On Jul 19, 12:06 am, " wrote:
On Jul 17, 6:39 am, Andrew VK3BFA wrote:

Here at Chaos Central the bench grinder has been hanging around for
years, grinding shovels, axes, plastic, aluminium - anything and
everything. Obviously, I had it BEFORE I did tool grinding at school
and learnt that it shouldn't be used for such things...will get a
decent wheel as soon as I can organise myself to find one....

And I will keep experimenting - just need to get some more steel to
grind......

Andrew VK3BFA.

Try googling " Dressing grinding wheel ".

Thats on the list too - but a flat diamond dresser like I learned to
use at school. Funny, machining started as a sideline to homebrew
electronics stuff - its taken on a life of its own!....the fly cutter
is to machine some plastic I am making into spacers for 450R ladder
line from a HF doublet antenna - the wife has now got her ham license
and wants a station inside the house, so am putting one together for
her....the metalworking skills are coming in useful, the new mast
outside her craft room window is mostly built (with removable
couplings turned from steel, with drain holes, and water barriers, and
nicely turned pins to hold them together....got a bit carried away,
but hey, I can now do it, so why not...all good practice) and
reasonable welds to hold the tubing together - the spacers are to keep
the ladder line clear of the pole.....so it doesnt whip against the
pole and create disturbance in the cosmic flow of Domestic Harmony....

(Honey, I know its 3am, its ****ing down with rain, but I can hear
something banging around outside - will you go and have a look?)

Bought some 8mm steel rod today at the hardware, will practice on that
to get geometry right - and even it will machine soft plastic of the
kitchen cutting board variety. The "real" fly cutter can wait till I
have a need for it on hard materials.
(and learn to machine a bit better as well...)

Having fun, stuffing around, in between all the other stuff that gets
in the way - ie, wife, kids, dog, house, job, etc etc....

So much to learn, so little time. While you are learning machining, I
am learning about Analog Devices DDS's. Have fun.

Dan

Dan, I suspect the AD devices are like machining - wade through the
stuff written by guys in long robes wearing pointy hats covered in
stars, and it devolves down to what does the job you need it to do.
And its a new language which doesn't help either - but sheer
determination and doggedness will get there in the end. It doesn't
matter you can go and BUY one - thats not the point...

And thanks everyone for the comments - some not necessarily making
much sense now, but in time they will .....

Andrew VK3BFA.

On Jul 19, 1:59 pm, Andrew VK3BFA wrote:

Try googling " Dressing grinding wheel ".

Thats on the list too - but a flat diamond dresser like I learned to
use at school.

And thanks everyone for the comments - some not necessarily making
much sense now, but in time they will .....

Andrew VK3BFA.

Read some of the info available on the internet when you have some
time. There are times to use a flat diamond dresser, times to use a
single point diamond, but I suspect the best dresser for your bench
grinder would be a star dresser. The star dresser will put a surface
on your wheel that will cut better than the surface gotten from using
a diamond dresser. Here are some words from Harold.

"The heating is a sign of nothing. It is impossible to grind without
generating heat. What is important is how the wheel is dressed, and
how
long you grind before quenching. Star type dressers do the best job
of
preparing a wheel for grinding, but they are difficult to use if you
expect
a wheel that runs true. They waste a lot of the wheel as you keep
trying to
improve the wheel condition. Diamond dressing is a poor method for
offhand
grinding because diamonds leave a wheel surface too smooth,
necessitating
greater pressure on the item in order to get it to grind. The
wheel, in a
sense, behaves as a bearing surface. A diamond, however, will true up
a
wheel with no problems, and by wasting almost none of the wheel in the
process. The best of all worlds is a wheel that has been diamond
dressed
to flatten it and get it running dead true, then slightly roughed up
with a
dressing stick, but not one of the solid boron carbide variety. They
leave
a wheel in worse condition than a diamond does. If a boron carbide
stick is
rounded at all, it tends to dull the grain of a wheel, making it
abrade
rather than cut. That leads to very poor grinding, and considerably
more
heating. The dressing stick in question is usually a 1" square
block that
is 6" long when new, and has the appearance of a very coarse stone,
shiny
black in color."

Dan