1907 Martin's Vibroplex

Below are numerous pictures of this 1907 Martin's Vibroplex. Its an odd example of a key from that time period. The serial number on the damper indicates its from 1907.

I've had this 1907 Martin's Vibroplex for a while and finally got around to testing it this week. When I found the key it was filthy -- with a layer of some sort of scum like it was stored near a coal burning stove for a long time. It was from an Indiana estate sale. I can recall seeing another example of this type of key a long time ago but I didnt save the picture. If anyone owns a key like this one or has seen one like it, I would appreciate it if you let me know about it.

If you've seen an example of this key or own one like it, contact me at w7is@aol.com . Thanks

In the below picture you can see the shorting levers tensioning spring has lost its tension and is pointing up. So it needs to be retensioned.

Another odd thing is the base is painted with a simulated leather effect. It appears to be the original surface paint. When I found the key, the feet on the bottom fell apart in my fingers when I tried to clean them. So I fitted they key with some self adhesive vinyl types that I like to use on keys. As you can see in the below pictures.

The finger pieces are also odd. Made out of what appears to be heavy Bakelite. They feel a little heavy and detract from the touch of the finger pieces for high speed code.

The last odd thing is the size. Its a mid sized key, slightly bigger than a Blue Racer.

Here is a picture showing a Mod X, with the 1907 in the middle and a 1919 Blue Racer.

Then main spring is fairly weak but it produces very good code with a light touch. The dots it makes are unlike any other key I've used --- with a distinct dot pattern. The only problem I had with the key is the main spring was loose in the dot arm. But it was no problem tightening the rivets.

Frank W7is

Les Logan 515 Improvements

The Les Logan 515 speed key is capable of producing some of the best code ever generated by a speed key. (at least on the two examples I have of the key) Below are some suggestions for obtaining the best performance from your key.

I've owned a number of Les Logan 515 speed keys. I bought one in 1960 from C&G Electronics in Tacoma, Wa. Then cut the dot arm off of it and converted it be used as an electronic keyer. After using the modified Les Logan as a keyer paddle for four years in the Navy, I disgarded it. Later I came across another model 515 and tried to adj it for proper code. But the key had a number of problems. Someone had tried to cut pieces of rubber off two of the rubber feet due it wobbled on the desk. Les Logan never learned the lesson from Vibroplex that 3 rubber feet are self leveling and cant wobble. The four feet are riveted on so are not easy to change out. So I used three self adhesive vinyl feet which are taller than the original feet. As shown in the below picture. It took less than 60 seconds to install the 3 new vinyl feet. Then the key sits level on the desk ---- without wobble :-)

The next thing I noticed wrong was the dot coil spring on the left side adjustment stop screw had too much spring tension. The spring was so strong that there was many times more spring dot tension and it couldnt be adjusted lower. So I replaced the spring with a lighter one. Then I noticed the damper wheel flopped around too much. The damper wheel is riveted into the center of the damper post. The key had a problem with dot stutter so I decided to remove the damper wheel and replace it with 3m double backed tape placed on edge. The rivet that holds the damper wheel in place has twisted threads on it. So in order to remove the rivet you can use a knife blade to both pry up on the rivet and at the same time turn it CCW. Its not easy to get the rivet out but it can be done. I used some 3M double backed tape that's designed to hold items to a wall. And I had to double up the doubled back tape to fully fit inside the damper post. As shown in the below picture. Also pictured is a brass speed control. More on that later.

The pictures below show how the 3m double backed tape was used in place of the damper wheel. The 3M material instantly dampens the dot arm and prevents dot stutter.

Below are pictured the parts I removed from the key. The damper wheel, its rivet and the dot coil spring that has too much spring tension. Its made out of spring material many times heavier than it should have been. I had some spring material in the junk box that worked just fine but you could also use a spring from such things as a ball point pen perhaps. This particular key had so much dot side coil spring tension, there is no way it would have ever been used. Which would explain why the key was in like new condition :-)

Below is a picture of the brass speed control that I added. I placed the original weight that was on the key onto the vertical upright on the speed control and then there is a 3oz brass ball weight on the vertical upright at the end. With those two weights, sliding the assembly back and forth on the dot provide a speed range of around 18 to 28wpm. If the end weight is removed the speed range increases to around 35wpm plus.

If you have a Les Logan that needs new feet I can provide you both the speed control and the rubber feet & 3m material for a very reasonable cost. Contact me at extendadot@aol.com

The code the model 515 produces (after the above modifications) is some of the best code ever produced by a speed key. At least on the two examples I have here. Producing very high quality crisp dots from low to high speed.

Frank W7IS

Testing Lionel J36 WW2 speed keys

Below is one of those rare Lionel J36 keys that has its plastic name plate intact.
Its serial number 28548. As the plastic label broke up, someone had the forethought to glue it back in place.



On the below key, the label is a reproduction.
After I finished fine tuning the above J36, I gave the key to an old Navy buddy who is trying to get his code speed up after being off the air for a number of years. Sliding the weight tube back and forth produces dots from 14 to 22 wpm using the type of end weights shown. But it requires up to 3 inches of free space behind the key as it more than doubles the length of the dot arm at the slow speed position.

I've had 2 Lionel J36 keys sitting here collecting dust for many years. I had briefly tested them to see what quality of code they could produce and was very disappointed. One key could only make 3 or 4 dots and on that one I assumed it needed a new main spring. And the other key had a tendency to produce flaky inconsistent code. So I set them aside until I had a few idle winter days to figure it out.

Well, that was 7 years ago :-)

As I took time out to test the key with the weak main spring, I tore it apart and then reassembled it. And it then started making decent dots. So I fine tuned the key and equipped it with a new speed control design that I had been experimenting with. When I came back to the key the next day it was again producing only 3 or 4 dots. The only thing I had done was take the key apart for inspection and reassemble it. So I tore it apart a second time and this time I noticed the short rod that holds the dot side coil spring had too much play in the dot arm frame. They had drilled the hole for the small rod too large. So I took up the slack by using a punch in three places along the frame. Now the key produces consistantly good dots. The main spring is a little weak but it will produce a string of around 15 dots and thats good enough.

So then I tore apart the other Lionel J36 and it also had the play in the arm that that supports the dot side coil spring. I took the slack out of its mounting in the same way and now both keys produce consistantly good dots. Although the second key will produce a string of over 30 dots. So has a more robust main spring.

Below is a picture of the dot arm coil spring and the round arm it attaches too.
Placing a coil spring against a thin metal rod is mechancially faulty to begin with.
Les Logan solved the problem on his keys by placing the dot side coil spring around the left side stop screw. I've never cared for the Vibroplex Lightning method where they support the dot side coil spring against a thin metal rod. A very lame way to secure a spring.


On both keys there was a dot stutter problem. So I locked the damper wheel into position and applied some 3M double backed tape around the wheel. The dot arm now contacts the 3M double backed tape rather than damping directly to the metal wheel. The keys still produce a little dot stutter but not nearly as bad.


While trying to find better ways to tame the dots on Lightning style keys, I have found that a design using a sliding weight tube works very well.
The hollow brass tube has just the right amount of resiliency to produce crisp dots at all speed ranges when used with a light weight aluminum body. As shown on the above J36 keys.

I have more info on other keys at my other postings on http://www.extendadot.com/


Frank W7IS SKCC #2346