See:-

http://www.tool-net.co.uk/data/index.php?ToolID=315811

The drill supposedly has a "three speed synchromesh gearbox"! :-)

--
Chris Green

wrote:
See:-

http://www.tool-net.co.uk/data/index.php?ToolID=315811

The drill supposedly has a "three speed synchromesh gearbox"! :-)

If you do a google search for this drill (Metabo Bst 12) lots of the
descriptions claim it has a "three speed synchromesh gearbox".
Curiouser and curiouser.

More to the point none of the sites seem to agree on its torque or the
battery capacity.

--
Chris Green

In article , wrote:
http://www.tool-net.co.uk/data/index.php?ToolID=315811

The drill supposedly has a "three speed synchromesh gearbox"! :-)

It presumably means you can change gear while the motor is running
... if you want to.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

Tony Bryer wrote:
In article , wrote:
http://www.tool-net.co.uk/data/index.php?ToolID=315811

The drill supposedly has a "three speed synchromesh gearbox"! :-)

It presumably means you can change gear while the motor is running
.. if you want to.

I went and took a look at the Metabo site and they describe it as
"3-level planetary gear" which makes a bit more sense.

--
Chris Green

It presumably means you can change gear while the motor is running
.. if you want to.

I can change gear on my mains drill. It makes a nasty crack and I only do it
when not concentrating. Unfortunately, it a cheap drill without rotor brake,
so you have to wait 10 seconds normally, which is a PITA.

Christian.

In article ,
wrote:
The drill supposedly has a "three speed synchromesh gearbox"! :-)

It presumably means you can change gear while the motor is running
.. if you want to.

I went and took a look at the Metabo site and they describe it as
"3-level planetary gear" which makes a bit more sense.

Yes. A planetary gear may be changed under full power with no distress -
car autos have been doing this for years.

A car type synchromesh system wouldn't last five minutes without the
clutch.

--
*The older you get, the better you realize you were.

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

On 26 Oct 2004 16:59:55 -0700, Jan Wysocki wrote:

Do you mean you need a 'crash' gearbox to be able to do clutchless
gearchanges like you can on a motorbike?

If you want to make a habit of it.

I'd assumed that a synchromesh gearbox would make it even easier,

Easier, yes. But it doesn't help reliability.

I have no idea how synchromesh works.

There's a bronze ring with a cone clutch on it and tapered lead-ins
for the splines on the sliding member.. When you try to engage the
dogs, the ring gets there first. Once the cone has spun to the
matching speed, it allows the dog splines to slide freely.

Do too much of it, you wear the nose off the dogs. then the blunt nose
jams in the socket, locks solid, there's a bang and the ring breaks
into fragments. You're now left with a rather sloppy crash box. On
some gearboxes, the exploding clutch can get caught in the works on
the way out and do more damage.

Porsche's gearbox design is different and doesn't use the same sort of
bronze cone. They're more robust for being used clutchless. OTOH, I
believe that if they break, they always lose that ratio.
--
Smert' spamionam

In article ,
Jan Wysocki wrote:
A car type synchromesh system wouldn't last five minutes without the
clutch.

Really? Do you mean you need a 'crash' gearbox to be able to do
clutchless gearchanges like you can on a motorbike?

A crash box and a motorcycle type aren't the same. On a crash box the
gears actually slide into mesh. A motorcycle box is constant mesh with dog
clutches to engage them.

I'd assumed that a
synchromesh gearbox would make it even easier, but then I have no idea
how synchromesh works. (I do know about epicyclic gear boxes.)

Synchromesh uses a friction clutch to 'spin' the gears to the correct
speed to engage silently. But it's only designed to work on a box with the
drive disengaged. To handle the engine's power, they'd be vast in size,
and require considerable effort from the driver.

--
*The statement below is true.

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

In article , Dave Plowman (News) wrote:

Yes. A planetary gear may be changed under full power with no distress -
car autos have been doing this for years.

A car type synchromesh system wouldn't last five minutes without the
clutch.

Really? Do you mean you need a 'crash' gearbox to be able to do clutchless
gearchanges like you can on a motorbike?
I'd assumed that a synchromesh gearbox would make it even easier, but then
I have no idea how synchromesh works. (I do know about epicyclic gear boxes.)

--
Jan

Dave Plowman (News) wrote:

But it's only designed to work on a box with the
drive disengaged. To handle the engine's power, they'd be vast in size,
and require considerable effort from the driver.

Do you mean drive disengaged, or just not while under power (ie with the
throttle pedal backed off)?
We have advanced driver training at work and the ex-police instructors
(especially the older ones) often change gear without using the clutch.
I do it myself when the mood takes me, and the higher gear changes seem
effortless. Changing down is a bit more awkward (matching revs) but
it's a potentially useful skill in case the clutch cable breaks.

On Wed, 27 Oct 2004 12:09:41 +0100, Rory
wrote:

We have advanced driver training at work and the ex-police instructors
(especially the older ones) often change gear without using the clutch.

That would be because "advanced drivers" are all too much a smartarse
hazard for everyone else _ESPECIALLY_ older police drivers.

Why would you change gear in a modern gearbox without using the
clutch? What advantage does this convey ? Make a habit of it on a V6
Carlton or some of the more powerful but weaker-boxed Sierras and you
were just asking for trouble (and look at the scrap pile round the
back of a police garage)

On Tue, 26 Oct 2004 23:22:10 +0100, "Dave Plowman (News)"
wrote:

A crash box and a motorcycle type aren't the same. On a crash box the
gears actually slide into mesh. A motorcycle box is constant mesh with dog
clutches to engage them.

Just how old are you ? 8-)

There are plenty of "crash boxes" with dogs - pretty much anything
post war. They're not sliding-gear boxes, they're not synchro boxes,
but in the absence of a better term we call them crash boxes just the
same.

Motorbikes have the advantage of a sequential shift too - they can
shift from one ratio to the other with a lot less faffing about than a
wobbling joystick.

What was the last crash box in production ? Landies ? bottom cog in
Heralds ?
--
Smert' spamionam

In article ,
Rory wrote:
Do you mean drive disengaged, or just not while under power (ie with the
throttle pedal backed off)?
We have advanced driver training at work and the ex-police instructors
(especially the older ones) often change gear without using the clutch.
I do it myself when the mood takes me, and the higher gear changes seem
effortless. Changing down is a bit more awkward (matching revs) but
it's a potentially useful skill in case the clutch cable breaks.

If you match the gear speeds through careful use of the throttle etc,
there's no need for any form of synchronizer. This was the basis of double
declutching - needed with crash boxes.

However, if the speed isn't exactly matched, the synchromesh cones, which
are a form of friction clutch - will try and do this, and if under load
will either not succeed or be subjected to loads they're not designed for.

--
*Growing old is inevitable, growing up is optional

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

In article ,
Andy Dingley wrote:
A crash box and a motorcycle type aren't the same. On a crash box the
gears actually slide into mesh. A motorcycle box is constant mesh with
dog clutches to engage them.

Just how old are you ? 8-)

There are plenty of "crash boxes" with dogs - pretty much anything post
war. They're not sliding-gear boxes, they're not synchro boxes, but in
the absence of a better term we call them crash boxes just the same.

On which car? I'm not familiar with commercial vehicle practice and was
only referring to cars.

Rover for one made a constant mesh box with dog clutch engagement - pre
WW2 - but it was hardly a common arrangement with cars. And it was mated
to a freewheel which makes down shifts less of a problem.

All the cars I can think of - made up until the advent of all synchro
boxes round about '70 - had a 'crash' first gear, where the gear teeth
were normally out of engagement. And this practice continued much later
with reverse gears.

There were a few earlier all synchro boxes on some cars, but these were
usually three speed. Or not actually - commonly a four speed with first
blanked off. Early Austin Healey and some Triumph models for example.

Motorbikes have the advantage of a sequential shift too - they can shift
from one ratio to the other with a lot less faffing about than a
wobbling joystick.

But they don't have synchromesh. A slight - or even not so slight -
'click' on engagement might well be acceptable on a bike, but not in a
quiet car. There's also the question of feedback of this action through
the lever.

What was the last crash box in production ? Landies ? bottom cog in
Heralds ?

Pure genuine crash box with no synchromesh at at all on any gear in a car?
Something dating back to the early '30s, before Vauxhall introduced
synchromesh in the UK.

--
*I can see your point, but I still think you're full of ****.

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

"Dave Plowman (News)" wrote in message ...
In article ,
Jan Wysocki wrote:
A car type synchromesh system wouldn't last five minutes without the
clutch.

Synchromesh uses a friction clutch to 'spin' the gears to the correct
speed to engage silently. But it's only designed to work on a box with the
drive disengaged. To handle the engine's power, they'd be vast in size,
and require considerable effort from the driver.

yup, you can drive cars clutchless in dire necessaity but you do have
to get the revs dead on.

NT

Yes. A planetary gear may be changed under full power with no distress -
car autos have been doing this for years.


Not quite true. The gears are in constant mesh, but the one operating is
selected by a clutch band within the gearbox. Also, the torque converter
is a lossy liquid coupling which reduces the impact on the clutch bands
and the drive train when the ratio is changed. The only common
constantly variable drives( other than electric/electronic) are the twin
pulley ones as pioneered in cars by DAF IIRC and now used in some stand
drills. In cars I understand that these latter have an unequalled
reputation for unreliability. I believe the Japanese may now have
engineered a viable unit, but it's not on my acceptable list for a few
years yet.

Regards
Capitol

In article ,
Capitol wrote:
Not quite true. The gears are in constant mesh, but the one operating is
selected by a clutch band within the gearbox.

Indeed. How else would you change gears with an epicyclic box?

Also, the torque converter
is a lossy liquid coupling which reduces the impact on the clutch bands
and the drive train when the ratio is changed.

But a TC isn't an essential with a conventional auto. Older designs used
fluid flywheels which had near zero 'slip' above a certain speed.

Of course, most modern autos reduce the engine power momentarily on a
change for reasons of smoothness.

The only common
constantly variable drives( other than electric/electronic) are the twin
pulley ones as pioneered in cars by DAF IIRC and now used in some stand
drills. In cars I understand that these latter have an unequalled
reputation for unreliability. I believe the Japanese may now have
engineered a viable unit, but it's not on my acceptable list for a few
years yet.

CVTs. And they do seem to be unreliable.

Audi use a twin layshaft twin clutch synchromesh box where the changes are
servo operated. By having adjacent gears on opposite layshafts it's
possible to have a full power change because as one clutch disengages, the
other takes up the load. Clever.

--
*OK, who stopped payment on my reality check?

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

"Dave Plowman (News)" wrote in message
...
In article ,
wrote:
The drill supposedly has a "three speed synchromesh gearbox"! :-)

It presumably means you can change gear while the motor is running
.. if you want to.

I went and took a look at the Metabo site and they describe it as
"3-level planetary gear" which makes a bit more sense.

Yes. A planetary gear may be changed under full power with no distress -
car autos have been doing this for years.

A car type synchromesh system wouldn't last five minutes without the
clutch.

Only on changing down. And even then you can reduce wear to very low
amounts if you listen carefully.

In article ,
G&M wrote:
Yes. A planetary gear may be changed under full power with no distress -
car autos have been doing this for years.

A car type synchromesh system wouldn't last five minutes without the
clutch.

Only on changing down. And even then you can reduce wear to very low
amounts if you listen carefully.

Under full power? Not so. When changing gear without the clutch either up
or down you remove the power near completely. If you didn't the revs would
go sky high as soon as you got into neutral. And that's assuming you
actually could under power - the gearchange would become very stiff.

An epicyclic auto changes gear by means of a clutch or brake band. These
can handle the maximum power output of the engine.

--
*If vegetable oil comes from vegetables, where does baby oil come from? *

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

On Thu, 28 Oct 2004 22:22:13 +0100, "Dave Plowman (News)"
wrote:

An epicyclic auto changes gear by means of a clutch or brake band. These
can handle the maximum power output of the engine.

There are plenty of car auto boxes that _can't_ handle this power on
the brake bands. Look at the small BW boxes that popped up in
big-engined UK cars through the '70s. For that sort of epicyclic, the
ratio between max torque for constant running and max torque during a
shift is quite high. They'd sit under your Rover or Jag quite happily
cruising flat out down the motorway in D, but start forcing gear
changes by holding it down in 1 or 2 with the loud pedal down, then
slipping it up a notch manually, and they soon started to complain.

Epicyclic gearboxes in tools like electric drills often use dog
clutches anyway.
--
Smert' spamionam

In article ,
Andy Dingley wrote:
An epicyclic auto changes gear by means of a clutch or brake band. These
can handle the maximum power output of the engine.

There are plenty of car auto boxes that _can't_ handle this power on
the brake bands. Look at the small BW boxes that popped up in
big-engined UK cars through the '70s. For that sort of epicyclic, the
ratio between max torque for constant running and max torque during a
shift is quite high. They'd sit under your Rover or Jag quite happily
cruising flat out down the motorway in D, but start forcing gear
changes by holding it down in 1 or 2 with the loud pedal down, then
slipping it up a notch manually, and they soon started to complain.

Eh? The 'kickdown' position does just this. It gives you a combination of
maximum power from the engine and maximum change up speeds from the box.
The box is designed to change up at the best possible revs for maximum
performance under these conditions. True you could lock the box in any
gear and over speed the engine if you wanted to, but that was a pointless
operation.

It's true some B-W 35 models didn't allow kickdown to first at speeds well
short of the maximum into first, but they all would do auto change ups at
maximum power. If yours didn't, the chances are the cable controlling the
box was badly adjusted. And since this also controlled the line pressure,
the box would wear out quickly due to slipping.

I wish I had a pound for every old Rover P6 or XJ6 I've come across with
this cable not correctly set. The vast majority of pro mechanics, let
alone DIY owners didn't seem to understand its functions and invariably
bodged things. But it was a poor idea - it's much better to use engine
vacuum for the main function with a separate kickdown mechanism.

But in any case, this was just a maker using too weak a product for cost
reasons. It's not intrinsic in the principle. Although most modern autos
have managed to replace some brake bands with clutches. My SD1 with a
three speed box has three multi plate clutches and one brake band. The
Model 35 you refer to had two of each.

Epicyclic gearboxes in tools like electric drills often use dog
clutches anyway.

Yes - there's no need for a smooth change on a drill. But what you can't
do under power is 'swop cogs' in the old way. You'll break the teeth.

--
*Toilet stolen from police station. Cops have nothing to go on.

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

Dave Plowman (News) wrote:

The only common
constantly variable drives( other than electric/electronic) are the twin
pulley ones as pioneered in cars by DAF IIRC and now used in some stand
drills. In cars I understand that these latter have an unequalled
reputation for unreliability. I believe the Japanese may now have
engineered a viable unit, but it's not on my acceptable list for a few
years yet.


CVTs. And they do seem to be unreliable.

But someone brings one out every few years. My parent have a Honda with
a CVT (rubber band drive), but it's only a couple of years old, so
that's not much to go on.

--
Spamtrap in use
To email replace 127.0.0.1 with blueyonder dot co dot uk

In article ,
Chris Hodges wrote:
CVTs. And they do seem to be unreliable.

But someone brings one out every few years. My parent have a Honda with
a CVT (rubber band drive), but it's only a couple of years old, so
that's not much to go on.

They do. The last Ford one was also withdrawn from sale after a couple of
years.

A mate who 'fixes' cars (cheaply) for a living says it's a nightmare
trying to source decent secondhand CVTs. They are in such great demand.

--
*Change is inevitable ... except from vending machines *

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

In article , Chris
Hodges wrote:
But someone brings one out every few years. My parent have a
Honda with a CVT (rubber band drive), but it's only a couple of
years old, so that's not much to go on.

AFAIK it was only DAFs and Volvo badged DAFs that used rubber bands
(I had a DAF 66 once). All the current CVTs use a steel belt with
metal blocks on it and the belt pushes rather pulls. My Jazz CVT is
a joy to drive and given the mileage I do is not likely to wear out.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

In article ,
Tony Bryer wrote:
But someone brings one out every few years. My parent have a
Honda with a CVT (rubber band drive), but it's only a couple of
years old, so that's not much to go on.

AFAIK it was only DAFs and Volvo badged DAFs that used rubber bands
(I had a DAF 66 once). All the current CVTs use a steel belt with
metal blocks on it and the belt pushes rather pulls. My Jazz CVT is
a joy to drive and given the mileage I do is not likely to wear out.

I reckon all CVTs have the steel belt.

DAF rubber band drives were called Variomatic or somesuch. The name CVT is
later.

--
*Beauty is in the eye of the beer holder *

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

"Dave Plowman (News)" wrote in message
...
In article ,
Tony Bryer wrote:
But someone brings one out every few years. My parent have a
Honda with a CVT (rubber band drive), but it's only a couple of
years old, so that's not much to go on.

AFAIK it was only DAFs and Volvo badged DAFs that used rubber bands
(I had a DAF 66 once). All the current CVTs use a steel belt with
metal blocks on it and the belt pushes rather pulls. My Jazz CVT is
a joy to drive and given the mileage I do is not likely to wear out.

I reckon all CVTs have the steel belt.

DAF rubber band drives were called Variomatic or somesuch. The name CVT is
later.


Yes, AIUI the CVT transmissions use a type of flexible steel belt, but the
DAF Variomatic use two rubber / fabric belts.

In article ,
:::Jerry:::: wrote:
Yes, AIUI the CVT transmissions use a type of flexible steel belt, but the
DAF Variomatic use two rubber / fabric belts.

Think they were just fairly normal 'V' drive belts that you'd find on
machinery?

--
*Can fat people go skinny-dipping?

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

Dave Plowman (News) wrote:

Think they were just fairly normal 'V' drive belts that you'd find on
machinery?

Sort of, machine belts don't normally transmit 20HP each. The DAF was a
CVT transmission-(constantly variable transmission), the brand name was
Variomatic. The reason for going to steel belts, AIUI, was the problem
of the rubber bands stretching under load, so when the unit went from
drive to over run, the stretched belt did rather nasty things, like
trying to free itself from the pulleys etc. It also used a standard
clutch assembly, which could have zero slip if your foot was a bit
careless, leading to nasty rubber band burning smells on occasions.

Standard Borg Warner type auto's, may be inefficient, but they have a
very high driver tolerance if built correctly, I've never had one die
under 180K miles.

Regards
Capitol

"Dave Plowman (News)" wrote in message
...
In article ,
G&M wrote:
Yes. A planetary gear may be changed under full power with no
distress -
car autos have been doing this for years.

A car type synchromesh system wouldn't last five minutes without the
clutch.

Only on changing down. And even then you can reduce wear to very low
amounts if you listen carefully.

Under full power? Not so. When changing gear without the clutch either up
or down you remove the power near completely.

You have to remove your foot from the accelerator obviously. But long
before electronic control gearboxes came along, this was the way synchromesh
boxes on the old Group 1 rally cars had to be used to get sensible changing
times, especially as your left foot was on the brake of course, having
replaced heel and toe around this time as the preferred method.

Of course for Group 4 you could fit a crash box which helped.

But the RS2000 synchro boxes easily lasted the rally and were then re-built,
which is certainly equivalent to a year's normal wear, not the five minutes
quoted.

"Chris Hodges" wrote in message
k...
Dave Plowman (News) wrote:

The only common
constantly variable drives( other than electric/electronic) are the twin
pulley ones as pioneered in cars by DAF IIRC and now used in some stand
drills. In cars I understand that these latter have an unequalled
reputation for unreliability. I believe the Japanese may now have
engineered a viable unit, but it's not on my acceptable list for a few
years yet.


CVTs. And they do seem to be unreliable.

But someone brings one out every few years.

Williams built an F1 car using one in late 80s but it was banned before
being used. If they had been allowed to race I bet the technology would be
well developed now.

Capitol wrote:


Dave Plowman (News) wrote:

Think they were just fairly normal 'V' drive belts that you'd find on
machinery?

Sort of, machine belts don't normally transmit 20HP each. The DAF was a
CVT transmission-(constantly variable transmission), the brand name was

Surely that should be Continuously Variable Transmission.

--
Chris Green

wrote:

Surely that should be Continuously Variable Transmission.
Yes

Capitol

In article ,
G&M wrote:
You have to remove your foot from the accelerator obviously. But long
before electronic control gearboxes came along, this was the way
synchromesh boxes on the old Group 1 rally cars had to be used to get
sensible changing times, especially as your left foot was on the brake
of course, having replaced heel and toe around this time as the
preferred method.

Of course for Group 4 you could fit a crash box which helped.

But the RS2000 synchro boxes easily lasted the rally and were then
re-built, which is certainly equivalent to a year's normal wear, not the
five minutes quoted.

'Five minutes' was poetic licence, but if you consider the size and type
of clutch used on an auto to handle the full engine power - it's perhaps
6" in diameter and a wet multi-plate design, similar to a motor bike, and
then the size and surface area of the baulk ring in a synchro hub, it's
rather obvious it's not intended to do much hard work.

--
*If Barbie is so popular, why do you have to buy her friends? *

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

"Dave Plowman (News)" wrote in message
...
In article ,
G&M wrote:
You have to remove your foot from the accelerator obviously. But long
before electronic control gearboxes came along, this was the way
synchromesh boxes on the old Group 1 rally cars had to be used to get
sensible changing times, especially as your left foot was on the brake
of course, having replaced heel and toe around this time as the
preferred method.

Of course for Group 4 you could fit a crash box which helped.

But the RS2000 synchro boxes easily lasted the rally and were then
re-built, which is certainly equivalent to a year's normal wear, not the
five minutes quoted.

'Five minutes' was poetic licence,

I guessed. But in fact if careful (and good at it) one could change up all
the car's life and not have a problem.


but if you consider the size and type
of clutch used on an auto to handle the full engine power - it's perhaps
6" in diameter and a wet multi-plate design, similar to a motor bike,

I don't think diameter is the main factor with a clutch. An F1 is smaller
than this after all and it's near 1000hp. Material choice and removal of
heat is the key to reliability.


then the size and surface area of the baulk ring in a synchro hub, it's
rather obvious it's not intended to do much hard work.

So don't make it do much hard work. Clutchless changing doesn't involve
just slamming it in and hoping for the best - though certain drivers seem to
think it does :-(

On 27 Oct 2004 (N. Thornton) wrote:

"Dave Plowman (News)" wrote in message
...

yup, you can drive cars clutchless in dire necessaity but you do have
to get the revs dead on.

I used to drive my parents' Mini like that. It was a '59 Austin Se7en
with the original 3-synchro magic wand box, not the later all-synchro
baulk ring type. I found it was easier if I pressed the dipswitch with my
left foot in order to get the timing right (not at night of course:-).

The synchromesh on those boxes didn't last long anyway, so I had to
double de-clutch on my driving test. That was nothing to do with me
driving clutchless of course (my mum had previously learnt to drive on
that car - say no more).

--
Richard Porter
Mail to username ricp at domain minijem.plus.com
"You can't have Windows without pains."

In article ,
Richard Porter wrote:
I used to drive my parents' Mini like that. It was a '59 Austin Se7en
with the original 3-synchro magic wand box, not the later all-synchro
baulk ring type. I found it was easier if I pressed the dipswitch with my
left foot in order to get the timing right (not at night of course:-).

The early boxes were cone synchromesh but soon replaced with baulk ring.
The all synchro boxes were very much later.

I don't know why it took so long for BMC to introduce baulk ring synchro
to the A Series box - the B Series one had it in the early '50s.

The Mini probably made the problem worse - the extra inertia of the
transfer gears.

The synchromesh on those boxes didn't last long anyway, so I had to
double de-clutch on my driving test. That was nothing to do with me
driving clutchless of course (my mum had previously learnt to drive on
that car - say no more).

It's probably easier to change gear without the clutch with no or poor
synchro anyway - it tells you if the revs are wrong much sooner. ;-)

--
*I believe five out of four people have trouble with fractions. *

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

"Richard Porter" wrote in message
...
On 27 Oct 2004 (N. Thornton) wrote:

"Dave Plowman (News)" wrote in message
...

yup, you can drive cars clutchless in dire necessaity but you do have
to get the revs dead on.

I used to drive my parents' Mini like that. It was a '59 Austin Se7en
with the original 3-synchro magic wand box, not the later all-synchro
baulk ring type.

Good box - internals were used in the Cooper Climax F1 car as well I
believe.

In article ,
G&M wrote:
I very much doubt it. It was barely up to handling the torque of the
original Mini. Later ones were beefed up.

That was the old 1.5 litre F1 and it only had to last 3 hours. I expect
the parts were selected and heat treated though.

Right. Of course you could completely replace the internals. IIRC Knight
made a 5 speed conversion with straight cut gears. Sounded wonderful.;-)

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

On Mon, 01 Nov 2004 23:49:22 +0000 (GMT), "Dave Plowman (News)"
wrote:

Right. Of course you could completely replace the internals.

Which is cheap to do. It also lets you play with the ratios. In terms
of manufacturing a small-volume gearbox, the case is the most boring
component, yet the most expensive to manufacture. There's a lot of
sense in "re-using" a mass-market gearbox, when the tweaked version
actually has almost nothing important in common.

Whatever happend to Jack Knight ? Last I heard they were working on
an all-mechanical non-viscous torque-splitting diff that felt like a
viscous diff, but wasn't. Worked well, but it turned nasty once there
was any wear in it.

--
Smert' spamionam

In article ,
Andy Dingley wrote:
Right. Of course you could completely replace the internals.

Which is cheap to do. It also lets you play with the ratios. In terms
of manufacturing a small-volume gearbox, the case is the most boring
component, yet the most expensive to manufacture. There's a lot of
sense in "re-using" a mass-market gearbox, when the tweaked version
actually has almost nothing important in common.

I'd say 'cheap' is a relative term. I was looking at the cost of
re-manufactured internals for an Austin Healey, and cheap they ain't -
compared to a maker's spare.

Whatever happend to Jack Knight ? Last I heard they were working on
an all-mechanical non-viscous torque-splitting diff that felt like a
viscous diff, but wasn't. Worked well, but it turned nasty once there
was any wear in it.

Many of this sort of things have been replaced by electronics - or
electronic based, which tends to move the design to different people.

--
*I wished the buck stopped here, as I could use a few.

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