IMPROVEMENTS IN OR CONNECTED WITH THE MANUFACTURE OF METAL TUBES
Year: 1882

page_text: LETTERS PATENT to James Robertson of Govan in the County of Renfrew,
North-Britain for an invention of "IMPROVEMENTS IN OR CONNECTED WITH
THE MANUFACTURE OF METAL TUBES
"3
PROVISIONAL SPECIFICATION left by the said James Robertson at the
Office of the Commissioners of Patents on the 6th June 1882.
JAMES ROBERTSON, of Govan, in the County of Renfrew, North-Britain,
"IMPROVEMENTS IN OR CONNECTED WITH THE MANUFACTURE OF METAL TUBES,"
"
This Invention, which relates to the manufacture of metal tubes, has special
reference to an improved mode and means of grinding and polishing or finishing
tubes of iron or steel, and to improvements in the construction and arrangements
of apparatus for rolling the tubes and effecting the grinding or polishing
operations.
The Invention comprises a mode and means of grinding and polishing metal
tubes when specially heated, and in a partially softened state, an improved
construction of skew rolls, for rolling tubes formed of asbestos, or preparations of
the same, in washers or spiral rings, and fixed on their rolling peripheries; An
improved construction of welding or sizing grooved rolls, having their acting
surfaces composed of asbestos, or preparations of same, formed into washers or
spiral rings, compressed and held together by rings or washers of metal, and bolts
or rivets; and also improved constructions of bulbous mandrels to be used in
rolling tubes, in which the bulb or head which bears on the inner surface of the
tubes, is formed of asbestos washers or rings, or acting surfaces of same compressed
between plates by a screw or other means. Also a mode of rounding, shaping, or
preparing bulbous welding mandrels composed of asbestos in the improved form
described, or metallic mandrels, by rolling the mandrels between two or more hard
metal rolls acting together, and when being rolled and rotated between the roll to
have graphite or other non-conducting lubricating or heat resisting materials rolled
in, or made to adhere to, the surface of the mandrels. These improvements may be
used in combination or employed independantly, the rolls and mandrels formed of

page_text: heat non-conducting materials being chiefly advantageous for the manufacture of
very thin tubes to prevent the abstraction of heat from the tube in welding,
or before it gets presented to the action of the finishing grind-stone.
In carrying out the first part of this Invention a grinding machine, or a number
of grindstones, which may be formed of natural rock or artificially made, is, or are
fitted in combination with the ordinary or specially formed skew rolling machinery
and usual welding furnace, or combined with a re-heating furnace or other heating
apparatus and skew rolls; and such grindstone or grindstones are rotated and
caused to act on the surface of the metal tube while at a red heat, and in a
partially softened state for the purpose of grinding and polishing and finishing the
outer surface of the tube. I use also as part of this Invention a stationary scraper
for cleaning the inner surface of the tube, acting in combination with the grinding
machine, and fitted on a long stem rod, which lies or rests on the lower inner
surface of the tube, as it is revolved and is moved on end by the skew rolls over
the face of the revolving grindstone or grindstones. The objects of grinding the
tube while in a hot state, are to enable the grindstone to have a greater "bite" or
better grinding effect on the tube and less wearing action on the grindstone itself,
than when grinding in a cold state. Also to prevent glazing and unequal wear on
the surface of the grinding stone, and to dispense with the use of water on its
surface, this new and improved method of grinding tubes, giving to the tube a
very perfectly cylindrical form and smooth surface, and imparting also to its
surface a darkish blue tint or colour.
It is preferred to employ this grinding finishing process combined with the
welding furnace and rolls, and if sizing rolls are used also, combined with such
rolls, and to have the furnace, welding rolls and sizing rolls in close and
convenient proximity to the skew rolling and grinding machine, so as to have the
tube presented and spirally rolled across the surface of the grindstone as quickly,
and with as little loss of heat as possible from the operations of these several
processes. When the tubes are first welded or formed and allowed to cool, then a
re-heating furnace for the tubes has to be placed near, to be used in combination
with the skew rolling and grinding machine to heat the tube into a sufficiently
hot state to effect this grinding and finishing process as described.
According to the second part of the improvements, the acting surfaces of skew
or welding or sizing rolls are constructed of asbestos washers or spirally cut sheets,
compressed and held firmly in a solid mass by end washers and bolts or rivets,
similar to the modes used of forming paper rollers for calendering and other
purposes, asbestos being a good nonconductor of heat, and when well compressed,
possessing a good wearing surface for withstanding heat and abrading action.
This part of this Invention is of advantage mainly for the welding or soldering and
finishing of very thin tubes, or tubes having little mass of metal in them, in
operating on which by the use of metallic rolls, the disadvantage occurs that the
rolls abstract the heat, or cool the tube too much, to effect the processes of welding
or of finishing in a sufficiently hot or perfect state, according to the processes
herein before described.
The third improvement of my Invention which is also mainly designed for
conserving the heat in the tubes during the rolling and finishing operations,
consists in forming the bulbous mandrels over which tubes are passed between
rolls in welding, of asbestos sheet washers compressed into a hard state and held
together between end washers or collars, by a screw or screws or other means and
afterwards turned or rolled into a somewhat similar form to an ordinary metallic
mandrel to be fixed on a stem rod. The heat non-conducting qualities of the
asbestos being the main object of using this description of mandrel, which is also
most required for the welding of tubes formed of plates of thin gauges, such
mandrels may be either used in combination with the improved construction of
rolls described or in combination with ordinary metallic rolls.
According to a further improvement of my Invention which also relates to
welding mandrels, I place two or more metal rolls (by preference only two) in a

page_text: housing frame with their axes parallel, or nearly parallel to each other, having
their surfaces opposite each other formed with hollow or plain counterpart to the
shape of the bulbous or otherwise formed mandrels to be used, between which
rollers the improved mandrel described, or an ordinary metallic mandrel is placed,
and one or both rolls brought together by screws while revolving, so as to grasp,
compress, and revolve the mandrel so as to shape and smooth it, Metallic
mandrels while being so operated upon by preference being heated to redness.
While being revolved between the rolls in the way described, graphite or other
heat resisting or lubricating substance or materials in a ground or friable state, is
placed and drawn in between the closing surfaces of the rolls and mandrel,
for the purpose of treating or coating the surface of the mandrel to increase its
durability.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Robertson in the Great Seal Patent Office on the
5th December 1882.
JAMES ROBERTSON, of Govan in the County of Renfrew, North-Britain,
* IMPROVEMENTS IN OR CONNECTED WITH THE MANUFACTURE OF METAL TUBES
"
My said Invention, which relates to the manufacture of metal tubes, has special
reference to an improved mode and means of grinding and polishing or finishing
tubes of iron steel or other metal and to improvements in the construction and
arrangement of apparatus for rolling the tubes and effecting the grinding or
polishing operations.
The Invention comprises (1) a mode and means of grinding and polishing metal
tubes when specially heated, and in a partially softened state, (2) an improved
construction of skew rolls (for rolling tubes) formed of asbestos, or preparations of
asbestos in the form of washers or spiral rings fixed on the peripheries of the rolls
(3) an improved construction of welding or sizeing grooved. rolls, having their
acting surfaces composed of asbestos or preparations of asbestos, formed into
washers or spiral rings compressed and held together by rings or washers of metal
and bolts or rivets, also (4) improved constructions of bulbous mandrels (to be
used in rolling tubes) in which the bulb or head which bears on the inner surface
of the tube is formed of asbestos washers or rings or combined with acting surfaces
of asbestos compressed between plates by a screw or other means. Also (5) a
mode of rounding, shaping or preparing bulbous welding, soldering, or finishing
mandrels whether metallic or composed of asbestos as described, such rounding,
shaping, or preparing being effected by rolling the mandrels between two or more
hard metal rolls acting together on the surface of the mandrels, while graphite or
other nonconducting lubricating or heat resisting material is rolled in or caused to
adhere to the surface of the mandrels.
These improvements may be used in combination or employed independently
the rolls and mandrels formed of beat monconducting materials being chiefly
advantageous for the manufacture of very thin tubes to prevent the abstraction of
heat from the tube in welding or before it gets presented to the action of the
finishing grindstone.
In carrying out the first part of this Invention, a grinding machine or number
of grindstones which may be formed of natural rock or artificially made, is or are
fitted in combination with the ordinary or specially formed skew rolling
machinery and usual welding furnace, or combined with a reheating furnace or
other heating apparatus and skew rolls. Such grindstone or grindstones are
rotated and caused to act on the surface of the metal tube, while at the red heat
and in a partially softened state for the purpose of grinding and polishing and
finishing the outer surface of the tube as it is revolved and moved longitudinally
by the skew rolls over the face of the revolving grindstone or grindstones.
The objects of grinding the tubes while in a hot state, are to enable the grind-
stone to have a greater bite or better grinding effect on the tube, and less wearing
action on the grindstone itself, than when grinding in a cold state, and also to
prevent glazing and unequal wear of the surface of the grinding stone or grinding
wheel, and to dispense with the use of water on its surface. This new and improved
method of grinding tubes gives to the tube a very perfectly cylindrical form and
smooth surface, and imparts also to its surface a darkish blue tint or colour,
by the uniform deposit of a thin coating of oxide on the clean surface in induces
in cooling.

page_text: In order that my Invention. may be properly understood, I have hereunto
appended two sheets of Drawings representing modifications of the machines and
apparatus which I employ in carrying out my Invention. In these drawings the
same letters of reference are used to denote like parts in the various figures. I use
the term ordinary skew rolls to denote the various well known forms of rolls in
use for producing frictional rotatory spiral action in their various forms of cylin-
drical, conical and internal skew set rolling surfaces or combinations of same, all
more or less suitable for my new and improved hot gringing process, as for example,
as are shown applied for this purpose in the Specification of Letters Patent granted
to me Numbered 3677, dated 20th December 1869 and in the specification of
Letters Patent granted to me Numbered 4201 dated 22nd October 1878. I
however show only applied the cylindrical form of skew roll in my grinding
machine, as being greatly the best form of skew roll for carrying out my said
Invention.
It is important in a grinding machine for this purpose to have it readily
adjustable for the various diameters of tubes to be operated upon, and this
necessitates that the grindstone should have an adjusting arrangement to bring
it forward on the tube as it wears down in the performance of its work, to have
also adjusting arrangements to bring the skew rolls together to grasp in the due
degree the various diameters of tubes, as also adjusting arrangements for the
supporting anvil on which the tube rests, and for the skew, roll which presses the
tube forward on the surface of the grindstone, which adjusting arrangements are
hereinafter shown in detail by figures 1 and 2 on sheet 1 of the accompanying
drawings. This apparatus consists of a grindstone A, keyed on a spindle A',
and working in the adjustable bearings A2 and A³, having keyed on it a driving
belt pulley As resting on a strong wooden frame B. A pair of cast iron cheeks
C and C resting on the wooden frame B carries the bearings of the skew rolls and
gear and adjusting apparatus for the same, the lower pair of skew rolls D and D¹
being keyed on the axis D2 with straight or slightly hollow surfaces, and rounded
off at the entering ends for the tube entering freely and being set in the frames
C and C in the fixed bearings D³ and D' to keep the acting surfaces of these rolls
in line with the ways or troughs in which the tubes are placed for entering into
and being discharged from the machine when ground or finished. The axis of
these rolls has keyed upon it the toothed gear wheel D³, into which is geared a
pinion De keyed upon a cross shaft D', carried in the bearings Ds and Dº fixed on
the cheeks, this cross shaft D' having keyed on it also the pulley D10 to be actuated
by a strap, and forming the driving gear of the lower pair of skew rolls. The
upper pair of skew rolls E and E¹ are also formed of iron, and of the same shape
and diameter as the lower pair of rolls, and their axes are also shown set at the
requisite angle in the opposite direction from that of the two lower rolls just
described, to produce frictional screwing action in the tube F shown placed between
these two sets of rolls.
The rolls E and E¹ are keyed upon their cross axis shaft E³, and are carried in
the adjustable slide block bearings E³ and E* which are raised and lowered by the
screws E5 and E6 and levers E7 and Es in the manner of ordinary slide bush pillow
blocks to raise and lower the pair of skew rolls to grasp, in the requisite degree,
the various required diameters of tubes. On the outer end of this roll, axis E² is
keyed the tooth spur wheel E, into which is geared the toothed pinion E10 keyed
on the cross shaft E, which shaft has keyed on its outer end the pulley E¹², to be
actuated by a belt which forms the actuating gear of the upper skew rolls.
These upper skew rolls E and E¹ are driven at a slightly greater circumferential
speed than the lower and corresponding pair of skew rolls, in order to tend to keep
the tube F being operated upon, up to the surface of the grindstone A and to the
guiding anvil pieces H and H. These anvil pieces are kept in line with the acting
face of the grindstone, or slightly back from it, by the adjusting screws H² and H³,
and the side frictional binding screw bolts H and H, and they serve to guide the
tube F in between the rolls from the entering side of the machine, and out from it

page_text: on the delivery side. The motions of the rolls and gear, as also the motion of the
tube and grindstone, are all indicated by the arrows placed on them. The cir-
cumferential speed of the grinding stone is the usual highest speed compatible
with safety, and that of the tube about 400 feet per minute, these speeds being
suitable for the rolls for straightening and rounding the tube at the same time as
they revolve and traverse it over the face of the grindstone.
A single skew roll G made of iron and of light proportions, and well rounded off
at the entering side for the tube, is keyed upon the axial cross shaft G¹ and set in
ordinary adjustable sliding bush bearings G2 and G³ to hold the tube F, being
operated upon, up to the revolving surface of the grindstone at the requisite degree
of pressure, and to adjust to any required diameter of tube by the screws G¹
and G5 and hand wheels Go and G7. This roll G is actuated or revolved by its
frictional contact with the tube alone, requiring very little force to revolve it.
For grinding taper tubes, this pulley G is held up to the tube by a hand lever, so
that it may be more readily adjustable, and as being more sensitive to the touch
than screws.
Immediately under and in contact with the periphery of the tube F being
operated upon, a cross anvil piece I, preferably of cast iron, and of slightly greater
length than the breadth of the grindstone is used, an end elevation of which is
shown in figure 1 by the dotted lines I. This anvil piece is supported in a slot in
the levers I and I² to be readily interchangeable for any required diameter of
tube. These levers are supported on their respective main frames or cheeks C
and C¹, by the strong snugs C3 and C4, and are secured to these snugs by the
fulcrum bolts Is and I, and extending back to the adjusting set pins I and IⓇ
(shown by the dotted lines in figure 1) which are screwed into snugs cast in the
check C and similar snugs cast on and screwed in the cheek C¹ and set screws I
and I, the ends of which abut up tightly against their respective levers, the anvil
supporting bar I placed at the opposite end of these levers being thereby raised or
depressed at pleasure.
The necessary mobility and adjustment of the grindstone pillow blocks A² and A³
to bring up the grindstone A to the tube as it wears down is effected by the
continuous screws A' and A5 and their corresponding nuts A° and A7 (seen in
figure 1) which move the pillow blocks on iron sliding bars placed on the wooden
frame B, and jam it tightly to any position. As the stone wears very slowly, these
screws seldom require to be touched. The grindstone is actuated by a belt placed
on the pulley A8 in the ordinary way. The main condition to attain excellence of
straightening and finishing as described by this process is to pass the tubes through
the machine as swiftly and as hot as possible.
It is preferred to employ this grinding and finishing process in combination
with the welding furnace and welding rolls, or equivalent welding die draw-bench,
or open jointed tube rolls, or draw-bench; and if sizing rolls or dies are used
this grinding and finishing process is also employed in combination with such rolls
or dies 2 and the welding or heating furnace or equivalent heating means or
apparatus which should be in close and convenient proximity to the skew rolling,
straightening and grinding machine, so as to have the tube presented and spirally
rolled across the surface of the grindstone as quickly and with as little loss of
heat as possible from the operations of the several processes.
The heating of the tube, or the maintaining of the tube in a heated state for the
grinding and finishing process, may be effected by the ignition of carbonic oxide gas
mixed with air in jets, or the tube may be placed in a gas chamber, or be heated
by an electric current.
Figures 3 and 4 are an elevation and plan of a heating or welding furnace with
the forward end broken off. Figures 5 and 6 are a side elevation and plan of a set
of ordinary welding rolls and trough K which may be fitted with power gear for
throwing the tube off the stem rod quickly. Figures 7 and 8 are an elevation and
plan of a grinding machine, as just described in connection with figures 1 and 2
(but without full details) and with entering and delivering troughs K, K' for the

page_text: tubes. Figures 9 and 10 are a side elevation and plan of a set of sizing rolls 3 and
delivery troughs K', and figures 11 and 12 are a side elevation and plan of
another grinding machine similar to figures 1 and 2 with entering and delivery
troughs K, K, and Figure 13 is a plan of a hand knife finning bench each part or
machine in itself, which may be of any ordinary or new form for effecting the
several processes and arranged to carry out in the best way this new and igproved
hot grinding process.
Referring to these drawings the course of the tube F to be operated upon is as
indicated by the arrows placed on it, being drawn from the furnace (figures 3 and 4)
passed through welding rolls and their trough (figures 5 and 6) and thence removed
either by hand or by power delivering apparatus, to the hand finning bench 4 shown
by figure 13, thence it is lifted by hand to the entering trough of the grinding
machine figures 7 & 8, and in being passed by the grinding machine across the face
of the grindstone, (as described in connection with Figures 1 and 2) gets the fins
and all rough protuberances ground off it. It is then delivered on to the delivery
trough K of this machine, thence the tube is entered by hand into the sizing
rolls 3 (figures 9 and 10) which deliver it into the entering trough K of the
grinding machine (figures 11 and 12) which grinds and finely finishes the tube
with ease, and still in a red-hot state to the delivery trough K₁ of this machine,
the course of the tube F through the several machines being indicated by arrows.
The after grinding machine (figures 11 and 12) may, however, be dispensed with,
by carefully finning the tube on the fin bench, figure 13, as it comes from the
welding rolls, and the tube may either bessed through the sizing rolls before or
after it is passed through the grinding machine (shown by figures 9 and 10) only
to get the desired finish.
When the tubes are first welded or formed and allowed to cool, then a reheating
furnace for the tubes has to be placed near, to be used in combination with the
skew rolling and grinding machine, to bring the tubes to a sufficiently hot state, so
that this grinding and finishing process may be effected as described.
Figure 14 is a side elevation and figure 15 a plan of a portion of a reheating
furnace J and grinding machine in small scale, without details, similar to that
described in connection with figures 1 and 2, having an ordinary channel trough K
at the entering side of the grinding machine (same as shown in connection with
figure 7 and 8, as also figures 11 and 12) but with a plain trough plate K¹ on the
delivery side in which I use a stem rod K³ like the ordinary stem rod of a set of
welding rolls with a slack fitting scraper sharp at the point for entering on the
tube, with the scraper end placed in the course or way of the tube between or near
the last pair or delivering pair of rolls D and E. The swift motion of the tube in
its hot state by the attrition of the stationary scraper lying on the under hot
surface of the tube being swiftly revolved, cleans off the scale or other roughness
from the tube internally at the same time, as it is being ground and finished
externally. The stem rod K² also serves as a guide on the trough plate in lieu of
the ordinary channel plates. The form of the loose bulbous scraper K³, placed or
formed on the end of the stem roll K², is better seen in the enlarged side sectional
elevation of portion of a tube F, and scraper K³ placed in it, and by the end
elevation of same shown by figure 19. This reheating process may nevertheless be
used as shown without this internal tube finishing process just described.
Metallic cylindrical objects, such as rods and shafts, can obviously be ground in
a hot state from the rolling mill, or be specially reheated for the grinding operation
which is effected by the same grinding arrangements and machines without any
modification or alteration in any of the parts of this hot grinding process, and it is
intended to finish rods and shafts in the same way in a hot state.
Figure 18 is a side sectional elevation, and figure 19 an end elevation of a skew
roll, having its acting surface composed of asbestos washers in the form which
paper rollers usually are made. This roll has a central boss E¹³ bored out, and an
axis E2 shown fitted therein, the external surface of the boss E's being turned and.

page_text: a movable wasber or ring E¼ bored out to fit the same. This ring E has shown
in it the screw bolts e. e.
Asbestos washers about one quarter of an inch thick, with holes cut out in the
centre to fit the central boss E¹s are shown in the mass E¹ which is compressed by
means of an hydraulic or other press, and held or drawn up by the bolts e, c. The
use of the hydraulic press and of the bolts e, e, gives to this mass of asbestos rings E
the requisite solidity, and when turned the smoothness necessary for skew rolls for
this grinding process.
For this grinding machine it is chiefly advantageous to use rolls formed of
asbestos, as described, on the tube entering side of the machine, because asbestos
is an excellent nonconductor of heat, and the asbestos mass is softer than iron; and
as the tube when taken from the finning bench described has always some protu-
berances left, these protuberances may partially indent themselves into the soft
mass of the asbestos, while if iron rolls were used, the iron surface would tend to
crush in these protuberances into the tube. Figure 20 is a side sectional elevation,
and Figure 21 an end elevation of a similar roll formed also in the same way of
asbestos rings. This roll differs only from that shown in Figures 18 and 19 in so
far as in this example bristles of steel or metallic wire el. e¹ are shown fixed between
the asbestos rings; or spiral flat sheets are coiled into the masses E15; in the manner
of a cylindrical wire brush. This arrangement is also mainly intended for the
entering rolls on the grinding machine D', E', (shown in figures 1 and 2, and to
produce rotating screwing action on the tube without the risk of crushing in fins
or protuberances on the hot tube before it reaches the grinding stone or wheel.
Metallic skew rolls for this hot grinding process may be formed for the tube
entering rolls of the grinding machine with surfaces formed into grooves and ridges,
or with screw or helical ridges, or fluted longitudinally for the purpose of presenting
less cooling surface to the tube, and to prevent the indentations of rough fins or
protuberances into the mass of the tube, by the surface of the rolls.
Figure 22 is a side elevation, and Figure 23 an end elevation of a pair of metallic
skew rolls D' and E¹ with spiral ridges to present in this way a reduced surface to
the tube, while securing the requisite length for straightening and driving action.
Figure 24 is a side elevation, and Figure 25 an end elevation of a similar pair of
skew rolls D¹ and E' with the surfaces formed into grooves and ridges in a wedge
form for a similar object. Figure 26 is a side elevation, and Figure 27 an end
elevation of a pair of skew rolls fluted longitudinally with small flutes or grooves
to produce a diminution of contact with the hot tube for like objects. Figure 28
is a side elevation, and Figure 29 a plan of a pair of skew rolls D₁ and E' of one of
the conical forms hereinbefore referred to, which also produce skew rolling action
on tubes or cylindrical objects, as indicated by the arrows on the tube F placed
between them. Figure 30 is a plan and Figure 31 a side elevation of another pair
of conical skew rolls of another and different disposition, with a tube F shown
between them, and arrows indicating the direction of skew or spiral motion given
to the tube.
These modifications of bevil rolls for producing skew rolling action, as well as
other modifications shown in the specifications of Letters Patent herein before
referred to are nevertheless much more difficult to apply for this hot grinding
process than the parallel rolls herein described owing mainly to their having. too
narrow acting surfaces. Figure 32 is an end elevation, and Figure 33 a side
elevation of a pair of tube welding rolls or tube forming or sizing rolls L and L', as
hereinbefore referred to, with their acting surfaces composed of asbestos washers, or
spirally coiled sheets of asbestos formed in a similar way to the skew rolls described
in connection with figures 18 and 20. These rolls are grooved for the tube as
shown, and afterwards turned out to the size required. One of the main difficulties
experienced in welding very thin tubes by the use of metallic rolls, is that the
metallic rolls abstract the heat to rapidly, but by the use of rolls formed with
surfaces of asbestos, which is an excellent nonconductor of heat, this difficulty is
obviated. Rolls of this construction when used in combination with or formed of

page_text: asbestos, are suitable for soldering tubes at a slow motion, the mandrel by preference
being made to revolve quickly as the tube is passed over it.
Figure 34 is a side sectional elevation, and Figure 35 an end elevation of a
mandrel, by preference with the central piece M, and stem rod prong M' fixed in
one piece of wrought iron, having the central piece screwed or secured to the screw
nut M2, the same diameter, or nearly the same diameter, as the mandrel. Between
this screw nut and the collar part M³ of the mandrel, are placed a series of asbestos
washers m, m, compressed hard on by a strong bydraulic or other press, and held
tightly by the screw nut M². The asbestos washers are afterwards pressed to the
diameter required. The mandrel may either be used as a stationary or as a
revolving mandrel.
Figure 36 is a side sectional elevation and Figure 37 an end elevation of a similar
mandrel, but the acting periphery in this modification is composed of four metallic
washers, having loosely inserted between them the five asbestos washers o. o. o. 0. 0
for the purpose of absorbing water. Tube welding mandrels have to be cooled
in water every time they are used, but by the use of these asbestos washers
which possess great power of absorpton of water, the mandrel is kept com-
paratively cool, while asbestos being a material which is not destroyed by
heat, the movable acting washers n, n, n, n, are preserved. In this arrangement
also the metallic washers may be readily replaced by new one when they do get
worn.
Figure 38 is a side elevation. Figure 39 an end elevation, and Figure 40 a plan
of a machine for rolling, shaping, and smoothing mandrels, which while adapted for
shaping and rounding up truly mandrels from wrought iron or steel is particularly
suitable for ordinary cast iron mandrels. The mandrels are by means of this
machine rolled shaped and smoothed after heating them to a red heat and by
compressing and revolving them between the rolls while graphite or similar
nonconducting or heat resisting and lubricating material is rolled in or caused to
adhere to the surface of the mandrels, until they are round and smooth. As is
well known cast-iron mandrels for welding tubes stand best with the skin of the
casting upon them, and this process of rolling and strewing graphite into the
surface of the mandrel, gives to the cast-iron mandrela, the smoothness and truly
round form obtained ordinarily by turning, and that without breaking the skin of
the casting. A pair of chilled rolls P. and P' are set in the strong housing Q.
and Q, the bushes of the roll P¹ being stationary, the necks of the roll P are set
in ordinary sliding bushes Q and Q³ and are moved outwards or inwards towards
the roll P at pleasure, for any required size of mandrel, and to give any required
degree of compression, by means of the screws Q and Q actuated simultaneously
by the toothed gear wheel Q and Q7 and the hand wheel Q. The rolls have
keyed on their outer end bosses, the toothed bevil wheels P2 and P3 which
gear into corresponding toothed bevil pinions R and R¹, one of which R' is
keyed on the main driving shaft R2 set in the bearings R³ and R* the pinion R
being adapted to move inwards or outwards according as small or large
mandrels are being operated upon. The housing is fixed on the sole-plate S
and an adjustable anvil piece I is fitted immediately under and in contact with the
mandrel being operated upon. The mandrel M as seen in Figure 40 is placed
between the rolls, and whilst it is being rapidly revolved is compressed by moving
forward the slide bearings Q and Q³ carrying the roll P, these slide bearings being
actuated by the band wheel Q8 and screw gear as described. A few revolutions of
the rolls P, P¹ while the mandrel M is revolved between them and graphite or other
lubricating and heat resisting materials in small quantity is strewn in between the
closing surfaces of the roll and mandrel, is sufficient to make the mandrel quite
smooth and round, and ready for use with the welding rolls. In the rough casting,
the graphite adheres sufficiently to the mandrel to enable it to be used for welding
several tubes, but it becomes necessary at intervals, to treat the surface of the
mandrel afresh with the lubricating materials. For wrought iron or steel mandrels,
it is of advantage to etch their surface with acids in order to form small crevices in

page_text: which the graphite may lodge, and be caused to adhere to the mandrel by the
compression of the rolls. Wrought iron or steel mandrels particularly are with
advantage bored with small holes 2, in their peripheries for the reception of the
graphite in the manner shown by side sectional elevation of the mandrel in Figure 41,
and the end elevation of same in figure 42. The rolling of the mandrel between
the rolls while the graphite is strewn in is continued until the small holes are packed
full and hard with the graphite.
Instead of graphite, dried vegetable or animal matter may be rolled on to the
surface of the mandrel, and be carbonised either by heat.or by means of acids, the
treatment by acids in particular tending to harden on the carbon film, or to
incorporate it with the surface of the metallic mandrel.
Whilst the mandrels are being revolved in the machine just described, the central
hole may be made true by a boring drill T brought forward by a screw T2 in the
manner of a vertical drilling machine. Or an arbor "speg" T₁ the same form and
size as the "speg on the end of the welding stem rod as shown by figures 43, 44
and 45, may be used in place of the drill T to keep the central cast hole in the
mandrel true with its external surface.
"
This process is of great advantage for ordinary stationary welding mandrels, but
it is particularly so for the welding mandrels when made to revolve.
Figure 46 is an end elevation and Figure 47 a plan of a similar machine of
smaller size but for the same purpose and mainly for placing on the tube-welders
mandrel bench to clean off the slag from the mandrels rapidly, instead of doing so
in the ordinary way, by the use of a file, and for the purpose also of rolling and
treating the surface of the mandrel afresh with the graphite or other lubricating
materials before the mandrel is used for every tube intended to be welded.. Such
treatment of the mandrel produces not only a great saving in mandrels, but also
tends to produce smoother and better welded tubes. The rolls of this machine
being small, are driven direct by straps, and only the one end is made movable by
the hand lever Qs, but otherwise it is the same in form as that just described in
connection with figures 38, 39 and 40.
Having thus described my said Invention, and the manner of performing the
same, I have to state that I do not restrict myself to the precise details herein
described or delineated, but what I believe to be novel and original, and therefore
claim as the Invention secured to me by the hereinbefore in part recited Letters
Patent is,-
First. The heating and grinding or polishing of metallic tubes in the manner
and by the improved means or appliances herein described.
Second. The grinding and polishing of metal tubes while in a heated state, by
means of grinding stones and apparatus arranged and combined substantially as
herein described and delineated.
Third. As means for grinding and polishing or finishing metal tubes or rods
(while in a heated state) the combination of a heating or reheating furnace or
furnaces, with skew rolling and grinding apparatus, substantially as herein described
with reference to figures 1 to 17 of the accompanying Drawings.
Fourth. The constructing of skew rolls (for rolling metal tubes) by combining
with metallic cores, annular washers or rings of asbestos, or of preparations of
asbestos to form the rolling or acting surfaces of such rolls, substantially in the
manner herein described with reference to figures 18 to 21 of the accompanying
Drawings.
Fifth. The constructing of grooved rolls for welding or soldering and sizing
metal tubes, by combining with metallic cores, annular washers or rings of asbestos,
or of preparations of asbestos, to form the rolling or acting surfaces of such rolls,
substantially in the manner herein described with reference to figures 32 and 33 of
the accompanying Drawings.
Sixth. The constructing of bulbous mandrels for use in rolling metal tubes by
combining with solid or hollow metallic cores or stems, annular washers or rings of
asbestos or preparations of asbestos, to form the bulbs or acting surfaces of such

page_text: mandrels, substantially in the manner herein described in reference to figures 34
and 35 of the accompanying Drawings.
Seventh. The coating or treating and preparing of bulbous metallic mandrels,
for use in welding tubes with graphite or other similar nonconducting, lubricating,
and heat resisting material, to form a smooth and hard skin on the bulbs or acting
surfaces of such mandrels, in the manner and by means of apparatus, substantially
such as herein described in reference to figures 38 to 47 of the accompanying
Drawings.
Eighth. The arrangement and construction of rolls and apparatus for rounding,
shaping, or preparing the bulbs or acting surfaces of bulbous mandrels for use in
welding metal tubes, and for rolling or pressing graphite or other similar noncon-
ducting, lubricating and heat resisting material on or into the acting surfaces of
such mandrels, substantially as herein described and illustrated by figures 38 to 47
of the accompanying Drawings.
In Witness Whereof, I the said James Robertson have hereunto set my
hand and seal this second day of December, in the year of our Lord One
thousand eight hundred and eighty two.
Witness,
W. R. M. THOMSON,
Patent Agent,
Glasgow.
JAMES ROBERTSON (L.S.)