Timing Edison DD phonographs

[Chuck]

The whole reason I posted this stuff about how to make
the viewing lamp, and the strobe disks is so that
the info on "how to" is clearly available.

Oh sure, yes, there are fancy gizmos of all types,
and there are computer programs that can make a strobe
disk for you.

But, what I am showing is that by using some simple
tools, and some math, the stuff can be made from scratch.

I guess I am just always fascinated by using methods
that employ "first principles".

My philosophy is why chase out any buy a gizmo, or
have a computer program do something for you, when
you can do it yourself, and also learn fascinating
things at the same time?

To me, it seems that things such as angular velocity,
sinewaves that have zero-crossings, light sources that
shut off instantly, and an A-C power delivery system
that has an extremely precise 60 cycles per second
extremely accurately, are all things that deserve
to be pondered, used, and enjoyed.

Making your own strobe disk and viewing lamp is
not just about the end result. It's about the fun
of getting there.

To me, using a computer program or chasing out
to purchase a battery operated gizmo is not nearly
as much fun as the stuff I have described.

But, that's just me, and Fran did ask in his original
post here about having an 80 rpm strobe disk for
an Edison Diamond Disc machine. It's extremely simple
to make one using paper and pencil.

Chuck

[fran604g]

*Double post deleted*

[fran604g]

An 80 rpm strobe disk is very easy to make.
Just draw out a little disc on a piece of paper
using a compass. Make it about the size of a diamond
disc record label.

Then, using an accurate protractor, mark off radial
lines every 4 degrees, all around the disc.

360 divided by 4 is 90, so there will end up being
90 marks. Use a pencil so you can erase it if you
make any mistakes.

When finished, enlarge the pinhole made by the compass
out to a snug diameter to fit the center post
on the turntable.

To use, view under neon or fluorescent light.
Incandescent filaments do not work so well for this
because they never completely go dark at the zero-
crossing of the A-C sine wave.

Just today, in another thread here I described in
full detail how to make the viewing lamp using
a neon bulb.

So, there you go, you can make the viewing lamp
and the 80 rpm disc.

Or....you can go out and buy one of them tachometer
gizmos and use it until the battery dies, then go get
another battery.

I was a draftsman for many years, so it's easier and
less costly (spell that zero dollars) for me to
draw up my own strobe discs.

About the markings on the Edison diamond disc
label, you could get some idea what speed would
strobe it if the angle from the center out to the
marks is known.

4 degrees is 80 rpm.
6 degrees is 120 rpm.
8 degrees is 160 rpm.

Those are the only ones I've made so far and use.

7200 divided by the total number of marks equals
the speed at which the pattern appears to stand still.
(For 60 cycle power)

There's more, much more....anybody still awake??
Haha.

Chuck

I like this idea, thanks Chuck. I should have thought of doing this, I used to mark out steel cones for shearing and rolling using a very large compass that I made and a similar technique to scribe the two ends.

Fran

[Chuck]

Fran,

Not to drift too far off-topic here, but since you
have experience laying out sheet metal in the flat,
then bending it and/or rolling it to form a 3-dimensional
shape, then you can sort of appreciate this fascination
I have with this process of making these strobe disks.

If you're curious about any more of the math behind it
or want to discuss any more about this, send me a PM.

One thing I'm really wondering about now and would
very much like to check out, is I wonder how the
strobe disk would compare to the tachometer gizmo
as far as agreeing dead-on about some speed, say 80 rpm?

One little oversight I see people make time and time
again, is that when using any device that has a digital
readout, they inherently and rather blindly seem
to trust what that readout says, as if it's accurate
just because it's digital.

Just one more thing: I'd say that for 80 rpm and 160 rpm
which are both very straightforward disks to make,
that the neon lamp, and the power company's 60 cycles
will provide a very accurate reading. Because, think
about it: You can run one of them older electric
clocks that has the synchronous motor, and it will keep
extremely accurate time over days, weeks, months.

This is because the power companies keep their
frequency very accurately adjusted to as close to 60
cycles as they can keep it. And, hey, you are already
paying them every month to use it, so why not get
all you can out of it?

Chuck

[fran604g]

Chuck, using my personal skills and available materials to make something useful has always been important to me. As a Chef for 25 years, it was paramount. Later on in life, as a machinist, I was capable of programming CNC machines and doing manual precision machining operations. About 12 years ago, my fascination and curiosity in the metal trades even compelled me to build my own coal fired forge and delve into the world of the Blacksmith. What fun!

I appreciate your fortitude.

Fran

[VintageTechnologies]

Chuck, using my personal skills and available materials to make something useful has always been important to me. As a Chef for 25 years, it was paramount. Later on in life, as a machinist, I was capable of programming CNC machines and doing manual precision machining operations. About 12 years ago, my fascination and curiosity in the metal trades even compelled me to build my own coal fired forge and delve into the world of the Blacksmith. What fun!

I appreciate your fortitude.

Fran

Fran, I was a machinist in my early life, but all of our tools were manual, no CNC in the shop. They were antiques, really. I mostly ran lathes and vertical milling machines, such as a Cincinnati No.5 built in 1929! It was so big (and also sitting on a platform) that I had to crawl atop to loosen and change the collets. I found a picture of one online to give you some idea of it: http://pittsburgh.craigslist.org/tls/4398428656.html

[fran604g]

Fran, I was a machinist in my early life, but all of our tools were manual, no CNC in the shop. They were antiques, really. I mostly ran lathes and vertical milling machines, such as a Cincinnati No.5 built in 1929! It was so big (and also sitting on a platform) that I had to crawl atop to loosen and change the collets. I found a picture of one online to give you some idea of it: http://pittsburgh.craigslist.org/tls/4398428656.html

Nice! What a monster! I used many Bridgeport style machines. The last place I worked, we had a Warner-Swasey turret lathe from the 40's that was a LOT of fun to set up and run; lots of levers and dials!

It was my job to keep the goons from wrecking it all the time.

It was a #3 like this one:

Warner-Swasey turret lathe.jpg (145.38 KiB) Viewed 1613 times

The owners manual had a picture of a factory set up with rows and rows of them, I thought it was the coolest thing ever!

This looks to be the manufacturing operation for them:

Warner-Swasey turret lathe2.jpg (192.16 KiB) Viewed 1613 times

[fran604g]

Hi folks,

An update on this topic with a timing "strobe wheel" image that was posted by a person on the Antique Phonograph Enthusiasts Facebook wall that works quite well, IMHO.

I downloaded the posted image and simply printed it out onto heavy matte photo paper so that the outside of the image circumference was the full width of the 8-½" x 11" photo paper. The outer circumference of the image is a little indistinct, so to remedy this, I located the relative center of the circle with my machinists square using the 90 degree "center square" attachment and then used a compass to adequately demarcate a more perfect circle before cutting it out with scissors. I then simply cut a 5/16" cross hatch with a razor blade at the center, where the hole was left by the compass point, so that I could push my finished strobe wheel onto the spindle of a turntable.

The imperfections created by the less than perfectly round printed image of the segmented concentric strobes are are so infinitesimal, that the assumption of a problem is actually negligible when viewed with a 60Hz light source.

Best,
Fran

[Phonofolks]

I beg to differ. I do believe the paper label on the diamond disc can be used as a record strobe and it makes sense that Edison decided to place this on their records. I play my diamond disks on a Bogen variable speed turntable set up to play vertical and lateral cut records. Over me is florescent lighting. When I play the Edison disks I move the lever to adjust the speed on the turn table from 78 to an 80rpm position. When I do this the strobe becomes a steady even pattern holding pretty much of a constant speed. The record also plays at a constant and correct speed. I believe this strobe was placed on the record not only for record dealer demonstration purposes, but for use on other non-Edison phonographs that could play diamond disc records. This assists and tells the consumer that you must play Edison disks at 80 rpm and not 78 rpm to get the proper sound. Again just my observations and thoughts.

Rick

[fran604g]

I beg to differ. I do believe the paper label on the diamond disc can be used as a record strobe and it makes sense that Edison decided to place this on their records. I play my diamond disks on a Bogen variable speed turntable set up to play vertical and lateral cut records. Over me is florescent lighting. When I play the Edison disks I move the lever to adjust the speed on the turn table from 78 to an 80rpm position. When I do this the strobe becomes a steady even pattern holding pretty much of a constant speed. The record also plays at a constant and correct speed. I believe this strobe was placed on the record not only for record dealer demonstration purposes, but for use on other non-Edison phonographs that could play diamond disc records. This assists and tells the consumer that you must play Edison disks at 80 rpm and not 78 rpm to get the proper sound. Again just my observations and thoughts.

Rick

Very interesting observance, Rick!

Fran