IMPROVEMENTS IN THE MANUFACTURE OF METAL TUBES
Year: 1878

page_text: LETTERS PATENT to James McDougall, junior, of Wednesbury, in the County
of Staffordshire, Tube Manufacturer, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF METAL TUBES."
PROVISIONAL SPECIFICATION left by the said James McDougall at the
Office of the Commissioners of Patents on the 2nd January 1878.
JAMES MCDOUGALL, junior, of Wednesbury, in the County of Staffordshire, Tube
Manufacturer. "IMPROVEMENTS IN THE MANUFACTURE OF METAL TUBES."
My Invention has reference to the manufacture of metal tubes generally, but
more especially to those used for bedstead work.
Tubes are at present made by bending plates into skelps, then welded, and
finished by passing them through single die plates two or more times, as required,
but only through one die each time.
By my Invention, after bending the plate up, I pass the skelp through two or
more dies and bells placed in a suitable bearing plate, one behind the other, so that
the first heat is utilized, and by applying a jet of water to the tube immediately it
passes through the first die, the tube is finished in less time, with less labour, and
with less expense in production.
I make the bearing plate for carrying the die plates with vertical slots, so that
the die plates can be easily lifted out and replaced by others.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said James McDougall in the Great Seal Patent Office on the 2nd July
1878.
JAMES MODOUGALL, of Wednesbury, in the County of Staffordshire, Tube Manu-
facturer. "IMPROVEMENTS IN THE MANUFACTURE OF METAL TUBES."
My Invention has reference to the manufacture of metal tubes generally, but
more especially to those used for bedstead work.
Tubes are at present made by bending plates into skelps, then welded, and
finished by passing them through single die plates two or more times, as required,
but only through one die each time.
By my Invention, after bending the plate up, I pass the skelp through two or
more dies and bells placed in a suitable bearing plate, one behind the other, so that
the first heat is utilised, and by applying a jet of water to the tube immediately it
passes through the first die, the tube is finished in less time, with less labour, and
with less expense in production.
I make the bearing plate for carrying the die plates with vertical slots, so that
the die plates can be easily lifted out and replaced by others.
On reference to the accompanying Sheet of Drawings, it will be clearly understood
how the dies or bells for drawing the tubes may be placed.
Figures 1 and 2 illustrate two forms of dies or bells as usually used in tube
making; Figure 3 is a side elevation, Figure 4 an end elevation, and Figure 5 is a
plan of a bearing plate arranged to hold two dies or bells a and b, while Figure 6
serves to show a similar bearing plate arranged for holding three dies c, d, and e.
The bars f, g, and h, i, and j are generally made loose to lift out, so as to arrange
the recesses for holding the bells for different sized tubes. This bearing plate would
be usually placed at the mouth of the heating furnace.
The process of making is generally as follows:-The flat strip of metal is first
drawn through a single die in the usual manner, for the purpose of forming it
roughly into the shape of a tube called a "skelp." The skelp is then returned into
the furnace and drawn through the double dies a and b, Figure 5, to finish the tube,
or through the three or more dies, as shown by c, d, e, Figure 6, it would thus be
finished in two processes.
The usual manner of making tubes from the skelp is to pass the skelp back, and
then draw it through a single die as the second process, again passing it back and
out through a third single die as the third process.
By using the double or more dies or bells, I save the time which would be
occupied in passing the tube backwards and forwards, and thus by my process tubes
are finished in a hotter state, which makes them softer and better in quality, besides
allowing them to be produced in larger quantity with a given plant, and therefore
at less.cost.
Instead of the bearing plate for receiving the die holders, many other means of
holding the bells in a separate position may be adopted, such as two or more sockets
connected by coupling rods with each other. When the jet of water is used, it
would be applied between the bells a and b, or c and d, or d and e, but for many
purposes, such as where the tubes are to be bent into different shapes, I prefer to
draw them without the use of the water jet.
I am aware that the attempt has been made to draw tubes by forming two
reductions in one bell, but the stiffness and other objections prevented success.
I

page_text: would therefore have it understood that I claim the use, in drawing tubes, of two
or more dies or bells, placed separately in suitable bearing frames or couplings.
In witness whereof, I, the said James M.Dougall, have hereunto set my hand
and seal, this Twenty-eighth day of June, One thousand eight hundred and
seventy-eight.
Witness,
THOMAS HIPWOOD,
Clerk to George Barker,
Patent Agent,
27, Colmore Row,
Birmingham.
JAMES MCDOUGALL. (LS)