I've just bought a diamond wheel-dresser which is a steel rod with a
block of steel at the end with a 1.5" x 1/2" face with coarse diamonds
stuck to it.
Anyone know how the diamonds are attached? And how rugged are these
things to having the diamonds knocked off?
Can you just push it against a wheel at any angle? I mean with the
leading or trailing edge of the dresser hitting the wheel first? Or
must you be careful to get the centre of the dresser to hit the wheel
first? Should the dresser be held against the tool rest, or can you
just hold it freehand? Are light "cuts" advisable? I've been a naughty
boy and used the wheel for aluminium. I have stood to one side, just
in case, however.

Also. I've just bought a new slower speed grinder (1425 rpm - 4-pole
on 50Hz) with a gray GP wheel and a white alumina wheel. Which would
be the best for touching up carbide-tipped lathe tools?
Way back, I just used the grey wheel that was in the grinder without a
thought. jack

wrote in message
...
I've just bought a diamond wheel-dresser which is a steel rod with a
block of steel at the end with a 1.5" x 1/2" face with coarse diamonds
stuck to it.
Anyone know how the diamonds are attached?

They are usually set in a copper alloy of sorts.

And how rugged are these
things to having the diamonds knocked off?

Unless yours is one of the plated variety (it would likely be nickel colored
if so), you don't have to worry about knocking the diamond off, it's not
just glued on the surface. It is held captive by being poured in the
matrix.

Can you just push it against a wheel at any angle? I mean with the
leading or trailing edge of the dresser hitting the wheel first? Or
must you be careful to get the centre of the dresser to hit the wheel
first?

It's your dressing tool (they're called a cluster diamond), so use it as you
wish, but if you want it to last, make sure only the diamond comes in
contact with the wheel. If you introduce it at a wonky angle, you may hit
the matrix instead of the diamonds, and that has the potential to screw up
the mounting such that you could lose diamonds on the periphery of the tool.

Should the dresser be held against the tool rest, or can you
just hold it freehand?

While you may be able to use it freehand, a rest helps control the cutting
action. It's also a little safer, If you slip freehand, you can end up
tangled with the wheel. You can believe me when I tell you that hitting a
running wheel with your hands can ruin a good day.

Are light "cuts" advisable? I've been a naughty
boy and used the wheel for aluminium. I have stood to one side, just
in case, however.

Don't horse it----but insure that it makes contact well enough to actually
do something to the wheel. Introduce it to the wheel, then work it
sideways, slowly feeding inwards until you have the surface of the wheel as
you like it. Keep it moving side to side to avoid creating grooves in the
wheel, which can actually ruin the dressing tool.


Also. I've just bought a new slower speed grinder (1425 rpm - 4-pole
on 50Hz) with a gray GP wheel and a white alumina wheel. Which would
be the best for touching up carbide-tipped lathe tools?

Neither one.

While I don't recommend them, aside from diamond or CBN, only a silicon
carbide wheel will perform with any degree of satisfaction on carbide.
Aluminum oxide (both of your wheels are aluminum oxide) is far too soft to
be effective.

If you want really good results, buy a diamond wheel, and run it wet.
Otherwise, a green silicon carbide wheel will work. The dust is
hazardous------causes silicosis-----and the finish such a wheel leaves
leaves a great deal to be desired. Silicon carbide (green wheel) isn't all
that much harder than carbide, so it tends to club it off instead of cut it
cleanly the way a diamond wheel does.

Way back, I just used the grey wheel that was in the grinder without a
thought. jack

And it did a poor job of almost everything, didn't it?

Harold

"Harold and Susan Vordos" wrote:

Also. I've just bought a new slower speed grinder (1425 rpm - 4-pole
on 50Hz) with a gray GP wheel and a white alumina wheel. Which would
be the best for touching up carbide-tipped lathe tools?

Neither one.

While I don't recommend them, aside from diamond or CBN, only a silicon
carbide wheel will perform with any degree of satisfaction on carbide.
Aluminum oxide (both of your wheels are aluminum oxide) is far too soft to
be effective.

If you want really good results, buy a diamond wheel, and run it wet.
Otherwise, a green silicon carbide wheel will work.


I tried a green wheel once and took Harolds advice and bought a diamond
wheel. Like night and day. The carbide isn't chipped with the diamond
unlike it was with green wheel.

Wes

Wes wrote:

I tried a green wheel once and took Harolds advice and bought a diamond
wheel. Like night and day. The carbide isn't chipped with the diamond
unlike it was with green wheel.

replace unlike with like

On Tue, 25 Dec 2007 21:50:42 -0500, Wes wrote:

Wes wrote:

I tried a green wheel once and took Harolds advice and bought a diamond
wheel. Like night and day. The carbide isn't chipped with the diamond
unlike it was with green wheel.

replace unlike with like

Green for roughing and forming, diamond for finishing

Gunner



"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

On Tue, 25 Dec 2007 19:30:43 -0800, Gunner Asch
wrote:

On Tue, 25 Dec 2007 21:50:42 -0500, Wes wrote:

Wes wrote:

I tried a green wheel once and took Harolds advice and bought a diamond
wheel. Like night and day. The carbide isn't chipped with the diamond
unlike it was with green wheel.

replace unlike with like

Green for roughing and forming, diamond for finishing

Does this mean that the diamond wheel wears out?
Or is the diamond wheel just so much more expensive that you avoid
risking damage as much as possible?

All I want to do is touch up the odd carbide tipped metal lathe tool,
and various HSS woodworking tools. Perhaps some diamond strops, or
files might be better? I suspect I will not be reshaping any carbide
tools, just putting an edge on them occasionally. jack

Gunner Asch wrote:

Green for roughing and forming, diamond for finishing

Seeing how well the 150g diamond cut vs the green wheel, I'm going to
disagree this time.

Wes

"Gunner Asch" wrote in message
...
On Tue, 25 Dec 2007 21:50:42 -0500, Wes wrote:

Wes wrote:

I tried a green wheel once and took Harolds advice and bought a diamond
wheel. Like night and day. The carbide isn't chipped with the diamond
unlike it was with green wheel.

replace unlike with like

Green for roughing and forming, diamond for finishing

Gunner


Yeah, if you believe the rumors. Green wheels offer no
advantages---diamond will rough faster and better.

Harold

On Wed, 26 Dec 2007 02:05:42 GMT, "Harold and Susan Vordos"
wrote:

wrote in message
.. .
I've just bought a diamond wheel-dresser which is a steel rod with a
block of steel at the end with a 1.5" x 1/2" face with coarse diamonds
stuck to it.
Anyone know how the diamonds are attached?

They are usually set in a copper alloy of sorts.

And how rugged are these
things to having the diamonds knocked off?

Unless yours is one of the plated variety (it would likely be nickel colored
if so), you don't have to worry about knocking the diamond off, it's not
just glued on the surface. It is held captive by being poured in the
matrix.

Thanks, Harold, this thing is silver all over (looks plated).
Does this mean it is fragile? If so, how should I care for it over and
above what you recommend in general?

Can you just push it against a wheel at any angle? I mean with the
leading or trailing edge of the dresser hitting the wheel first? Or
must you be careful to get the centre of the dresser to hit the wheel
first?

It's your dressing tool (they're called a cluster diamond), so use it as you
wish, but if you want it to last, make sure only the diamond comes in
contact with the wheel. If you introduce it at a wonky angle, you may hit
the matrix instead of the diamonds, and that has the potential to screw up
the mounting such that you could lose diamonds on the periphery of the tool.

This has many 50 grit diamonds, maybe thousands. I doubt you could hit
matrix without being wasted by diamonds beforehand.

Should the dresser be held against the tool rest, or can you
just hold it freehand?

While you may be able to use it freehand, a rest helps control the cutting
action. It's also a little safer, If you slip freehand, you can end up
tangled with the wheel. You can believe me when I tell you that hitting a
running wheel with your hands can ruin a good day.

This I know, but don't ask me how

Are light "cuts" advisable? I've been a naughty
boy and used the wheel for aluminium. I have stood to one side, just
in case, however.

Don't horse it----but insure that it makes contact well enough to actually
do something to the wheel. Introduce it to the wheel, then work it
sideways, slowly feeding inwards until you have the surface of the wheel as
you like it. Keep it moving side to side to avoid creating grooves in the
wheel, which can actually ruin the dressing tool.

By horse it, I guess you mean push it in so hard it slows the wheel?

Also. I've just bought a new slower speed grinder (1425 rpm - 4-pole
on 50Hz) with a gray GP wheel and a white alumina wheel. Which would
be the best for touching up carbide-tipped lathe tools?

Neither one.

While I don't recommend them, aside from diamond or CBN, only a silicon
carbide wheel will perform with any degree of satisfaction on carbide.
Aluminum oxide (both of your wheels are aluminum oxide) is far too soft to
be effective.

Why is one white and one grey? The Al2O3 white one is meant for HSS
and apparently does a better job on that, so what is the grey one
meant to do? The white wheel has WA 12 L stencilled on it, and the
grey has A 60 M, I think (not too sure about the A as only half of it
got stencilled) Then there is the maker's brand, and 40 m/s.

If you want really good results, buy a diamond wheel, and run it wet.

Can you do this on a 1425rpm dry grinder? What would an 8" diamond
wheel likely cost? Would you just let water drip slowly from a bottle
on a shelf via a plastic tube?

Otherwise, a green silicon carbide wheel will work. The dust is
hazardous------causes silicosis-----and the finish such a wheel leaves
leaves a great deal to be desired. Silicon carbide (green wheel) isn't all
that much harder than carbide, so it tends to club it off instead of cut it
cleanly the way a diamond wheel does.

Way back, I just used the grey wheel that was in the grinder without a
thought. jack

And it did a poor job of almost everything, didn't it?

Seemed OK to me, but then, I'm just an inexperienced amateur.
Maybe it had a SiC wheel in it, coz it seemed to put a nice edge on
out carbide tools. This was just a small lathe in a university
laboratory workshop.No critical work was ever done on it.

Thanks for your help, Harold, jack

wrote in message
...
On Wed, 26 Dec 2007 02:05:42 GMT, "Harold and Susan Vordos"
wrote:

wrote in message
. ..
I've just bought a diamond wheel-dresser which is a steel rod with a
block of steel at the end with a 1.5" x 1/2" face with coarse diamonds
stuck to it.
Anyone know how the diamonds are attached?

They are usually set in a copper alloy of sorts.

And how rugged are these
things to having the diamonds knocked off?

Unless yours is one of the plated variety (it would likely be nickel
colored
if so), you don't have to worry about knocking the diamond off, it's not
just glued on the surface. It is held captive by being poured in the
matrix.

Thanks, Harold, this thing is silver all over (looks plated).
Does this mean it is fragile? If so, how should I care for it over and
above what you recommend in general?

That be the case, yeah, the diamond isn't all the securely set. I highly
recommend you do not use it to knock off the aluminum you mentioned. Use a
dressing stick or a star dresser to remove the aluminum, then use the
diamond to smooth the wheel.

You may not like the surface the diamond cluster leaves. Diamond, being
very sharp and hard, will prepare the surface so smoothly that it won't
grind as well as a wheel that is dressed with a star dresser. The
advantage of the cluster diamond is that it's a lot easier to get the wheel
true. You may find that you can use a (sintered) dressing stick to
slightly rough the wheel once it's true, which will actually improve its
cutting characteristics. I use dressing sticks almost exclusively for my
pedestal grinder, although on rare occasion I'll use a mounted diamond to
move a lot of wheel when it's required. For grinding HSS off hand, a
diamond dressed wheel is not good at all.


Should the dresser be held against the tool rest, or can you
just hold it freehand?

While you may be able to use it freehand, a rest helps control the cutting
action. It's also a little safer, If you slip freehand, you can end up
tangled with the wheel. You can believe me when I tell you that hitting
a
running wheel with your hands can ruin a good day.

This I know, but don't ask me how

I happen to know a bit about that as well! I'm getting the distinct idea
that it's for the same reason.
:-(



Are light "cuts" advisable? I've been a naughty
boy and used the wheel for aluminium. I have stood to one side, just
in case, however.

Don't horse it----but insure that it makes contact well enough to actually
do something to the wheel. Introduce it to the wheel, then work it
sideways, slowly feeding inwards until you have the surface of the wheel
as
you like it. Keep it moving side to side to avoid creating grooves in the
wheel, which can actually ruin the dressing tool.

By horse it, I guess you mean push it in so hard it slows the wheel?

I'm not convinced you could put enough pressure on the wheel to do that.
In your case, if you push too hard, you could dislodge diamonds. The
aluminum that's present will do its best to do so anyway. I was struggling
with the notion that you had a matrix set cluster, not a plated one. Be
real careful with the plated one-----the only thing that holds the diamond
on is the plating that is applied to the entire thing. Diamonds, being
conductive, allow for full encapsulation with nickel, so once you uncover
half the diamond, it's free to fall out, and often does. I suggest a light
touch, allowing the diamond to do it's work without grooving the wheel.
Keep the cluster in constant sideward motion, so it can't establish grooves
in the wheel. They'll undercut the sides of the diamond, then they'll
release.


Also. I've just bought a new slower speed grinder (1425 rpm - 4-pole
on 50Hz) with a gray GP wheel and a white alumina wheel. Which would
be the best for touching up carbide-tipped lathe tools?

Neither one.

While I don't recommend them, aside from diamond or CBN, only a silicon
carbide wheel will perform with any degree of satisfaction on carbide.
Aluminum oxide (both of your wheels are aluminum oxide) is far too soft to
be effective.

Why is one white and one grey? The Al2O3 white one is meant for HSS
and apparently does a better job on that, so what is the grey one
meant to do? The white wheel has WA 12 L stencilled on it, and the
grey has A 60 M, I think (not too sure about the A as only half of it
got stencilled) Then there is the maker's brand, and 40 m/s.

How the aluminum oxide is made makes a difference in how it performs.
That's why Norton offers various types of aluminum oxide wheels. Some are
far better suited to grinding particular types of alloys---such as the 38A,
which cuts fast and cool when grinding HSS. They all work, just some work
better than others. The rank novice may not notice the differences at
first.

Regards the markings, they defy common markings, so it's hard to say what
they mean. I'd venture a guess that the L is the hardness, as is the M.
The 12 is a mystery, unless it stands for 120, which would be a fine wheel.
W I have no idea, but the A likely designates aluminum (oxide). The
other marking makes more sense, with the A obviously aluminum (oxide), and
the 60 the hardness. There's a lot more to wheel markings than yours
display. My guess is they're not American made.


If you want really good results, buy a diamond wheel, and run it wet.

Can you do this on a 1425rpm dry grinder? What would an 8" diamond
wheel likely cost? Would you just let water drip slowly from a bottle
on a shelf via a plastic tube?

For carbide lathe tools, the type 1 wheel isn't a good choice. Carbide is
best ground without hollow grinding, so a type 6 wheel is the wheel of
choice. One that would serve your purpose very well would be only 6"
diameter, and would have a 3/4" face (on the side of the wheel, which is the
working surface). It yields flat grinds, so you don't undercut the tool,
weakening the edge. That's important if you put tools to work. No big deal
for scratch cuts, however, but then you are likely not taking advantage of
the use of carbide if that's how you're using it. HSS would likely serve
better unless you're machining hard materials.


Otherwise, a green silicon carbide wheel will work. The dust is
hazardous------causes silicosis-----and the finish such a wheel leaves
leaves a great deal to be desired. Silicon carbide (green wheel) isn't
all
that much harder than carbide, so it tends to club it off instead of cut
it
cleanly the way a diamond wheel does.

Way back, I just used the grey wheel that was in the grinder without a
thought. jack

And it did a poor job of almost everything, didn't it?

Seemed OK to me, but then, I'm just an inexperienced amateur.
Maybe it had a SiC wheel in it, coz it seemed to put a nice edge on
out carbide tools. This was just a small lathe in a university
laboratory workshop.No critical work was ever done on it.

If it put an edge on the tool and actually moved the carbide, it most surely
was silicon carbide. Aluminum oxide is substantially softer than silicon
carbide. So much so that when you apply tungsten carbide to an aluminum
oxide wheel, it tends to glaze each of them without doing much more. You'd
have a dreadful time trying to put an edge on tungsten carbide tools with
aluminum oxide, and they'd likely cut very poorly because the cutting edge
wouldn't be keenly sharp, which is key to performance with light cuts using
carbide tools. Roughing cuts are far more forgiving, assuming you go to
negative rake. That's a whole different world, not to be confused with
machining with positive rake.

Harold

Thanks for your help, Harold, jack

wrote in message
...
On Wed, 26 Dec 2007 02:05:42 GMT, "Harold and Susan Vordos"
snip---

Why is one white and one grey? The Al2O3 white one is meant for HSS
and apparently does a better job on that, so what is the grey one
meant to do?

Sorry----I failed to address your question about the gray wheel.

I think you'll find it is bonded harder than the white one, so it is
intended for grinding soft materials, such as mild steel, or even high
carbon steels in the annealed condition. The rule of thumb is hard wheels
for soft materials, and soft wheels for hard materials. It's all about how
long it takes for the wheel to shed dull bits to re-sharpen itself.

Hardness, in grinding wheels, is not related to the media, it's related to
how the wheel is bonded. A J wheel is softer than an M wheel.

Harold

On Wed, 26 Dec 2007 08:25:11 GMT, "Harold and Susan Vordos"
wrote:


wrote in message
.. .
On Wed, 26 Dec 2007 02:05:42 GMT, "Harold and Susan Vordos"
snip---

Why is one white and one grey? The Al2O3 white one is meant for HSS
and apparently does a better job on that, so what is the grey one
meant to do?

Sorry----I failed to address your question about the gray wheel.

I think you'll find it is bonded harder than the white one, so it is
intended for grinding soft materials, such as mild steel, or even high
carbon steels in the annealed condition. The rule of thumb is hard wheels
for soft materials, and soft wheels for hard materials. It's all about how
long it takes for the wheel to shed dull bits to re-sharpen itself.

Hardness, in grinding wheels, is not related to the media, it's related to
how the wheel is bonded. A J wheel is softer than an M wheel.

Thanks for all your help, Harold.

I'm going to take my 4 wheels in to Australian Abrasives to ask
exactly what they are and to see if they have a diamond wheel that
would suit my application and my purse.

I'm assuming that diamond wheels are basically flat steel plates with
diamonds bonded to the side face of the wheel opposite the motor.
I will try to rig up a table and jig to hold tools at the correct
angle to this flat surface.

What would be an ideal speed for a diamond wheel, and how much water
is required if indeed it is? Would a drip a second, or similar be
adequate, or is it best to flood the area?

I've got a couple of extremely cheap 4" diamond cut-off wheels for a
4" angle grinder. One is labelled for wet cutting, and the other with
radial cutouts, for dry cutting of glass and ceramics and so on.
I wonder if these might be used for some rough tool shaping if the
angle grinder were clamped securely to a bench. The diamonds appear to
be rather coarse, and far apart, and the wheels are designed for max
rpm of 14500.

I wonder if any Australians here know where is a good place to get a
diamond wheel.

jack

wrote in message
...
snip-----

I'm assuming that diamond wheels are basically flat steel plates with
diamonds bonded to the side face of the wheel opposite the motor.
I will try to rig up a table and jig to hold tools at the correct
angle to this flat surface.

They are typically made of aluminum, not steel. The wheel I use, which is
commonly found on diamond grinders, is 6" in diameter, and 3/4" thick, It
has a counterbore 5/16" deep, 4-1/2" diameter. There is a 1-1/4" bore, and
a bolt circle, countersunk, for mounting the wheel. The working face is
3/4" wide, and can be obtained in either 1/16" or 1/8" thickness of diamond.

It's best to build a table that extends part the face of the wheel on the
outside, so the tool is supported when grinding the sides. Both sides of
the wheel (left and right) will be used, depending on the handing of the
tool in question, so it's important that the motor be able to be reversed.
The table should be adjustable between 0 degrees and up to 10 degrees of
angle. It need not have calibrations, just be adjustable easily. You'll
find you often change the angle on the table as you grind different features
of a given tool. Table centerline should be slightly below the centerline
of the wheel, so the wheel contacts the tool at the centerline. I'd
suggest 3/8", unless you use large tools. if you intend to grind on up to
3/4" tools, then I'd shoot for 1/2" below center with the table. That way
you won't be too low when grinding on small tools.


What would be an ideal speed for a diamond wheel, and how much water
is required if indeed it is? Would a drip a second, or similar be
adequate, or is it best to flood the area?

Ideal speed would be maximum allowable speed of the wheel, but you'll find
that a 3,450 or 3,600 RPM motor will provide excellent service. A slower
motor will function, but expect slower results. I suggest sticking with
the 3,000+ speed.

Regards coolant, the grinder is best built with a pan, which would have a
drain that returns the coolant for reuse. A chemical additive will keep
it from rusting. I use a small circulating pump, and feed the wheel at
its center, using some 3/16" copper tubing. I have a valve in the circuit
to control flow. I keep a steady stream, although it's a small one.
Drops tend to allow heating and cooling instead of a constant cooling. I'd
personally advise against a drip system, although I'd be first to agree they
work. They're just not quite adequate if you're roughing a tool, which is
often required because of edge chipping. You're also subject to thermal
shock if the interval between drips gets spread out to far.


I've got a couple of extremely cheap 4" diamond cut-off wheels for a
4" angle grinder. One is labelled for wet cutting, and the other with
radial cutouts, for dry cutting of glass and ceramics and so on.
I wonder if these might be used for some rough tool shaping if the
angle grinder were clamped securely to a bench. The diamonds appear to
be rather coarse, and far apart, and the wheels are designed for max
rpm of 14500.

If they're the HF variety of wheel, I'm familiar with them, having purchased
a set for use in the house building project that seems to consume all my
time. The problem you'll face with them, unless you have the one that
has no serrations, is the bumpy grind. Carbide doesn't take kindly to
interrupted cuts, so you could expect some chipping if you use them for that
purpose. They're not great for use on edge because there's a steel band
in the center of the wheel that won't cut. In abrasive materials (concrete,
for instance), the band is ground back in the course of use. Carbide would
likely act as a bearing, so the blade wouldn't cut well once that center
section was in contact with the tool. In general, I'd say they're not well
suited, but you might explore their use for grinding a chip breaker.

As an aside, I can send you a couple pics of my home made grinder. They'd
be small, under 100 kb in size. I'm on a dialup. Let me know if you'd
like to have them.

Hope some of this helps!

Harold