Extendadot

Evolution of the --- Dot Speed Control

2009-01-13T05:00:00Z

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Making a speed control is not a difficult process.  I have provided detailed info below on how you can make your own round dot arm trombone speed control using off the shelf hollow tubing.   You can even make one if you dont own a drill press. Provided your handy with basic hand tools and have a decent vise with a V grove for holding tubing.    www.onlinemetals.com now has two outlets in the US. They are the single source for anything you might need for metals.

The concept for the speed controls came about after many years of frustration trying to slow down the dots on speed keys.  The idea was to attempt to distribute the weight along the dot arm equally. To balance the dot arm so that it can produce higher quality dots.  And to also provide a way to extend part of the weight beyond the end of the key. Extending the weight further behind the key allows lighter weights to be used.   If you load up the dot arm with heavy weights in an attempt to slow down the dots, the key can become clunky and awkward to send with.

It evolved into three experimental designs.

1. For the round dot arm, a hollow tube that slips over the round dot arm and acts as a trombone to allow the end weight to extend several inches beyond the rear of the key for slow speeds.
2. For the flat dot arm, an aluminum body with a slot milled to fit over the flat dot arm.  A weight rod slides back and forth in the aluminum body to vary the speed.
3. For the larger round dot arms on the McElroy/TAC keys, an aluminum body that fits over the dot arm -- with a weight rod that slides back and forth in the aluminum body to vary the speed.

Pictured below from top to bottom:

1. Top picture shows the experimental Mac/Tac speed control using a nickel silver weight rod that slips inside a larger trombone section. The trombone section then slides inside the aluminum body for a dual slide.   Which can extend the weight up to 5 inches behind the key if desired.   Its shown with two small brass weights. Having a weight at the front and rear balances the design as the body slides back and forth on the dot arm.    Its fairly easy to duplicate on a drill press.

2. Pictured second from the top -- is the flat dot arm version with its sliding weight tube. You can see the milled slot for attaching to the flat dot arm.   Its not easy to duplicate but it can be done using a "V" block to hold the aluminum body as the slot is milled. Then the V block is transfered to the drill press for drilling the various holes.   And finally the V block is moved to a manual tapping device for the hole tapping.

3. Pictured at the bottom is the round dot arm hollow tube and as shown -- there is a weight at the front and rear of the device to help keep it in balance for best quality dots.   Its easy to duplicate using off the shelf hollow tubing.    The item can be drilled on the drill press and then the two holes tapped to accept the 8-32 nylon thumb screws.   Fairly easy to duplicate with items usually found in a home shop.

What follows is detailed info on how to make your own trombone speed control as shown in the bottom picture above:

1. The round seamless tubing can be obtained from www.onlinemetals.com
      You will need the .025 diameter by .03 wall brass or aluminum tubing and make a ferrule out of .375 dia by .065 wall tubing.    Cut off a small length of the ferrule material and ream it out slightly with a size D drill bit.   A complete 115 piece set of drill bits can be obtained from http://www.cdcotools.com/index.php for a very reasonable cost.    Cut a length of .025 tubing 3" long and attach the ferrule to one end by first drilling out the ferrule with the size D drill bit using a power hand drill.   It should be a very snug fit over the .025 tubing -- where you have to tap it on with a hammer. Taking care to not bend the tubing.  The ferrule needs to be very tight snug fit to the tubing.   It may take you several trys to get one thats correct. Reaming out the ferrule end with a larger drill bit helps to start the ferrule onto the tubing. The drill press vise I like to use is the grizzly.com H7575. Its the perfect size and has accurate V groves for holding tubing.    The tubing with the ferrule can then be placed in the V grove of a drill press vise and using a 1/8" drill bit,  drill a hole through the center of the ferrule and immediately place an 8/32 tap in the drill press chuck and tap the hole by turning the drill press chuck by hand.   That will keep the tap running straight in the hole.    Then do the same for the other end of the tubing.     I use a 1" long 8-32 nylon thumb screw in the ferrule as that extra length allows attaching a standard small weight to the thumb screw.   If your local hardware store dosnt have the nylon thumb screws you can obtain them from McMaster.com for a reasonable cost.     If your fairly good around shop tools and have a decent drill press with a V groved drill press vise, you can make your own hollow weight tube fairly easily.      Grizzly.com has their small milling machine at a reduced price in 2010 and its an excellent value.    If you have a drill press equipped with an X-Y cross slide table from Grizzly, it allows you to move the vise back and forth easily.  The grizzly G8750 X-Y compound slide table is 63 lbs and works really well with a drill press.     It may take several attempts to make a decent speed control before you have one thats acceptable.    The trick is to tap the 8-32 holes at front and rear of the speed control all the way through both sides.  That way you dont need a special bottoming tap.     The below picture shows the Grizzly H7575 drill press vise on the G8750 63 lb compound slide table.   I equipped the drill press with a keyless chuck from CDCO Tools.   Which allows fast changes between a center drill and the drill bits.  All the holes should be started with a center drill.    CDCO tools provides an excellent set of center drills.   The below picture shows a V block in the vise that holds the item to be drilled. I use V blocks whenever possible as you can remove the V block and place it back on the vise  while retaining the same position of the work piece.   The vise jaws were made to run parallel with the drill bit chuck by setting it up with a magnetic dial indicator.

As far as the flat dot arm on the Lightning and Champion keys, its very easy to make a speed control.
The rectangular weights for the flat dot arm have 8-32 threads all the way to the bottom. All you need do is attach the same 1/4" hollow tube to the bottom of your existing weight using a short 8-32 screw.    Use a file to shave off half of the 1/4" tube where it contacts the bottom of the weight so that it fits snuggly on the bottom of the rectangular weight.     So in no time at all you can both a round dot arm and a flat dot arm key equipped with your home made speed control.    You could even make them if you dont own a drill press if you can live with the holes not being perfectly straight.

You can use 000 steel wool to burnish the surface and it will give the brass a nice burnished appearance.    Or polish them by placing the tubing in a power hand drill and use standard polishing compound. Coat the finished speed control with Krylon Crystal Clear coat to preserve the surface.

If you desire further info you can reach me via email:   extendadot@gmail.com

Frank W7is

Dot Stutter and How to Manage it

2009-01-12T08:00:00Z

Dot stutter occures when your key produces an extra half dot at times.
Some keys suffer from dot stutter more than others. On keys that have little or no dot stutter, you will find that the dot arm dosnt flop around on the damper wheel. As the reason for dot stutter is the movement of dot arm as its being dampened. When your dot arm flops around on the damper, it just stands to reason it could add an additional half dot at times. & If you load up your dot arm with more weights in order to slow it down, you will notice dot stutter gets worse as the heavier dot arm causes the damper to move around more.
The best way to prevent Dot Stutter is to lock the damper in position and place 3M double backed tape around the damper wheel.  A side effect of using the 3M tape is the key will then become almost silent as the 3m material absorbs all the dot arm motion. Another side effect of the 3m material is you be able to use a narrower dot contact spacing for sending higher speed code.

There are a number of ways to help prevent dot stutter:
A. Using a wider dot contact spacing
B. Increase the dot side coil return tension
C. Unscrew the right side stop screw further to allow the dot arm to contact the damper wheel more securely.
D. Place 3M double backed tape (on edge) around the damper wheel.
Using the 3m double backed tape fix provides the best defense against dot stutter.

1. Use a wider dot contact spacing. The wider the dot contact spacing, the less a problem you will have with dot stutter.

2. Sometimes increasing the dot coil return tension will help -- but not on all keys. Each key can have different keying characteristics due to the wide variation in main spring stiffness.
3. Another thing that can help is to allow the dot arm to hit the damper more securely. You can accomplish this by backing off the right side stop screw until the dot rod just touches the damper, then back off the stop screw another quarter turn or more. So that the dot rod hits the damper wheel more securely and dosnt allow it to flop around as much. Using 3m double backed tape around the damper wheel helps even more -- as in the next step.
4. You can find ways to dampen the dot arm more effectively. Such as placing 3m double backed tape around the damper wheel. As long as the dot arm contacts the 3m tape instead of the metal damper wheel, the 3m tape will almost instantly dampen the movement of the dot arm. I've found quite a few speed keys that could never be adjusted for decent code without using the 3M double backed tape fix. So today I use the 3M damping material on all the speed keys.
The type of 3m double backed tape is the Scotch 3M #314 used as mounting tape to hold items to walls. But any type of the 3m double backed tape would probably work just as well.

1. First,the articulated damper arm needs to be locked in position using a rubber band, string, dental floss etc.. On this key I used dental floss. The thin dental floss can slip under the damper post and become almost invisible. As shown in the below picture.
2. After you lock the damper arm in position with dental floss, lock the damper wheel by tightening its center screw. Then place some 3m double backed tape onto the damper wheel so that the tape is slightly larger diameter than the metal wheel. The side that contacts the dot arm can be cut flat so that more surface area contacts the dot arm.
With the 3M double backed tape in place, all the damping will take place on the surface of the 3m tape. The 3m double backed tape will almost instantly dampen the dot arm. Thus preventing dot stutter.   It will also reduce the amount of noise the key makes. A worthwhile advantage to using the 3M material on the damper wheel, is you can then unscrew the right stop screw further in order to allow the dot arm to contact the 3m material more securely. Which helps to prevent dot stutter by not allowing the dot arm any chance to flop around on the 3m material.

Once the 3M material is placed around the damper wheel, you will then be able to use a much narrower spacing for the dot contact. And that will allow using the key with a lighter touch. And a lighter touch allows for producing higher quality high speed code. So the 3M tape fix has a lot advantages. You can easily remove the 3m tape later if desired. And a person could even paint the white 3m material with silver paint to match the nickel plated piece parts.

1926 Vibroplex Custom Ivory Key

2009-01-11T19:53:00Z

I placed two small Vibroplex weights on the vertical uprights as shown in the picture below on this aluminum speed control.    In this configuration the dot arm is balanced along its full length as the weight is distributed equally.   The uprights are made of 1" nylon 8-32 threaded scews. Set up this way, the key produces such great code its every bit as good as machine generated.

This custom 1926 Vibroplex Original with Ivory finger pieces has a dot arm assembly taken off an earlier key around 1907.   Those early Martin Vibroplex keys had much longer main springs than later keys.    I equipped it with an aluminum speed control due to the keys light touch.

In the slow speed position, the speed control extends the end weight a considerable distance beyond the end of the key.    The pendulum motion of the longer dot arm produces higher quality low speed dots and at the high speed position it distributes the weight more evenly across the dot arm. Which produces higher quality high speed dots.
Its a much better way to slow the dots down compared to using extra weights on the dot arm.    If you simply pack the dot arm with weights to slow it down, it just makes the key clunky and awkward to send with.

1917 Vibroplex with Aluminum speed conrol

2009-01-02T04:00:00Z

Vibroplex advertising from back in the 1917 era indicated they provided a service to take in trade older keys needing refurbishing. This 1917 key has definitely been refurbished. It has a dot arm assembly of the type used in 1907. And the base of the key was once nickel plated. The keys made around 1907 had fairly light main springs. This key has a very light touch and it works best when equipped with a light weight aluminum speed control. Due to its tendancy to be easy to slow down, I have it equipped with an aluminum end weight. Its quite a bit of history with piece parts taken off earlier keys.
I suspect that Vibroplex used a number of piece parts off many other keys in their attempt to put one key in good working condition. This key is a real kick in the pants to use on the ham bands :-)

The Great Les Logan Deluxe 501 "T" handle bug

2009-01-01T13:00:00Z

I've owned a number of the Les Logan "T" handle speed keys. The Les Logan 501 Deluxe "T" handle key pictured above was the only speed key ever produced that had an easy to replace dot and dash contact post. The large coin silver contact on the post simply unscrews and can be replaced in just a few seconds. If you ever have a chance to pick up a Les Logan Deluxe Chrome model 501, you wont be sorry. Les Logan didnt place serial numbers on his keys although on a few keys he used a manufacturer code -- if you can figure out what it means. So there is no way to tell when a certain key was manufactured. He sold the Speed X brand to EJ Johnson around 1947. Johnson used up the supply of the "T" handle bases he inherited from Les Logan. When those were gone, Johnson changed the design. And that was the end of the "T" handle bugs. The only situation you might run into is the adjuster knobs can seize up in the pot metal casting for the "T" handle. The knurled knobs can get scored up as you try the free them. You can run an 8-32 tap through the holes and use anti-seize compound on them. Which should keep it from seizing up for many years. Towards the end of production of the Speed X brand Speed Keys in 1972, Johnson let the quality control slide quite a bit. Some of those small based Johnson keys towards the end of production were of marginal quality. Pictured above shows an aluminum speed control on this great model 501. The handle made it easier to carry the key around from different operating positions. This particular Deluxe 501 shows no signs it was ever used. It still has the two screws that were used to secure it to the bottom of the shipping box. This Deluxe was dropped off at a Goodwill store. So there is no way to find out where its been since 1947. The other Deluxe 501 key I came across was new in the box and never used. It was left at a church rummage sale of all places. Another mystery as why it was never used. Both of them are very fine keys and make great code.

Below is the picture of a new in the box Deluxe 501. They shipped it screwed down to a heavy cardboard product.

At one time I enjoyed using the T handle Les Logans so much I placed 3 model 500 black crinkle bases at the operating positition. Each one was adjusted for a different speed and I used them in quite a few CW contests.
I made articulated finger pieces so the keys were easier to key.

In this case you wood have to say they are More Logans --- as shown below :-)

Vibroplex Mod X Speed Control and Adjustment Procedure

2009-01-01T09:32:00Z

                  Adjustment Procedure for the Mod X Vibroplex
                                      By Frank Geisler.

As far as I know, nothing has ever been written on how to properly adjust a Mod X Vibroplex. I hope you find the below adjustment procedure helpful.

Following the above diagram numbering:

#1 Dash Side Spring Tension, turning in -- increases dash tension.
#2 Dash Lever, dash lever pushes on leaf spring contact to produce a dash.
#3 Dash Lever Contact Spacing Adj Screw, set so that at idle the dash lever isnt touching the leaf spring contact.   About 1/64" spacing.
#4 Dot/Dash arm left stop screw
#5 Dot/Dash arm right stop screw
#6 Dot Side Spring Tension Adj Screw.
#7 Dot/Dash Contact Post (adjusts the spacing to the contact leaf spring)

A. Set Right Stop Screw (5) so that the dot/dash arm is along the centerline of key.
B. Set the damper wheel so it just touches the dot/dash arm.
C. Set the Dash lever contact spacing adj screw (3) so that the dash lever has about
      1/64" clearance from the leaf spring contact.
D. Set the Left Stop screw (4) so that the leaf spring contact has a travel of about
     1/32" or more to the dot/dash contact post.
E. Set the Dash Side Spring Tension (1) so that the Dash Lever (2) has enough
tension to push it away from the leaf spring contact.    You will fine tune this tension later. The more spring tension you can tolerate, the better.
F. Set the dot side spring tension adj screw (6) so that the dot/dash arm has proper
tension against the damper wheel. You will fine tune this spring tension later --so that the key produces proper high quality dots. The more tension you can tolerate, the better.

The adjustment procedure for the Mod X is more complicated than other keys due to the way all the adjustments interact. The spacing between the leaf spring contact to both the dash arm and the contact post is critical to produce dots with no stutter.   On one of the Mod X keys I found someone had replaced the leaf spring with a heavier more rigid leaf spring.    The long leaf spring spring tension is a big part of the dash side tension. So the modified Mod X with the very stiff leaf spring was incapable of producing good code.   To reduce the leaf spring tension I cut off half of its surface area.   That key now produces quality code. Dot stutter is when you occasionally get an unwanted half dot.  "Dot stutter is the bain of speed keys" (((
Send code with the key and experiment with the contact spacing that produces the best code. There is a very narrow range of adjustments that end up producing high quality code.  Fine tuning the spring tension adjustments for best code.
If you dont have the adjustments set up correctly, the key can become very awkward to send with.

While I was fine tuning a 1914 Mod X, I had to place some 3M double backed tape around the damper wheel to improve the damping.    I wasnt able to produce stutter free code without using the 3M material to help damper the dot/dash arm motion. The below picture shows the 3m material around the damper wheel and I also equipped it with a speed control weight arm to allow better control over the dot speed.   Before placing the 3m double backed tape over the damper wheel, lock the wheel in position by tightening the lock nut at the center of the wheel. As shown in the below picture.
The idea is for the 3M material to absorb the motion of the dot/dash arm.   I've tried many other types of materials such as cork, vinyl, sponge rubber etc.. But none of them worked as well as the 3m material placed on end.


Here is a picture of this 1914 Mod X in its original Oak wooden carrying box. The box is dovetail contruction and has a fitted cover that slides in place.   This particular Mod X has had very little use and has been well taken care of over its life. No sign of rust and the decal is still in good shape.

If you have any questions about the Mod X, feel free to contact me
at w7is@aol.com .
I own a number of Mod X keys dating from 1911 until the production ended in 1920.
When they came out with the new and improved Mod X. I personally didnt find it much of an improvement and that might be why production was halted around 1921. Although around the same time Vibroplex changed the design of the Original style keys to a bent lug pivot rather than the pinned pivot dash lever.

Frank W7IS