of dressing the green silica(?) grinding wheels used for Carbide lathe tools?

Many thanks.

Roger in Vegas
Pets have owners. Cats have staff.

"Roger Hull" wrote in message
s.net...
of dressing the green silica(?) grinding wheels used for Carbide lathe
tools?

Many thanks.

Roger in Vegas
Pets have owners. Cats have staff.

My personal choice has always been with a dressing stick. As much as some
rave on about star dressers, they are very wasteful of grinding wheels, and
difficult to use in getting a grinding wheel to run true, something that is
very important when grinding toolbits. Dressing sticks (the sintered
type, not the solid boron carbide variety) will leave a sharp surface,
almost as good as the star dresser type, and will do it without wasting any
of the wheel. You're likely to not see any difference between one dressed
with a star dresser and the other with a dressing stick in how they cut but
you will see the difference in how well the wheel turns out.

Dressing green silicon wheels (and black ones as well) is very bad for your
health (silicosis). Breathing the dust should be avoided at all costs.
Dressing with a star dresser really compounds the problem because so much
more of the wheel is wasted.

Harold

On Sun, 4 Jan 2004 20:18:09 -0800, Roger Hull
wrote:

of dressing the green silica(?) grinding wheels used for Carbide lathe tools?

Many thanks.

Roger in Vegas
Pets have owners. Cats have staff.

I'll give it a try. They have a diamond point dresser that are cheap
, maybe $14. You'll need some kind of cross slide to hold it. IIRC
they should be set up into the wheel and take light passes until you
get a steady cut. I can't remember if it strobes or you listen or
both. I'm sure it could be done by hand if your really careful.
Maybe drill a hole in the end of a steel bar for it to go into and a
set screw and a sturdy straight edge in front and or side of the
wheel. Best to make something up so you don't have to worry about it
grabbing. I need to get around to doing this myself also.

On Sun, 4 Jan 2004 20:18:09 -0800, Roger Hull
wrote:

of dressing the green silica(?) grinding wheels used for Carbide lathe tools?

Many thanks.

Roger in Vegas
Pets have owners. Cats have staff.

Diamond wheel dresser. Pretty cheap.

All the supply companies sell them. $20 or so in the US.

Gunner

"Gun Control, the theory that a 110lb grandmother should
fist fight a 250lb 19yr old criminal"

Glendo makes a diamond wheel dresser that is essentially a heavy, flat
section of blue spring steel that carries a diamond dresser. The diamond
stick is adjustable longitudinally (in and out ??) and you just flex the
spring steel carrier and let it return with the diamond against the wheel.

Bob Swinney


"Gunner" wrote in message
...
On Sun, 4 Jan 2004 20:18:09 -0800, Roger Hull
wrote:

of dressing the green silica(?) grinding wheels used for Carbide lathe
tools?

Many thanks.

Roger in Vegas
Pets have owners. Cats have staff.

Diamond wheel dresser. Pretty cheap.

All the supply companies sell them. $20 or so in the US.

Gunner

"Gun Control, the theory that a 110lb grandmother should
fist fight a 250lb 19yr old criminal"

Harold & Susan Vordos wrote:

My personal choice has always been with a dressing stick.

I'm not familiar with those. How to they compare to a diamond dresser?

Ted

"Ted Edwards" wrote in message
...
Harold & Susan Vordos wrote:

My personal choice has always been with a dressing stick.

I'm not familiar with those. How to they compare to a diamond dresser?

Ted

For dressing wheels on a pedestal grinder, they are far superior. Diamonds
leave a wheel very smooth, necessitating greater pressure be applied to get
good grinding action. Wheels so dressed are very poor for grinding tool
steels. You might say that the wheel starts behaving like a bearing
instead of a grinding wheel. A dressing stick, being softer than diamond,
will remove bits by breaking the bond instead of cutting them like a diamond
does. That yields a far better (slightly rougher) surface for off hand
grinding, yet it is easy to get the wheel running true and flat.

Diamond dressed wheels cut very hot as compared to those dressed by a star
dresser. On machine tools with rigid setups and flood coolant, that's not
an issue. The problems of a star dresser have already been discussed, so
what you get is a compromise of the two when you use a dressing stick.
Dressing sticks are generally made of silicon carbide (or they may be boron
carbide) and resemble a hand stone, usually about an inch square, six inches
long, very coarse, perhaps 24 grit, and not expensive. The only negative
effect of using one is that they have a slight tendency to dull abrasive
grains that do not get knocked off the wheel. The surface they yield is
a good offset, though, so they are a good dressing device, especially for
grinding HSS. I highly recommend one for any shop.

Harold

Harold & Susan Vordos wrote:

"Roger Hull" wrote in message
s.net...
of dressing the green silica(?) grinding wheels used for Carbide lathe
tools?

Many thanks.

Roger in Vegas
Pets have owners. Cats have staff.

My personal choice has always been with a dressing stick. As much as some
rave on about star dressers, they are very wasteful of grinding wheels, and
difficult to use in getting a grinding wheel to run true, something that is
very important when grinding toolbits. Dressing sticks (the sintered
type, not the solid boron carbide variety) will leave a sharp surface,
almost as good as the star dresser type, and will do it without wasting any
of the wheel. You're likely to not see any difference between one dressed
with a star dresser and the other with a dressing stick in how they cut but
you will see the difference in how well the wheel turns out.

Dressing green silicon wheels (and black ones as well) is very bad for your
health (silicosis). Breathing the dust should be avoided at all costs.
Dressing with a star dresser really compounds the problem because so much
more of the wheel is wasted.

Harold

For dressing the wheels on bench grinders I have always liked the clustered
diamond ones. The rectangular ones about 3/8 x 1" with a handle, looks like a T
with a real narrow top.

michael

How's the snow, Harold?

"michael" wrote in message
...
snip---

For dressing the wheels on bench grinders I have always liked the
clustered
diamond ones. The rectangular ones about 3/8 x 1" with a handle, looks
like a T
with a real narrow top.

michael

Aside from the way-too-smooth surface created, they do an outstanding job.
I still prefer a dressing stick over them. Or both, one to get the wheel
running smooth and flat, the other to produce a better surface for grinding
manually. If you haven't done it, it's hard to understand. I have. I
do. Lots of converts to "doing it right". :-)

How's the snow, Harold?

Yeow! 15" on the ground and it's snowing as we speak, with below freezing
temps over the past couple days. Weatherman said we can expect the most
severe snow storm we've had in years. It's going to be a long night!
Supposed to turn to rain after a foot or so drops in the next 24 hours.
Worst weather I've seen since moving here in '96. Figures! g

Harold

Harold & Susan Vordos scribed in
:

Diamond dressed wheels cut very hot as compared to those dressed
by a star
dresser. On machine tools with rigid setups and flood coolant,

yes, I've noticed that. but, having only a diamond dresser (all I
could get would you believe) I'll not give it up. out of true
grinding wheels give me the absolute heebies

swarf, steam and wind

--
David Forsyth -:- the email address is real /"\
http://terrapin.ru.ac.za/~iwdf/welcome.html \ /
ASCII Ribbon campaign against HTML E-Mail - - - - - - - X
If you receive email saying "Send this to everyone you know," / \
PLEASE pretend you don't know me.

"DejaVU" wrote in message
...
Harold & Susan Vordos scribed in
:

Diamond dressed wheels cut very hot as compared to those dressed
by a star
dresser. On machine tools with rigid setups and flood coolant,

yes, I've noticed that. but, having only a diamond dresser (all I
could get would you believe) I'll not give it up. out of true
grinding wheels give me the absolute heebies

And there's no need to. Using the diamond to get a wheel running true is
the best of all worlds. The trick to getting the wheel to cut freely is
then to touch it with the dressing stick, which roughens the surface every
so slightly, making it cut much better. For a few bucks you can see for
yourself. I promise you you won't be disappointed.

Harold

Hey Harold,

Hmmm.. my rememberer is too slow, but my forgeterer makes up for it by
being too quick!! So I can't recall what it was you did to protect
the house project for the winter. Is it something that you have to
keep brushing the snow off to stop accumulation? Hate to think you
and the missus have to do a "navy watch" system every night you get
some frozen precip.

Take care. Don't overdo it.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXXXXX
On Mon, 5 Jan 2004 22:20:45 -0800, "Harold & Susan Vordos"
wrote:


"michael" wrote in message
...
snip---

For dressing the wheels on bench grinders I have always liked the
clustered
diamond ones. The rectangular ones about 3/8 x 1" with a handle, looks
like a T
with a real narrow top.

michael

Aside from the way-too-smooth surface created, they do an outstanding job.
I still prefer a dressing stick over them. Or both, one to get the wheel
running smooth and flat, the other to produce a better surface for grinding
manually. If you haven't done it, it's hard to understand. I have. I
do. Lots of converts to "doing it right". :-)

How's the snow, Harold?

Yeow! 15" on the ground and it's snowing as we speak, with below freezing
temps over the past couple days. Weatherman said we can expect the most
severe snow storm we've had in years. It's going to be a long night!
Supposed to turn to rain after a foot or so drops in the next 24 hours.
Worst weather I've seen since moving here in '96. Figures! g

Harold

Hey Harold,

I kinda missed where this thread was going. Are you advocating use of
a stick for touch-up after truing with the diamond on my surface
grinder and on my Black Diamond drill sharpener?

You know, I've got some dressing sticks I picked up with wheel stones
at auctions. At least one white and a few black, but never used any
of them. Sounds like I should learn. Does the stick "colour" mean
anything we should know about, say relative to colour of the wheels?

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXXXX
On Tue, 6 Jan 2004 01:55:53 -0800, "Harold & Susan Vordos"
wrote:


"DejaVU" wrote in message
...
Harold & Susan Vordos scribed in
:

Diamond dressed wheels cut very hot as compared to those dressed
by a star
dresser. On machine tools with rigid setups and flood coolant,

yes, I've noticed that. but, having only a diamond dresser (all I
could get would you believe) I'll not give it up. out of true
grinding wheels give me the absolute heebies

And there's no need to. Using the diamond to get a wheel running true is
the best of all worlds. The trick to getting the wheel to cut freely is
then to touch it with the dressing stick, which roughens the surface every
so slightly, making it cut much better. For a few bucks you can see for
yourself. I promise you you won't be disappointed.

Harold

"Brian Lawson" wrote in message
...
Hey Harold,

I kinda missed where this thread was going. Are you advocating use of
a stick for touch-up after truing with the diamond on my surface
grinder and on my Black Diamond drill sharpener?


Hey Brian,
No, never for machine type grinding, that defeats the purpose of the
diamond. Conditions on a precision machine are far different from offhand
grinding, though. I'm not certain when diamonds became the dressing tool
of choice, but there was a time when precision grinders were dressed with
star dressers. In today's demanding world of precision and fine finishes,
that wouldn't fly.

The point of my post is that dressing wheels with a star dresser is
wasteful, and achieving respectable results can be difficult. A diamond
works very well for truing the wheel, but the superior finish it leaves on
the wheel creates a couple problems that are not in the best interest of
offhand grinding, especially tool bits. Because of the slick nature of a
diamond finished wheel, it takes considerable more pressure to get the wheel
to cut. It also cuts one hell of a lot hotter. Anyone that knows
enough to run a cutter grinder knows that wheels are hand dressed when
sharpening end mills. That prevents over heating of the cut, and the wheel
demands dressing often to maintain the cool cutting condition. The
same principle applies to offhand grinding. By using a dressing stick,
the wheel is slightly roughened, which lowers cutting pressure tremendously,
and heating as well. That is not to say that diamonds don't have a place
on cutter grinders, or on pedestal grinders, but you have to know when to
use one, and when not to. There's nothing wrong with using a diamond to
get a wheel running true, but it should be slightly roughed up with a
dressing stick before using it to grind offhand. If that's not right, then
the shop where I was trained did it wrong for years.


You know, I've got some dressing sticks I picked up with wheel stones
at auctions. At least one white and a few black, but never used any
of them. Sounds like I should learn. Does the stick "colour" mean
anything we should know about, say relative to colour of the wheels?

Fine grained dressing sticks that are white are primarily intended for
dressing diamond wheels. Yeah, I know, that sounds nuts, but diamond wheels
get loaded with particles and get glazed such that they start not cutting
well. By running a fine stone on the diamond, the crud is removed and the
wheel surface restored. You're not really doing anything to the diamond,
and if you do, you're doing it wrong. The dressing operation should do no
more than clean the wheel, and the diamond tends to remove material from the
dressing stick, as it should be. You don't want to remove the matrix bonding
the diamond for obvious reasons. Dressing diamond wheels should not be a
prolonged operation, one should stop the moment the wheel is cleaned.

The dressing stick I used for years for that purpose was black in color, but
a friend recently gave me a new one, which is white. The black one is no
doubt silicon carbide, the white one aluminum oxide. Both will clean a
diamond wheel, and I have no idea why they are made from both abrasives.
In the scheme of things, the aluminum oxide one would certainly be softer,
kinder to diamonds, but the hardness difference between diamonds and silicon
carbide is so great I'm not convinced it makes a significant difference.

If you have in your collection of dressing sticks one that is very coarse,
made of shiny black bits of abrasive, it is most likely a silicon carbide
stick made for dressing aluminum oxide grinding wheels. There would be no
harm in trying it on a grinding wheel on your pedestal grinder, which is
where I highly recommend these items be used. If it is a dressing stick,
the wheel is readily abraded. I suggest you not use a white one on an
aluminum oxide wheel, use only a black one.

It was common practice for us to use dressing sticks to relieve the sides of
wheels when we had face work to do. Even on precision grinders, face work
is generally done with hand dressed wheels, and for the same reasons,
keeping heat down. It was not uncommon to get heat checking on faces of
heat treated tool steels otherwise, so how the wheel was dressed was rather
critical. Face grinding keeps a lot more of the wheel in contact, so more
heat is generated. The rapid heating and subsequent quenching by coolant
was the source of heat checking. Hand dressing is almost mandatory for that
operation. That would be true if the side of the wheel was used to kiss
the face. If the wheel head is turned, a right angle is dressed on the
wheel and grinds both the cylinder and the face with the periphery of the
wheel. By grinding that way, the problem of heating is reduced to
manageable levels.

Hope this helps~

Take care.

You too!

Harold

"Brian Lawson" wrote in message
...
Hey Harold,

Hmmm.. my rememberer is too slow, but my forgeterer makes up for it by
being too quick!! So I can't recall what it was you did to protect
the house project for the winter. Is it something that you have to
keep brushing the snow off to stop accumulation? Hate to think you
and the missus have to do a "navy watch" system every night you get
some frozen precip.

Take care. Don't overdo it.

Brian Lawson,

Hey Brian,

I ended up draping a string reinforced visqueen tarp over the interior,
which is supported in the center by the floor trusses of the second story of
the house. The sub-floor is not installed. The tarp drains from the
center, and there are temporary crickets directing the water towards the
drain, which is 3" diameter drain pipe. It's worked pretty well so far, but
anything that hits the roof ends up going down the drain, nothing comes off
the sides because the tarp is, for lack of better description, a very flat
funnel, only about 20" taller on the edges than the center. In order to
prevent snow from tearing it down, I've had to get up on a ladder each day
(that it snowed) and reach in as far as I can with a broom and drag the snow
off the outside edges. It's complicated by the rebar that's on 15" centers
sticking up. the rebar, however, is the anchor point of the tarp, so it
serves a useful purpose in spite of being a PIA. Of all years to get record
snow, naturally it had to be this one. We have about 19" on the ground
now, it's put down 4" since late last night. If we make it past today,
we're supposed to warm up. It's been interesting, Brian! What really
irritates me is last year we had no snow.

I appreciate your concern.

Harold

"Harold & Susan Vordos" wrote in message
I ended up draping a string reinforced visqueen tarp over the interior,
which is supported in the center by the floor trusses of the second story
of
the house. The sub-floor is not installed. The tarp drains from the
center, and there are temporary crickets directing the water towards the
drain, which is 3" diameter drain pipe. It's worked pretty well so far,
but
anything that hits the roof ends up going down the drain, nothing comes
off
the sides because the tarp is, for lack of better description, a very flat
funnel, only about 20" taller on the edges than the center. In order to
prevent snow from tearing it down, I've had to get up on a ladder each day
(that it snowed) and reach in as far as I can with a broom and drag the
snow
off the outside edges. It's complicated by the rebar that's on 15"
centers
sticking up. the rebar, however, is the anchor point of the tarp, so it
serves a useful purpose in spite of being a PIA. Of all years to get
record
snow, naturally it had to be this one. We have about 19" on the ground
now, it's put down 4" since late last night. If we make it past today,
we're supposed to warm up. It's been interesting, Brian! What really
irritates me is last year we had no snow.

I appreciate your concern.

Harold

And where in WA state are you? Vancouver, Yelm, Seattle, Bellingham,
Spokane?

I agree with Harold in all respects save one. If you have a badly worn
bench grinder wheel and you want to get it flat again, a star dresser will
do the job much faster than anything else. That's why I keep one in my shop.

Grant

Harold & Susan Vordos wrote:

"Brian Lawson" wrote in message
...

Hey Harold,

I kinda missed where this thread was going. Are you advocating use of
a stick for touch-up after truing with the diamond on my surface
grinder and on my Black Diamond drill sharpener?



Hey Brian,
No, never for machine type grinding, that defeats the purpose of the
diamond. Conditions on a precision machine are far different from offhand
grinding, though. I'm not certain when diamonds became the dressing tool
of choice, but there was a time when precision grinders were dressed with
star dressers. In today's demanding world of precision and fine finishes,
that wouldn't fly.

The point of my post is that dressing wheels with a star dresser is
wasteful, and achieving respectable results can be difficult. A diamond
works very well for truing the wheel, but the superior finish it leaves on
the wheel creates a couple problems that are not in the best interest of
offhand grinding, especially tool bits. Because of the slick nature of a
diamond finished wheel, it takes considerable more pressure to get the wheel
to cut. It also cuts one hell of a lot hotter. Anyone that knows
enough to run a cutter grinder knows that wheels are hand dressed when
sharpening end mills. That prevents over heating of the cut, and the wheel
demands dressing often to maintain the cool cutting condition. The
same principle applies to offhand grinding. By using a dressing stick,
the wheel is slightly roughened, which lowers cutting pressure tremendously,
and heating as well. That is not to say that diamonds don't have a place
on cutter grinders, or on pedestal grinders, but you have to know when to
use one, and when not to. There's nothing wrong with using a diamond to
get a wheel running true, but it should be slightly roughed up with a
dressing stick before using it to grind offhand. If that's not right, then
the shop where I was trained did it wrong for years.


You know, I've got some dressing sticks I picked up with wheel stones
at auctions. At least one white and a few black, but never used any
of them. Sounds like I should learn. Does the stick "colour" mean
anything we should know about, say relative to colour of the wheels?


Fine grained dressing sticks that are white are primarily intended for
dressing diamond wheels. Yeah, I know, that sounds nuts, but diamond wheels
get loaded with particles and get glazed such that they start not cutting
well. By running a fine stone on the diamond, the crud is removed and the
wheel surface restored. You're not really doing anything to the diamond,
and if you do, you're doing it wrong. The dressing operation should do no
more than clean the wheel, and the diamond tends to remove material from the
dressing stick, as it should be. You don't want to remove the matrix bonding
the diamond for obvious reasons. Dressing diamond wheels should not be a
prolonged operation, one should stop the moment the wheel is cleaned.

The dressing stick I used for years for that purpose was black in color, but
a friend recently gave me a new one, which is white. The black one is no
doubt silicon carbide, the white one aluminum oxide. Both will clean a
diamond wheel, and I have no idea why they are made from both abrasives.
In the scheme of things, the aluminum oxide one would certainly be softer,
kinder to diamonds, but the hardness difference between diamonds and silicon
carbide is so great I'm not convinced it makes a significant difference.

If you have in your collection of dressing sticks one that is very coarse,
made of shiny black bits of abrasive, it is most likely a silicon carbide
stick made for dressing aluminum oxide grinding wheels. There would be no
harm in trying it on a grinding wheel on your pedestal grinder, which is
where I highly recommend these items be used. If it is a dressing stick,
the wheel is readily abraded. I suggest you not use a white one on an
aluminum oxide wheel, use only a black one.

It was common practice for us to use dressing sticks to relieve the sides of
wheels when we had face work to do. Even on precision grinders, face work
is generally done with hand dressed wheels, and for the same reasons,
keeping heat down. It was not uncommon to get heat checking on faces of
heat treated tool steels otherwise, so how the wheel was dressed was rather
critical. Face grinding keeps a lot more of the wheel in contact, so more
heat is generated. The rapid heating and subsequent quenching by coolant
was the source of heat checking. Hand dressing is almost mandatory for that
operation. That would be true if the side of the wheel was used to kiss
the face. If the wheel head is turned, a right angle is dressed on the
wheel and grinds both the cylinder and the face with the periphery of the
wheel. By grinding that way, the problem of heating is reduced to
manageable levels.

Hope this helps~

Take care.


You too!

Harold

"Grant Erwin" wrote in message
...
I agree with Harold in all respects save one. If you have a badly worn
bench grinder wheel and you want to get it flat again, a star dresser will
do the job much faster than anything else. That's why I keep one in my
shop.

Grant

I agree that the star dresser could be faster under that circumstance. I'm
not convinced it would beat a diamond, though. Another very good use for
the star type dresser is on larger wheels used in welding shops. Star
dressers, just like diamonds or dressing sticks, have a place. It's a wise
person that knows when to use the right one.

Harold

"lane" lane_nospam@copperaccents_dot_com wrote in message
...

And where in WA state are you? Vancouver, Yelm, Seattle, Bellingham,
Spokane?

Just outside a little town called Onalaska. It's south and east of
Chehalis (I-5 corridor). We're roughly half way between Portland and
Seattle. We live on a ridge at about 1,300 feet so we regularly get snow
when the valley doesn't. Since my last post it has put down two more
inches, so we're now at 21". Makes me think I'm back in Utah. :-)

Harold

"Harold & Susan Vordos" wrote in message
...

Just outside a little town called Onalaska. It's south and east of
Chehalis (I-5 corridor). We're roughly half way between Portland and
Seattle. We live on a ridge at about 1,300 feet so we regularly get
snow
when the valley doesn't. Since my last post it has put down two more
inches, so we're now at 21". Makes me think I'm back in Utah. :-)

Harold


Yes I know where that is. I live in Arlington, 50 miles north of Seattle.
We've got about 5" of the white stuff. Weather man says the snow should all
be gone by tomorrow afternoon.

Lane

Another option that is not mentioned in this thread is the wheel truer
that is supplied with K.O. Lee Tool and Cutter Grinders. It has a
handle just like a star wheel dresser, but in place of the star wheels
it has what looks like a small grinding wheel. I like this tool very
much. It conditions the wheel much like a dressing stick, but works
much faster. It is easier to do fine dressing than with the
star-wheel type. I also find that it shapes grinding wheels more
easily than a dressing stick.

Ron

Hey Guys, and Fitch (I hope),

OK....my turn for Questions and Answers (hopefully) on the rotary
convertor I'm about to attempt to hook up.

First.... the question.... I have a 3 phase wound rotor motor to use
as a convertor for 220VAC single phase to 220VAC three phase. How do
I "hook up" with this? Do I short-out the slip-rings and just
consider it a squirrel cage, or do I wire to both the rotor and
stator, or wire to the stator and take the three phase off the
slip-rings (actually I don't think THAT works), or.....or....or????
.................................................. .

Now for the description, for those that are still reading.
Long-winded, as usual, but it helps me out to do so. Sorry.

I was fairly recently blessed with two freebie 20HP motors. Except,
different to any earlier postings here that I recall, these are wound
rotor motors.

These were in use on AC geared traction elevators, and were wired for
"Dynac" use, which is a 1960's method of getting speed control almost
like a DC operation from AC motors, using some special mechanical
features and controls and incorporating either 2 or 4 medium size
thyratron tubes. Gladly get into details for anybody that wants, but
this is merely explanatory/descriptive here as I won't be using any of
that mode.

The motors were made by Bull Motors, England, as 208 VAC, 3Phase,
60Hz, 1150 RPM, 67 Amp, all copper windings. One pair of 1/2" X
5/8" brushes on each slip-ring. One of the two motors has had the
stator redone locally fairly recently (and that's the one I want to
use), and in the external junction box it just has three stator lead
connections ,and three direct to the slip-rings connections for the
rotor. The second motor has some BAD gooey rubbery disintegration of
the 3 of the wires as they feed through the motor frame to the stator,
and so I don't want to use this motor; BUT.. it has a small Bull
original print diagram in the junction box showing that the motors had
9 leads... 3 to the slip-rings for the Delta connected rotor, and 3 to
the STAR stator field pieces and 3 connected together to form the
STAR. I assume that the STAR shorted leads are done internally on
the rewound motor I hope to use..

These motors are fairly beasty things, with about a 20 pound flange
coupling still in place on a 2-3/8" rotor shaft turned down to 2" for
the coupling. I may well cut the couplings off later, but I can't
pull them in situ here without a largish puller. And I've wondered,
and maybe somebody can tell me, if the heavy coupling would actually
assist in strengthening the output after reaching full RPM. If so,
would heavier be even better? I can pour lead in to do that!. In
original operation, this flange was coupled to a special 20" diameter
X 12" long brake drum with1" thick flange with the external diameter
having pressed in copper bars through it parallel to the motor shaft,
so they were pretty heavy and added a lot of inertia "smoothing" to
the speed variations in operation.

Any suggestions? Or do I still need to call Marty for the rotary he
has for sale????

Take care.

Brian Lawson,
Bothwell, Ontario.

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

ps..... Also posted to modeleng-list

Brian Lawson wrote:

Hey Guys, and Fitch (I hope),

OK....my turn for Questions and Answers (hopefully) on the rotary
convertor I'm about to attempt to hook up.

First.... the question.... I have a 3 phase wound rotor motor to use
as a convertor for 220VAC single phase to 220VAC three phase. How do
I "hook up" with this? Do I short-out the slip-rings and just
consider it a squirrel cage, or do I wire to both the rotor and
stator, or wire to the stator and take the three phase off the
slip-rings (actually I don't think THAT works), or.....or....or????
..................................................

Now for the description, for those that are still reading.
Long-winded, as usual, but it helps me out to do so. Sorry.

I was fairly recently blessed with two freebie 20HP motors. Except,
different to any earlier postings here that I recall, these are wound
rotor motors.

These were in use on AC geared traction elevators, and were wired for
"Dynac" use, which is a 1960's method of getting speed control almost
like a DC operation from AC motors, using some special mechanical
features and controls and incorporating either 2 or 4 medium size
thyratron tubes. Gladly get into details for anybody that wants, but
this is merely explanatory/descriptive here as I won't be using any of
that mode.

The motors were made by Bull Motors, England, as 208 VAC, 3Phase,
60Hz, 1150 RPM, 67 Amp, all copper windings. One pair of 1/2" X
5/8" brushes on each slip-ring. One of the two motors has had the
stator redone locally fairly recently (and that's the one I want to
use), and in the external junction box it just has three stator lead
connections ,and three direct to the slip-rings connections for the
rotor. The second motor has some BAD gooey rubbery disintegration of
the 3 of the wires as they feed through the motor frame to the stator,
and so I don't want to use this motor; BUT.. it has a small Bull
original print diagram in the junction box showing that the motors had
9 leads... 3 to the slip-rings for the Delta connected rotor, and 3 to
the STAR stator field pieces and 3 connected together to form the
STAR. I assume that the STAR shorted leads are done internally on
the rewound motor I hope to use..

These motors are fairly beasty things, with about a 20 pound flange
coupling still in place on a 2-3/8" rotor shaft turned down to 2" for
the coupling. I may well cut the couplings off later, but I can't
pull them in situ here without a largish puller. And I've wondered,
and maybe somebody can tell me, if the heavy coupling would actually
assist in strengthening the output after reaching full RPM. If so,
would heavier be even better? I can pour lead in to do that!. In
original operation, this flange was coupled to a special 20" diameter
X 12" long brake drum with1" thick flange with the external diameter
having pressed in copper bars through it parallel to the motor shaft,
so they were pretty heavy and added a lot of inertia "smoothing" to
the speed variations in operation.

Any suggestions? Or do I still need to call Marty for the rotary he
has for sale????

The 3 leads from the wound rotor would normally go to a
starter/speed control box. The box would have a sequence
of resistors that would be inserted between the leads
coming off the rotor, with maximum resistance for starting/
slowest speed and zero resistance for max speed.

The difference between starter service and speed control
service is that for speed control, the resistors have to be
able to dissipate heat on a continuous basis. For starting
service, they are rated for intermittent duty and don't have
to be as big, wattage wise.

I don't have a clue as to what a good starting resistance would
be. If I were doing this, I'd probably try 100-200 watts
of light bulb for each resistance to see if it would start.

I can check my books at home tonight. I have an old Audel's
book on elevator controls and it might have more information.

On Fri, 09 Jan 2004 13:04:46 -0800, Jim Stewart wrote:
I don't have a clue as to what a good starting resistance would
be. If I were doing this, I'd probably try 100-200 watts
of light bulb for each resistance to see if it would start.

The cold resistance of the bulbs might be too low to allow
soft start. Something on the order of 20 to 40 ohms sounds
about right for starting a 20 hp wound rotor motor.

Gary

In article , Gary Coffman says...

The cold resistance of the bulbs might be too low to allow
soft start. Something on the order of 20 to 40 ohms sounds
about right for starting a 20 hp wound rotor motor.

How about some of those old screw-in heater elements,
that have light bulb bases, but are conical ceramic
with resistance wire wound around them, for old time
space heaters?

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

jim rozen wrote:

How about some of those old screw-in heater elements,
that have light bulb bases, but are conical ceramic
with resistance wire wound around them, for old time
space heaters?

Or one of those water heater elements that you some times see in the
surplus catalogs. The important part is to take that resistance out
of the circuit and short the rotor leads together once its running.
The low speed (relatively) wound rotor motor with the rotor leads
shorted together to minimize rotor losses ought to make a great
converter once its running.

Fitch

Hey Guys,

Me again. Need more help. Doing some interior changes inside the new
house.

To create some additional closet space, I want to extend a wall in my
back hallway about 3 feet along an easily viewed path. I want to make
it longer from an "outside" corner, and that existing corner has a
nice metal bead.

My question is: Should I remove that existing corner-bead so I can
get at the actual "edge" of the existing drywall for the mud and new
tape, or should I hope to just tape over the existing corner-bead to
the new portion of the wall extension? I want the extended wall to
be "flat" from end-to-end. I suspect that I should remove the
beading, but I don't want to damage the ceiling where it joins if I
don't need to.

If I should rip out the old corner-bead, I should do that before I
frame the extension, because then the beading will be "trapped" and
impossible to get out..

All comments and suggestions welcome, but ASAP please, because SWMBO
says I'm just dinking around here trying to get out of doing it. and
we all, know THAT'S not true, eh!

Thanks! Take care.

Brian Lawson,
Bothwell, Ontario.

cross-posted to modeleng-list

Brian Lawson wrote:
Hey Guys,

Me again. Need more help. Doing some interior changes inside the new
house.

To create some additional closet space, I want to extend a wall in my
back hallway about 3 feet along an easily viewed path. I want to make
it longer from an "outside" corner, and that existing corner has a
nice metal bead.

My question is: Should I remove that existing corner-bead so I can
get at the actual "edge" of the existing drywall for the mud and new
tape, or should I hope to just tape over the existing corner-bead to
the new portion of the wall extension? I want the extended wall to
be "flat" from end-to-end. I suspect that I should remove the
beading, but I don't want to damage the ceiling where it joins if I
don't need to.

If I should rip out the old corner-bead, I should do that before I
frame the extension, because then the beading will be "trapped" and
impossible to get out..

All comments and suggestions welcome, but ASAP please, because SWMBO
says I'm just dinking around here trying to get out of doing it. and
we all, know THAT'S not true, eh!

Thanks! Take care.

Brian Lawson,
Bothwell, Ontario.

If you look carefully at the corner or hold a straightedge against it, you
will notice it is flared out, that is the corner is a bit proud WRT the rest
of the wall. If you don't take the cornerbead out it will be obvious when
you look down that wall. I would go even further and take the sheetrock out
a stud bay or two beyond the corner. Also, nailing a new stud up against
existing sheetrock/corner bead is not the best practice, better to nail wood
against wood with no sheetrock between them.

Brian Lawson wrote:
... My question is: Should I remove that existing corner-bead so I can
get at the actual "edge" of the existing drywall for the mud and new
tape,

I definitely would.

or should I hope to just tape over the existing corner-bead to
the new portion of the wall extension?

I think that this would just create (buried) problems down the road.

I want the extended wall to be "flat" from end-to-end. I suspect that I should remove the beading,

Indeed, that's the best way to get it flat.

but I don't want to damage the ceiling where it joins if I
don't need to.

The ceiling went up first, so the bead should stop a "touch" before it.


If I should rip out the old corner-bead, I should do that before I
frame the extension, because then the beading will be "trapped" and
impossible to get out..

Right. Note that the bead may be fastened up with tabs punched out of
itself with a special tool, or with drywall screws. Nails are possible,
I suppose.

All comments and suggestions welcome, but ASAP please, because SWMBO
says I'm just dinking around here trying to get out of doing it. ...

You have my sympathy.

Bob

On Mon, 26 Jan 2004 22:01:59 GMT, "ATP"
wrote:

Brian Lawson wrote:
Hey Guys,

Me again. Need more help. Doing some interior changes inside the new
house.

To create some additional closet space, I want to extend a wall in my
back hallway about 3 feet along an easily viewed path. I want to make
it longer from an "outside" corner, and that existing corner has a
nice metal bead.

My question is: Should I remove that existing corner-bead so I can
get at the actual "edge" of the existing drywall for the mud and new
tape, or should I hope to just tape over the existing corner-bead to
the new portion of the wall extension? I want the extended wall to
be "flat" from end-to-end. I suspect that I should remove the
beading, but I don't want to damage the ceiling where it joins if I
don't need to.

If I should rip out the old corner-bead, I should do that before I
frame the extension, because then the beading will be "trapped" and
impossible to get out..

All comments and suggestions welcome, but ASAP please, because SWMBO
says I'm just dinking around here trying to get out of doing it. and
we all, know THAT'S not true, eh!

Thanks! Take care.

Brian Lawson,
Bothwell, Ontario.

If you look carefully at the corner or hold a straightedge against it, you
will notice it is flared out, that is the corner is a bit proud WRT the rest
of the wall. If you don't take the cornerbead out it will be obvious when
you look down that wall. I would go even further and take the sheetrock out
a stud bay or two beyond the corner. Also, nailing a new stud up against
existing sheetrock/corner bead is not the best practice, better to nail wood
against wood with no sheetrock between them.


Hey ATP,

OK. I will remove the beading. This was the most descriptive reply,
and all makes sense when I think about it too. But it will mean a lot
of extra work to cut back to the next stud due to the shortness of the
wall. I will also have to be really lucky to be able to do the one
"around the corner" too, but I will have at it!!

I've done plain drywalling before, but never had to "join" to any
existing, so this is all good advice.

Thanks again to all. See you all on the other side of the wall!!

Brian.

Brian Lawson wrote in
:

Hey Guys,

Me again. Need more help. Doing some interior changes inside the new
house.

To create some additional closet space, I want to extend a wall in my
back hallway about 3 feet along an easily viewed path. I want to make
it longer from an "outside" corner, and that existing corner has a
nice metal bead.

My question is: Should I remove that existing corner-bead so I can
get at the actual "edge" of the existing drywall for the mud and new
tape, or should I hope to just tape over the existing corner-bead to
the new portion of the wall extension? I want the extended wall to
be "flat" from end-to-end. I suspect that I should remove the
beading, but I don't want to damage the ceiling where it joins if I
don't need to.

If I should rip out the old corner-bead, I should do that before I
frame the extension, because then the beading will be "trapped" and
impossible to get out..

All comments and suggestions welcome, but ASAP please, because SWMBO
says I'm just dinking around here trying to get out of doing it. and
we all, know THAT'S not true, eh!

Thanks! Take care.

Brian Lawson,
Bothwell, Ontario.

cross-posted to modeleng-list


remove the bead.
You are going to have to patch near the ceiling anyway. Mud will hide a
lot of stuff



--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

You need to remove the corner bead entirely. It might not be a bad idea to
remove about 12" of drywall in the hallway to get rid of the build-up that
tapers back from the corner bead. If you don't do both, there will be a hump
in your wall. And definitely do it before you frame.
Gary Brady
Austin, TX

In order for the result to be flat,

1. Remove metal corner bead which is vertical;
2. Ensure that the added 3' of framing lines up with existing framing
-
otherwise there will be a high or low ridge at the boundary;
3. Shave down the drywall after the corner bead is removed - there may
be mud build-up prior to the corner.
4. Tack up a strip of drywall on the last new stud (the new corner).
Using a drywall square or a string line (no chalk) span the old joint
to see how far into the old work sanding/shaving must occur in order
to make it look like one original wall.
5. After mudding/taping/sanding the joint, shine a flashlight down the
wall at night. I have found ocean waves under such examination.

Dust everywhere,
Tom

Brian Lawson wrote in message . ..

To create some additional closet space, I want to extend a wall in my
back hallway about 3 feet along an easily viewed path. I want to make
it longer from an "outside" corner, and that existing corner has a
nice metal bead.

My question is: Should I remove that existing corner-bead so I can
get at the actual "edge" of the existing drywall for the mud and new
tape, or should I hope to just tape over the existing corner-bead to
the new portion of the wall extension?

Hey Tom,

'Nother good one. Lots of tips. Thank you too.

Brian
XXXXXXXXXXXXXXXXXX
On 26 Jan 2004 15:13:52 -0800, (Tom Kendrick)
wrote:

In order for the result to be flat,

1. Remove metal corner bead which is vertical;
2. Ensure that the added 3' of framing lines up with existing framing
-
otherwise there will be a high or low ridge at the boundary;
3. Shave down the drywall after the corner bead is removed - there may
be mud build-up prior to the corner.
4. Tack up a strip of drywall on the last new stud (the new corner).
Using a drywall square or a string line (no chalk) span the old joint
to see how far into the old work sanding/shaving must occur in order
to make it look like one original wall.
5. After mudding/taping/sanding the joint, shine a flashlight down the
wall at night. I have found ocean waves under such examination.

Dust everywhere,
Tom

Brian Lawson wrote in message . ..

To create some additional closet space, I want to extend a wall in my
back hallway about 3 feet along an easily viewed path. I want to make
it longer from an "outside" corner, and that existing corner has a
nice metal bead.

My question is: Should I remove that existing corner-bead so I can
get at the actual "edge" of the existing drywall for the mud and new
tape, or should I hope to just tape over the existing corner-bead to
the new portion of the wall extension?

My access to newsgroups is through Google and they don't do asap

Lay a straightedge against the existing wall and see if there is room
for the mud at the corner, if so leave the corner bead.
Because it is an oudside corner you can just hacksaw a kerf through
the corner bead 1/2 in from the cieling and remove it from that point
down and not disturb the cieling if you do end up removing it.

Hey People,

Well, my late friends widow has finally decided to liquidate his shop
now, and asked me to assist as a bit of a go-between. She lives on
the out-skirts of Windsor, so handy to SW Ontario, southern Michigan,
Northern Ohio, etc. If anyone is interested in a well supplied whole
shop, or in a nice South Bend lathe, or any other individual stuff,
lemme know and I'll send along a MS WORD list of the inventory of the
115VAC machines only. Stuff in tool-boxes is just too numerous to
list, so if you have a specific in mind, let me know about that too.

Take care.

Brian Lawson,
Bothwell, Ontario.

1-519-695-2799

cross-posted to modeleng-list

Hey guys,

Looks like some items of interest for some of us. No lathes or mills
though, but have a quick peek.

Take care.

Brian Lawson,
Bothwell, Ontario.

cross-posted to modeleng-list
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