Friday, November 22, 2019

A trip back in time

Recently, I have been going thru lots of moving boxes, sorting, discarding and yes, shredding.
Anything with name or addresses on it, financial records etc, it all goes thru my multi cut shredder.
Yap, that is a few bags of shreddies :-)

We are still trying to merge two households, Jean and mine, together.  Could use more room, so time to start another round of down sizing.

Among my finds, I came across some of my earlier wood working projects.  Some survived all these years because they were in use at my parents place and stayed there until I cleaned the house to sell, umpteen years ago.   Others I keep with me because they were working prototypes that I build for my edufication in anything electrical, electronic related.

All these pieces were build between 1968 and 1972.  Let's have a closer look at how they survived.

The projects in question.
3 legged table, 4 legs Octagonal stool, microphone and headset holder (Wireless set No 19)
6 poles electrical motor/generator and a crystal radio featuring a homemade variable capacitor

The furniture

The stool

The stool was my first shop class project of 1969.  I remember the days when high schools (or in my case the then brand new Polyvalente Beloeil)  had real shops.  We had woodworking, mechanical, electrical, welding and automotive shops.  Care to guess which ones I prefer? Yap, woodworking and electrical :-)
The shop was filled with brand new green Poitras and General machines (both made in Quebec Canada).

The idea was to use the skills we just learned in industrial drafting classes, to draw plans for our projects, full size templates etc. from a list of dimensions given to us  Good thing because they were a lot of angles, and the instructor keep saying, don't try to uses wood putty to hide your mistakes, I will know and you will automatically loses points :-)  Emphasis on clean joinery.

Simple joinery, nothing too complicated, both dados, rabbets.  And lots and lots of damn small angle pieces :-)

The screws are not original, were added later by probably my brothers or dad at mom request, similarly for the two tones paint scheme. Not mine, yuck :-)
Originally left bare wood, Lepage white wood glue and finish nails was what held the joinery together.  Guessing it rack thru the years, glue failed, nail not enough to keep it together, screws were added at a later date.

The under shot, showing all those darn little angle blocks all around.
It beefed up the join.

Yes, it is a signed original.  Robert Demers Group 4
Well although numerous were made by the kids thru the years, 
mine is no doubt unique by its own quirks :-) 

 The wood was dimensioned by machines: RAS, Jointer, planer, tablesaw etc.
all the joinery was made by hand.  Coping saw for all the decorative cuts, followed by a good deal of rasping and sanding :-)
All the angle were also cut by handsaws, back saws.  Dadoes, rabbets hand cut backsaw and chisel.

That piece will be stripped of its paint, joinery cleaned and re-glued, nailed, no screws!!
Added to Bob's To Do List, Vol 2, page 56

The Table

Another project of the same era (Group 4) was that small 3 legs table.  I like its design.

That one somehow survived without any added screws

Top is held captive by a dado.  Again glued and nailed (2)

There is a decorative stopped chamfer around the front of the top.
Hand cut, block plane, chisels and no doubt lots of sanding.

The under carriage is all held together by mortise and tenon joinery.
My very first circa 1969/70. 

It has stayed pretty tight.

That joint is pulling a part slightly, I can see the shape of the tenon under strong back light

Another signed original, albeit the signature in pencil is getting pretty faded

If you think this three legs design is unstable or unusual, by happenstances I do have a few antique three legged tables (3 or 4) around the house. So not that uncommon.

The RADIO gears

From L-R
6 poles electrical motor, rotor shown removed for cleaning
to its right is my home brew variable capacitor tuned radio and above it is a older (not built by me, roughly 1930s) Galena radio inductive tuned

The motor

It started with a school assignment in my Electrical/Electronic classes.  Between these two and physic classes simultaneously, it drove me nuts for years.  In the morning it was the Right hand rule, in the afternoon the Left hand rule, to explain the same electro magnetic phenomena, huhhh? Make up your mind!! That's because in Physic they still use conventional current flow, from Positive to Negative and in electronic, electrons flows from Negative to Positive.  Took me years to come to grip that is the same thing, backward. No one was lying.  Had many a philosophical discussions on this subject over a few beers.

Anyhoo, the assignment was to build a simple two poles motor, which quickly turned into an in house competition among ourselves as to which one would be better, faster etc.
So of course, I had to build a 4 poles.  Problem was, someone else came up with a 4 poles, so off I went back to the drawing board and built a 6 poles!  Dad, who helped me with some construction details, such as brazed welding my rotors, said that it would be pointless to try a 8 poles, its is getting too heavy, so don't even think of it.  All the enameled copper wires came from old car distributors coil.

A tad messy to open and get the wiring unwound, it is bathing in oil for cooling.  Probably were filled with PCBs or some other toxic chemicals?  But wow, lots of wire for nothing.  Made good use of that kind of wires :-)

As you can imagine, it is heavy and has a lot of mechanical friction, thus it is a monster.  Not the fastest spinning in my class, but by far the stronger one, torque arg, arg!!
My biggest challenge was to come up with a brush system.  I used the same system I used in my 4 poles.  A small pill bottle, put in 6 small area but long pieces of copper pipes and filled the whole thing with some sort of car body filler (??) and make sure nothing is shorting together before the putty hardened.

Once dry, cut off the bottle, and you are left, after a few trials and errors, with round cylinders with somewhat equally spaced copper strips sticking out all around.  It work but is finicky to adjust for the best combination of sparks and rotational torque :-)

You can make out, the copper strips exposed from the putty

It was also the most current hungry motor tested that day.  We used a car 12 volts battery to test all our motors with an ammeter.  The fastest were oh surprise, also the lightest :-)

My 4 poles was donated to the school at my professor request, but I kept this monstrosity as a reminder of my foolishness.  What can I say, I always felt like the need to be different :-)

That attitude would come back to hunt me a couple times in my military career :-)

The Capacitively tuned radio.

Not really my design, found that in an old electronic magazine.  Did I ever mentioned that for a while I was collecting electronic magazines? I have Radio-Craft from 1937 all the way to its last days as Radio Electronic. A Hugo Gernsback publications   My favorite column was TV Troubleshooting with Jack Darr.  Learned many things from him, which served me well thru the years.

Most design of crystal radio used an adjustable coil to effect some selectivity (tuning). The variable capacitor, working with the adjustable broadcast radio (AM) coil affect a much better tuning range and is more selective.  So of course, had to built one.  It's like the 4 poles, 6 poles thinghy :-)

The variable capacitor mechanism.

The variable capacitor is made by two plates of plywood, the inside face are lined with aluminum foil, taking care not to have the plates shorted out throughout its adjustable range.  Normally there is a sheet of wax paper in between the plates for added protection.  Long lost. A spring want to keep the plate opened, while the end of the screw is pushing the hinged one in and out.  Note the use of a metal plate for re-enforcement were the screw end is bearing against it.
The tunable coil is from a standard AM radio  (Oscillator coil) which gives me the right frequency tuning range (AM band) in conjunction with the design size of my variable capacitor.  Somewhere in the 100s of Picofarads range.

I built a few designs of crystal radio thru the years.  Experimented with older designs I came across which used a chunk of galena crystal as the detector.  Hence the name crystal radio. 

My very first radio, a Christmas gift of long ago (mid 60s) that sparked my future career.
It used a "modern" 1N60A semiconductor point contact diode instead of a Galena crystal, as do most design since these diodes came around

An antique crystal radio, using a galena crystal, long Missing In Action.
And if you are wondering, the coil is missing a screw at one end...

My second Crystal radio, early 70s

The coiling of the connecting wires is purely for look, no intended inductance action required.

The beauty of the design is the very minimalist number of pieces required to make it work.
No power is required, all the "power" is derived from the RF signal, hence a good antenna and a good ground are required for operation.
Add a RF rectifier (Galena crystal, Semi conductor diode or even a rusty razor blade).  Ever heard of Fox holes radio in WWII ?  Yap, build those also :-)

The rectified audio signal is of course very weak, only as strong as the received signal, hence you cannot drive a speaker without some sort of amplification, or you can used high Impedance (Hi Z) headphones using electromagnetic driver.  A thin metal plate, set to vibrate by the changing magnetic field in a electro magnet pulling or pushing the thin metal plate.  That would be old school headsets, which were made by the bazillions in the 30s and up.

I still remember the first time I heard loud and clear Italian speaking on one of my first radios. I was all excited, I am pulling in distant stations!  That lasted briefly until my sister pointed out to me that there are Italian speaking radio stations in Montreal ... Darn !! OK well, 20 miles  away is not bad :-)

Adding to Bob's To Do List: Install a long wire antenna and find a suitable ground (copper pipes or electrical ground) to get them working.

Microphone and headset holder.

That was made for holding up these WWII era headset and microphone set.  

From a WWII era, Wireless set No 19 Radio Transmitter, as used in tanks

Nothing fancy. 
A piece of wood, used whatever piece of scrap metal I had.  
Hacksaw and filing, bending pieces in the vice, drilling holes.
Ain't pretty but is sturdy :-)

My radio room, circa Dec 12, 1973.
Wireless Set No 19 showing, along with a speaker housing I made.

I had pretty well the complete set up, including the gas generator set, which I was not allowed to run inside my room for some reasons that escape me after all these years....

And finally, my very first bench setup, in a spare room in the basement.  Made all kinds of wood and electronic projects on it.  Fixed stuff to make money etc.  Nice built I was pretty proud of it, except for one small design feature...

Built the whole thing in place.
Bench, drawers on metal slides (biggest expense of the project), bookcase, perf board

My last project built on that bench, 1975.
A 12/24 hr programmable CMOS alarm clock with calendar and etc.
Lets admire the beautiful butt joint joinery, glued and nails again :-)

You see, I built it entirely inside the room, never dawn on me, that one day I may have to move it out of the room.  Sure enough, no way out.  I cut it in three pieces to fit the doorway, but never moved it out.  My younger brother screw it back together and used it for many more years.  It finally met its demise when I had the house empty to sell

Joined the Airforce and left my beloved bench behind at my parent's place

For years, anytime I came home to visit, mom would tell her friends, Bob would be home on such and such days, bring your broken TV to be fixed.
That's me working on the floor, something I have lots of experience with :-)
Kept telling Mom, you know they pay me good money in the Airforce now a days, 
I don't need the extra income.

My apartment living room in 1981.  No, its not me on the pic.
Oh, I was collecting cameras at the time :-)
The only things left from this stereo system are the Moving Coil cartridge 
Turn table and its Pre-Pre-amp.

As you can see, I was always surrounded by electronics and woodworking projects of necessity.
So today as I am unpacking long forgotten boxes, I decided to set them up in a man cave corner to enjoy them again.

The corner I started with, which quickly became too small.

So I move it on the other side of the 50 in plasma TV .
Came across some of my video equipment, gotta play with that too :-)

Bob, looking back at time gone by... Still a collector, woodworker, Radio electronic geek after all these years

Reporting for duty at Boot camp, Feb 19, 1976
ERFC St-Jean Qc.

Monday, November 11, 2019

Today is Remembrance day.

Please take the time to reflect on those who gave their lives for us.

It is really a pittance of time ...

RCAF veteran 1976-2013