I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.

What would be a suitable polish? Or if it's likely to be too hard for a
polish, could it perhaps be sanded first?

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.

Daniele

D.M. Procida wrote:
I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.

What would be a suitable polish? Or if it's likely to be too hard for a
polish, could it perhaps be sanded first?

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.

Daniele
It doesnt have to be THAT smooth.

However the trouble is, that anything you take off it will slow the tape
down.

Th 'pro' approah wuld be to get the spindle off and make a new one, or
turn it down and fit a machined sleeve to it.

But for non critical applications, go to Halfords and get some wet and
dry of the finest grade - about 600 grit, cut strips and simply wind
round the capstan while running.

You can use jewellers rouge or valve grinding compound or even T-cut for
a final polish.

"The Natural Philosopher" wrote in message
...
D.M. Procida wrote:
I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out. What would be a suitable polish? Or
if it's likely to be too hard for a
polish, could it perhaps be sanded first?

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.

Daniele
It doesnt have to be THAT smooth.

However the trouble is, that anything you take off it will slow the tape
down.

Th 'pro' approah wuld be to get the spindle off and make a new one, or
turn it down and fit a machined sleeve to it.

Wet and Dry goes to 1200......and on to "Flour Paper".
*Then* it might be worth using rouge etc

D.M. Procida wrote:

I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.

Don't you stand a fair chance of unbalancing the flywheel in the
process?

What would be a suitable polish? Or if it's likely to be too hard for a
polish, could it perhaps be sanded first?

Normally I'd turn the capstan on a lathe to get rid of the pits.

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.

P180 paper would probably do the job, leaving a finish smooth enough to
polish using a cotton mop on a polisher spindle using an abrasive stick
to dress the mop. However the chances are that in the process of sanding
and polishing that you will get the flywheel out of shape.

The Natural Philosopher wrote:

D.M. Procida wrote:
I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.

What would be a suitable polish? Or if it's likely to be too hard for a
polish, could it perhaps be sanded first?

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.

It doesnt have to be THAT smooth.

However the trouble is, that anything you take off it will slow the tape
down.

Speed it up, not slow it down.

However, I'd bet that it would make an unmeasurable difference. The
pitting's very, very light.

Th 'pro' approah wuld be to get the spindle off and make a new one, or
turn it down and fit a machined sleeve to it.

But for non critical applications, go to Halfords and get some wet and
dry of the finest grade - about 600 grit, cut strips and simply wind
round the capstan while running.

It's not the capstan, it's the flywheel, that needs attention.

Daniele

"Steve Firth" wrote in message
.. .
D.M. Procida wrote:

I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.

Don't you stand a fair chance of unbalancing the flywheel in the
process?

What would be a suitable polish? Or if it's likely to be too hard for a
polish, could it perhaps be sanded first?

Normally I'd turn the capstan on a lathe to get rid of the pits.

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.

P180 paper would probably do the job, leaving a finish smooth enough to
polish using a cotton mop on a polisher spindle using an abrasive stick
to dress the mop. However the chances are that in the process of sanding
and polishing that you will get the flywheel out of shape.

Capstan flywheel - or capstan spindle? The finish on the flywheel has no
functional consequence.

John wrote:
"Steve Firth" wrote in message
.. .
D.M. Procida wrote:

I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.
Don't you stand a fair chance of unbalancing the flywheel in the
process?

What would be a suitable polish? Or if it's likely to be too hard for a
polish, could it perhaps be sanded first?
Normally I'd turn the capstan on a lathe to get rid of the pits.

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.
P180 paper would probably do the job, leaving a finish smooth enough to
polish using a cotton mop on a polisher spindle using an abrasive stick
to dress the mop. However the chances are that in the process of sanding
and polishing that you will get the flywheel out of shape.

Capstan flywheel - or capstan spindle? The finish on the flywheel has no
functional consequence.


I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

Bob

On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin
wrote:


I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

--
Frank Erskine

On 27 Dec, 15:20, Frank Erskine wrote:
On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin

wrote:

I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

--
Frank Erskine

Tape capstan used to be the most precisely machined surface in an
average household, taking anythng off the capstan will affect tape
speed if its the part in contact with the tape bewtween it and pinch
wheel.

Adam

John wrote:

I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.

Don't you stand a fair chance of unbalancing the flywheel in the
process?

What would be a suitable polish? Or if it's likely to be too hard for a
polish, could it perhaps be sanded first?

Normally I'd turn the capstan on a lathe to get rid of the pits.

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.

P180 paper would probably do the job, leaving a finish smooth enough to
polish using a cotton mop on a polisher spindle using an abrasive stick
to dress the mop. However the chances are that in the process of sanding
and polishing that you will get the flywheel out of shape.

Capstan flywheel - or capstan spindle? The finish on the flywheel has no
functional consequence.

Not even where the belt makes contact with it? I imagine it must have
only a tiny effect, if any, but since the flywheel is meant to be smooth
and not pitted, it seems better to restire it to that condition.

Daniele

In article
,
D.M. Procida wrote:
I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.

Is it on a face a drive belt or pulley bears on?

What would be a suitable polish? Or if it's likely to be too hard for a
polish, could it perhaps be sanded first?

They're normally made of a casting alloy - unfortunately sometimes Mazak
which can develop pits if kept in adverse conditions - although not
normally in a house. Now obviously if you grind these out in some way
you'll also alter the diameter and therefore speed. I'd be inclined to
fill them with good body filler then just smooth that down.

It will need to be the very finest abrasive paper, because it needs to
have an extremely smooth surface.

--
*If work is so terrific, how come they have to pay you to do it?

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

Frank Erskine wrote:
On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin
wrote:

I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

'Fraid not Frank, Smaller diameter =faster rotation for a fixed
peripheral speed.

Bob

On Sat, 27 Dec 2008 16:07:07 +0000, Bob Minchin wrote:

Frank Erskine wrote:
On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin
wrote:

I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

'Fraid not Frank, Smaller diameter =faster rotation for a fixed
peripheral speed.

Yebbut elsewhere the OP has mentioned a belt drive to the flywheel.....


--

The Wanderer

Statistics show that statistics can't be trusted.

On Sat, 27 Dec 2008 16:21:24 +0000, The. Wanderer wrote:

On Sat, 27 Dec 2008 16:07:07 +0000, Bob Minchin wrote:

Frank Erskine wrote:
On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin
wrote:

I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

'Fraid not Frank, Smaller diameter =faster rotation for a fixed
peripheral speed.

Yebbut elsewhere the OP has mentioned a belt drive to the flywheel.....

Huh, idiot. Just got my head working......


--

The Wanderer

All wighy, rho sriyched yhe ket pads on my ketboawd?

D.M. Procida wrote:
The Natural Philosopher wrote:

D.M. Procida wrote:
I'm restoring an old tape recorder. The capstan flywheel is very
lightly pitted. I'd like to polish this out.

What would be a suitable polish? Or if it's likely to be too hard
for a polish, could it perhaps be sanded first?

It will need to be the very finest abrasive paper, because it needs
to have an extremely smooth surface.

It doesnt have to be THAT smooth.

However the trouble is, that anything you take off it will slow the
tape down.

Speed it up, not slow it down.

However, I'd bet that it would make an unmeasurable difference. The
pitting's very, very light.

Th 'pro' approah wuld be to get the spindle off and make a new one,
or turn it down and fit a machined sleeve to it.

But for non critical applications, go to Halfords and get some wet
and dry of the finest grade - about 600 grit, cut strips and simply
wind round the capstan while running.

It's not the capstan, it's the flywheel, that needs attention.

It would help if you properly described what bit you are actually talking
about. Do you mean the peripheral surface of the part the tape wraps round,
against which it is held by a pinch wheel and thus pulled past the recording
heads?

If so then I'd leave it alone unless the pits have sharp edges which might
damage the tape. The capstan surface should be almost mirror smooth. Some of
the advice you've been given such as 180 grit it bleedin' absurd. 180 grit
is rough as a dog's arse. 1000 grit is what you'd call a fine grit but even
that, or in fact any grade of abrasive paper will destroy the original
finish. You get surfaces that smooth by fine polishing with things like high
speed felt mops containing very mild abrasives in a slurry form.

If you remove material and decrease the capstan's diameter then the tape
speed will slow down NOT speed up. This is hardly rocket surgery. Smaller
diameter = lower peripheral speed for a given diameter not the reverse. It's
the capstan that drives the tape not vice versa!

If you remove the pits then the tape will no longer run at the right speed
which is fairly pointless. You'll also never remove them without machining
even if they're only a few thou deep. You can't polish off large amounts of
metal like that by hand and have any hope of keeping the capstan truly
circular. I've spent half a lifetime polishing crankshaft journals in race
engines so I know what it takes to remove a given amount of metal and what
surface finish you end up with. Half a thou is a shed load to remove by any
sort of polishing even when you're rotating the part on a lathe. You're
normally only talking about the odd tenth of a thou or even fractions of a
tenth for the final polishing operation.

The most I'd do just to make sure the pits didn't have sharp edges is go
over the surface very lightly with a fine metal polish, or even toothpaste,
and a cloth. Try on an old capstan first to make sure that even this doesn't
just lead to scratches.
--
Dave Baker

Dave Baker wrote:


It's not the capstan, it's the flywheel, that needs attention.

It would help if you properly described what bit you are actually talking
about.

He did. He said it's the flywheel. You then spend the rest of your post
ranting about the capstan. Perhaps you could spend slightly less time
being angry and slightly more time reading?

If he reduces the diameter of the flywheel and the flywheel is driven by
a belt then reducing the diameter of the flywheel will speed the tape
up.

Piddling about with the flywheel and flatting it in an attempt to remove
pits (which is just about inevitable if one does it by hand) will
introduce "wow". It depends if the aim is to have a working tape
recorder or a pretty one that doesn't function properly.

Steve Firth wrote:
Dave Baker wrote:


It's not the capstan, it's the flywheel, that needs attention.

It would help if you properly described what bit you are actually
talking about.

He did. He said it's the flywheel. You then spend the rest of your
post ranting about the capstan. Perhaps you could spend slightly less
time being angry and slightly more time reading?

If he reduces the diameter of the flywheel and the flywheel is driven
by a belt then reducing the diameter of the flywheel will speed the
tape up.

If something is driven by a belt then it's a pulley not a flywheel! It might
well be a pulley that's attached to a flywheel but it clearly isn't the same
thing. So you clearly don't know for sure which bit he/she is talking about
either. Until he/she makes clear which bit is being discussed, what it's
made of, whether it's functional or decorative, whether it contacts the tape
or a belt or not we're all ****ing in the wind here.
--
Dave Baker

Dave Baker wrote:

Steve Firth wrote:
Dave Baker wrote:


It's not the capstan, it's the flywheel, that needs attention.

It would help if you properly described what bit you are actually
talking about.

He did. He said it's the flywheel. You then spend the rest of your
post ranting about the capstan. Perhaps you could spend slightly less
time being angry and slightly more time reading?

If he reduces the diameter of the flywheel and the flywheel is driven
by a belt then reducing the diameter of the flywheel will speed the
tape up.

If something is driven by a belt then it's a pulley not a flywheel!

It's the flywheel. You obviously know ****-all about tape recorders.

It might well be a pulley that's attached to a flywheel but it clearly
isn't the same thing.

No, it's a belt drive to the edge of the flywheel.

So you clearly don't know for sure which bit he/she is talking about
either.

I know exactly what he's talking about. But then unlike you I know what
the inside of a tape recorder looks like.

Until he/she makes clear which bit is being discussed, what it's made of,
whether it's functional or decorative, whether it contacts the tape or a
belt or not we're all ****ing in the wind here.

No, you're flaming away with unrighteous anger because you don't know
what you're talking about.

In article ,
Dave Baker wrote:
If he reduces the diameter of the flywheel and the flywheel is driven
by a belt then reducing the diameter of the flywheel will speed the
tape up.

If something is driven by a belt then it's a pulley not a flywheel! It
might well be a pulley that's attached to a flywheel but it clearly
isn't the same thing. So you clearly don't know for sure which bit
he/she is talking about either. Until he/she makes clear which bit is
being discussed, what it's made of, whether it's functional or
decorative, whether it contacts the tape or a belt or not we're all
****ing in the wind here.

It's quite common on tape recorders to have a flywheel as part of the
capstan assembly which is a cylinder in shape - and driven by a flat
rubber belt, so no actual pulley. On some, the motor driving this will
have a stepped shaft, and the belt moved from one to another to change
speed. No actual pulley on that shaft either. Sounds quite crude but works
ok in practice. Of course more upmarket machines will have a directly
driven capstan or capstans where the motor is driven by an oscillator etc
to achieve speed changes. But then this usually means separate motors for
the feed and take up spools too - so more expensive.

--
*The more I learn about women, the more I love my car

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

(Steve Firth) wrote:

It's the flywheel. You obviously know ****-all about tape recorders.


Excellent. Profanity *and* personal abuse.

In article ,
Steve Firth wrote:
I know exactly what he's talking about. But then unlike you I know what
the inside of a tape recorder looks like.

There are so many variations in the way the various drives work I doubt
anyone knows them all.

--
*Who is this General Failure chap anyway - and why is he reading my HD? *

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

Bruce wrote:

(Steve Firth) wrote:

It's the flywheel. You obviously know ****-all about tape recorders.

Excellent. Profanity *and* personal abuse.

When were you elected the language policeman for the newsgroup,
****nuts?

Dave Plowman (News) wrote:

In article ,
Steve Firth wrote:
I know exactly what he's talking about. But then unlike you I know what
the inside of a tape recorder looks like.

There are so many variations in the way the various drives work I doubt
anyone knows them all.

All no. But in context it's easy to work out which type Danielle was
talking about. And it's easy to tell that LoudMouth didn't have a clue.

On Sat, 27 Dec 2008 16:07:07 +0000, Bob Minchin
wrote:

Frank Erskine wrote:
On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin
wrote:

I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

'Fraid not Frank, Smaller diameter =faster rotation for a fixed
peripheral speed.

If it's a flywheel driven at a constant speed, a smaller diameter
(hence circumference) will propel the tape less distance for each
revolution.

--
Frank Erskine

Frank Erskine wrote:
On Sat, 27 Dec 2008 16:07:07 +0000, Bob Minchin
wrote:

Frank Erskine wrote:
On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin
wrote:

I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

'Fraid not Frank, Smaller diameter =faster rotation for a fixed
peripheral speed.

If it's a flywheel driven at a constant speed, a smaller diameter
(hence circumference) will propel the tape less distance for each
revolution.

No Frank - sorry but you are wrong. the deck has a belt drive and so the
flywheel rotational speed will increase.

Bob

Steve Firth wrote:
Dave Baker wrote:

It's not the capstan, it's the flywheel, that needs attention.
It would help if you properly described what bit you are actually talking
about.

He did. He said it's the flywheel. You then spend the rest of your post
ranting about the capstan. Perhaps you could spend slightly less time
being angry and slightly more time reading?

If he reduces the diameter of the flywheel and the flywheel is driven by
a belt then reducing the diameter of the flywheel will speed the tape
up.

Piddling about with the flywheel and flatting it in an attempt to remove
pits (which is just about inevitable if one does it by hand) will
introduce "wow". It depends if the aim is to have a working tape
recorder or a pretty one that doesn't function properly.


She.

At least, I assume that Daniele is female.

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

Steve Firth wrote:
Dave Plowman (News) wrote:

In article ,
Steve Firth wrote:
I know exactly what he's talking about. But then unlike you I know
what the inside of a tape recorder looks like.

There are so many variations in the way the various drives work I
doubt anyone knows them all.

All no. But in context it's easy to work out which type Danielle was
talking about. And it's easy to tell that LoudMouth didn't have a
clue.

You are a rude and churlish person who I have no interest in squabbling with
A) because it's Xmas and B) because I gave up doing that many years ago on
Usenet after realising it was pointless and there's always someone new who
wants to troll or bicker. If you don't mind I'll just pop you in the
killfile instead and talk to the grownups, some of whom are no doubt
familiar with the extent of my engineering background.
--
Dave Baker

On Sat, 27 Dec 2008 19:24:31 +0000, Bob Minchin
wrote:

Frank Erskine wrote:
On Sat, 27 Dec 2008 16:07:07 +0000, Bob Minchin
wrote:

Frank Erskine wrote:
On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin
wrote:

I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

'Fraid not Frank, Smaller diameter =faster rotation for a fixed
peripheral speed.

If it's a flywheel driven at a constant speed, a smaller diameter
(hence circumference) will propel the tape less distance for each
revolution.

No Frank - sorry but you are wrong. the deck has a belt drive and so the
flywheel rotational speed will increase.

Ho hum. As Dave B suggested above, we're talking, aren't we, about a
flywheel, NOT a pulley. The capstan motor rotates at a constant speed,
driving the pulley, hence the flywheel at a constant rotational speed.
If we reduce (by grinding, turning or whatever) the diameter of the
flywheel its circumference will also reduce.
If, as _you_ suggested above, that the Teac deck drives (is not
driven) on the periphery of the flywheel, then the resultant tape
speed will be reduced.

--
Frank Erskine

On Dec 27, 7:27*pm, Rod wrote:
Steve Firth wrote:
Dave Baker wrote:

It's not the capstan, it's the flywheel, that needs attention.
It would help if you properly described what bit you are actually talking
about.

He did. He said it's the flywheel. You then spend the rest of your post
ranting about the capstan. Perhaps you could spend slightly less time
being angry and slightly more time reading?

If he reduces the diameter of the flywheel and the flywheel is driven by
a belt then reducing the diameter of the flywheel will speed the tape
up.

Piddling about with the flywheel and flatting it in an attempt to remove
pits (which is just about inevitable if one does it by hand) will
introduce "wow". It depends if the aim is to have a working tape
recorder or a pretty one that doesn't function properly.

She.

At least, I assume that Daniele is female.

A reasonable, but wrong, assumption. He is Italian, hence the odd (to
English eyes) spelling.

(Note: You are not the first person to make that mistake on this
group. He wasn't offended last time; he almost won't be offended the
next time it happens either.)

Dave Baker wrote:

Steve Firth wrote:
Dave Plowman (News) wrote:

In article ,
Steve Firth wrote:
I know exactly what he's talking about. But then unlike you I know
what the inside of a tape recorder looks like.

There are so many variations in the way the various drives work I
doubt anyone knows them all.

All no. But in context it's easy to work out which type Danielle was
talking about. And it's easy to tell that LoudMouth didn't have a
clue.

You are a rude and churlish person who I have no interest in squabbling with
A) because it's Xmas and B) because I gave up doing that many years ago on
Usenet after realising it was pointless and there's always someone new who
wants to troll or bicker. If you don't mind I'll just pop you in the
killfile instead and talk to the grownups, some of whom are no doubt
familiar with the extent of my engineering background.

You proved that you didn't know what you were rattling on about. Like
most LoudMouths, you assumed instead of thinking. And if your skills
with a kill-file match your other talents you'll be reading this.

Heck, you're too dumb to realise that Outhouse Excess doesn't have a
kill file.

Rod wrote:

She.

He.

In article ,
Steve Firth wrote:
Dave Plowman (News) wrote:

In article ,
Steve Firth wrote:
I know exactly what he's talking about. But then unlike you I know
what the inside of a tape recorder looks like.

There are so many variations in the way the various drives work I doubt
anyone knows them all.

All no. But in context it's easy to work out which type Danielle was
talking about. And it's easy to tell that LoudMouth didn't have a clue.

Perhaps you should check out Dave's site - his engineering expertise isn't
in question. And well engineered tape recorders don't use rubber band
drives anyway. That's reserved for the bottom of the market.

--
*Depression is merely anger without enthusiasm *

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

Martin Bonner wrote:
On Dec 27, 7:27 pm, Rod wrote:
Steve Firth wrote:
Dave Baker wrote:

It's not the capstan, it's the flywheel, that needs attention.
It would help if you properly described what bit you are actually
talking about.

He did. He said it's the flywheel. You then spend the rest of your
post ranting about the capstan. Perhaps you could spend slightly
less time being angry and slightly more time reading?

If he reduces the diameter of the flywheel and the flywheel is
driven by a belt then reducing the diameter of the flywheel will
speed the tape up.

Piddling about with the flywheel and flatting it in an attempt to
remove pits (which is just about inevitable if one does it by hand)
will introduce "wow". It depends if the aim is to have a working
tape recorder or a pretty one that doesn't function properly.

She.

At least, I assume that Daniele is female.

A reasonable, but wrong, assumption. He is Italian, hence the odd (to
English eyes) spelling.

(Note: You are not the first person to make that mistake on this
group. He wasn't offended last time; he almost won't be offended the
next time it happens either.)

As God is my judge I had no idea this was a male we were trying to help
There should be a LOL in there I suppose. Look it up on Google.
--
Dave Baker

Steve Firth wrote:
Dave Plowman (News) wrote:

In article ,
Steve Firth wrote:
I know exactly what he's talking about. But then unlike you I know
what the inside of a tape recorder looks like.

There are so many variations in the way the various drives work I
doubt anyone knows them all.

All no. But in context it's easy to work out which type Danielle was
talking about. And it's easy to tell that LoudMouth didn't have a
clue.

It's Daniele not Danielle. Maybe you should spend more time reading and less
time shouting angrily at other people The missing L is significant.
--
Dave Baker

Dave Plowman (News) wrote:
In article
,
D.M. Procida wrote:
I'm restoring an old tape recorder. The capstan flywheel is very
lightly pitted. I'd like to polish this out.

Is it on a face a drive belt or pulley bears on?

What would be a suitable polish? Or if it's likely to be too hard
for a polish, could it perhaps be sanded first?

They're normally made of a casting alloy - unfortunately sometimes
Mazak which can develop pits if kept in adverse conditions - although
not normally in a house. Now obviously if you grind these out in some
way you'll also alter the diameter and therefore speed. I'd be
inclined to fill them with good body filler then just smooth that
down.

With respect to your electrical expertise which vastly surpasses mine I'd
say that filling with body filler would lead to any drive belt abrading some
of that out and it getting into the rest of the works. I think no one is
still sure what part of the mechanism we are being asked about here but if
the pits are not functionally detrimental I'd leave them alone. Once the
covers are back on no one is going to be any the wiser.
--
Dave Baker

Martin Bonner wrote:
On Dec 27, 7:27 pm, Rod wrote:
Steve Firth wrote:
Dave Baker wrote:
It's not the capstan, it's the flywheel, that needs attention.
It would help if you properly described what bit you are actually talking
about.
He did. He said it's the flywheel. You then spend the rest of your post
ranting about the capstan. Perhaps you could spend slightly less time
being angry and slightly more time reading?
If he reduces the diameter of the flywheel and the flywheel is driven by
a belt then reducing the diameter of the flywheel will speed the tape
up.
Piddling about with the flywheel and flatting it in an attempt to remove
pits (which is just about inevitable if one does it by hand) will
introduce "wow". It depends if the aim is to have a working tape
recorder or a pretty one that doesn't function properly.
She.

At least, I assume that Daniele is female.

A reasonable, but wrong, assumption. He is Italian, hence the odd (to
English eyes) spelling.

(Note: You are not the first person to make that mistake on this
group. He wasn't offended last time; he almost won't be offended the
next time it happens either.)

My mistake - thanks for the pleasantly worded correction. :-)

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

Frank Erskine wrote:
On Sat, 27 Dec 2008 19:24:31 +0000, Bob Minchin
wrote:

Frank Erskine wrote:
On Sat, 27 Dec 2008 16:07:07 +0000, Bob Minchin
wrote:

Frank Erskine wrote:
On Sat, 27 Dec 2008 15:08:13 +0000, Bob Minchin
wrote:

I've been wondering about this. Bearing in mind the OP commnet about a
reduced flywheel diameter leading to the tape speeding up, I can only
assume that this Teac deck drives on the periphery of the flywheel.

That would make the tape slower, surely? For a given rotational speed
the reduced circumference would reduce the speed of the tape...

'Fraid not Frank, Smaller diameter =faster rotation for a fixed
peripheral speed.

If it's a flywheel driven at a constant speed, a smaller diameter
(hence circumference) will propel the tape less distance for each
revolution.

No Frank - sorry but you are wrong. the deck has a belt drive and so the
flywheel rotational speed will increase.

Ho hum. As Dave B suggested above, we're talking, aren't we, about a
flywheel, NOT a pulley. The capstan motor rotates at a constant speed,
driving the pulley, hence the flywheel at a constant rotational speed.
If we reduce (by grinding, turning or whatever) the diameter of the
flywheel its circumference will also reduce.
If, as _you_ suggested above, that the Teac deck drives (is not
driven) on the periphery of the flywheel, then the resultant tape
speed will be reduced.

Still wrong as I understand it Frank.
The flywheel is both a flywheel and a pulley for the flat belt from the
capstan motor.
The belt runs at a fixed linear rate and drives the flywheel periphery.
In the centre of the flywheel is the capstan, which in turn drives the
tape. Danielle is talking of polishing the flywheel periphery thus
reducing its circumference. So in a unit time, the same length of belt
will rotate a (marginally) smaller flywheel slightly more revolutions
and hence the tape will run faster.

tape speed capstan diameter
________________ = ________________
belt speed flywheel diameter

I can see that there is a different interpretation of drives/driven in
what I wrote above and so is ambiguous. I meant that the deck drives the
flywheel periphery. At no time did I think the tape would be driven by
anything other than the capstan.

Bob

"Steve Firth" wrote in message
...
Bruce wrote:

(Steve Firth) wrote:

It's the flywheel. You obviously know ****-all about tape recorders.

Excellent. Profanity *and* personal abuse.

When were you elected the language policeman for the newsgroup,
****nuts?

I think this is one of your saddest moments. In the past I've always
respected you posts but in this case you've hit rock bottom. I have no
intention to go into the semantics of flywheels, belts and pulley. You're
both grasping on so little information it's unbelievable. We still don't
have a clue whether it's significant the flywheel has pits or if it's made
smaller will alter the speed of the tape. You're both ****ing in the wind
upstream. I prefer downstream myself, then it less likely to come back and
haunt me.

Dave Baker wrote:

It's Daniele not Danielle. Maybe you should spend more time reading and less
time shouting angrily at other people The missing L is significant.

oooh reduced to sniping at typos, you must be desperate.

D.M. Procida wrote:

I'm restoring an old tape recorder. The capstan flywheel is very lightly
pitted. I'd like to polish this out.

Right, there seems to be a certain amount of confusion and trouble
arising from this.

What's pitted is the capstan flywheel, i.e. the flywheel pertaining to
the capstan. It's on the capstan shaft, inside the machine.

The flywheel is driven by a flat rubber belt, in turn driven by a pulley
on the capstan motor.

I have absolutely no intention of dicking around with the surface of the
capstan.

No-one is a moron, ****wit or idiot for not understanding this first
time.

When I say the flywheel is very lightly pitted, I mean very lightly
pitted indeed. It's not so much the pits themselves that concern me, but
their very slightly raised edges. These are what I'd like to polish
down.

In any case, what needs to be polished out are very tiny superficial
blemishes. Probably they don't affect the sound at all - the flywheel
must weight about 750g, just for a start - but it's possible that they
induce a tiny amount of vibration in the captsan's rotation.

The tape recorder is a Teac A-3340, a semi-pro four-track from the early
1970s, and truly gorgeous.

Daniele