I have an ancient AEG STSZ350 jigsaw that recently started popping and
These are the brushes:
And the brush holders/commutator:
And finally the jigsaw's type plate:
I've found a company that supplies brushes purporting to be suitable
for this model, but they look different:
The replacement brushes have caps on the ends of the springs, whereas
the brushes in my jigsaw just have the springs without caps or wires.
Are these replacements suitable? Is it a newer design?
Or is there a "universal" brush type I could use? (Maybe re-use the
Finally, comments about the state of the commutator would be welcome.
The brush holders look like they have become warm at the ends and as the
length of the new ones are not that much greater than the old ones, I'd
be more checking that the rushes move freely in the holders and that the
springs are still exerting a good pressure.
The replacements with the copper braid look much more common type than
yours and could well be a revised design. The brass end cap could well
fit inside or over the end of the holder.
Spring steel is not such a good conductor compared to copper.
Look at the sparks. Small sparks near the end of the brushes is normally
a contact problem (brush length, spring pressure or friction) whereas a
ring of sparks running around the commutator is indicative of possible
No they don't look that worn compared to the new ones but they have been
getting a bit hot which is not good in a plastic bodied tool. Hence my
suggestion to check they are completely free to move in the holders.
A first option might be stretching the springs. Basically if they've
been sat for 40 years in a compressed state then possibly they could
be expected to have lost some of their tension/elasticity. Simply by
stretching them out you might be able to re-introduce some of that
tension and elasticity.
Or maybe not, but it will cost nothing to try in any case.
The OP explained that the tool has been little used.
The reason AEG hand tools were taken over in the 90's
isn't because their tools and motors were rubbish;
precisely the opposite. Just like German tanks in WW2
they were over-engineered to the extent that they cost
that much more to produce than the Japanese Compton
that was then coming on line.
AFAIAA in the 70's and 80's AEG never produced
many DIY or consumer tool lines. Most if not all of
their tools were heavy duty. "Heavy" being the operative
word for some of them.
Providing its been stored in dry conditions the OP would need
to subjecting the tool to a good deal of hard use before the motor
as against the brushes would show any sign of failure.
On Tue, 4 Apr 2017 19:15:03 +0100, "michael adams"
Yeah, you got that right! This jigsaw is built like a Panzer!
But how can I tell whether the armature is shagged?
By the way, I left it in the garage over winter and it probably got
damp. When I switched it on in February, it "popped" a couple of times
(like a small balloon popping) and the sparking was noticeable through
the ventilation slits. However, since I've had it indoors in the warm
for a few weeks, the popping never occurred again, but the sparking is
still evident. Also, the motor tends to slow down then speed up
somewhat. I'm not actually trusting it to use for sawing, but am using
my new Makita instead. But, as just explained to Harry above, this old
jigsaw fits my AEG fret saw like this one:
On Wednesday, 5 April 2017 18:27:46 UTC+1, MM wrote:
Before you do anything, make sure the brushes are not worn/burned right down and are free to slide in the holders.
The face of the brush should not be pitted.
If the armature is OK, and the brushes are OK (as above) the brushes should "bed in" with a few minutes running.
You will always get slight sparking on power tools running on AC and for other more technical reasons.
If there are sparks running round the commutator or there is popping and crackling after the brush check, it's the armature shagged.
As well as long use,this can be caused by corrosion if it's been left in a damp place or condensation or overcurrent due to partial seizure.
I've ordered replacement brushes (£5.89) and will clean the commutator
with emery. I remember when we serviced old dynamos on Ford Pops and
Austin Sevens and similar, which were bread-and-butter cars when I
started my apprenticeship. Some of those old cars had a third brush
that you could adjust. I've watched a few YourTube vids to refresh my
memory. If it carries on sparking and/or popping after I've replaced
the brushes and given it a good clean, I'll junk it. The popping noise
was the worst. Made me really jump! Very much like a balloon popping.
As a matter of interest, when an armature is shagged, what IS it that
actually goes bad with it? The windings?
Also, I reckon I need to get some graphite grease or something for the
gears before I reassemble.
It can often be the commutator.
Everything anyone could possibly ever want to know about commutators
IMHO once you've fitted the replacement brushes and they slide easily in the
shoes, the tool should work straightaway. So all the above is probably
superfluous, for another 40 years anyway.
On Wednesday, 5 April 2017 21:10:20 UTC+1, MM wrote:
down and are free to slide in the holders.
uld "bed in" with a few minutes running.
other more technical reasons.
crackling after the brush check, it's the armature shagged.
n a damp place or condensation or overcurrent due to partial seizure.
Any number of things can go wrong but mostly to do with insulation breakdow
Occasionally the connections fail where they connect to the commutator segm
It's possible to fit new coils but uneconomic with power tools.
The latest technology has no commutator and no windings on the rotating bit
(Only rare earth magnets).
So, almost nothing to go wrong except the electronics that generate AC..
If as you say the saw has had little use, if you bought it yourself
fair enough, ( if it's inherited and you took this statement on trust
then possibly not, as applies to numerous tools offered on eBay)
then apart from the effects of damp, rodents attack etc then
there's no reason why all the electrical components shouldn't
be in first class condition. The plastic sheathing may be a bit
brittle but not such as to cause failure.
Same with the brushes. There's no reason why the brushes should
be worn if the tool's had little use. And AEG tools were
designed for heavy use before needing brush replacements.
My guess as suggested before is that the springs have weakened
over the course of the 40 years and the brushes aren't making
sufficient contact with the armature at all times.
If stretching them doesn't solve the problem then possibly
if you can remove the springs from the brushes you could try
heating them to maybe white hot and then rapidly quenching them
in cold water to restore the temper/springiness.(AINAM) At this
stage its the springs I'd be concentrating on. Failing that
say if you can't get them back on - new brushes.
As replacement brushes cost considerably less than would a
replacement armature I'd replace the brushes first and see
if that has any effect before worrying about the state of
So its first springs - then brushes - then the armature.
On Thu, 6 Apr 2017 08:28:02 +0100, "michael adams"
Yep, new brushes are on the way to me, and I bought a sheet of 600
wet-or-dry today (couldn't obtain emery cloth here).
Yes, I bought the tool brand-new in the mid-70s in Cologne where I
lived and worked at the time. (Migrant worker!)
I suppose you wouldn't happen to know anything about the AEG fret saw
attachment, which I purchased separately? I've still got all the
parts, but I cannot find the darned user guide, which is NOT available
on the internet. I've searched high and low. I doubt anyway that the
guide ever existed as a PDF, but a few days ago I thought maybe
someone had photocopied it and uploaded to the web. No dice.
This is the tool:
As I recall, the guide tube has to be adjusted as close to the
workpiece as possible. It made much more accurate cuts than without
Wolfcraft used to produce a very similar tool, suitable for any
jigsaw, but while their table is still available, they've stopped
making the blade guide. Mind you, I was surprised to see just how many
keen DIY-ers on YouTube have constructed thei own blade guides, using
skate roller bearings and suchlike!
According to one of the pictures accompanying this ebay listing,
there's some information of a kind on a label inside the lid of
If you blow up the picture of the label, and can remember any
German maybe that might be of some use.
While from the big picture on the box it appears that the plate
is included with the attachment, in all the other pictures
it appears the plate is that of the saw. So the biggest
problem presumably is working out how to attach the arm
to the saw (plus how to mount or fix the saw in an upside
down position). Maybe a bit of jiggling about is in order
Whereas you've got a blade guide but no table ?
Wolfcraft are a funny outfit. For a few years there, along with
Bosch they made the best portable drill stands on the market.
Movement of the head was via rack and pinion with a heavy
hexagonal steel pillar with the rack machined into one
face and heavy case iron bases. But the funny thing was
that the first version had a one part head - the bit to
which the drill was clamped - which moved up and down
the pillar. It was only after a year or two, that they
worked out that a two part head with the top part clamped
to the pillar imparted far more rigidity. You'd imagine
this was something that was discovered within a few years
of portable drill stands first being developed maybe
50 or 60 years ago. Although possibly they thought that
having a hexagonal pillar which prevented rotation of the
head around the pillar, obviated the need for a two part
head. Well it didn't.* So that second version was the
best of both worlds - an expensive to produce hexagonal
pillar which prevented rotation and a two part head
for even more rigidity.
It maybe goes without saying the present day version has
a cheaper round pillar with the rack screwed on.
Many of the head components on most versions appear to be cast
magnesium or an alloy of the same - and going by comments
online can be mistaken for plastic. And may possibly may be
a possible cause of failure in the long term or at least the
weakest part of the design.
* All versions available on eBay occasionally, along with
Bosch, although not always distinguished as such. And usually
drowning among a sea of rubbish. The cast iron bases
are prone to rust which can put people off and keep
prices down in some cases.
On Fri, 7 Apr 2017 08:56:38 +0100, "michael adams"
Yes, I've read that.
No, the saw is dead easy to attach. The saw table is made for the saw,
but have have been another optional accessory separate to the fre saw
frame. I have both parts, anyway.
The base plate on the jigsaw has three threaded holes and the saw
table is attached with three machine screws from the top surface
(countersunk). It's a very well-engineered piece of kit.
Problem is that I've looked at a range of new jigsaws in various
outlets and none have threaded holes for the AEG fret saw attachment,
or even any holes at all. The base plate on my new Makita is too large
to even fit into the recess on the underside of the AEG saw table.
Hence my desire to get the old AEG jigsaw working again.
The Wolfcraft saw table I mentioned elsewhere is "universal" and thus
suitable for most jigsaws. The attachment is made by the use of four
clamps underneath. But, as also mentioned, Wolfcraft discontinued the
blade guide component.
No, I have the table as well. The one thing that's missing is a
functioning jigsaw! Maybe those new brushes will arrive today. They
were posted second class.
On Fri, 7 Apr 2017 08:56:38 +0100, "michael adams"
Success! I cleaned the commutator, undercut the mica a bit, put the
new brushes in, used some lithium beased grease, sparingly, on the
worm and wheel, and also on the plunger and cam, reassembled. It
works! It sparked a ~little~ bit for the first 10 seconds, but then I
think the brushes bedded in a bit and there were hardly ~any~ sparks.
And no popping noises or slowing down, which was happening before.
So I'm in the process of assembling the jigsaw and fret saw
frame/table, but I decided to make a proper stand for it rather than
just use the G-clamp. So that's taken me all afternoon.
Great exercise, thanks one and all for all the tips.
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