes during the operation; they will also
allow the tool to enter the tube as far as required and so that the cutter goes just
inside the boiler plate, and when the wedge is driven in keep the tool in place
so that the cutter goes through the tube close to the edge of the plate which edge
acts like one half of a pair of shears; the set screws also prevent the tool from shift-
ing, otherwise as the wedge is driven in it would carry the tool with it at first
until the cutters bite.
Even when the tool is cut all through, the ferrule (or the part left in the boiler
plate) may sometimes be difficult to get out; to avoid this I fix in the centre of
one half only of the tool but in a longitudinal direction another cutter of exactly
the height that the tube to be cut is thick and which will therefore cut or split the
ferrule just at the completion of the blow which drives the cutter through the
tube after the tool is used twice as above mentioned the split piece of the ferrule
will generally drop out and the rest of it can be easily removed.
After the wedge has been driven home there is a difficulty or almost an impossi-
bility to withdraw it: to obviate this I cut a key way through the wedge itself at
such a place that when the wedge is driven home one end of the key way is slightly
inside the flange: I make a wedge (hereafter called the draw key) to fit the key
way, and by inserting it in the aforesaid key way by one slight blow it starts the
wedge back.
In cutting the key way it is important to make that end of it which the draw key
is driven against of semi-circular section in order that the pressure is in the centre
of the wedge, and not all at the top or all at the bottom.
To use the tool, it is inserted inside a tube which is fixed in a boiler, and adjusted
by means of the set screws which are screwed against the boiler plate so that the
knives will touch that part which has to be cut; for instance if the tube has to
be cut inside the boiler near the tube plate the tool is fixed by means of the adjust-
ing screws so that the cutters will when pressed up against the tube cut it just
inside the boiler, the tube plate acting as a shear edge, the wedge is then intro-
duced and a few blows of a hammer drives it in this opens the two halves and
drives the cutters into and through the tube walls cutting through except at the
two sides where the wedge makes the opening, and the longitudinal cutter also
splits the ferrule. The draw key is then inserted to start the wedge back. To cut
the two side places which the cutters do not touch the tool must be taken out and
turned round sufficiently and the wedge driven in again, and the cut will be com-
plete all the way round and the ferrule will be split in two places.
EXPLANATION OF DRAWINGS AND DETAILS OF CONSTRUCTION.
Fig. 1 is a section of tool showing:-
-
A A the two halves of the tool with B B flanges at each end;
CC adiusting screws through each flange;

page_text: DD cutters showing section of angle of one side and vertical on the other which
for reasons before given it is very important to adhere to;
E E ends of tool;
Fig. 2 is an elevation of front of tool showing the two flanges with two set screws
to each; the flattening at top and bottom is an important feature when the tool is
used for boiler tubes as it allows the tool to be fixed between rows of tubes;
12 feather.
Fig. 3 is plan of wedge showing-
h feather way;
I, key way for starting back wedge.
Fig. 4 is a section of tool across the top of the cutters; this shows the flattening
of the cutters at the top and bottom; I take off about 1" on each side of the peri-
phery and I sharpen the flat parts; I regard this shape of the cutters as a very
important part of my invention for the commencement of the cutting takes place
at each corner of the flattening, and when the corners once start the cutting or
tearing of the tube is quickly effected.
Figs. 5 and 6 show shape of draw key.
Fig. 7 is an illustration of the manner of fixing a loose cutter; this is I think
the preferable way of making the tool; it is made in one piece, a slot is cut for I
which is fitted in and made secure by two or more studs.
Fig. 8 gives section of 1) made to fit in slot of Fig. 7 and shows studs for fixing.
To fit in the longitudinal cutter J I make it a separate piece, and I cut for it a
suitable slot in A (Figs. 2 and 7) slanting one end as drawn at j Fig. 7, and D
being made to fit up close to it, as shown in Fig. 7, keeps it in position. If the
cutters are made solid with A a suitable slot must be made for J, and in using
the tool care will be taken that it is never turned round to allow J to fall out.
Fig. 1 shows three separate parts viz. A, D, E-E is not however strictly neces-
sary; may be a disc and screwed on to A as shown in Fig. 9 and E would be
dispensed with.
•
The drawings show each half cutter D fixed with two studs (Figs. 8 and 9);
more may be used if preferred, or one stud and a steadying pin: this applies also
to the method illustrated in Fig. 1.
Figs. 1 and 2 are drawn the actual size to suit a 3" tube, therefore although the
drawings are reduced in reproduction the proportion of the parts will be easily
ascertained; although the flat parts of the cutters are not shown in Figs. 1 and 2
they will be readily perceived in Figs. 4, 8 and 9; the 1" hereinbefore mentioned
as taken off the periphery is the proportion for a 3" tool.
I claim nothing in respect of making the tool in halves, and using the wedge;
or for the taper shape of the hole made for it in the tool, but I except the feather
and feather way, which I regard as novel and important in assisting to keep the
tool straight. I claim nothing in respect of the flange by itself but only in com-
bination with the adjusting screws.
I claim nothing in respect to making the cutters solid with the tool.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1 The tube cutter for cutting fixed tubes having the cutters flattened in their
periphery and made with one side vertical and the other side at an angle as above
described or substantially similar thereto.
2 The flange flattened at top and bottom (or not flattened as the work requires)

page_text: in combination with the adjusting screws as hereinbefore described or substantially
similar thereto.
3 The feather and feather way in the halves of the tool and of the wedge as
above described or substantially similar thereto.
4 The longitudinal cutter as above described or substantially similar thereto.
5 The starting back arrangement and accompanying draw key as above
described or substantially similar thereto.
6 The method of making the cutters separate and fixing them to the tool as
above described and illustrated in Figs. 1, 7 and 8, or substantially similar thereto.
Dated this 30th day of December 1897.
ALFRED HOWARD,
Applicant's Agent.