Coils

[Chiron]

I've wanted to check out some things using big coils - not the sort used
for RF circuits, but large coils such as might be found in a Tesla coil.
I don't have the funds to special order them or to buy them pre-made
(assuming they even come that way). I expect I'll have to wind my own...
but...

How the heck do you do that? What sort of arrangement would work for
that? Trying it by hand left me exhausted and with poorly-wound coils of
insufficient turns. Surely there is some simple arrangement whereby you
can feed in wire and magically get out coils.

Can anyone point me in the right direction with this? I'd appreciate
it. I've already tried Google, with little success.

I also tried buying a used "coil-winding machine," but it's just a
powerful motor with a chuck for holding the coil's form. No speed
control at all, no reasonable controls. There is a toggle switch that
selects the motors direction, and doesn't even let you turn the damned
thing off. If it's plugged in, it's rotating one way or the other at
full speed and power.

I'd appreciate any helpful ideas. Thanks.


--
That's odd. That's very odd. Wouldn't you say that's very odd?

[Randy Day]

In article <kQkUq.1524$1B1....@newsfe14.iad>, chir...@gmail.com
says...

>
> I've wanted to check out some things using big coils - not the sort used
> for RF circuits, but large coils such as might be found in a Tesla coil.
> I don't have the funds to special order them or to buy them pre-made
> (assuming they even come that way). I expect I'll have to wind my own...
> but...

[snip]

> I'd appreciate any helpful ideas. Thanks.

Googling on 'diy testla coil' brought up:

http://www.rmcybernetics.com/projects/DIY_Devices/homemade_tesla_coil.htm

Car ignition coils from a scrapyard are
one option.

[Chiron]

Thanks, Randy. However, I am not particularly interested in making a
Tesla coil; I simply mentioned that to give an idea of the types of coils
I was interested in creating. Big coils, lots of windings, air core,
potentially very high voltages and relatively high frequencies. Some
with fairly high magnetic flux density, perhaps. I am looking for
flexibility.

I've used ignition coils previously, which are OK for some uses.
Unfortunately, they are limited. IIRC, they have an iron core which
limits their upper frequencies.

The solution, as I see it, is to wind my own coils so that I can choose
their size, wire gauge, number of turns, core, and other variables.


--
Some of the things that live the longest in peoples' memories never
really happened.

[John Fields]

---
That's all true but, if you're asking for help, very little can be
offered without your stating what you want to do.

--
JF

[Chiron]

On Thu, 26 Jan 2012 18:28:58 -0600, John Fields wrote:

<snip>

> That's all true but, if you're asking for help, very little can be
> offered without your stating what you want to do.

I want to wind coils. That is what I want to do.

I don't want to *have* coils, per se; I want to *wind* my own coils, so
that I can adjust them for whatever variables seem interesting,
necessary, or otherwise useful.

I do not have in mind any particular project to build. I want to putter
around with them, as my interests may lead me. So maybe I'll want a
large magnet; or a transformer of some sort; or a Tesla coil, Oudin coil,
hell, I don't know, maybe even motor windings.

Maybe think of it as a sort of "teach me to fish" kind of thing. Instead
of needing to track down this kind of coil, or that kind, I'd be able to
make whatever I needed.


--
Being popular is important. Otherwise people might not like you.

[George Herold]

No magic devices. We use a lathe to wind coils. Built a little spool
holder with adjustable 'friction', turn on the lathe and start
counting. (We've added a turn counter.) Scatter wound coils are
pretty easy, if you want something more 'controlled' then our
production peolpe put a layer of tape on after each layer or two.

Maybe a foot operated AC switch would help make your coil winding
machine more 'user friendly'.

George H.

[Winston]

George Herold wrote:

> Maybe a foot operated AC switch would help make your coil winding
> machine more 'user friendly'.

http://www.youtube.com/watch?v=YqErTwU1rSE

Look at 0:06 and starting at 1:02.

See how he's adapted a cable to allow foot
control of the motor speed?

As soon as I saw that I thought "Coil Winder"!

The Foredom FCT-1 is an electronic solution
that would plug right in without any
'metalworking heroics'.

Nifty!

--Winston

[default]

I've wound a number of Tesla coils and a 1 KW induction coil with ~13
miles of wire in the secondary... According to the DC resistance, I
nailed the length of wire to within 300 feet of my design goal - not
too shabby out of 13 miles.

First few TC's I did were by holding the PVC tube and guiding wire on
while rotating the tube in my hands. That got old fast.

I built a coil winder with a large PM DC motor. Fixed the motor
horizontally, to a 2X6 plank ~50" long.

I used a reel drive motor from a computer (1" X 15" tape reels), but
there's lots of "treadmill motors" these days with similar power and
size on the surplus market.

For the mandrels, I laminated a pair of spruce 2X4's together, drilled
a hole through the center and mounted a short length on the motor by
just drilling the hole undersize and beating it on with a hammer
(healthy motor with a 3/8" X 2" shaft).

I turned the mandrels using a variable power supply (24 volt battery
charger with a variac to control voltage) and some wood chisels, rasps
and sandpaper to make a friction fit to the 1-1/2" to 3" PVC coil
forms. Turning wood is a lot of fun....

The fixed center of my winding lathe, was a construction out of wood
using a 3/8" bolt as the lathe "center." Turn two mandrels and leave
one on the motor and one on the center, with the PVC tube between.

Winding is a snap - took less time to build the, admittedly crude,
lathe, and wind the 3" wide long coil, than it would have taken to
wind the coil alone.

I wound a total of 12 coils in the 2" to 4" diameter range and had
loud noisy sparks 8 feet long out of some of them.

They can easily be coated with thick layer of epoxy or varnish by
leaving the coil on the lathe, rotating it slowly, while using a
credit card to spread the epoxy evenly. It rotates slowly while the
epoxy sets up so there are no sags and you get beautiful results.

I just set the power supply so it is tensioning the wire then hold the
wire back with one hand and guide it on with the other as the motor
turns. Precut masking tape holds the wire in place long enough to
cement the end down (under tension).

The induction coil was the same deal, but I made four large bobbins
out of 3" PVC for the cores, and 1/8" thick Plexiglas donuts for the
end plates. They are 3-1/3" wide, since I had plain adding machine
paper on rolls to use as layer insulation.

I'd wind a layer using the TC winder with one mandrel to hold the
bobbin (and a shorter bed on the lathe for this project). A layer
took about 2 minutes using #32 AWG wire. Then tape it in place long
enough to paint it with quick drying varnish to hold the turns, wrap
it with a layer of paper and do another. Took about a week of spare
time to finish 4 bobbins with some 24 layers on the outside coils and
30 on the inside ones. Took about a month total to build the
induction coil. I wound the primary in four layers and brought out
the starts and finishes so I could wire them in series or parallel to
use as an AC HV transformer or DC induction coil.

AC performance is ~10,000 volts and DC unknown (but jumps a 5" spark
with no problems) The whole thing got vacuum impregnated with wax
(using my pressure cooker on the range top with a vacuum pump attached
to it filled with molten wax - the wound bobbins soaked in the oven
overnight on "warm" to get the wax to flow easily)

My stove is electric - I wouldn't do it that way with gas since the
paraffin is flammable and the varnish is hot and out gassing residual
solvents when the vacuum pump is running. Hotplate outdoors with a
fire extinguisher standing by makes more sense....

Oak box, porcelain conical turret insulators, with brass wood screws,
and a largish 1930's X-ray machine ammeter on the primary, and switch
box to serve different primary combinations for different voltages.
The coils are potted in wax, the iron protrudes out either side of the
box. Weight is ~35 pounds and it should have handles or wheels on it.

Another, perhaps easier, way to do it is with "pies." Bobbins are
only 1/8" wide with plastic film side plates, and the wire is jumble
wound on - depending on the large number of bobbins to provide
insulation between layers. I was working from a 1930's book on the
subject and just adapted what they had to modern materials.

I use the induction coil to excite the Tesla coils - I found that up
to around 200 hertz the TC performs much better. They resonate at
~100 KHZ. Higher and either the iron loses are too great or the waves
aren't damped out before the next spark comes along.

[Chiron]

On Fri, 27 Jan 2012 05:50:41 -0800, George Herold wrote:

> On Jan 26, 5:54 pm, Chiron <chiron...@gmail.com> wrote:

<snip>

>
> No magic devices. We use a lathe to wind coils. Built a little spool
> holder with adjustable 'friction', turn on the lathe and start
> counting. (We've added a turn counter.) Scatter wound coils are pretty
> easy, if you want something more 'controlled' then our production peolpe
> put a layer of tape on after each layer or two.
>
> Maybe a foot operated AC switch would help make your coil winding
> machine more 'user friendly'.
>
> George H.

Thanks, George. Maybe I can work something out with this motor I've got
(the alleged "coil winder." Its one advantage is that it already has a
counter on it. I think a foot-operated switch would be a great idea.

I wonder whether there is any sort of foot-operated switch that lets you
adjust the speed... that would be a major help, since this motor turns
faster than I can feed in wire (10,000 RPM).

I've been seeing people talking about PWM. I've never worked with that,
but it might be something to try for the motor.


--
If you learn one useless thing every day, in a single year you'll learn
365 useless things.

[Chiron]

Thanks, Winston. That sort of foot-operated switch, that allows variable
speeds, sounds perfect.

The guy who made the video seems very inventive.


--
Have no friends not equal to yourself.
-- Confucius

[Chiron]

On Fri, 27 Jan 2012 10:24:53 -0500, default wrote:

> On Thu, 26 Jan 2012 22:54:08 GMT, Chiron <chir...@gmail.com> wrote:
>

<snip>

Wow! Thanks, "default," whoever you are. You've given me some great
ideas to try. I appreciate it.




--
"All the people are so happy now, their heads are caving in. I'm glad
they
are a snowman with protective rubber skin"
-- They Might Be Giants

[Winston]

Chiron wrote:

(...)

> Thanks, Winston. That sort of foot-operated switch, that allows variable
> speeds, sounds perfect.

Yup, just plug one of these in and tyrap your trigger to 'constant ON'.
Only nine are available here, but they cost only 30.50 each! http://tiny.cc/3q4in

<http://www.ebay.com/itm/FOREDOM-FCT-1-FLEXSHAFT-FOOT-SPEED-CONTROL-ELECTRONIC-/190543102689?pt=LH_DefaultDomain_0&hash=item2c5d4102e1>

> The guy who made the video seems very inventive.

He does very nice work.

--Winston

[George Herold]

On Jan 27, 1:51 pm, Chiron <chiron...@gmail.com> wrote:
> On Fri, 27 Jan 2012 05:50:41 -0800, George Herold wrote:
> > On Jan 26, 5:54 pm, Chiron <chiron...@gmail.com> wrote:
> <snip>
>
> > No magic devices.  We use a lathe to wind coils.  Built a little spool
> > holder with adjustable 'friction',  turn on the lathe and start
> > counting.  (We've added a turn counter.)  Scatter wound coils are pretty
> > easy, if you want something more 'controlled' then our production peolpe
> > put a layer of tape on after each layer or two.
>
> > Maybe a foot operated AC switch would help make your coil winding
> > machine more 'user friendly'.
>
> > George H.
>
> Thanks, George.  Maybe I can work something out with this motor I've got
> (the alleged "coil winder."  Its one advantage is that it already has a
> counter on it.  I think a foot-operated switch would be a great idea.
>
> I wonder whether there is any sort of foot-operated switch that lets you
> adjust the speed... that would be a major help, since this motor turns
> faster than I can feed in wire (10,000 RPM).

Wow.. much to fast, in my opinion. (That actually sounds a bit
scary.) We use the back gear in the lathe to really slow it down. Is
there some way to rig up some reduction gearing?

George H.

[default]

On Fri, 27 Jan 2012 19:07:41 GMT, Chiron <chir...@gmail.com> wrote:

>On Fri, 27 Jan 2012 10:24:53 -0500, default wrote:
>
>> On Thu, 26 Jan 2012 22:54:08 GMT, Chiron <chir...@gmail.com> wrote:
>>
><snip>
>
>Wow! Thanks, "default," whoever you are. You've given me some great
>ideas to try. I appreciate it.

Another way might be to mount two pairs of fixed (not swivel) casters
so the wheels are pointing up on a 2X6" board in two groups spaced so
they support the ends of the tube.

The tube (coil form) rides in the valley formed between the upright
casters.

Then to drive the tube with a motor... a hole drilled in the end of
the coil form - straight through (two hole, in and out) and a short
length of reinforced rubber tubing (think: oil lines for autos) to
connect to the motor shaft to a bar run through the holes on the coil
form. Hose clamps to keep the motor shaft from slipping in the
tubing.

Upside - easier than turning mandrels for each diameter tubing

Downside - is the axis of the motor would have to move up and down to
accommodate different diameters of tubing so it drove it in the
center.

Even something as basic as a couple of V groove blocks to drop the
coil form in is much easier than trying to hold them by hand.

A holder for the feed spool of wire is another necessity in my
opinion. You want the wire to come off the top of the feed, and go on
to the top of they coil form - to avoid kinking.

With very fine gauge wire (think: winding guitar pickups and #37 - 40
AWG) it is easier if the wire comes off the end of the spool (spirals
off the axis). That kinks heavy wire but thin wire just twists and
takes it.

With Tesla coils, the gains tend to be incremental. A small
difference here and there can make a huge difference in output spark
length (if that is your goal). One of my best coils is 26 AWG
wire-wrap wire with "Kynar" insulation and silver plated conductor -
coated with epoxy.

Another thing with TC's: electrostatic field control makes a
difference - you don't want a point where electrons can leak off a
"point" like just the diameter of the coil form - so the output
terminal has to over shadow the last turns of wire - electrostatic
field on the terminal suppresses corona that would emerge from the
coil.

If you are doing Tesla coils - other than the obvious hazards like
electrocution, there's ozone and X-rays to guard against. Ozone is a
serious issue. You can smell it in the PPM range but when it
increases it doesn't smell any more strong, and it can cause lung
cancer (and UV light/ozone can bleach things, cause eye cataracts and
damage plastics).

X-rays aren't a problem until you put high vacuum toobs (like radios
used to use) on the output terminal (little #47 bulbs light green -
the X-rays fluoresce the glass envelops) Regular light bulbs aren't
good for X-rays they just behave like plasma globes.

[John Fields]

On Fri, 27 Jan 2012 18:51:42 GMT, Chiron <chir...@gmail.com> wrote:

>If you learn one useless thing every day, in a single year you'll learn
>365 useless things.

---
And, after four years passes - and you've paid attention - you'll have
learned 1461.

--
JF

[asdf]

On Fri, 27 Jan 2012 04:12:09 +0000, Chiron wrote:

> I want to wind coils. That is what I want to do.

I stumbled upon some homemade coil winding machines projects just by
looking for coil/inductor formers, winding, etc on google. Didn't save
the links but they sprung out pretty easily.

[Cydrome Leader]

This is the method I preferred. You can wind a coil by hand faster than
you can around talking about it, or waste time making some contraption.

The largest coil I made was about 5' long on 10" PVC pipe.

The trick is to not stop once you start winding, and to tape the edges
down if you do take a break so you don't lose tension in the winding. If
it unravels when you wind it, you're screwed. Cut the wire off and start
over.

Don't wind magnet wire on warm PVC either. PVC shrinks enough in the cold
for the windings to loosen and slip over each other.

Winding a secondary coil is one of the easier tasks in making a tesla
coil. Once you make it you're done- all the other parts including the
primary require lots of fiddling with.

I'm not sure what size coils you want, but I've always liked 20 guage
copper. It's strong enough to not tear and thick enough wide edgewise with
a wooden block to force the windings down and next to each other as you
turn your coil form. I've wound coils by throwing a PVC pipe on some felt
over an open dresser drawer with a spool of wire on the other side of the
room. The front edge of the drawer keeps the coil from rolling away. Save
the energy wasted on rube goldberg winding machines for your spark gap.

[Michael A. Terrell]

http://www.lindsaybks.com/dgjp/djgbk/coil/index.html


--
You can't have a sense of humor, if you have no sense.

[default]

I have to disagree. I seriously doubt you can possibly keep up with a
motorized winder entirely by hand, and it was no problem for me to
kludge together a winder in less time than it takes to wind one.

I used wire in the 22-32 range. The induction secondary coil has
~67,800 turns of 32 on it. No way that would be done in a week by
hand.

The winder got adapted with some poly side plates and Teflon center to
wind a rotor coil for a motorcycle alternator. Self supporting coil
with epoxy in the layers.

I do a fair amount of woodworking, and have a small table saw, so my
time to build might be different than yours.

I did a primary with wood slats supporting the wire and individual
spiral grooves to hold each turn - cylinder shape, spiral, and conical
versions. Rotary gap with a few blank compact disks laminated for the
rotor. One of the better, simpler, gaps was a pair of 2" diameter
copper pipe caps sweated on to short lengths of copper pipe to
dissipate heat.

[Ian Field]

"Chiron" <chir...@gmail.com> wrote in message
news:kQkUq.1524$1B1....@newsfe14.iad...

> I've wanted to check out some things using big coils - not the sort used
> for RF circuits, but large coils such as might be found in a Tesla coil.
> I don't have the funds to special order them or to buy them pre-made
> (assuming they even come that way). I expect I'll have to wind my own...
> but...
>
> How the heck do you do that? What sort of arrangement would work for
> that? Trying it by hand left me exhausted and with poorly-wound coils of
> insufficient turns. Surely there is some simple arrangement whereby you
> can feed in wire and magically get out coils.

Buy your enamelled copper wire on plastic drums and make sure you can get at
the start of the winding before you hand over the cash.

[Chiron]

On Sat, 28 Jan 2012 06:32:06 -0500, Michael A. Terrell wrote:

<snip>
>
>
> http://www.lindsaybks.com/dgjp/djgbk/coil/index.html

This is great. I'm familiar with Lindsay - I've gotten books from them
before. Thank you for this link.



--
You can't hold a man down without staying down with him.
-- Booker T. Washington

[Chiron]

On Fri, 27 Jan 2012 12:33:47 -0800, George Herold wrote:

<snip>

>>
>> I wonder whether there is any sort of foot-operated switch that lets
>> you adjust the speed... that would be a major help, since this motor
>> turns faster than I can feed in wire (10,000 RPM).
>
> Wow.. much to fast, in my opinion. (That actually sounds a bit scary.)
> We use the back gear in the lathe to really slow it down. Is there some
> way to rig up some reduction gearing?
>
> George H.

I'm sure there's some way to do it, but I'm not sure *I* could do it.
I'm not mechanically gifted.

I really got taken with this "coil winder," I think. It's mostly just a
fast, powerful (1/7 HP) motor on a platform, with a chuck and a counter.
I cannot imagine how anyone could have used the thing for winding coils.
OTOH, it *is* a nice, big motor that could probably be useful for
something. Maybe a Van de Graaff generator or something...

>>
>> I've been seeing people talking about PWM.  I've never worked with
>> that, but it might be something to try for the motor.

--

Rarely do people communicate; they just take turns talking.

[et...@whidbey.com]

Since the motor is a 10,000 rpm motor I assume it is either a DC motor
or a "universal" motor. Like a drill motor. I have used lamp dimmers
on these types of motors. Properly rated for the current the motor
draws they work well and are cheap. And they are PWM devices so the
torque will stay pretty constant. Even though the cheap ones are made
for resistive loads only according to the package I have never had one
fail prematurely.
Eric

[Jamie]

Must be some expensive house whole dimmers? Most I've seen are phase
angle firing with triacs or quadacs.

Jamie

[et...@whidbey.com]

Whoops! You're right Jamie. The cheap ones are as you describe. I do
have some 12 volt PWM motor controllers that I built myself from kits
and was thinking of those. Nevertheless, the cheap lamp dimmers do
work pretty well for controlling the speed of universal motors.
Thanks,
Eric

[Ivan Vegvary]

>
> How the heck do you do that? What sort of arrangement would work for
> that?

I've wound several coils to keep my pinball machines going. Usually on a cardboard or plastic core. Core diameter about 3/8 inches, final coil diameter a little over an inch.

I own an old metal lathe that can be run as slow as 50 RPM. Bought a cheap click type counter and attached it to the lathe so I can count revolutions. I feed the magnet wire by letting it slip through my hands. After you've would your second one, they come out rather pretty.

Ivan Vegvary

[Jasen Betts]

On 2012-01-27, Winston <Win...@Bigbrother.net> wrote:

> George Herold wrote:

> See how he's adapted a cable to allow foot
> control of the motor speed?
>
> As soon as I saw that I thought "Coil Winder"!

mount a chuck on the back wheel of a domestic sewing machine,

--
⚂⚃ 100% natural

[Winston]

And see how this guy uses a cheap calculator
as a turns counter?! Genius!

http://www.youtube.com/watch?v=_z4OVsFWYyw

--Winston

[Michael Black]

On Mon, 30 Jan 2012, Winston wrote:

> Jasen Betts wrote:
>> On 2012-01-27, Winston<Win...@Bigbrother.net> wrote:
>>> George Herold wrote:
>>
>>> See how he's adapted a cable to allow foot
>>> control of the motor speed?
>>>
>>> As soon as I saw that I thought "Coil Winder"!
>>
>> mount a chuck on the back wheel of a domestic sewing machine,
>
> And see how this guy uses a cheap calculator
> as a turns counter?! Genius!
>

That sort of thing wasn't uncommon 35 years ago, once there were cheap
calculators. One could also use a pedometer, now made cheap since they've
become faddish, and thus available in cereal and garage sales.

Of course, one could just strip an old cassette deck, and use the counter
from that, so long as one could properly connect it to the rest of the
mechanism.

Michael


> http://www.youtube.com/watch?v=_z4OVsFWYyw
>
> --Winston
>

[Winston]

Michael Black wrote:
> On Mon, 30 Jan 2012, Winston wrote:

(...)

>> And see how this guy uses a cheap calculator
>> as a turns counter?! Genius!
>>
> That sort of thing wasn't uncommon 35 years ago, once there were cheap calculators.

> One could also use a pedometer, now made cheap since they've become faddish, and
> thus available in cereal and garage sales.

I bought a couple for just that use. Unfortunately they stop working
properly at lower battery voltage and the 'calculator' solution yields
a unit with a larger display anyway.

> Of course, one could just strip an old cassette deck, and use the counter from that, so long as one could properly
> connect it to the rest of the mechanism.

Thassa lot of work. I'd go as far as putting an opto interrupter
wired across the "=" key of a dollar store calculator but not
much more. :)

--Winston

[George Herold]

A colleague made a magnetic quadrature counter that could do
direction....
which is nice if you want to take a few turns off.
(Hall sensors and two magnets)


The electronics were made for a different signal.
http://www.teachspin.com/instruments/moderni/experiments.shtml#die

You get four counts per revolution.

George H.

[Winston]

Wow! I was just getting used to the ultra-fine divisions in regular
encoder wheels and you show me an apparatus with sub-wavelength
resolution! Incredible!

--Winston

[Michael A. Terrell]

Chiron wrote:
>
> On Sat, 28 Jan 2012 06:32:06 -0500, Michael A. Terrell wrote:
>
> <snip>
> >
> >
> > http://www.lindsaybks.com/dgjp/djgbk/coil/index.html
>
> This is great. I'm familiar with Lindsay - I've gotten books from them
> before. Thank you for this link.

You're welcome. I'm in the early stages of design to build one with
stepper motors and an Arduino board to control them. There is also
EMC/Linux CNC that could be used with an old PC.

[Michael A. Terrell]

Winston wrote:
>
> Jasen Betts wrote:
> > On 2012-01-27, Winston<Win...@Bigbrother.net> wrote:
> >> George Herold wrote:
> >
> >> See how he's adapted a cable to allow foot
> >> control of the motor speed?
> >>
> >> As soon as I saw that I thought "Coil Winder"!
> >
> > mount a chuck on the back wheel of a domestic sewing machine,
>
> And see how this guy uses a cheap calculator
> as a turns counter?! Genius!

Skycraft surplus has used a four banger on their wire measuring
machine for a long time. It was old when I first saw it in 1987.
Instead of a mechanical cam, the calculator was hacked and the switch
was part of the mechanics.

[George Herold]

> --Winston- Hide quoted text -
>
> - Show quoted text -

Grin... sure but it costs a bit more than an encoder wheel.
Each count is 1/8th of the wavelength, less than 100nm... does that
count as nanotech? :^)
What I hadn't known about the quadrature technique is that the (phase)
noise stays all on the 'rim' of the circle. I guess that's 'obvious'
in retrospect.

George H.

[Winston]

George Herold wrote:
> On Jan 31, 12:05 am, Winston<Wins...@Bigbrother.net> wrote:

(...)

>> Wow! I was just getting used to the ultra-fine divisions in regular
>> encoder wheels and you show me an apparatus with sub-wavelength
>> resolution! Incredible!
>>
>> --Winston- Hide quoted text -
>>
>> - Show quoted text -
>
> Grin... sure but it costs a bit more than an encoder wheel.

That's reasonable!

> Each count is 1/8th of the wavelength, less than 100nm... does that
> count as nanotech? :^)
> What I hadn't known about the quadrature technique is that the (phase)
> noise stays all on the 'rim' of the circle. I guess that's 'obvious'
> in retrospect.

I'll take your word for it.

--Winston