wws wrote:
"Alex" wrote in message
m...

Is there any online machining tutorial?
Books are rather expensive.

Thanks



Which aspect?
What is your experience-where do you want to start?
The best place to start is dirty hands,get a file or ten and a chunk of
metal and make something.Or copy something.After a month of that you
will figure out ways to use power tools and then toolroom machines to
save time and work.And calloses(sp?.)

Here's what my first project was:

1) Obtain the following items:

- Scriber (or a sharp pencil)
- Steel rule
- Hacksaw
- Power drill with 10mm or more HSS drillbit; ideally a nice column
drill
- About 100mm of mild steel, perhaps 25mm wide by 3mm deep
- A g-clamp or two
- A flat file
- A round file

2) Now use the scriber and the steel rule to mark out the end of the
steel bar like so:

-----------------------------------------------
|\
| \ A
| \-------------------- B
|
| +
| \
| C \
| \
-----------------------------------------------

Ok, that + sign is where you're going to drill the 10mm or so hole; it
should be placed so that the top edge of the circle cut just meets the
top line, but it meets the slanting line underneath such that it makes a
hooked thingy (plan this out by holding the round end of the drill over
the + to gauge the approximate extents of the hole). I can't remember
the exact dimensions, but if I give you a hint and say that it's going
to be a bottle opener, you can measure a bottle and work out dimensions
that will allow the hook part to get under the edge of a bottle cap
while the long bar at the top sits roughly in the middle of the cap.

3) G-clamp the bar to a stout bench, with the place where the hole will
be either over empty space or (ideally) over a bit of scrap wood. Drill
the hole. You will probably find that it overlaps or underlaps your
lines. Adjust the lines to suit the hole - the need to meet it on
tangents to the circle. The intial lines were just guides to let you get
the proportions right to place the hole.

4) G-clamp the bar to a stout bench, but so that the long line marked B
above is protruding in a way that you'll find easy to hacksaw. Hold the
saw at a comfortable angle, but close to the plane of the metal bar
rather than close to being 'across' the metal, since hacksaws work
better with more teeth in contact. Keeping carefully to the line and
holding the hacksaw from both ends, saw down to where it meets the
circle. Slow down as you get close to the point of contact, and don't
overshoot or you'll cut into the far side of the circle and produce a
blemish.

5) Re-clamp the bar so you can cut along C, and repeat the above
procedure. A chunk of scrap metal will now fall off, which you will
keep, because it will come in useful as soon as you throw it away.

6) Re-clamp and cut A.

7) Now, you'll have a workable bottle opener, but it'll have nasty rough
edges. So get your file and start by smoothing over the edges you've cut
(with the flat file), paying particular attention to getting a smooth
interface with the circular hole, since that looks real neat; use the
round file for the interface since it fits the shape of the hole better.
Then go round the thing just gently chamfering or rounding the edges
(apart from the point where line C meets the circle! Keep a sharp point
there!) in order to make it comfortable and unlikely to cut anybody by
accident.

8) For bonus points, put it in your barbeque at top whack until it glows
at least orange hot, then (using tongs) fling it straight into cold
water with as much salt as will dissolve in, which might make it harder
(so it won't bend as fast). However it will now be more fragile -
throwing it at concrete might shatter it instead of just denting one end.

Tada!

THEN make another one. This time, use a CNC milling machine to cut the
bits out. It's easier, but you get a pile of swarf instead of a nice
chunk of metal that will prove useful the minute it's thrown away.

THEN make another one, but this time make it with a shorter handle, and
use a lathe to turn a nice shaped cylindrical handle. Mill a slot in the
end to receive the 'handle' of the shorter opener, of precisely the
width of the steel, so it slides in with some effort. Clamp it into the
slot and use the column drill to drill a hole through both of them,
along an axis perpendicular to the bottle opener. Put a steel rod
through that fits easily, but without a visible gap (hahah! Already
drilled the hole before reading about the rod that just fits the hole?
Learning experience!). Get some silver solder and flux. Liberally coat
the steel rod in flux and push it in. Zap the thing with a blowtorch
*from the other side* until it's just starting to glow then poke silver
solder wire at the tiny gap between steel rod and handle; it should melt
and disappear inside. Continue until it appears at the far side, where
the blowtorch is applied. Remove heat and allow to cool. Don't get the
actual bottle opener head any hotter than cannot be avoided - it'll ruin
the hardening.

File the protruding ends of steel rod down until it is jus nearly flush
with the handle, then pop it back in the lathe and finish the surface off.

Then start giving bottle openers to your friends as you try to figure
out ways to use more and more tools in making them ;-)


wws


ABS