METALS AND METAL WORKING
There is something about working metals that makes a tremendously
strong appeal to a fellow and yet it is just as easy to fashion these
elements as it is to shape wood, that is, if you have the right kind of
tools to do it with.
Then there is another good thing about working metals and that is the
tools you need don’t cost very much and you can soon make enough useful
things to pay for them.
Metal working, like wood working, can be divided into two classes and
these are (1) the strictly practical, and (2) the purely ornamental,
but you can often combine them in an object which possesses both
utility and artistic merit.
It is my intention to tell you in this chapter about the tools that
you need to do ordinary metal work, such as sawing, drilling, bending,
filing, etc. As in working wood you ought to have a bench, or a good
strong table will do.
=Your Kit of Tools.=--To work metals you will need certain tools
according to the kind of work you intend to do. If you get all of
those I have listed below you will have nearly all the hand tools you
need to do any kind of a job that may come up. The following list is
quite a full one and a kit which includes all of them will cost in the
neighborhood of fifteen dollars. You don’t need to buy all of them at
once, however, but just get a tool at a time as you must have it until
your kit is complete.
=The Various Kinds of Tools.=--Metal working tools are tempered harder
than wood working tools and are made of what is known as _tool-steel_.
For your kit of machinists’ tools get (1) a ball pein hammer which
weighs about 8 ounces--this is a regular machinists’ hammer; (2) a pair
of 4 inch side cutting pliers; (3) a pair of 8 inch tinners’ snips
which makes a 2 inch cut; (4) a jeweler’s adjustable saw frame; (5) a
hack saw frame to hold an 8 inch saw blade; (6) a hand drill stock with
a chuck for holding round shank drills from 0 to ³⁄₁₆ inch in diameter.
(7) Four Morse twist drills ¹⁄₁₆, ³⁄₃₂, ¹⁄₈ and ³⁄₁₆ inch in diameter;
(8) a 6 inch steel rule, graduated into 8ths, 16ths, 32nds and 64ths of
an inch; (9) a machinist’s steel square with a 2¹⁄₂ inch blade; (10)
a pair of 3 inch spring dividers; (11) a pair of 3 inch inside spring
calipers; (12) a pair of 3 inch outside calipers; (13) a center punch;
(14) a No. 1 set of screw cutting taps and dies, this set contains a
_stock_ or handle and five taps and five dies which cut ⁷⁄₆₄, ⁹⁄₆₄,
⁵⁄₃₂, ³⁄₁₆, and ⁷⁄₃₂ inch in diameter.
(15) A few files--flat, hand, round and half-round in shape and the
_smooth_ and _second cut_ will be the most useful; (16) several screw
drivers, small and large; (17) a soldering copper that weighs about ¹⁄₂
a pound; (18) a can of soldering paste, or you can make a soldering
fluid yourself, and (19) an alcohol lamp, which I told you how to make
in the last chapter, or a Bunsen burner if you have a supply of gas,
and (20) a machinist’s vise. All of these tools are shown in Figs. 27
and 28.
[Illustration:
_TINNER’S SNIPS_
_SOLDERING COPPER AND ALCOHOL LAMP_
_FLAT NOSE SIDE CUTTING PLIERS_
_FLAT NOSE PLIERS_
_ROUND NOSE PLIERS_
_A BENCH LEVEL_
_A WIRE GUAGE_
_A ROSE COUNTERSINK_
_A TAPER REAMER_
_OIL CAN AND OIL STONE_
_SET OF SCREW CUTTING TAPS AND DIES_
_MACHINIST’S VISE_
FIG. 27. THE CHIEF METAL WORKING TOOLS]
[Illustration:
_JEWELLER’S HAMMER_
_BALL PEIN HAMMER_
_HAND DRILL STOCK AND DRILL_
_SPRING DIVIDERS_
_SPRING CALIPERS OUTSIDE_
_SPRING CALIPERS INSIDE_
_JEWELLER’S ADJUSTABLE SAW FRAME_
_HACK SAW_
_6″ STEEL RULE_
_MACHINIST’S STEEL SQUARE_
_CENTER PUNCH_
_COLD CHISEL_
1--_SHELL SQUARE TAPER_
2--_ROUND OR RAT TAIL_
3--_HAND OR FLAT_
_KINDS OF FILES_
FIG. 28. SOME OTHER METAL WORKING TOOLS]
=Some Hints on Using the Tools.=--(1) When you want to rivet something
use the ball pein end of the hammer to pound down the end of the rivet
as this will spread it out in every direction evenly and you can make
it nice and round. (2) Side cutting pliers are useful to hold and bend
bits of metal with and to cut off pieces of wire as well. (3) Tinner’s
snips are simply large powerful shears and you can cut sheet metal up
to ³⁄₃₂ of an inch thick with an ordinary pair. When you cut a sheet of
heavy metal with them let the lower blade and handle rest on your bench
and you can get a better leverage on it. Metals that are thicker than
³⁄₃₂ inch must be sawed.
(4) While metals can be sawed by using a special saw blade in a scroll
saw frame you should use a jeweler’s saw frame with jeweler’s saws for
metal--I prefer the _Fish Brand_ for fine work. (5) For heavier work
use a machinist’s hack saw; put the piece of metal in a vise and have
the part you want to saw close to the jaws of the vise so that it will
not vibrate; use a little pressure on the outward, or cutting stroke,
and let up on it as you draw the saw back or you will dull the teeth.
(6) In using twist drills, and these are the only satisfactory kind for
metal work, be mighty careful not to press too hard on the drill stock
and don’t try to crowd the drill into cutting faster than it will cut
at the speed with which it is turning. In drilling iron keep plenty of
oil on the drill point.
(7) You can measure much more accurately with a steel rule than you can
with a wood rule and whereas measurements in cabinet work down to ¹⁄₁₆
inch are close enough, for metal work it should not be more than ¹⁄₃₂nd
of an inch, and for machine work make your measurements to ¹⁄₆₄th of an
inch. (8) A small steel square is better in every way for metal work
than a carpenters’ try square but you will find it quite expensive.
(9) The advantage of spring dividers over the ordinary kind is that you
can set them very accurately and they will stay where you set them. In
scribing a circle with a pair of dividers mark the center with your
center punch first as this will prevent your dividers from slipping.
(10) Inside calipers are used for measuring the inside diameters of
cylinders and the like, and, conversely (11), outside calipers are used
for measuring the outside of anything that is round. In either case you
measure the distance between the points of your caliper with your rule
to find the diameter of the thing. (12) A center punch is always useful
to make a starting point in metal with, for it can’t be rubbed off or
lost sight of.
(13) A set of taps and dies to cut screw threads with in metal of
whatever kind is a joy forever. All metal work becomes easy if you have
a set of these screw cutting tools and it is next to impossible to make
things if you haven’t got them.
When you are cutting threads in a piece of metal with the tap, the hole
in the metal must of course be a trifle smaller than the diameter of
the tap; the tap is put into a handle called a _stock_ and as you cut
the threads in the metal don’t turn the stock continuously around but
give it one complete turn forward and then half-a-turn backward and you
will be less apt to break the tap.
The same method holds good when you are cutting threads on a rod with
a die; in this case the rod must be a little larger than the hole in
the die. In threading iron use plenty of oil on the tap or die, but for
brass and the softer metals a lubricant is not needed.
(14) In filing work press down on the outward or cutting stroke and
ease up on the file on the return stroke for the teeth of a file are
set like the teeth of a saw, that is, so that the cut is made on the
out stroke.
A small file can be held in one hand and the work you are filing in the
other which can be rested on the edge of the bench but heavier work
must be put in a vise and the file held firmly by the handle with one
hand and the end steadied and guided by the fingers of your other hand.
(15) In putting in a screw always use the largest size screw-driver
whose blade will fit the slot in the head of the screw; this will
prevent the blade of the screw-driver from twisting the edges of the
slot out of shape.
(16) Before a soldering copper can be used, if it is a new one, it must
be _tinned_, that is the point of it must be coated with solder. To
tin it get a pine board about 1 inch thick, 4 inches wide and 6 inches
long, and put some brown resin and bits of solder on it.
File off the copper until the point is sharp and it is bright and
smooth; heat the copper and then melt the resin and solder on the board
with it and rub the copper in them on all sides until a film of solder
is formed on it.
(17) It is cheaper to buy a stick of soldering paste than it is to make
it but you can easily and cheaply make a good _soldering fluid_ by
dissolving a teaspoonful of _zinc chloride_ in an ink bottle full of
clean water.
In heating the soldering iron keep it near the tip of the flame; if
you use an alcohol lamp don’t have the wick too high and if you use a
Bunsen burner adjust the openings in it until the flame is as nearly
invisible as you can get it.
_About Sharpening Tools._--The only metal working tools you will
need to sharpen are the twist drills and these can be sharpened on a
_carborundum oil stone_. Hold the beveled edge of the drill point on
the stone and move it to and fro, being very careful to keep the drill
perfectly straight up and down while you are sharpening it.
=Metals and their Uses.=--Like woods each metal has its especial uses
and it will depend largely on what you are going to make as to the kind
of metal you should make it of.
There are five chief metals and a couple of _alloys_, which are formed
by melting and mixing two or more metals together, which you will find
the most useful and I shall describe these for you in detail.
_Iron._--This is the most useful metal we have. When it is pure it has
a silvery color, is very _tenacious_, which means that it is tough; it
is _malleable_, that is it can be hammered without cracking, and it is
_ductile_ in that it can be drawn out into wire without breaking.
It is hard to get pure iron for nearly all of it contains a small
percent of carbon, silica, phosphorus, sulphur or other elements.
These substances in iron give it different properties. For instance
_cast-iron_ has a large amount of carbon in it; this kind of iron is
good to cast into molds but it cannot be hammered or drawn without
danger of cracking or breaking.
_Wrought iron_ has very little carbon or other substances in it and
this makes it easy to work because it can be hammered or drawn. _Steel_
contains more carbon than wrought iron but it has less carbon than cast
iron; steel can be cast, forged, tempered and hardened by heating it
red hot and then suddenly cooling it.
_Tin._--This is a white metal that looks very much like silver, and it
is so malleable that it can be hammered out into very thin sheets and
which you know so well as _tin-foil_.
It is not found in very many places but the ancients called Britain
the _Tin Islands_ because they got it chiefly from there. What we
ordinarily call _tin_ is really _tin plate_, that is thin sheet iron
coated with tin, and it is used as a covering for other metals because
it does not rust or oxidize in air.
Tin is largely used in making alloys such as soft solder, type-metal,
pewter, etc. It has a very low melting point.
_Zinc._--This is a bluish white metal and though it is sometimes found
in a pure state it is usually found in combination with other elements.
When it is heated to different temperatures it behaves in various
ways; for instance when it is cold it is quite brittle, but at 100 to
150 degrees _Fahrenheit_,[18] it can be easily rolled into sheets and
rods; curiously though when it is heated to 200 degrees or over it gets
brittle again.
[18] The _Fahrenheit_ thermometer scale is the one generally used in
this country. Fahrenheit was a German scientist who lived 200 years
ago, and he invented the mercurial thermometer.
Zinc is easy to cut and when mixed with copper it forms the alloy we
know as brass.
_Lead._--This is the softest metal known and it has a bluish-gray
color. It is very heavy and melts at a low temperature.
Lead was one of the earliest metals known and if you will read the
_Book of Job_ you will find it mentioned there. It has been used
from time immemorial in making water-pipes, utensils, etc., and the
ancient Romans made weights of it. Since it is so soft it can be easily
hammered into any shape or it can be rolled or drawn.
It is also largely used in forming alloys with other metals, thus
_solder_ is made of 50 parts of lead and 50 parts of tin; _type-metal_
is made of 80 parts of lead and 20 parts of antimony; and _pewter_ is
made of 25 parts of lead and 75 parts of tin.
_Copper._--This metal is found in a pure state in large quantities
around Lake Superior in the United States and in Chili, South America.
It is a fairly hard metal of a reddish color, has a high luster, is
malleable, and ductile.
Long before iron was known utensils and weapons for the chase and war
were made of copper and copper tools have been found that were made by
the ancients and tempered even as steel is tempered now, but the art
was lost when iron came into use.
Copper is now largely used in the arts and trades as for the sheathing
and bolts of ships, the conducting parts of electrical apparatus, in
making alloys, such as bronze of which tin is the other metal. Copper
is easily hammered and drawn but it is so tough that it is hard to saw
and drill.
It does not oxidize in dry air but in moist air it gradually changes
and takes on a layer of _carbonate of copper_ which gives it a very
beautiful and artistic appearance and makes it look as if it was a
thousand years old.
_Aluminum._--This metal is found everywhere in nature but as it is
never found free it is only in the last few years that it has been
extracted in large quantities and cheaply enough to bring it into use.
It has a bright bluish white color nearly like that of tin and is the
lightest common metal known.[19] It does not tarnish either in dry or
moist air; it is malleable and ductile and as easy to work as brass
but it is very hard to solder but there are soldering compounds on
the market by which it can be soldered. Aluminum can be bought[20] in
sheets of any thickness, or in rods or tubes of any size.
[19] Aluminum when mixed with magnesium makes an alloy called
_magnaleum_ and this is lighter than aluminum alone.
[20] Sold by the Aluminum Co. of America, 120 Broadway, N. Y.
=A Few Useful Alloys.=--When two or more metals are melted together and
mixed they form what is called an alloy.
_Brass._--This well known alloy is made by mixing zinc with copper.
There are twenty or more different kinds of brass but common brass is
made of 36 parts of zinc and 64 parts of copper.
Brass is harder than copper and while it can be hammered and drawn it
is not nearly as malleable or as ductile as copper. It can be sawed,
drilled, threaded and machined easily and is about the best alloy you
can use for making small parts of machines.
_Type-metal._--All kinds of metals _shrink_ when they cool after being
run into a mold and so the edges of the castings are never very sharp.
Now type metal which is an alloy made of 80 parts of lead and 20
parts of antimony will _expand_ and this is the reason why type is
so beautifully clear and sharp. So if you want to cast little parts
of machines and engines and the like you can do a good job by using
type-metal. As it melts at a low temperature you can melt it in an iron
ladle over the kitchen fire.
_Pewter._--This alloy, which is made of 75 parts of tin and 25 parts of
lead, in Colonial days was much used for making all kinds of table-ware
and household utensils and it will come into vogue again I hope. More
will be said about this alloy and how to work it in the next chapter.
=How to Do Metal Work.=--Now that you know about tools and the
properties of metals there are a few other little things which, if you
will bear them in mind, will enable you to make nearly anything you
want to. The first has to do with drawing and the others with working
the metals themselves.
=First Sketch Your Ideas.=--To start out and try to make an object
which you have in mind without sketching it on paper first so that you
can see just what size to cut and shape it, and how it will look when
you have finished it, is the first step toward being a disappointed boy.
When you get an _abstract idea_ for a design or a machine that you
want to put in _concrete form_ take a rule and compasses, pencil and
paper and draw it out _to scale_, that is, make a drawing of it and
mark the sizes, or dimensions, of each part just as it should be when
the thing is done.
By roughly sketching the object, or, better, by making an accurate
working drawing of it before you do anything else you will save time,
patience and materials.[21]
[21] How to make working drawings is explained in Chapter V. Fuller
directions will be found in _Inventing for Boys_, by the present
author, published by Frederick A. Stokes Company, N. Y.
=Sheet Metal Work.=--_Cutting and Sawing._--After having traced or
otherwise marked out the design or shape you want on the sheet of metal
with the sharp point of your center punch or an awl, or _scribed_ it
with your dividers you can cut it out with your snips if the sheet is
thin enough. If it is too thick to be sheared then saw it out with your
jeweler’s or hack saw.
Should you want to make a hole or an open design of any kind in thin
sheet metal you can easily punch it in with your center punch, or cut
it out with a stencil cutter’s chisel, which is simply a very sharp
cold chisel.[22] But should the metal be too thick to punch or cut in
this way drill a small hole in it and you can then saw out the part
with a jeweler’s saw frame and blade just as you would saw out a piece
of wood with a scroll saw, though you may have to hold the metal in a
vise.
[22] See Chapter VIII.
_Making Seams and Joints._--The next thing to do after having cut out
the different pieces of metal is to put them together. The way you do
this will again depend very largely on the thickness of the metals, but
in any event where the pieces meet, a seam or a joint must be made.
[Illustration:
=A=--_LAP SEAM_
=B=--_GROOVED SEAM_
=C=--_LAP SEAM RIVETED_
=D=--_BUTT JOINT BOLTED_
=E=--_BOX LAP JOINT_
=F=--_BOX GROOVED SEAM_
=G=--_BUTT & PIECED JOINT_
=H=--_CORNER BUTT JOINT SCREWED_
=I=--_CIRCULAR LAP SEAM_
=J=--_CIRCULAR FOLDED SEAM_
=K=--_CIRCULAR OVERFOLD SEAM_
FIG. 29. HOW METAL SEAMS AND JOINTS ARE MADE]
If the metal is thin the pieces can be lapped and then soldered or
riveted together as shown at A in Fig. 29 or you can make a folded seam
as shown at B. If, however, the metal is thick you can make a lap seam
and either rivet or bolt it together with screws having nuts on them as
shown at C.
A strong _butt seam_ can be made by _hard soldering_ or _brazing_ the
edges together but it takes a hot flame and considerable skill to do
a good job of this kind. Another way to make a butt seam of two thick
sheets of metal is to lay them with their edges together and then
rivet a strip or plate on both sides of them as shown at D.
In making corner joints one or both edges of the sheet should be bent
over as pictured at E when they can be soldered, riveted or bolted
together; or a grooved seam can be made as shown at F if the metal is
thin enough.
If the pieces of metal are say ¹⁄₁₆ inch or more thick you can put a
three cornered piece of metal in the corner and drill and thread it so
that the pieces which form the butt joint can be screwed to it as shown
at G, or if one of the pieces is thick enough you can drill and thread
it and screw the other piece to it as shown at H.
When putting ends on tubes and cylinders you can make a circular lap
seam as shown at I, or a circular folded seam as at J or a circular
overfolded seam as shown at K.
=How to Solder Metals.=--The great secret in soldering metals is to
have them perfectly clean and then if you use the right kind of _flux_
and the proper solder you will not have any trouble.
_Fluxes._--After you have cleaned the surfaces to be soldered you must
use a flux to prevent the metal from oxidizing and to make the solder
stick. Different metals require fluxes of different kinds.
When soldering bright new tinware use powdered resin for the flux, but
if the parts are old then scrape and clean them well and use a flux of
_zinc chloride_ solution. To make it dissolve 5 cents’ worth of zinc
chloride--which is muriate of zinc--in a small clean inkbottle full of
warm water; or you can make the muriate of zinc by dissolving some zinc
clippings in muriatic acid and to make the soldering fluid add some
water to it.
This kind of a soldering fluid is a good flux for tin, iron, steel,
brass and copper. It is good for all ordinary work but it must be
washed off from iron or steel as it will rust them very quickly. To
solder copper _sal ammoniac_ can be used.
The only kind of a flux to solder zinc with is a solution made of 10
per cent. of muriatic acid and 90 per cent. of water. For lead, pewter
and any alloy with lead in it use tallow, Gallipoli oil or Venice
turpentine. Resin can be used successfully for all metals provided they
are scraped bright and clean before they are soldered.
_Solders._--Just as certain metals require given fluxes so also do
these metals need special solders.
For soldering tinware a fine tinner’s solder made of 1 part of tin and
1 part of lead flows best. For soldering lead use a fine plumber’s
solder which is formed of 1 part of tin and 2 parts of lead. To solder
pewter which melts at a low temperature use a pewterer’s solder which
is composed of 3 parts of lead and 1 part of bismuth.
=Bolts and Rivets.=--Where two pieces of metal are to be fixed together
so that they can be taken apart again, machine screws with nuts on
them, or bolts,[23] will be found useful.
[23] Machine screws and bolts for model work can be bought of Luther
H. Wightman, Boston, Mass.
A good kind of rivet for small work is known as _tinner’s_ rivets;
they are made of iron and have a length of ⁵⁄₃₂ of a inch. Now a rivet
can either be hammered down so that the point spreads out and forms a
_burr_, or a _washer_, which is called a _burr_, can be slipped down
over it and the end then peined down. Copper-rivets as small as ¹⁄₄
inch in length can be bought at most hardware stores.
=Bending Sheet Metal.=--To bend a metal sheet put it on a wood or metal
form and pound it into shape with a wooden mallet.
The edges of a piece of sheet metal can be bent either by pounding it
over the sharp corner of an iron bar, or if a very small part is to be
bent use a pair of round or flat nose pliers. A thick piece of sheet
metal can be bent by putting it in your vise and pounding over the edge
with a hammer.
=Finishing Up Metals.=--Of course all the rough parts must be smoothed
up with a file; then use emery paper or emery cloth to rub out the
file marks and finally finish off the surface by polishing it with
_crocus_[24] put on with a cloth.
[24] Crocus is a powder made of iron rust.
=Coloring Metals.=--Many things that you make of metal can be greatly
improved in appearance by coloring them.
_Bluing Steel._--First polish the articles and clean them by immersing
them in a hot solution of _caustic soda_. Now put the screws, or
whatever it is you want to blue, in an iron pan half full of dry, clean
sand and heat them over a fire.
Keep moving the articles around with a pair of tweezers until they are
the color you want them and then drop them into clean oil.
_Bluing Brass._--Polished pieces of brass can be given a fine color by
putting them in a solution made as follows:
Stir 1¹⁄₂ drams of _antimony sulphide_,[25] 2 ounces of _calcined soda_
in ³⁄₄ of a pint of water; to this solution add 2¹⁄₄ drams of _kermes_.
Stir well, filter it and then mix it with 2¹⁄₄ drams of _tartar_, 5¹⁄₂
drams of _hyposulphite of soda_ dissolved in ³⁄₄ pint of water when it
is ready to use.
[25] This and all other chemicals can be bought of Eimer and Amend,
Fourth Ave. and 18th Street, New York.
_Giving Brass a Green Color._--Make a solution of 2 ounces of _copper
sulphate_, ¹⁄₂ an ounce of _sal ammoniac_ and 25 ounces of water.
Suspend the articles to be greened in the solution and boil it until
you get the color you want.
_Giving Brass a Dull Look._--First clean the articles thoroughly; then
mix ¹⁄₄ ounce of _iron rust_ and ¹⁄₄ ounce of _white arsenic_ in 4
ounces of _muriatic acid_. Use a brush and paint the articles with this
solution until it takes on the proper dull appearance. Then wipe it
off, oil, dry and lacquer it.
_Frosting Brass Articles._--Hang the brass articles in a boiling
solution of _caustic potash_, wash them off in clean water and dip them
in _nitric acid_ until the oxide is gone, wash them again and throw
them in sawdust to dry; heat them a little and lacquer while they are
warm.
_Lacquering Brass and Copper._--To lacquer a brass or a copper article
dip it in a weak solution of _sulphuric_ acid and water and then wash
it in clean water. Next put the article on a piece of sheet iron and
heat it over a gas jet or in an oven.
It must not be heated enough to color it but just so that when you
place your moistened finger to it it will sizzle; now put on the
lacquer and this can be done by brushing the article over with a
camel’s hair brush or by dipping the article into the lacquer.
_How to Make the Lacquer._--Put 1 ounce of _tumeric powder_, 2 drams of
_annatto_ and 2 drams of _saffron_ into 1 pint of alcohol.
Let it stand for a week or 10 days and shake it often; pour the
clear liquid into a bottle and put in 3 ounces of yellow shellac;
let it stand for a couple of weeks more; shake it often and pour off
carefully. Then you can put it on. Lacquers can be bought ready made
from Hanson and Van Winkle, Dealers in Electroplating Supplies, Newark,
N. J.