When were abrasives dropped from 78s?
frenchy
record production (because electric pickups had become the norm).
1935, late 30s, etc. Is there any real definitive date that has ever
been nailed down, even if for specific companies? Was wondering,
because for the heck of it as a test, I played one side of a Victor-
made Tommy Dorsey record from 1941 with a loud needle on my fully
rebuilt and fine-tuned Orthophonic acoustic machine. (Yeah I know
this is a no-no but it was just for this test and it's a common,
average, worthless record.) Based on what I've read, I would think
this record would have no abrasives in it.
But when I lifted the soundbox only halfway thru the song, I pulled
the needle out, and it looks just like any other worn needle from
playing an old 20s record. Plain as day, nicely chiseled at the tip.
I was expecting to see a basically untouched needle. So Is the
material in newer 78s like this still abrasive enough to do this kind
of needle wear, or would it have to have specific abrasives in it?
Thanks!
Mark
Richard Knoppow
"frenchy" <mf10...@msn.com> wrote in message
news:e8d15b82-c11a-4d53...@u16g2000pru.googlegroups.com...
I am not sure abrasives were ever used in 78s. They may
have been used in some Vitaphone records. Unfortunately, the
person I knew who was intimately involved with the
development of electrical recording at Western Electric died
some years ago.
Supposedly, the reason for the abrasive was to grind
crude needles to shape. Perhaps it was done but I've heard
modern transfers of Vitaphone records and they do not sound
especially noisy.
They were cut inside out so that the increased groove
velocity would compensate to some degree for stylus wear.
The theaters were not supposed to use a needle for more than
one play.
Anyway, I think the material of which 78s are made is
somewhat abrasive inherently and does not need anything
added. In short, I think this is by way of being an urban
myth.
--
Richard Knoppow
Los Angeles
WB6KBL
dick...@ix.netcom.com
frenchy
> somewhat abrasive inherently and does not need anything
> added. In short, I think this is by way of being an urban
> myth.>>
This test record was from '41, it isn't in perfect unplayed condition
of course, but it's in pretty nice shape. So I don't think it would
solely be a case of a really scratched up record causing excessive
needle wear regardless of the composition. I could imagine a record
would continue to wear the grooves all the way through the smoother
shellac coating, and down to the rough material that the record is
mainly made out of. But maybe that's what's really happening in this
case.
I think I'll try this test a little more on some other of my worthless
records that are newer than this, with differing amounts of wear. As
for abrasives being added to records, seemed like an almost unanimous
consensus on the internet that they were added, but later dropped when
tonearms became electric and much lighter and no longer used steel
needles. That was supposed to account for them becoming much more
quiet also (background hiss from needle friction.)
George Conklin
"Richard Knoppow" <dick...@ix.netcom.com> wrote in message
news:SPydnWRbp9C8LpnW...@earthlink.com...
They were, and the principle was the wear the needle, not the record. I
played 1950s-era 78s on my Acme-conversion DD setup right up to the end of
the production. Still do from time to time. Little Richard, for example.
Richard Knoppow
"George Conklin" <n...@earthlink.net> wrote in message
news:RK-dnQAp36KkTJjW...@earthlink.com...
AFAIK abrasive was not used in 78s, and certainly not before
electrical recording. Any abasive would tend to make the
needle ride the entire groove and cause considerable wear.
Remember there are frictional forces at work also.
--
George Conklin
Abrasives were used long before electrical recording. The question was
when they were dropped, and that is something I don't remember offhand, but
I am not going to stop and look right now either.
IGot2P
The following is an excerpt from
http://arts.jrank.org/pages/5537/recording-reproduction.html
"The shellac used for 78-rpm records was coarse-grained and had abrasive
powders added to withstand the considerable pressures of the early heavy
pickups. The result was an obtrusive hissing noise as a continuous
accompaniment to the music. With the new vinyl discs background noise
was reduced and they were also lighter, flexible, and unbreakable."
Don
Richard Knoppow
"IGot2P" <d...@crsales.com> wrote in message
news:he4tec$81h$1...@news.netins.net...
nothing. First of all the material used for 78s contained
shellac as a binder but also contained many other materials
notably rare earths. I have never seen an authentic formula
since they were mostly proprietary. Also analyse what this
is saying: that abrasives were used to withstand the
considerable pressures of early heavy pickups. You would
want exactly the opposite, as smooth a surface as you could
get. Also, noise level varied considerably in pressing
material. Probably the quietest was HMV but it was also
brittle. Some American record makers used quite noisy
material, Decca comes to mind. I don't think this was due to
abrasives being added but to the texture of the materials
used. The problem with heavy and, in particular, stiff,
pickups is that they made the side walls of the grooves
crumble. Abrasive material would just have made the
situation worse.
I rather think the idea of abrasive material being in
78 records stems from what may have been a practice in
motion picture sound discs but I am not sure it was even
used there.
Steel needles are comparitively very soft and will
eventually wear to the shape of the groove, filling it,
regardless of the original shape. The best steel needles
were ground to shape and shadowgraphed to examine their
shape. Cheap needles were just however they came.
Shadowgraphed needles were good for one play on the 16"
discs used for motion picture sound and early broadcast
transcriptions and perhaps two plays on a 10" 78. After that
the began to destroy the groove.
Records with crumbled grooves have a typical gray look
and there is no way to repair them.
Hard needle material, particularly diamond at least
keep their shape although a diamond needle in a very stiff
pickup will still crumble the groove walls. At least it will
not pick up the crumbled material and drag it through the
groove. This last is exactly what would happen if abrasive
material was added to the mix.
There are some here, like George, who seem to be very
sure of their historical knowledge but I would like to have
some original sources, not second or third hand stuff
especially where no one really knows the origin.
I once asked Dr John Frayne, who I knew quite well,
about the development of early electrical recording. Some of
the method was referred to as Maxwell's Blunder due to the
decision not to use jewelled needles in the playback
machines. This was simply false economy. It is my memory
that he told me that no abrasive materials were used.
Richard Knoppow
"frenchy" <mf10...@msn.com> wrote in message
news:e8d15b82-c11a-4d53...@u16g2000pru.googlegroups.com...
Around the late 1940's or early 1950s record companies
began to release "disk jocky" records. These were the same
as the home 78s but pressed on vinyl or some similar
material, about the same stuff that was used for syndicated
broadcast transcriptions. It was infinitely quieter than
shellac but too soft to last long when played on most home
phonographs. Broadcast stations had better picups with
generally either diamond or sapphire needles and could play
these records without damaging them.
These records continued to be made AFAIK until displaced
by 45s.
frenchy
withstand the
> considerable pressures of early heavy pickups. You would want exactly the opposite, as smooth a surface as you could get. >>
Then if this source is accurate, I'd see no other reason for abrasives
being used other than to wear the needle to fit the groove, to wear
the needle and not the record. Again I'm just going by a multitude of
sources that said abrasives were there for that purpose.
Plus I would think it would only matter if abrasives were added to the
surface shellac, i.e. what the needle is riding on... not the
materials that made up the core. I'm assuming the shellac was present
over the whole surface, including the insides of the grooves. Perhaps
it doesn't require many plays with unchanged needles and other poor
use to wear thru the shallac in the grooves. If that happened, then
the needles would be abraded by whatever the core was made out of...
probably pretty rough on a needle also. Maybe that's what's happening
with this '41 record I tried, I dunno.
Richard Knoppow
Some records were made with a core, notably Columbia at
certain dates. I don't know how this process was done but
most 78s were made in the same way from cakes of pressing
material called officially "pre-forms" AKA biscuits. The
pressing material was first ground up and then mixed with
solvents in a large mixer. The resulting tar-like substance
was measured out into the pre-forms and travelled down a
conveyor belt to the pressing machines. The pressing machine
has two platens, the upper one being movable. The platens
hold the stampers and have pipes in them in which is
circulated hot and cold water. The stampers are clamped into
the press. For single sided records a stamper with a non
slip pattern is clamped to the bottom platen. After this the
press is heated by circulating the hot water through it. The
operator then places a label on the bottom and top stampers
and then places a pre-form at the center of the bottom
platen. The heated press is then closed and pressure applied
to flow the pressing material out along the stampers and
into the areas between what will become the grooves.
Remember, the stamper is a mold so its a sort of negative
record with raised lines where the grooves will be. After a
set time with the heat cold water is circulated through the
pipes in the press to set and harden the pressing material.
After the press has cooled enough it is opened and the
record taken out and put on another conveyer. Sometimes this
was enough to finish the record but in most pressing plants
the extra pressing material, called flash, at the edges of
the record was trimmed off and the finished record cleaned
with compressed air before being inspected and packaged.
This seemingly crude process was used in exactly the
same form for making long playing records, the only
difference being the pressing materia, vinyl for Lps, and
the termperature and cycling time of the press. One cause of
poor records, BTW, comes from trying to speed up the press.
If the flow time or is not long enough, the cooling time too
short, or the temperature too high or too low, the plastic
material will not flow correctly leaving a record that is
warped or has holes in it. A major problem is "non-fill"
where some of the "grooves" in the stamper were simply not
entirely filled with pressing material. The closer groove
spacing and smaller grooves of Lps made the pressing process
much more critical than it was for 78s.
Some other processes were used to make records. When
RCA designed the 45 it also designed an automatic injection
molding process to make them. RCA made 45s this way but many
were made on old fashioned pressing machines.
Another method was used by Allied Record Manufacturing
Co., a major producer of custom records and broadcast
transcriptions. This method used round cakes of sintered
pressing material instead of biscuits. These cakes were
slightly larger than the record to be pressed. It was placed
in a pretty much conventional record pressing machine but
could essentially melt in place. This reduced the problems
associated with the flow of the material over the stampers
such as strains left in the records which could cause
mechanical distortion later. This distortion shows up as
fluttering in the sound. I don't know if any other company
used this method of making pressings.
The point of this description is that most records are
made of homogeneous material. There is no surface material
and core although the surface is glazed by the pressing
process. I think Columbia used their sandwich construction
mostly during WW-2 when high quality shellac and other
materials vital for record manufacture were in very short
supply. The core of these records looks like fiberous
cardboard. I don't know if the core was a separate piece of
if two materials were sandwiched to make the preform
something like Tutti-Fruity ice cream. I suspect there must
be something in the literature of the time describing this
but there really was no technical publication devoted to
record manufacturing prior to the establishment of the
Journal of the Audio Engineering Society. That makes it
difficult to track down authentic information about older
processes.
I know about Lp making because I was involved with the
custom record business some years ago. Strictly small
quantity, job shop stuff, but still the same as the big
guys. When we had a really large order it went to CBS at
Santa Maria, they could press tens of thousands of records
if you wanted.
frenchy
made of homogeneous material. There is no surface material
and core although the surface is glazed by the pressing
process. >>
Ah ok, I had assumed they were coated with shellac, makes sense.
Well, *something* wore the needle on this '41 record, maybe I'm just
making an incorrect assumption that a needle would not get chiseled if
there were not abrasives added... the other materials in the mix could
be enough to wear thru the steel of the needle. If there are no
specific abrasives in this record, that must be the only answer.
Vinyl is another story of course, no way would that wear a needle if
someone was fool enough to run a steel needle on it. I'll keep
goofing around with my crude experiments and note what I find if
anything interesting.
Jeffrey D Angus
> Ah ok, I had assumed they were coated with shellac, makes sense.
> Well, *something* wore the needle on this '41 record, maybe I'm just
> making an incorrect assumption that a needle would not get chiseled if
> there were not abrasives added...
Think about the geometry of the needle in the groove.
What is the actual contact area and how much pressure
is on the need (from the weight of the tone arm.)
Think as how a single edge razor blade gets hot (and
eventually dull) cutting cardboard boxes. You'd think
that the steel blade is considerably harder than cardboard.
Jeff
--
�Egotism is the anesthetic that dulls the pain of stupidity.�
Frank Leahy, Head coach, Notre Dame 1941-1954
George Conklin
George Conklin
> <<. Also analyse what this> is saying: that abrasives were used to
> withstand the
> > considerable pressures of early heavy pickups. You would want exactly
the opposite, as smooth a surface as you could get. >>
>
> Then if this source is accurate, I'd see no other reason for abrasives
> being used other than to wear the needle to fit the groove, to wear
> the needle and not the record. Again I'm just going by a multitude of
> sources that said abrasives were there for that purpose.
>
Virtually every book on early recording mentions the abrasive issue as
part of the process. I suspect by the late 1930s and the start of
electrical playback (or even Orthophonic recording) that abrasives were not
specifically added, but I don't have time to go back and try to reread 15
years of MAPS materials..... Or Hill and Dale News either.
Ken Doyle
records have added abrasive, even those from the 50s. Steel needles were
used in many one-speed phonographs right up to the end of production.
Ken D.
"frenchy" <mf10...@msn.com> wrote in message
news:e8d15b82-c11a-4d53...@u16g2000pru.googlegroups.com...
frenchy
> Abrasives in shellac records were reduced in the mid 30s. All shellac
> records have added abrasive, even those from the 50s. Steel needles were
> used in many one-speed phonographs right up to the end of production.
> > Ken D.>>
Victor was still selling their even harder "Tungstone" needles into
the 40's as well.
The idea of a razor being dulled by infinitely softer cardboard is a
good analogy. I bet even a vinyl record (in the process of being
destroyed!) would eventually chisel a steel needle, not as quick as a
shellac record though. In addition when you think about it, when a
record is played thru, each point in the record's grooves is only
touched once by the needle... but that tiny needle point is absorbing
all that accumlated rubbing all by itself.
I think that answers all my dumb questions guys, thanks for all the
thoughtful replies.
Mark French
Jim Mueller
Vinyl records can and do wear down diamond styli.
--
Jim Mueller wron...@nospam.com
To get my real email address, replace wrongname with dadoheadman.
Then replace nospam with fastmail. Lastly, replace com with us.
Dr. Barry L. Ornitz
>
> Some records were made with a core, notably Columbia at certain
> dates. I don't know how this process was done but most 78s were made in
> the same way from cakes of pressing material called officially
> "pre-forms" AKA biscuits. The pressing material was first ground up and
> then mixed with solvents in a large mixer. The resulting tar-like
> substance was measured out into the pre-forms and travelled down a
> conveyor belt to the pressing machines.
Actually no solvents were used. What was added was plasticizer,
typically DOP (di-octyl phthalate or more properly di-ethyl-hexyl
phthalate). PVC, polyvinyl chloride, itself is a rigid, brittle plastic.
The addition of plasticizers is what makes vinyl soft and flexible. In
layman's terms, the plasticizer is a lubricant which allows the long PVC
chains to slide past each other with reduced effort.
I have no idea if it was added before the early 1950's, but fly ash was a
common additive to PVC in records from this time period onward. It was
used as a filler material to lessen the amount of vinyl needed and it was
quite cheap. Fly ash particles are typically from one half to one
hundred microns in size. It is composed mainly of silicon dioxide
(SiO2), aluminum oxide (Al2O3), calcium oxide (CaO), and iron oxide
(Fe2O3) along with a host of other oxides. The silica is present in two
forms, an amorphous form which creates round spherules, and a crystalline
form whose particles are sharp and pointed. Today most fly ash is used
in Portland cement but a small portion is used in manufacturing vinyl
siding. In addition to fly ash, carbon black was added to vinyl for
producing records. I do remember some specialty advertising gimmicks
where transparent red or blue vinyl was used. These records were
typically more flexible than their black counterparts.
The silica and alumina containing vinyl records would certainly be
somewhat abrasive. Somehow I doubt if this was a desired result.
Dr. Barry L. Ornitz
Nordic Breeds
>
> Some records were made with a core, notably Columbia at certain
> dates. I don't know how this process was done but most 78s were made in
> the same way from cakes of pressing material called officially
> "pre-forms" AKA biscuits. The pressing material was first ground up and
> then mixed with solvents in a large mixer. The resulting tar-like
> substance was measured out into the pre-forms and travelled down a
> conveyor belt to the pressing machines.
Actually no solvents were used. What was added was plasticizer,
frenchy
Hmm then steel shouldn't fare well against it either : )
Michael Coslo
> "frenchy" <mf10...@msn.com> wrote in message
> news:0dfc09b8-283d-44de...@13g2000prl.googlegroups.com...
>> <<. Also analyse what this> is saying: that abrasives were used to
>> withstand the
>>> considerable pressures of early heavy pickups. You would want exactly
> the opposite, as smooth a surface as you could get. >>
>> Then if this source is accurate, I'd see no other reason for abrasives
>> being used other than to wear the needle to fit the groove, to wear
>> the needle and not the record. Again I'm just going by a multitude of
>> sources that said abrasives were there for that purpose.
>>
>
> Virtually every book on early recording mentions the abrasive issue as
> part of the process.
Dunno if they did or didn't.
But
It might be intuitive to think that adding an abrasive would help wear
down a needle to some proper shape. Our intuitions are often quite wrong
though.
It might wear the needle into whatever the "proper" shape was, but if
you look at a piece of sandpaper after use, it wears out itself in doing
it's job. Kind of whay we don't buy only one piece of sandpaper that
lasts forever. It destroys itself doing it's job.
So would a record that had abrasives in it.
- Mike -
frenchy
>
> - Mike ->>
Sure, I don't think anybody believes that a record doesn't suffer ANY
wear while it's wearing away at the needle. Just much more spread
out. That continuous groove from beginning to end, vs. a single
needle point.
Michael Coslo
Another thing - why didn't at least custom needles get run through a
process to give them the "right shaped point" to begin with? That would
not be a terribly difficult thing to do on a production line. The things
had to be sharpened somehow, and I'm envisioning a whole batch at one
time being taken to the right shape by some analog of playing on a record.
- Could this be a case of something that was going to happen anyhow -
the needle changing shape via wear, and the record wearing out - and
saying "Yeah, that's how it's designed to work"?
- Mike -
frenchy
> process to give them the "right shaped point" to begin with? That would
> not be a terribly difficult thing to do on a production line. The things
> had to be sharpened somehow, and I'm envisioning a whole batch at one
> time being taken to the right shape by some analog of playing on a record.>>
Since a needle gets chiseled on the sides, if that was done beforehand
then the user would be required to insert the needle in the exact same
alignment. Besides, steel needles don't take very long at the start
of the record to begin to fit the groove.
Victor did some prepping of the point on their Tungstone needles but
looks like it was just to soften the sharp cut at the end of the wire
tip. Those needles end up becoming chisled as well but takes more
than a few grooves. Another thing is, every record from different
companies doesn't have exactly the same groove shape, they differed a
lot especially acoustical records. Differed in width, depth, angles
etc.
> Could this be a case of something that was going to happen anyhow -
> the needle changing shape via wear, and the record wearing out - and
> saying "Yeah, that's how it's designed to work"?>>
I doubt it. They could have said the hell with making the records
last very long and went with much more permanent needles in the
acoustic era, but they went with steel instead. It lasts thru one
record side, and is surprisingly easy on the records. With those
heavy soundboxes required back then, and on lateral records, there
just isn't anything else easier on the disc than steel that lasts thru
a whole side or two reliably and is so cheap. Cactus and fiber
needles are gentler on the grooves, but often won't last a whole side
and can grunge up the grooves with crud and are more $$ and don't
sound as good.
George Conklin
"Nordic Breeds" <wa4...@live.com> wrote in message
news:hedcnk$5ur$1...@news.eternal-september.org...
No one has argued that vinyl records had or needed something to grind
down a steel needle!!! If you really want to hear absolutely crappy vinyl
records, just listen to those molded by companies like Rebel Records in 1974
during the first oil embargo. They sound like ground up sandpaper from
recycled material.