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