Turnaround - Download as DOC

Document Sample
Turnaround - Download as DOC Powered By Docstoc

                                                                                                             April 2002

                            PO Box 52096, Berea 4007, South Africa
CHAIRMAN’S CHIRP                                                 congratulated on keeping five lathes going almost
                                                                 continuously for four days.
                                                                 I know the Cape Town chaps do a lot of demonstrating to
Preparations are well underway for Congress after rather a       the public, but unless we hear about it, we cannot share
slow start when we had difficulty finding a suitable venue       these experiences with the members of AWSA. This is a
that we could afford in Durban. We finally settled on            pity!
Glenwood High School as it is able to provide very similar
facilities to those we enjoyed at Hudson Park in East            We have had good response to our requests for articles and
London. Certain facilities may be better, like a fully           Brian is able to publish some fantastic ones in this issue of
airconditioned plenary room for the large demonstrations,
but certain other aspects may prove less convenient, like all    Turnaround.     We are also now receiving more local
demo rooms being on the first floor. There is a lift!!! Cheap    Guild Newsletters. I really encourage all guilds/
dormitory accommodation is available with food, and the          associations to produce their own Newsletters, however
school caterers will be providing all our meals during           short or simple they may be, as from our own experience
Congress in their large tuck shop. Their main hall is large      here in Durban, good communication with our members
and we can hold the Instant Gallery, AGM, auction etc all        has been one of the main strengths that has doubled our
in this venue. In the very near future Application Forms to      membership over the last five years. Please also send your
attend will be distributed.                                      Newsletters to other local Editors and Chairmen. Use Email
                                                                 and it costs nothing extra.
Our second difficulty has been to find an overseas turner
who is able to attend Congress and tour the country. It          John Mills – Chairman
appears that August in the UK is a very busy time for them
and the two that we have approached so far, Mark Hancock
and Laura Ponting are fully booked. Mark cannot even
come next year. We will try for a bit longer, but the bottom
line is that we may not have a visiting turner for Congress.

The good news is that both Reg Sherwin, whom many of
you already know, and a lesser known to us German turner
Johannes Volmer, who seems to be one of the fathers of
oval turning techniques, both want to visit SA at their own
expense and tour around meeting local turners and giving
demonstrations. Reg may well come during November and
Johannes next year. I have indicated to both of them that we
would be happy to host them and provide accommodation
and local transport.

If we do not have a visiting turner at Congress we hope to                 John Mills’ bowl blank pile
have a couple of other surprises for you all, which we think     (Actually logs for feeding boilers at a sugar mill in
you will enjoy!!!                                                Mozambique. They use wood to get the boilers started and
                                                                 then burn bagasse – the cane residue. Mostly fever tree but
I HOPE YOU ARE ALL PREPARING SOME                                some very turnable material also)
                                                                                 AWSA DETAILS
                                                                 Dates        : 9, 10 ,11 August
                                                                 Registration : Thurs 8 Aug pm and Fri 9 th am.
In the last Turnaround I mentioned that Schalk was
                                                                 Place : Glenwood High School, Mc Donald Rd.
working at getting AWSA involved in Hobby-X and I am
delighted to see from the two articles published that it was a
                                                                 Cost : TBA – Dependent on overseas turner
great success and excellent publicity for our Association.
The Witwatersrand and Pretoria clubs are to be
HOBBY-X                                                     edge turning, square platters and the secrets of captive ring
                                                            turning particularly fascinated people.
Reported by Trevor Pope - Wits Woodworkers
Association                                                 Apart from the fact that it was great fun entertaining the
                                                            huge crowd, quite a number of new members were
The turners put on a most impressive display, under         recruited for the Pretoria Woodworking Association,
the auspices of the Association of Wood-turners of          including at least two from the fairer sex. A father and
South Africa. There were five lathes that were almost       daughter are presently undergoing basic turning tuition
constantly in use, demonstrating a variety of               from At Smit.
techniques. Two more people were on duty to answer
                                                            A retired gentleman from Kenton- on-Sea, on a visit to his
questions from the visitors in front of the display area    family in Pretoria, saw the turning demonstrations at the
where a variety of turned work was on display,              Hobby X. He made an appointment the following week
showing the quality of work done in the club. The           with At Smit to gather more information on lathes and
show ran over 4 days (07th to 10th March at the MTN         turning aspects. He was so impressed and enthusiastic with
Sundome) from 09h00 to 19h00. A fantastic effort            what he saw that he left Pretoria for home with a brand new
was made by the Jo‟burg turners with help from At           swivel head lathe in the back of his car. He undertook to
Smit, Roger Courtney and Louw Trichard from the             contact his nearest wood tuning association/guild for
Pretoria club. The stand generated considerable             further guidance and help.
interest from the public all to promote the craft.          As a promotional exercise for woodturning, the Hobby X
                                                            demonstrations were definitely a great success
Toyota donated twenty shirts for the demonstrators, so
we were able to put on a uniform display that made it
clear to the public who was manning the stand.
Thanks to Schalk for his particular effort in planning
and organising the overall display and to Toyota for
their support! Thanks also to Hardware Center for
providing some of the lathes for the demos, as well as
arranging the space for the demos. (The bill is in the
post for commission from all the referrals we made on
enquiries we received about lathes, tools, etc.)

                                                            Hobby- X – A general view of the exhibition

                                                            I‟m sure you enjoyed Izak‟s article in the January
                                                            issue. Here is the second in the series.
                                                            WOODS I HAD A TURN WITH…PART II
                                                            Last month I mentioned teak (Tectona grandis) as one of
Hobby-X demo – Schalk avn Niekerk shows them                the woods that kiaat is often confused with. That reminded
how                                                         me of an article I read many years ago in a Woodworker
                                                            magazine. It really taxed my patience to dig around in my
Hobby X                                                     “archives”, and, Woodworker, November 118\982 had it
                                                            all!! I am reproducing the article verbatim in its entirety
A report from the Pretoria participants                     with due recognition to Woodworker magazine and the
                                                            author of the article, the then timber expert of the magazine
Seven wood turners from Pretoria from the Pretoria          Bill Brown.
Woodworking Association combined forces with the
turners from Johannesburg to put up a continuous turning    A Tale of Teak……
demonstration on at least four lathes for the four day      What does teak, that most dependable of woods, have in
duration of the Hobby X over the period 7 – 8 March 2002.   common with the musical stage? Quite a lot, according to
                                                            our timber expert, Bill Brown, who here tells the tale of the
                                                            King of Siam, Anna and teak.
The members participating enjoyed the experience (and
admiration from the public) as well as the opportunity to   True teak, the product of Tectona grandis, is a wood
get some training practice. Many and varied questions       renowned for its durability and stability in service, but it is
from the public were answered. Aspects such as natural      outstanding in several other aspects. At one time it was the
only timber classed A1 at Lloyds, Kipling wrote poems in          years Chinese merchants had exploited the teak from these
connection with the wood, a war was fought over it, and a         forests, and one such organisation, Kim Sing Lee, sold out
famous musical has teak connections.                              to BBTCL, thus allowing them to get a toe-hold in Siam.
Teak is highly resistant to fire, both as wood and as a           Anna Harriette Crawford was born in Caernarvon, north
growing tree, in fact, it is said that forest fires improve the   Wales, in 1834 and when she was six years old her parents
quality of young teak trees, and it is certainly true that fire   sailed for India. Her father was an army captain whose
aids the germination of teak seeds. The seeds are enclosed        regiment had been ordered to reinforce troops there in the
in a husk which needs to be removed in order to assist            face of impending war. A year later her father was killed.
germination. A forest fire does this without harm to the
seed so that new seedlings encourage natural regeneration.        When Anna was 15 her mother married again but the
                                                                  stepfather and Anna did not get on and when she later met
Teak is highly resistant to termite (white ant) attack, and       and fell in love with a young British army major, Thomas
because of its short fibres, tends to break under impact          Louis Leonowens, there was much domestic strife
without splintering. It was for this reason it was used           culminating in Anna marrying her “own Leon” in 1851.
extensively for railway carriage construction and for             The break with her stepfather was now complete, but
backing armour plating in warships, thereby reducing              unfortunately the stepfather was the executor of the estate
accidental potential damage to humans.                            her father had left her, in fact that was to affect her later
It is the only tropical hardwood tree that is commercially
ring-girdled prior to felling, and the only one whose             Anna had an unfortunate marriage. She had lost her first
extraction from the forest developed around the use of            two children through illness very early. There were two
elephants. It is said a well-trained animal could haul about      other children, Avis, born in 1854 and Louis Thomas born a
150 logs, each of about a ton, from forest to riverside in a      year later. In 1857 the Indian Mutiny broke out and when it
season.                                                           subsided, Anna found she had not only lost her friends and
                                                                  relatives but also her fortune.
Ring-girdling prevents the flow of sap from the roots to the
crown of the tree and so allows excess moisture to                In 1856 Leon was ordered to Singapore and there the
evaporate through the leaves. In other words the tree             family lived, but in 1858 Leon died of sunstroke brought on
partially seasons at stump, enabling the felled logs to float     by carrying out a tiger hunt during the heat of the day –
down river to the sawmills. Girdling is done by cutting into      typical of mad dogs and Englishmen. Anna‟s stepfather
the bark with an axe, at about breast height, the cut going       had, in the meantime obtained possession of the old house
right through the sapwood and completely circling the bole.       in Caernarvon and now she had nothing beyond the two
It is done annually, and girdled trees are allowed to stand       children.
for two or three years before felling.
I wonder how many people who have seen that delightful            To earn a living, Anna opened a school for officers‟
musical The King and I realise the element of truth that is in    children and this came to the notice of Tan Kim Ching, the
the story. Or the fact that Anna, the governess in the story,     Siamese consul of Singapore, who had been instructed by
not only existed, but represents a direct connection with the     the King of Siam to secure and English governess for the
teak trade of London extending back from the present time         royal children. After protracted negotiations, Anna
to the mid-19th century, when Thailand was Siam.                  received a letter from the king himself offering her the job,
The teak trade actually started in India and Burma, one of        and it is from this stage onwards that the basis of the play
the principal British organisations being the Bombay              and film developed with, of course, a certain amount of
Burma Trading Corporation Ltd, whose shipping mark                poetic licence.
BBTCL was literally the only one seen on teak when I was          Among the pupils none attracted Anna so much as Prince
a boy. It was an extremely powerful company, but there            Chulalonkom and his sister Princess Chanthara Monthon.
was a fly in the ointment, so to speak. In fact there were        Both were exceptionally bright and being of about the same
two flies: the corrupt King Thebaw of Burma and the               age as Anna‟s children, became firm friends.
French consul of the time, one M. Haas, whose ambition it
was to oust the British from Burma in connivance with the
king. A treaty was negotiated between France and Burma            In 1867 Anna became ill and against the king‟s wishes went
under which the French would set up a state bank, take over       first to Ireland and the to New York to try to recuperate,
the ruby mines, and exploit the teak forests of Upper             taking Avis and Louis with her. A year later, King
Burma. In the event, the treaty signed by King Thebaw fell        Somdetch Paraminder Maha Mongkut was dead and was
into British hands and the Foreign Secretary, Lord                succeeded by his son Prince Chulalongkom. Anna never
Salisbury, took appropriate action typical of the time:           returned to Siam and although the king remembered her
within a couple of months am expeditionary force was sent         and Louis generously in his will, neither received the
to Burma and the ensuing campaign led Kipling to write the        inheritance. The executors stopped it.
poem Mandalay.
                                                                  The new king was extremely progressive and pro-western;
This third Burmese War was quickly over and was                   he had his sons educated at English public schools and
probably the only war to be fought on behalf of the timber        abolished slavery, established telephone and telegraph
trade. The BBTCL eventually recovered and expanded,               services, constructed roads, hospitals and so on, carried out
although a number of its staff were killed by the Burmese.        reforms of law and taxation.
The best teak forests in Siam were in the territories of the      Louis Leonowens was by now very restless, he went to
Laos states of Upper Siam, and although independent, they         Australia, but in 18822 he returned to Siam where his
acknowledged the King of Siam as suzerain. For many               friend the king made him an officer in the army. It was
perhaps inevitable that Louis became a man of considerable     progress to be updated whenever new information and
influence wit the king and eventually he set up in the teak    experience become available. My knowledge of the
trade as Leonowens and Company of Bangkok.                     materials and processes involved is very limited indeed,
                                                               assembled from scraps of information from various books
King Chulalongkom died in 1910 and in more recent year,        and articles on blacksmithing, knife making and model
Leonowens became a subsidiary of a prominent firm of           engineering. I therefore welcome any feedback from
timber importers and are still represented in what is now an   anyone who has any comment or anything to add.
international group of timber companies based in London.
As an individual much caught up in romanticism of timber       This article describes the process of making a gouge in the
and trees, I like to believe that it was Anna‟s work at the    following steps:
court f Siam that led to the young prince adopting the          Basic metallurgy (the minimum we need to know
western idea of s and for providing the opportunity for        about tool steels, simplified to the extreme)
young Louis to exploit the teak forests. As the song says,      Selecting suitable steel
“Getting to know you. Getting to know all about you”,           Grinding a flute
which being interpreted could mean „It‟s not what you           Hardening the steel to its maximum possible hardness
know, but who you know, that counts‟.                               (which is too hard to be useful)
                    xxxxxxxxxxxxxxxx                            Tempering (softening it very slightly to a practical
like Lebanon, cedar, teak is one of the oldest trade timbers
of the world, and was used in Babylon and Egypt 4000
                                                               The finished product is by no means the ultimate gouge.
years ago – B. Hausen: Woods Injurious to Human Health
                                                               You will not be throwing out your Sorbys or Titanium
– p. 117.
                                                               coated tools in favour of these, but they work well enough
As seen from the above, teak is indigenous to the East and     to be in everyday use filling the gaps in your range of
more specifically to India, Burma, Thailand, Indo-China        gouges. If, for example, you already have a high quality
and Java, and has been planted in Africa and the West          12mm HSS bowl gouge, try supplementing it with a 6mm
Indies. According to W.A. Lincoln – World Woods in             gouge for detail work, a 10mm gouge with a long pointed
Colour – p. 268, the true teak of Burma is a uniform           bevel for delicate finishing cuts, and a 16 or 18mm heavy
golden-brown colour without markings, but most other teak      gouge with a very steep blunt bevel for working across the
is rich brown with darker chocolate-brown markings.            bottom inside deep bowls.
Indian teak is wavy grained and mottled, but generally
straight to wavy grained, coarse textured, uneven, oily to     The main advantage of home-made gouges is that they cost
the touch, and sometimes with a white glistening deposit.      next to nothing. This means you can make as many as you
The average weight is 650kg/cub. M. It works well but has      like and modify flute shapes, bevel angles and grinds to
a severe blunting effect on cutting tools. Stains well and     your heart‟s content because they are almost expendable.
takes a satisfactory finish, especially on an oil finish.      The main disadvantage is that you will almost certainly
                                                               have to sharpen more often, particularly on hard, abrasive
Warning: Fine machine dust is a skin irritant. Teak has        woods where they are unlikely to hold an edge as well as
long been known for its toxic properties. The first case of    High Speed Steel. More sharpening means they won‟t last
dermatitis was reported in 1896, while the first full          as long, but who cares? On wet wood they perform well,
description of a case of contact allergy was given in 1905.    you may not even notice any difference between these and
Chemical investigations revealed two sensitisers causing       your expensive gouges. The other limitation is that they are
allergic contact dermatitis.                                   vulnerable to heat (the section on tempering explains why).
Next month: How is the hardness of wood determined?            This does mean you need to keep them cool while
What have Ocotea Bullata, Celtis africana and Phoebe           sharpening, particularly with smaller tools. Just dip them in
porosa in common                                               water frequently while sharpening and don‟t ever let the tip
                                                               get hot enough to burn your fingers.

@@@@@@@@@@@@@@@@@@@@@@@@@                                      (VERY) BASIC METALLURGY

MAKING YOUR OWN BOWL                                           To make cutting tools we need steel which can be hardened
                                                               sufficiently to hold a durable edge. Ordinary steel, usually
GOUGES - By Grant Marshall - Knysna                            called Mild Steel can‟t be hardened because it lacks
                                                               sufficient carbon. Our focus is therefore on Carbon Steel
With the current high cost of imported tools these days,       (also called High Carbon Steel or Tool Steel) which
buying a range of different sizes of gouges is very            contains between 0.8% and 1.2% carbon. For now we can
expensive and having additional specialised gouges with        forget about High Speed Steel, I‟ll explain why later.
different bevel angles for special cuts is a luxury few can
afford. While most turners are happy to make scrapers or       When heated to above its transformation temperature
thin parting tools, most probably imagine that bowl gouges     (“Cherry Red” in blacksmith‟s terms, or about 800 degrees
would be too difficult to make in a home workshop. The         C), steel has an affinity for carbon, combining with it to
fact is that with simple equipment and a basic grasp of the    form a carbon-iron compound called iron carbide. Below
principles, making a usable gouge is not difficult at all.     that temperature it doesn‟t like carbon. Allowing it to cool
                                                               very slowly from red hot will cause it to dissociate into its
Here follows a fairly detailed account of my own               constituent components of iron and carbon. This process is
explorations into the field of home-made gouges. I am still    called annealing and will cause a softening of the steel.
learning as I go so this article is very much a work in        Cooling it very rapidly, on the other hand, (by quenching it
in oil or water) gives it no time to separate and the carbon     Here are some examples:
atoms get trapped inside the iron crystal structure. This                 Any round spring steel
yields a very hard and very brittle steel measuring 65 - 66               Torsion Bars and anti Roll Bars from cars
on the Rockwell C hardness scale. Unfortunately this too                  suspension
hard to be useful because the micro edge chips off instantly              Torsion spring rods used in some car boots
in use.                                                                   McPherson strut or shock absorber shaft
                                                                          “W”- shaped camp bed leg
To be useful we need to temper it, in other words to soften               Bakkie tonneau cover support rod
it very slightly by heating it just enough to turn a precise              Any round tool steel
amount of the very hard stuff back into carbon and iron
                                                                          Long screwdriver
which will make it more flexible and tougher. How hot we
make it determines how much turns back. Too much heat
causes too much softening and the hardness is lost.              Note that some things like shafts and tools may have been
                                                                 casehardened, which means the outside is hard but the
That‟s pretty much all we need to know about this vast and       middle isn‟t. For gouges we need to harden all the way
complex field. To summarize: We take a piece of carbon           through because our cutting edge is located somewhere
steel, heat it red hot and quench it very quickly to harden it   near the middle. Steel used in things like garden tools and
as much as possible. Then in a process called tempering we       crowbars may not contain enough carbon to be hardened
soften it just a little to achieve a durable hardness.           enough.

The exact temperatures involved vary depending on the            To test the suitability of steel on the spot try punching,
precise content of the steel, but for our purposes               filing or hacksawing it, you‟ll soon know if it is hard
transformation temperature is around 780 - 820 degrees C         enough because the file will skate off it without cutting it.
(cherry red when viewed in your workshop in daylight).           Back in your workshop you can use a spark test to get an
Conveniently for us, this is also exactly the temperature at     idea of the composition of the steel. Touch a piece of mild
which carbon steel becomes non magnetic, so when a               steel on your bench grinder so you get a stream of sparks
magnet won‟t stick to your red hot gouge you‟re at the right     out into space. Take a good look at the sparks and compare
temperature. For tempering we use much lower                     them to the sparks you get from the tip of a file or an allen
temperatures, around 150 to 350 degrees C and here we can        key (both are high carbon steel). Notice how carbon steel
make use of the colours of the oxides released onto the
                                                                 produces a lot more sparks than mild steel and they are
surface during heating. (See the table of temperatures and
colours.) We‟ve all seen a piece of clean shiny steel change     much finer and whiter and they explode much more in
colour as it is heated, going from pale yellow, through          flight. The more little explosions, the more carbon in the
straw and brown to purple to blue (as novice turners we          steel. Basically, any steel you want to use for tool making
may have seen the tips of our gouges go those same pretty        must make sparks exactly like the allen key makes. Just for
colours during overzealous sharpening). That first pale          fun check out the sparks from the back end of a drill bit or
yellow appears at 200 and that‟s about right to temper the       from your best gouge (high speed steel). HSS produces
steel to the hardness we want (about 62 Rockwell C). The         very few sparks, they are deep red in colour, they don‟t
purples and blues mean a higher temp has been reached and        explode at all and they fly in curving paths.
the steel has been softened too much for our purpose
                                                                 Okay, so now you have a suitable length of carbon steel rod
MATERIALS                                                        and you want to make a gouge.

There is no shortage of sources of carbon steel suitable for     FLUTING
tool making. The ideal would be to buy a rod of the right
diameter from a specialist steel supplier. The advantage         Start with an over-length piece so if you really make a mess
here is you get a description of its exact composition and       of it you can cut the end off and try again. You can anneal
you get precise instructions for hardening and tempering so      (soften) the section you want to work on by heating it to red
there‟s no guessing. Whether this will yield a better tool
                                                                 hot and letting it cool very slowly over a period of several
given our crude home-workshop methods is debatable.
                                                                 hours. Poking it into a braai and then leaving it there while
Different steel manufacturers will have different names for
their steels but you will need to ask for a cold work carbon     the fire burns itself out is ideal. This will make it a bit
tool steel that can be hardened and tempered in a home           easier to work but isn‟t really necessary. Initially you
workshop. Bohler Steel makes one called “K460”, other            should try to copy the flute shape and proportions of a good
names are “Oil hardening drill rod”, “O1”, BO1”, and             gouge until you know enough to experiment with different
“Silver steel”. These steels may have small amounts of           shapes. A good basic shape would be somewhere between a
other alloys added to them to give them particular               U and a V with the bottom of the flute a bit lower than
properties.                                                      centre.
                                                                 Small tools are easier to make than larger ones at first. I
But we don‟t need to buy fancy steel to make a usable            find it best to keep the flute fairly short for several reasons.
gouge. There‟s plenty of useful junk steel available. Almost     Firstly the tool is stiffer because more of its length is solid.
any steel harder than mild steel will probably work, and         It is safer because only the fluted end is hardened and you
anything that was springy in its previous life will do fine. A   are less likely to snap it in use. Lastly a short flute seems to
motor stripper or a junk shop should yield plenty of             eject shavings better and the stream of chips doesn‟t hit
different sizes.                                                 your hand. You can always lengthen the flute later and
                                                                 perhaps improve on the profile of it when you do.
                                                                   habit of bursting into flame unless the tool is completely
Start by drawing lines on with a felt tip pen to indicate the      submerged when you quench it. This is where the heavy
top edges of the flute. Flatten the top with an angle grinder      wire handle is useful. Work outside and be prepared for a
down to the two lines. Start cutting the flute from the tip        fire anyway. If you buy the steel for the tool the
(which is still expendable). You can use a cutting disc first      manufacturer should tell you what liquid to use for
to make a slot and then switch to a thicker grinding disc to       quenching. Some refinements to the process are to add
widen it and shape it, but I‟ve done the whole thing with          about 8 or 9% salt to the water to raise it‟s boiling point, or
one or the other depending on the size of the flute. It‟s a        to pour a 4cm layer of oil onto the water so the tool passes
messy process, so I‟ve taken to working outside on my              through the oil first. Warming the oil to about 60 degrees
driveway with the tool clamped to a stepladder. Use a              aparrently helps because it thins it and you get better
protective face-shield so you can get in really close to see       contact with the metal.
what‟s happening. Beware of the spark stream, I set myself
alight once. Stop often and use a felt tip pen to highlight        The exact hardness you obtain depends on the actual steel,
spots that need more work or that are complete and mustn‟t         but it will be somewhere around 64 - 66 Rockwell C. As it
go any deeper. I find it easiest to do a short section at a time   is it‟s pretty useless, the edge will be brittle and will blunt
and get it perfect before going further up the length.             quickly. You can test it for hardness by filing it or punching
                                                                   it carefully with a cold chisel. Try it at the tip and further
I hang onto my old angle grinder disks because some have           back on the shaft. Your fluted section should be much
worn to a profile that works well for this purpose. It‟s good      harder than the raw material, and a lot harder than the file
to try to work in both directions while shaping the flute, but     or cold chisel.
absolute symmetry isn‟t essential. There could even be
advantages to an asymmetrical flute, who knows? It‟s               After hardening the fluted section will be a dull black.
important to avoid grooves or ridges in the profile of the         Polish the outside to a bright silver with a strip of sanding
flute because these will appear as notches or points in your       belt or water paper. Now you need to grind away the
cutting edge. You will need to grind at least 0.5mm of steel       surface metal inside the flute because it lost some carbon
off the inside of the flute after hardening, so don‟t go too       during the heating process and we need to get to good fresh
deep, particularly on small tools.                                 steel about 0.5mm deeper. If it was heated I a charcoal fire
                                                                   this will be less of a problem, but regrind anyway just to be
When you‟re happy with the flute you can grind off some            safe. Grind carefully so as not to overheat the steel. The
of the tip to begin forming the bevel but don‟t sharpen it too     surface of the flute forms your cutting edge so it‟s worth
much yet or the thin edge will overheat during hardening..         trying to get it perfectly smooth and even. Avoid
                                                                   overheating it while you grind, dip it in water often to keep
HARDENING                                                          it cool. If you roll up a sheet of water paper and polish the
                                                                   flute your tool will take a better edge and eject shavings
Hold the tool with tongs or wrap some heavy wire around it         better.
so you can hold it completely submerged in the quench
medium while agitating it. For small tools up to about 8 or        TEMPERING
10mm dia you can try heating with a plumber‟s butane
blowtorch, but for larger tools you will probably need an          Once you have it clean and shiny there are 2 ways of
oxyacetylene torch to provide sufficient heat. You might           tempering the tool. The first method is easiest to control.
even be able to approach your local exhaust repair shop and        Simply put the tool in your kitchen oven for an hour at 200
use their torch. If that‟s not available you could try rigging     degrees C. When you take it out it should be a uniform pale
up some sort of blower into a charcoal braai to form a             yellow colour and its hardness should now be about 61 or
makeshift forge. Heat the fluted section slowly to red,            62 Rockwell C, but this is not absolute, it varies with the
applying the heat from underneath to avoid overheating the         alloy/carbon content of the steel and the accuracy of the
thin edges of the flute. Test it with a magnet as soon as it       oven thermometer. An exact hardness is difficult to achieve
begins to glow, and test frequently when you think you are         without specialist equipment so be prepared to experiment a
close. When the magnet doesn‟t stick you are at around 800         little. Treat the colours and temperatures as relative to each
degrees, note the colour. Remember that “cherry red” looks         other for that particular tool/steel. If a tool tempered to very
different in different light conditions. You can go about 50       pale yellow doesn‟t appear to be holding an edge well it
degrees more to be safe, but hotter than that isn‟t a good         could still be too brittle, try tempering it again at a slightly
idea. Keep it at that temperature for a minute or two trying       higher temperature to darker yellow.
to keep the whole thing an even colour. It‟s not necessary to
harden further back than the flute itself. Bear in mind that       Do remember to remove every last trace of quenching oil
the magnet only gives you an accurate indication while the         from the tool before putting it in your oven. If you don‟t
temperature of the tool is rising. If you accidentally             you‟ll have to live with the smell for a long time. It‟s also
overheat it and then test it while it is cooling you don‟t get     worth putting a temporary handle on a tool at first so you
the same result.                                                   can test it, or at least hot glue it into the handle so you can
                                                                   get it out if it needs further heat treatment.
Now plunge it quickly into a large container of water or oil
and agitate it vigorously (waggling it is apparently better        The second method is quicker but consistent results are
than stirring it), trying to cool the whole thing as quickly (in   difficult to achieve. Heat the tool slowly and gently with a
less than a second) and as evenly as possible. Uneven              soft flame from a blowtorch along the fluted part, as evenly
cooling will cause warping and slow cooling will cause             as possible and avoiding the very tip (which will overheat
hardness problems. Water is easy and clean but it can cause        easily). When the colour changes to a pale yellow and
cracks to appear particularly in larger tools. Oil (such as old    before it goes a darker straw or purple, dunk it quickly in
motor oil) works, but it‟s messy, smelly and has a nasty           water to stop any further softening. Note that any variations
in colour will cause variations in hardness in the finished           steel, shape it and send it away for hardening by
tool. I prefer to combine both methods, getting a fairly              professionals.
precise hardness in the fluted section with the oven, then
softening the rest of the body of the tool a little more with a       OTHER TOOLS
flame. I would rather my tools bend in use than snap.
                                                                      These same principles can be applied to other tools. Old
With an understanding of the tempering process it‟s easy to           files are a good source of very high carbon steel but as files
see why you can easily ruin a carbon steel tool by                    they are dangerously brittle. They can be annealed in a
overheating it on the grinder while sharpening. Regular               charcoal fire and then cut with a hacksaw or drilled before
dipping in water will prevent overheating while grinding. If          hardening and tempering. Or they can be placed in the oven
it makes a hissing sound when you dip it, it was already              and tempered for use as scrapers. If you are going to use the
over 100 degrees and the very edge could be very much                 whole file as a scraper, it‟s a good idea to soften the main
hotter. At 250 it is ruined. Temperature, oxidation colour            body more than the tip to lessen the chance of it snapping in
and hardness are all linked. Once the steel at the tip goes           use. Bluing the body with a blowtorch should do the trick.
dark blue its hardness has dropped to about 50 Rockwell C             And choose a fine file so there‟s less to grind off to make it
and rendered it useless. The soft steel must be ground away           smooth.
or the tool can be salvaged by re-hardening and re-                   HSS planer blades can be cut up and slotted with an angle-
tempering.                                                            grinder for use as scraper tips. Because of its tungsten
                                                                      content, even if the steel goes blue it shouldn‟t affect its
                                                                      ability to hold an edge.

High speed steel is a tool steel that retains its hardness even
at very high working temperatures because it has about 6%
tungsten added to it. In use it isn‟t necessarily harder then
carbon steel, it just doesn‟t lose hardness at around 200 deg
C like carbon steel does, in fact heating it to around 550
deg has no effect on it. And its transformation temperature
isn‟t 800 degrees either, it‟s over 1200 degrees. It‟s simply
not feasible to harden and temper it in a home workshop, it
requires far higher temperatures, more accurate temperature
control and a reducing atmosphere to protect the steel from
oxidation during heating.
If you really want to make HSS tools it is better to buy the                    The stages of fluting the gouge

                                    HEAT TREATMENT TEMPERATURES FOR CARBON STEEL

        Temperature             Colour - Glowing Steel
Fahrenheit       Centigrade
     2350          1288         Dazzling White
     2200          1204         White
     1975          1079         Light Yellow
     1825           996         Lemon
     1725           941         Orange
     1650           899         Salmon and Scaling
     1550           843         Bright Red and Scaling
     1375           746         Cherry Red
     1250           677         Medium Cherry Red
     1075           579         Dark Cherry Red
     1050           566         Blood Red
      900           482         Faint red (GLOW)
     Temperature                Colour - Polished Steel           HARDNESS     TYPICAL APPLICATIONS
Fahrenheit    Centigrade
      750           400         Grey
      610           321         Pale blue                            53Rc
      567           297         Bright Blue                          55Rc      Cheap Kitchen knives
      550           287         Dark Blue                            56Rc      Springs
      531           277         Purple                               57Rc      Cold Chisels and punches
      509           265         Brown & Purple                       58Rc
      491           255         Brown                                59Rc      Taps and Scribers
      469           243         Gold Yellow/Straw                    60Rc
      428           220         Pale Yellow                          61Rc
      400           200         Very Pale Yellow                     62Rc      Woodturning tools
                                     SOME THOUGHTS ON DESIGN
                                       Compiled by Andrew Stevens
'Design is the process of making things better for people.' - Richard Seymour

'Design is not just about how something looks, but how it works.' - James Dyson
      'A plan for arranging elements in such a way as to best accomplish a particular purpose.' - Charles Eames

'If you can't explain it on the phone, then it's probably not worth doing.' - Bob Gill

‘Design is not all a matter of problem-solving, neither is it all a matter of art. It is both. The two parts of it are
inseparable.’ - David Pye

'After the colours have faded and the grain patterns have become obscure, only the form of a bowl will ensure its
survival as a desirable object. A bowl of spectacular colour or grain will draw gasps of admiration regardless of its
shape, but this is no indication of how good a bowl it is. It is the timber that is being praised, not the bowl. While it is
all very well to use grain and colour to stunning effect, these characteristics will never outlast the shape - the most
important aspect of a bowl.
Form is all too often regarded in visual terms only. But because bowls are also handled, the tactile qualities are just as
important.' - Richard Raffan Turned-Bowl Design, p40.

'Unstructured creation, freed of a grounding in classical rules, most often results in cerebral popcorn. It is usually also
self-indulgent, appealing only to the creator - a case of beauty being only in the eye of the one beholder!'
Hugh O'Neill: Woodturning, A guide to Advanced Techniques, p.54

'When you are learning the skills involved in woodturning, improving your techniques is important for your sense of achievement
and satisfaction. Mastery of the techniques is essential if you are to create good work, and without a high degree of skill, your work
will be limited. However, command of technique should not be seen as an end in itself; it is simply the means by which you can
produce a beautiful bowl. Form is paramount.'
                                     Bert Marsh,Woodturner, p24
Our appeal for news and articles from around the country               and Louw Trichardt whose work is published here.
has borne fruit. Not a bumper crop but with nurturing the              Also to Graham Ward and Allan Ferguson whose articles
seeds arising from your resent efforts are likely to produce           will be published in a future Turnaround
more prolific yields.                                                  Thanks also to Elliot Murray for his very detailed report on
On behalf of the members, many thanks to those who                     the AWSA EL 2001 Congress. This is being applied as a
contributed.                                                           very useful set of guidelines for the Durban Congress
I have more than I can publish in this edition so the surplus          committee.
will be carried over the next.                                         I now get newsletters from four of the eight AWSA
Thanks to the following for their effforts.                            chapters. They are :
Izak Cronje, Grant Marshall, Andrew Stevens, Trevor Pope,

REGION                  CONTACT                           PHONE             e- MAIL
Gauteng (Witwatersrand) Trevor Pope                       011 622 7018
Western Cape            Gigi Laidler                      021 7977755
East London             Nigel Waters                      043 735 4669
Pretoria                Louw Trichardt                    012-653 1874
Durban                  Brian Kitching                    031-560 1497

To spread our news far and wide, I would like you all to e-mail your newsletter to all the other regions, even if only to
the secretary or area representatives for them to distribute to their members.
See the January Turnaroud for more contact details. Keep those articles rolling.                      Cheers,       Brian

Shared By: