Sunday, February 28, 2010

Motorific Tractor - Trailer

I still have one of my favorite childhood toys, my Motorific cars and truck. While the cars are commonplace on the the toy collector scene, it appears that the tractor-trailer, (or Articulated Lorry, as our British friends would call it), is quite rare. My guess is that few are even aware what a cleverly engineered toy this is.  That is why I consider the Motorific Semi-Truck "blog-worthy" While the Motorific cars went forward only, (one variant had a clever two-speed transmission- perhaps a subject for a future blog), the Semi could back up and unhitch it's trailer.  Then you could have it return, back up and hitch the trailer, then drive away. All in all, an innovative bit of engineering that deserves to be remembered. 
The loading dock has a series of guide grooves and levers which started, stopped, and reversed the truck; released or hitched the trailer, and switched the truck into the appropriate groove for loading/unloading; or simply passing by.
Step one:
Truck enters loading dock track.
Pressing Lever #1 will direct truck into dock area.

Step two:

Truck enters dock and advances towards the reversing trip.

Step three:

Truck hits trip and begins to back up.
Tractor's reverse guide pin drops into slot.

 Step 4:

Truck backs up.
Note how trailers wheels are steerable.
An ingenious design which made the whole idea possible.

Step 5:    Truck parks and shuts off.
Step 6:   Lever #1 releases trailer.
Step 7:   Lever #2 starts truck.  Truck leaves loading dock,
               resetting trips for next time.

Here are some inside views of the works.
The chassis was compact, and unfortunately, a bit fragile.  Mine has a few cracks, which I glued years ago.  But I played with it a lot back then. Look closely and you will see tire marks on the tracks and chrome worn thin from handling.
The chassis had to fit a gear reduction drive, reversing mechanism, steerable front wheels and retractable reversing guide pin, a long with 2 AA batteries and a motor in a very small space.

Bottom view:  Forward/Off/Reverse switch visible, along with front and rear guide pins, and trailer hitch/steering mechanism.

I remember paying $20 for the whole set back in 1970, after the Motorific line was discontinued and the set was relegated to the discount rack.  A recent Ebay search revealed no sets for sale, but one person wanted $69 for the bare tractor chassis alone. I would venture to say that my $20 was not a bad investment.
Sadly, not just the Motorific line, but the Ideal Toy Company itself, has passed into history.

Wednesday, February 24, 2010

My Fiber Optic Phone Jack Design

A few years ago, I developed a prototype phone jack that used up to 8 optical fibers instead of wires. Unfortunately, the design was never used, but I think it is a pretty cool design, anyway.
   One end was a standard phone jack that I hollowed out and installed one of our polymer waveguide connectors attached to a fiber ribbon.
  The other end was a receptacle of my own design.

    Using optical fibers presents some challenges not encountered with electrical connections.  Primarily, dirt contamination and eye safety.  My connector solved both in a way that I feel was superior to other designs.
I created a clamshell arrangement that opened when the plug was inserted.  An important feature of my design is that the clamshells moved back and away from the optical connector.  This ensured that dirt would not be pushed in, but pushed away instead.
When the plug was removed, the clamshells closed tight, preventing dirt from entering and light from escaping.  The clamshells were recessed deep into the housing, making them difficult to tamper with.

The connector body was easy to fabricate and had few parts.  Internally, for demonstrator purposes, it had one of our polymer 1x8 splitters instead of 8 optical fibers.  That is why you see only a single fiber on one side.

Overall, a nice design and a good demonstrator for our waveguide business, but we were not a connector manufacturer and did not commercialize it.

Tapering the end of a glass optical fiber

My first patent was for a machine which tapered the ends of a glass optical fiber.  Back then, we had to insert optical fibers, which are only 125 microns, or  0.0049 inches in diameter, into holes in a soft plastic material.  We were making optical waveguides in a sheet of polymer and had to connect fibers to them, much like one would connect wires to an electronic circuit board. A simple cleaved fiber had very sharp edges which would damage to sides of the soft polymer hole. chamfer those edges, but how to do it? Fibers are tiny, glass, flexible, and fragile.
  We had precision polishing equipment available to us, so I decided to make a fixture which would fit onto the polisher. I would use the rotating motion of the machine to rotate the fiber, which was just a few feet long and could be coiled up.  The polisher was designed to hold parts in 5 inch rings, so I made my ring compatible with that.

 The concept was easy enough.  The ring would naturally rotate as the machine ran.  I made a track on the top of the ring for a steel ball.  The ball had a hole in it, into which was inserted a fiber holder.  An arm held the ball stationary, but free to spin as the ring rotated under it.

The first attempt, using a flat track on top of the ring, was a failure.

The spinning ball wanted to align it's rotating axis horizontal, when I needed it angled down towards the polishing pad.  Some additional thought and a few calculations revealed that there was a way to make the spinning ball's axis point exactly where I wanted it.

The resulting ring looked strange, but it worked!  The fiber was now touching the polishing pad with nearly zero pressure.  I could sharpen that fiber to a point, if I wanted to. 
While we no longer use the idea ourselves, I occasionally see it referred to in scientific literature and other patents.

Tuesday, February 23, 2010


Usually, eaves. The overhanging lower edge of a roof.
I like eaves. Trouble is, the little farmhouse
I bought years ago didn't have them. To me, the house looked just plain ugly.  Step one in my home beautification effort was to add a pair of dormers.
That I left to a master carpenter.
After considerable thought and design, I decided to tackle the issue of eaves, or lack thereof.

My solution was to build prefabricated eaves, hoist them into place and bolt them on. Being more of a cabinetmaker than a carpenter, I made them far stronger than normal construction methods, with glued, screwed, and dadoed joints. I wanted them straight and true, and I wanted them to remain straight and true as I hoisted up the 16 foot long sections.
I made a simple rope hoist and raised them into position. Once in place, I used several strong bolts in each section. On most, I also replaced the roof sheathing with a piece that covered the extended roof.
While the eaves were still on the ground, I attached the aluminum soffit and prefabricated the rest of the aluminum cap.  That minimized the amount of work that needed to be done while on a ladder.   I hate ladders.

Much more attractive now!  Don't you agree?


Flying is not for everybody, but it may be for you.  You won't know until you try it.  

     My first plane ride was in this beautiful 1929 New Standard, base at Old Rhinebeck Aerodrome, which is about 50 miles up the Hudson River from New York City. That was about 25 years ago.  
This plane launched my flying hobby, which has provided many years of adventures.
 I learned to fly when I was single and had few responsibilities, which certainly helped.  It was much cheaper back then, too.  The Piper Tomahawks I rented cost only $35/hour, and that included fuel.  When I see the $100+ hourly cost  posted on local airports today, I cringe.  Another disadvantage new pilots have is far fewer airports than when I learned to fly.

A friend found a bargain 1972 Grumman Traveler, so we jointly bought it.  Both the airplane and the friendship are thriving, 20 years later.. 
Above: Our plane parked in front of Kutstown (Pennsylvania) Diner.  I would fly in once a week for breakfast, and to keep my skills sharp.
At Right: On approach to Kutstown runway.
One of the more challenging runways in the area, it was short and uneven, with a deep quarry and high rock pile at one end, a road, telephone poles and houses at the other.  Approach speed was critical, especially in a fast landing plane like a Grumman. 
Grummans are intolerant of wrong approach speeds.  A few MPH (80 and above) fast and you'll float the whole length of the runway.  Too slow and you get behind the power curve and close to the relatively high stall speed of 57 MPH.  Gusty or variable winds, along with the effects of the quarry, tightened the margin for error even more. The Grumman, along with runways like Kutstown, are great for keeping skill sharp.  
   Sadly, Kutstown closed last year, denying future pilots of a wonderful experience. 

Flying provides a perspective on the world that is priceless.  You simply can't buy experiences like the sheer terror joy of a well executed approach and landing at someplace like Kutstown.  As a bonus, you could treat yourself to a great Pennsylvania Dutch style breakfast.  Then return to your home airport 50 miles away, hop in your car and get to work on time.
  Along the way, treat your self to some fantastic views!  Above:  A view out of the cockpit.  Altitude:  1,200 feet.  Airspeed: 110MPH.  Worries:  None  :o)

Seemingly impossible day trips become possible. At Left:   Lake Placid, NY.  By car from PA?  Impossible.  By Grumman?  Just a couple of hours

 At Right:  Chicago, and the former Miegs Field. Another great airport new pilots will never know.
   Chicago is about 6 hours away. Not exactly a day trip, but an easy weekend trip.   On this trip, I wasn't stopping to Chicago, however. I was on my way home from a friends wedding in Appleton, Wisconsin.   Chicago merely provided some memorable views on a very memorable trip.

 While I miss flying as frequently as I used to, I've got enough experiences to last a lifetime.

Reynolds Solar Hot Water Heater

We purchased an old Reynolds Aluminum solar hot water heater from someone who removed it when they replaced their roof. It was not running but restorable. All major components were there and repairable except for the hot water tank. That was replaced with a standard 80 gallon electric hot water heater. Below: Front of panel removed from housing. Above: Rear of panel, with Jack standing guard.
The panels each had a pinhole leak, and tons of auto radiator stop leak inside the tubes. After flushing them out, I soldered the holes with aluminum solder. A tricky operation, since the melting point of the solder is just slightly lower than the aluminum panel. I used a torch to heat the panel while using an electric iron to melt the solder. It is a very strong repair.

Next came reassembly and installation on the roof. Not an easy task, as the panels weigh 200 pounds each! 90% of the weight is the 1/4" tempered glass window. The heat absorber is a clever design, made from one continuous piece of extruded aluminum. It is a shame Reynolds is no longer around.
Next step was installation of the pumps, heat exchanger, electronic controls and tank. I was not about to buy an expensive solar hot water tank when a standard Whirlpool 80 gallon electric heater is nearly as good. The main difference between the original Bradford-White and the Whirlpool is that the Bradford has 4 ports on top, while the Whirlpool has 3. While 4 ports is ideal to separate the heat exchanger from the water supply and outlet, it works fine with 3. A pipe tee in the inlet port provides the 4th port.

Below Left: Original Bradford tank.

On the Right: New Whirlpool tank with the heat exchanger, a Model 100 Crown Top, and pumps installed.

The Reynolds was a well engineered system with everything contained within the circular heat exchanger. It is very compact, yet not difficult to maintain.

 Below:  A picture of what is inside. The red pump on the left is the antifreeze pump, and has a cast iron body.  The gold pump is the fresh water pump, and is stainless steel.  They are both original Grundfos pumps, and are very well made. Behind the pumps is the expansion tank.  Above that is a sight-glass I added.  It lets me see the antifreeze and whether it is flowing.

The next step was to run 5/8" aluminum tubing from the basement to the roof. I ran it up the outside wall, hiding the insulated tubing inside aluminum rain spouts to match the house. It looks like an additional downspout and is not very noticeable.

The original aluminum fittings are of a type I have not seen anywhere else. The ones on my system were no longer usable, so I replaced them with aluminum AN style aircraft fittings.  I also bought the tubing from an aircraft supply house.   Here is a picture of an AN fitting:
 They are flare fittings, which of course requires the tube to be flared using a flaring tool.  Flare fittings are extremely reliable, which is why they are used on airplanes and critical things like auto brake lines.

 Even though the panels are a prominent feature on the rear of the house, they are nearly invisible from the front.
Was it worth the effort? Yes! On any sunny day, even in winter, the system can make 80 gallons of hot water. In the winter, the max temperature is 120°, while on summer days, the system can easily reach it's high limit setting of 160°. The system has been running nearly a year now and has supplied 65% of our hot water needs over that period. See chart below:

I record the tank temperatures every day, once in the morning and once in the evening. I also record the number of hours the system ran. From this I can calculate the percent contribution made by the solar heater. I will post an updated chart that shows the average contribution is now over 65%. The solar contribution does not look impressive in this chart because I started collecting data in November, just in time for the sun to reach it's minimum for the year. In July the system produced 85% of our hot water. It is not cold weather but cloudy days and weak sunshine that limit the system. I have observed the panels warming up to over 100°F only 1 1/2 hours after sunrise on mornings with the ambient temperature at 20°F and below.
Total cost for getting this system up and running was $1,000. It is saving us over $300/year at current rates, for a payback in about 3 years. We will appreciate it even more if energy cost rise as predicted.
I believe there are many of these systems sitting unused on roofs around the country. I missed out on getting another one by mere hours. I knew of a house with one of these systems and had considered stopping and asking them about it. Then one day, I went by and they were getting a new roof. Unfortunately, the panels were already scrapped! These well designed systems still have life in them and deserve to live a few years longer.

   UPDATE:  2010 was an even better year for the system, with a few months approaching 100% solar, and a yearly average of 76%.   I switched the backup source of hot water from propane to electric when my propane heater failed. I decided that the old fashioned tank style heater with a pilot light is too inefficient, and tank-less ones too expensive.  It was far more cost effective to install an inexpensive 60 gallon electric as the backup.  This has worked out well, for I still have monthly electric bills that are very low, if not zero. See my Solar Electric Upgrade post for charts on electricity production.

My propane usage dropped so low that my former propane company no longer wants my business.

UPDATE 2012:  I compiled 3 years worth of daily records and put them into a new post.
The system has now been operating for over 4 years, and has required nothing more than a gallon of antifreeze over that time.  I stopped taking daily records, figuring that 3 years worth was sufficient to prove the value of these systems.  Given my 3 year average of nearly 2,000 hours of operation, I estimate that it has nos surpassed 9,000 hours.  If these are original pumps, they may have 50,000 hours of total running time.
UPDATE 2014: The system has now been in operation over 5 years, and has paid for itself twice over.  The automotive heater hose that is used to connect the panels to the pipes failed. Their lifetime is much shorter in the severe conditions of a solar heater than it is in an automobile.  I recommend replacing them every four years.  The panels, pumps, and heat exchanger all look like they have many years of life left in them.

Mini Mill Modifications / Shumatech DRO

I have not yet modified my Mini Mill to the extent I have the lathe, but I have added the upgrades I consider most essential:  Belt Drive conversion, Gas Spring mod, and most importantly, a Shumatech DRO.  My previous experience with mills was on Bridgeports with DRO's and I really missed having one. Especially on the Harbor Freight Mini Mill, with it's non-standard dials and considerable backlash.
Fortunately, Scott Shumate had created the affordable Shumatech DRO-350.  Also fortunate, the Chinese developed amazingly cheap digital calipers with a data output port.  Put them together, and the hobby machinist can have a DRO that rivals commercial units for a fraction of the cost.

The Shumatech is a fun to assemble kit.  It takes about 4 hours to solder.  It is more than just a simple readout, with several built in functions like finding centers, drilling bolt hole circles and compensating for tool diameters.  It has made me a much better mini-machinist.
       Kits are available from Wildhorse Innovations in the USA and Model Engineers Digital Workshop in the UK.

Adding the scales is fairly easy. There are many ways of accomplishing this, and every installation I've seen is different. Here is my way. My Z axis mount is different than most, for the scale beam moves while the caliper head is stationary. I prefer stationary heads where possible, because the wires do not have to move with the head.
  While there are many ways to mount the scales, I recommend you attach the wires my way.  Out the bottom of the scale.  Why?  Three reasons:  It is a much stronger arrangement.  The bottom of the readout head is thick and makes a great strain relief.  Also, the wires run through the head, instead of exiting immediately.  The solder pads are fragile and having the extra wire inside reduces the chances for fatigue.  Finally, wires exiting the top are often in the way.  I could not have mounted my X scale so compactly if the wires exited the top.

My latest acquisition is a rotary table.  With a 5 inch lathe chuck attached using clamps of my own design, it has been a valuable addition.  I could not have made my lathe modification without it.
      This Rotary Table and many other fine accessories are available from Little Machine Shop.

My brackets.  This photo shows two which are complete, and two which still need holes drilled.  The brackets are a few thousands lower than the table surface when tightened. This ensures that the chuck is firmly clamped to the rotary table.  A centering plug may be fabricated to ensure exact centering, but since this is a 4 jaw independent chuck, I haven't bothered.  It is necessary to use round head cap screws because the heads are slightly inside the T slots.  Because of this, each screw can be turned only two turns at a time, making installation and removal a little slow.

Update:  For information on my solid column conversion, click here.
For info on upgrading to a larger table, click here.

Model Railroad Display Table

 My brother Stan is an avid model railroader and a member of the National Association of S Gaugers. (NASG)  Recently, one of his good friends, Wally, had to retire to live with his son and sell his home of 50 years, where he and his wife raised their family.  During those 50 years, Wally slowly built an elaborate model railroad in his basement.  Sadly, the railroad could not be salvaged and had to be demolished before the house was sold.  Stan decided to preserve a piece of it in the form of a tabletop display. My job was to make the table.

I had several requirements for this table. First, it had to accommodate the centerpiece of the display, Wally's 40 year old hand built coal tower.  Then I decided that I wanted to give Wally as much flexibility as possible, not knowing just how much room he has in his new quarters. So, I made the table convertible.  The display could be either on top, or below with a glass top.  That way he could use it as a conventional table, if need be.

Since the table was merely an open frame, and corner braces would be unattractive, I had to design very strong joints.
     I began by making the upper and lower frames, using dovetailed joints. The corners were also notched using a dado blade, as were the legs.
This created a strong locking joint that was very stiff in all directions.  In fact, it was reasonably sturdy with no glue at all.  That is exactly what I needed.  I did not want to rely on the glue for strength.  Neither did I want to resort to nails or screws.  Instead, 2 short dowels in each corner lock the legs in place.  Another reason it had to be strong is that it needs to survive a trip from Pennsylvania to Illinois.

The completed table.  It is made from 40 year old clear pine that Wally had in his basement.  Years ago, he turned his basement into a recreation room with pine paneling. He had some beautiful boards left over.  12 feet long, 12 inches wide and nice, tight grain.

Try to find something like that today.
I'm sure Wally will appreciate it even more, knowing it is made out of his wood. The boards had a distinctive stripe that I matched up around the sides.  I like the effect.

All that is needed now is to carefully box up the buildings and complete the shipping crate.

 I hope Wally, who is now 90, will enjoy it for many years.