Angle grinder - brush is sparking badly
 

I purchased a 9" angle grinder (Wolf) on eBay. After using it for about 30
minutes, one of the brushes started sparking badly. I could hear the arcimh
amd and see the flashes right through the yellow casing! I removed the
inspection cover and ran the grinder, I could see bright blue sparking
travelling right around the commutator ()if that's the segmented copper
drum that the brushes rub against) and flying out from where the nearest
brush contacts the commutator. Is this something I should worry about, or
is it normal? Is there any maintenance operation I can do to cure it?

Thank you.

Al

Angle grinder - brush is sparking badly
 

"AL_n" wrote in
:

I purchased a 9" angle grinder (Wolf) on eBay

PS.. I should have mentioned that the grinder is brand new - never used
prior to purchase.

Angle grinder - brush is sparking badly
 

On Jul 15, 2:34*pm, "AL_n" wrote:
I purchased a 9" angle grinder (Wolf) on eBay. After using it for about 30
minutes, one of the brushes started sparking badly. I could hear the arcimh
amd and see the flashes right through the yellow casing! I removed the
inspection cover and ran the grinder, I could see bright blue sparking
travelling right around the commutator ()if that's the segmented copper
drum that the brushes rub against) and flying out from where the nearest
brush contacts the commutator. Is this something I should worry about, or
is it normal? Is there any maintenance operation I can do to cure it?

Thank you.

Al

if it's new, don't touch, send right back. Should be under guarantee.

Angle grinder - brush is sparking badly
 

AL_n wrote:
"AL_n" wrote in
:

I purchased a 9" angle grinder (Wolf) on eBay

PS.. I should have mentioned that the grinder is brand new - never used
prior to purchase.

let brushes bed in, if it persists, take it back. Could be shorted turn.

Angle grinder - brush is sparking badly
 

harry wrote in
:

On Jul 15, 2:34*pm, "AL_n" wrote:
I purchased a 9" angle grinder (Wolf) on eBay. After using it for
about 3
0
minutes, one of the brushes started sparking badly. I could hear the
arci
mh
amd and see the flashes right through the yellow casing! I removed
the inspection cover and ran the grinder, I could see bright blue
sparking travelling right around the commutator ()if that's the
segmented copper drum that the brushes rub against) and flying out
from where the nearest brush contacts the commutator. Is this
something I should worry about, or is it normal? Is there any
maintenance operation I can do to cure it?

Thank you.

Al

if it's new, don't touch, send right back. Should be under
guarantee.


Yes, I could send it back, but I was hoping I wouldnlt have to. But I guess
I'll have to. It arcs really violently when actually cutting, i.e., when
the motor is under load.

Thanks also to N.P.

Al

Angle grinder - brush is sparking badly
 

AL_n wrote:
harry wrote in
:

On Jul 15, 2:34�pm, "AL_n" wrote:
I purchased a 9" angle grinder (Wolf) on eBay. After using it for
about 3
0
minutes, one of the brushes started sparking badly. I could hear the
arci
mh
amd and see the flashes right through the yellow casing! I removed
the inspection cover and ran the grinder, I could see bright blue
sparking travelling right around the commutator ()if that's the
segmented copper drum that the brushes rub against) and flying out
from where the nearest brush contacts the commutator. Is this
something I should worry about, or is it normal? Is there any
maintenance operation I can do to cure it?

Thank you.

Al
if it's new, don't touch, send right back. Should be under
guarantee.


Yes, I could send it back, but I was hoping I wouldnlt have to. But I guess
I'll have to. It arcs really violently when actually cutting, i.e., when
the motor is under load.

Thanks also to N.P.

That is pretty consistent with a brush not being bedded in.

with electric RC/aircraft and brushed motors, its enough to make em
unflyable - or was till the advent of 2.4Ghz sets.

The technique is generally to run for 10 minutes or more on no load. For
the greatest mechanical wear and least arcing.

Once the brushes 'fit' the commutator it should stop. Apart from a sort
of twinkling in the gap.




Al

Angle grinder - brush is sparking badly
 

The Natural Philosopher wrote in news:ivpqcp$mv6$1
@news.albasani.net:

That is pretty consistent with a brush not being bedded in.

with electric RC/aircraft and brushed motors, its enough to make em
unflyable - or was till the advent of 2.4Ghz sets.

The technique is generally to run for 10 minutes or more on no load. For
the greatest mechanical wear and least arcing.

Once the brushes 'fit' the commutator it should stop. Apart from a sort
of twinkling in the gap.


Thanks. I tried that, but it was arcing as violently as it did under load,
now. It sounds almost as bad a s Frankinstein's lab! I took the brush out
to have a look, and it had worn down about 4mm-5mm! And there were bits
chipped off from one edge. Is it worth trying to clean up the brass
commutator a bit with a toothbrush or something? I guess it is abrading the
brush for some reason. Perhaps some stone chippings got in there or
something.. I was cutting concrete.

One thing surprised me: the wire that goes to the graphite brush is not
fixed in! It goes into a hole in the graphite but there is nothing holding
it in place other than good luck! Is that normal?

Al

Angle grinder - brush is sparking badly
 

AL_n wrote:
The Natural Philosopher wrote in news:ivpqcp$mv6$1
@news.albasani.net:

That is pretty consistent with a brush not being bedded in.

with electric RC/aircraft and brushed motors, its enough to make em
unflyable - or was till the advent of 2.4Ghz sets.

The technique is generally to run for 10 minutes or more on no load. For
the greatest mechanical wear and least arcing.

Once the brushes 'fit' the commutator it should stop. Apart from a sort
of twinkling in the gap.


Thanks. I tried that, but it was arcing as violently as it did under load,
now. It sounds almost as bad a s Frankinstein's lab! I took the brush out
to have a look, and it had worn down about 4mm-5mm! And there were bits
chipped off from one edge. Is it worth trying to clean up the brass
commutator a bit with a toothbrush or something? I guess it is abrading the
brush for some reason. Perhaps some stone chippings got in there or
something.. I was cutting concrete.

One thing surprised me: the wire that goes to the graphite brush is not
fixed in! It goes into a hole in the graphite but there is nothing holding
it in place other than good luck! Is that normal?

No. It's a defective unit, take it back, and insist on a replacement or
refund.


--
Tciao for Now!

John.

Angle grinder - brush is sparking badly
 

John Williamson wrote:
AL_n wrote:
The Natural Philosopher wrote in news:ivpqcp$mv6$1
@news.albasani.net:

That is pretty consistent with a brush not being bedded in.

with electric RC/aircraft and brushed motors, its enough to make em
unflyable - or was till the advent of 2.4Ghz sets.

The technique is generally to run for 10 minutes or more on no load.
For the greatest mechanical wear and least arcing.

Once the brushes 'fit' the commutator it should stop. Apart from a
sort of twinkling in the gap.


Thanks. I tried that, but it was arcing as violently as it did under
load, now. It sounds almost as bad a s Frankinstein's lab! I took the
brush out to have a look, and it had worn down about 4mm-5mm! And
there were bits chipped off from one edge. Is it worth trying to clean
up the brass commutator a bit with a toothbrush or something? I guess
it is abrading the brush for some reason. Perhaps some stone chippings
got in there or something.. I was cutting concrete.

One thing surprised me: the wire that goes to the graphite brush is
not fixed in! It goes into a hole in the graphite but there is nothing
holding it in place other than good luck! Is that normal?

No. It's a defective unit, take it back, and insist on a replacement or
refund.


I am coming to the same conclusion.

Angle grinder - brush is sparking badly
 

The Natural Philosopher wrote in
:


No. It's a defective unit, take it back, and insist on a replacement
or refund.


I am coming to the same conclusion.


I have got the seller to agree to a large discount if I keep it, so I'd
like to at least have a crack at repairing it.

I can see now that one of the copper contact bars on the commutator is
standing slightly proud of the rest. I could have a go at flettening it
down with some 1000 grade wet&dry.

I'm not sure why it would have become proud of the rest. Anyone seen that
before?

Al

Angle grinder - brush is sparking badly
 

On Jul 16, 10:20*am, "AL_n" wrote:

I can see now that one of the copper contact bars on the commutator is
standing slightly proud of the rest. I could have a go at flettening it
down with some 1000 grade wet&dry.

Usual practice is to turn them in a lathe. You'll want more than 1000
grit if you try and sand it, and sanding is also bad as there's a risk
of grit embedding in the copper, then turning into a brush-chewing
device in the future. Mind you, modern brushes are a bit tougher than
old.

I'd set up some sort of lathe centres to support the ends of the
armature, then file it rather than sanding. An accurately circular
commutator is important, else you get sparking across the dips.

I'm not sure why it would have become proud of the rest. Anyone seen that
before?

Usually by a commutator segment becoming loose, which is a bitch of a
problem to fix. Epoxy might do it, but it helps if you can get the
segment out first - or else clean it and trust to thin cyano. On big
commutators, they're sometimes drilled and screwed through the face
(with a well-countersunk screw).

Angle grinder - brush is sparking badly
 

On Jul 15, 2:51*pm, The Natural Philosopher
wrote:

let brushes bed in, if it persists, take it back. Could be shorted turn.

An open coil is more likely than a shorted one. On an armature this
small, single coils don't short, they go several at a time and so the
fault for a short would be much more obvious than merely increased
sparking.

Angle grinder - brush is sparking badly
 

In article ,
AL_n wrote:
I have got the seller to agree to a large discount if I keep it, so I'd
like to at least have a crack at repairing it.

I can see now that one of the copper contact bars on the commutator is
standing slightly proud of the rest. I could have a go at flettening it
down with some 1000 grade wet&dry.

Hope the discount is large enough to cover the cost of a new armature etc
- and that's assuming one is available as a spare. Isn't Wolf one of those
once pround names now just made in China etc like everything else?

--
*Save a tree, eat a beaver*

Dave Plowman London SW
To e-mail, change noise into sound.

Angle grinder - brush is sparking badly
 

Andy Dingley wrote in
:

On Jul 16, 10:20*am, "AL_n" wrote:

I can see now that one of the copper contact bars on the commutator
is standing slightly proud of the rest. I could have a go at
flettening it down with some 1000 grade wet&dry.

Usual practice is to turn them in a lathe. You'll want more than 1000
grit if you try and sand it, and sanding is also bad as there's a risk
of grit embedding in the copper, then turning into a brush-chewing
device in the future. Mind you, modern brushes are a bit tougher than
old.

I'd set up some sort of lathe centres to support the ends of the
armature, then file it rather than sanding. An accurately circular
commutator is important, else you get sparking across the dips.

I'm not sure why it would have become proud of the rest. Anyone seen
that before?

Usually by a commutator segment becoming loose, which is a bitch of a
problem to fix. Epoxy might do it, but it helps if you can get the
segment out first - or else clean it and trust to thin cyano. On big
commutators, they're sometimes drilled and screwed through the face
(with a well-countersunk screw).


Thanks for the info.

I bought this Wolf gringer to replace my old CE one whose switch stopped
working. The armature and brushes look almost identical, as if they may
have been made by the same company. The new one is Wolf and the old one os
CE. I'm just wondering if I can take the armature out of the old grinder
and put it in the new one. Probably too much to hope for!

If I keep this faulty Wolf one, I get it for almost nothing. So I'd rather
buy a new armature for it (or even get the old commutator professionally
repaired, rather than pay out for a whole new grinder. I read somewhere
that Wolf tools recently went bust so I don't know how feasable it is to
buy components for them.

Al

Angle grinder - brush is sparking badly
 

On Friday, 15 July 2011 16:34:16 UTC+3, AL_n wrote:
I purchased a 9" angle grinder (Wolf) on eBay. After using it for about 30
minutes, one of the brushes started sparking badly. I could hear the arcimh
amd and see the flashes right through the yellow casing! I removed the
inspection cover and ran the grinder, I could see bright blue sparking
travelling right around the commutator ()if that's the segmented copper
drum that the brushes rub against) and flying out from where the nearest
brush contacts the commutator. Is this something I should worry about, or
is it normal? Is there any maintenance operation I can do to cure it?

Thank you.

Al

Angle grinder - brush is sparking badly
 

Angle grinder - brush is sparking badly
 

On 10/16/2016 3:24 PM, Bob Minchin wrote:
wrote:
On Friday, 15 July 2011 16:34:16 UTC+3, AL_n wrote:
I purchased a 9" angle grinder (Wolf) on eBay. After using it for
about 30
minutes, one of the brushes started sparking badly. I could hear the
arcimh
amd and see the flashes right through the yellow casing! I removed the
inspection cover and ran the grinder, I could see bright blue sparking
travelling right around the commutator ()if that's the segmented copper
drum that the brushes rub against) and flying out from where the nearest
brush contacts the commutator. Is this something I should worry
about, or
is it normal? Is there any maintenance operation I can do to cure it?

Thank you.

Al

If it really is only one brush sparking it might be either sticking in
the holder, worn too short or the spring is weak usually due to over
heating.
If they are both sparking then all probability is that the armature is
knackered and usually new ones are more than the tool is worth.

At one time Wolf was a very good brand (1950s and 60s) but the name has
been sold and appears on all sorts of Chinese low quality tools these days.

2011 post so no point replying to that.

However *my* experience with various drills, vacuum cleaners, angle
grinders, etc is that it is very often worth replacing worn out brushes.
First symptom is sometimes device stopping without much preliminary
sparking.

I agree that armature failure gives dramatic sparks.

If the manufacturer's brush prices are too silly, I've not had problems
with eBay clones. Also, I've cut down or abraded larger brushes to fit
motors on a number of occasions.

Angle grinder - brush is sparking badly
 

On Friday, 15 July 2011 14:40:30 UTC+1, AL_n wrote:
"AL_n" wrote in
:

I purchased a 9" angle grinder (Wolf) on eBay

PS.. I should have mentioned that the grinder is brand new - never used
prior to purchase.

I was going to say that your machine is either a 110v fitted with a 240v plug or a 240V fitted with a 110v plug.

Angle grinder - brush is sparking badly
 

Damn, we have now gone back to 2011.
Ithought this shower had almost caught up too
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
On Friday, 15 July 2011 16:34:16 UTC+3, AL_n wrote:
I purchased a 9" angle grinder (Wolf) on eBay. After using it for about
30
minutes, one of the brushes started sparking badly. I could hear the
arcimh
amd and see the flashes right through the yellow casing! I removed the
inspection cover and ran the grinder, I could see bright blue sparking
travelling right around the commutator ()if that's the segmented copper
drum that the brushes rub against) and flying out from where the nearest
brush contacts the commutator. Is this something I should worry about, or
is it normal? Is there any maintenance operation I can do to cure it?

Thank you.

Al

Angle grinder - brush is sparking badly
 

Maybe we need to set up a home for old Angle grinders. Is there no Angle
grinder museum yet?
The number of queries, old and new we seem to see on this list does make
one wonder if, in the future archaeologists will find these devices and
wonder what early humans did with them, they will probably assume they were
used in some ritualistic worship tradition or something.

Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Weatherlawyer" wrote in message
...
On Friday, 15 July 2011 14:40:30 UTC+1, AL_n wrote:
"AL_n" wrote in
:

I purchased a 9" angle grinder (Wolf) on eBay

PS.. I should have mentioned that the grinder is brand new - never used
prior to purchase.

I was going to say that your machine is either a 110v fitted with a 240v
plug or a 240V fitted with a 110v plug.

Angle grinder - brush is sparking badly
 

"Brian Gaff" wrote in message
...
Maybe we need to set up a home for old Angle grinders. Is there no Angle
grinder museum yet?
The number of queries, old and new we seem to see on this list does make
one wonder if, in the future archaeologists will find these devices and
wonder what early humans did with them, they will probably assume they
were used in some ritualistic worship tradition or something.

Unlikely now that communication is preserved for millennia now.
We have an excellent idea of what the Greeks and the Romans got up to now.

"Weatherlawyer" wrote in message
...
On Friday, 15 July 2011 14:40:30 UTC+1, AL_n wrote:
"AL_n" wrote in
:

I purchased a 9" angle grinder (Wolf) on eBay

PS.. I should have mentioned that the grinder is brand new - never used
prior to purchase.

I was going to say that your machine is either a 110v fitted with a 240v
plug or a 240V fitted with a 110v plug.

Angle grinder - brush is sparking badly
 

On 16/10/2016 15:24, Bob Minchin wrote:
wrote:


At one time Wolf was a very good brand (1950s and 60s) but the name has
been sold and appears on all sorts of Chinese low quality tools these days.


My Father has a Wolf muti set up ... Drill stand,wood working lathe,
circular saw, jigsaw ... all powered by wolf 2/8" single speed hand drill.
All in cast aluminium not a piece of plastic in sight.
The set is now more than 60 years old.

Angle grinder - brush is sparking badly
 

On 10/20/2016 3:40 PM, rick wrote:
On 16/10/2016 15:24, Bob Minchin wrote:
wrote:


At one time Wolf was a very good brand (1950s and 60s) but the name has
been sold and appears on all sorts of Chinese low quality tools these
days.


My Father has a Wolf muti set up ... Drill stand,wood working lathe,
circular saw, jigsaw ... all powered by wolf 2/8" single speed hand drill.
All in cast aluminium not a piece of plastic in sight.
The set is now more than 60 years old.

I remember them!

Angle grinder - brush is sparking badly
 

On 10/20/2016 4:16 PM, newshound wrote:
On 10/20/2016 3:40 PM, rick wrote:
On 16/10/2016 15:24, Bob Minchin wrote:
wrote:


At one time Wolf was a very good brand (1950s and 60s) but the name has
been sold and appears on all sorts of Chinese low quality tools these
days.


My Father has a Wolf muti set up ... Drill stand,wood working lathe,
circular saw, jigsaw ... all powered by wolf 2/8" single speed hand
drill.
All in cast aluminium not a piece of plastic in sight.
The set is now more than 60 years old.

I remember them!

And here is one

http://www.ebay.co.uk/itm/VINTAGE-WO...AOSwmfhX569 e

Angle grinder - brush is sparking badly
 

In article ,
rick wrote:
On 16/10/2016 15:24, Bob Minchin wrote:
wrote:


At one time Wolf was a very good brand (1950s and 60s) but the name
has been sold and appears on all sorts of Chinese low quality tools
these days.


My Father has a Wolf muti set up ... Drill stand,wood working lathe,
circular saw, jigsaw ... all powered by wolf 2/8" single speed hand
drill. All in cast aluminium not a piece of plastic in sight. The set is
now more than 60 years old.

And the time taken to fit an accessory meant it was quicker to do it by
hand. And, of course, the speeds were all wrong.

--
*Friends help you move. Real friends help you move bodies.

Dave Plowman London SW
To e-mail, change noise into sound.

Angle grinder - brush is sparking badly
 

On Thursday, 20 October 2016 16:35:50 UTC+1, Dave Plowman (News) wrote:
In article ,
rick wrote:
On 16/10/2016 15:24, Bob Minchin wrote:
wrote:


At one time Wolf was a very good brand (1950s and 60s) but the name
has been sold and appears on all sorts of Chinese low quality tools
these days.


My Father has a Wolf muti set up ... Drill stand,wood working lathe,
circular saw, jigsaw ... all powered by wolf 2/8" single speed hand
drill. All in cast aluminium not a piece of plastic in sight. The set is
now more than 60 years old.

And the time taken to fit an accessory meant it was quicker to do it by
hand. And, of course, the speeds were all wrong.

Long ago someone gave me a B&D circular saw attachment. I tried it, it was marginally quicker than sawing by hand. In fairness though I don't remember how sharp it was. Steel teeth of course.

It's also a question of what folk could afford. I remember balking at a hammer drill at £80 in the 1980s.


NT

Angle grinder - brush is sparking badly
 

wrote in message
...
On Thursday, 20 October 2016 16:35:50 UTC+1, Dave Plowman (News) wrote:
In article ,
rick wrote:
On 16/10/2016 15:24, Bob Minchin wrote:
wrote:


At one time Wolf was a very good brand (1950s and 60s) but the name
has been sold and appears on all sorts of Chinese low quality tools
these days.


My Father has a Wolf muti set up ... Drill stand,wood working lathe,
circular saw, jigsaw ... all powered by wolf 2/8" single speed hand
drill. All in cast aluminium not a piece of plastic in sight. The set
is
now more than 60 years old.

And the time taken to fit an accessory meant it was quicker to do it by
hand. And, of course, the speeds were all wrong.

Long ago someone gave me a B&D circular saw attachment. I tried
it, it was marginally quicker than sawing by hand. In fairness though
I don't remember how sharp it was. Steel teeth of course.

It's also a question of what folk could afford.
I remember balking at a hammer drill at £80 in the 1980s.

I bought one in the very early 70s but then I was building
the whole house from scratch on a bare block of land and
was spending vastly more than that on the materials.

Bought a big circular saw too.