Extendadot Speed Control



 Below are two Vibroplex Deluxe Jeweled bearing speed keys equipped with the Extendadot Trombone speed control.   One made of brass and the other made of stainless steel.   It allows sliding the speed control weight beyond the end of the key by several inches in order to slow down the dots.  For the really slow speeds it can have a weight at the both front and rear on the Nylon uprights.   The front nylon upright tightens the trombone down on the dot arm.   Anything you place on the dot arm has to be very secure or it will kill the dots.   The full sized gold plated Vibroplex Presentation is on the left and the chrome plated Vibroplex  blue racer is on the right.  There weren't very many blue racer deluxe keys made and this one is from 1947.   In order to use the Trombone speed control, all you do is slide it onto the dot arm and adjust the left and right stop screws for the slightly larger diameter of the dot arm.  

And attached is a youtube video I made  of a 1906 Vibroplex Deluxe using the Extendadot with an extension for lower speeds.  Those early Vibroplex's had extra long main springs, which causes them to be critical to adjust for best code.. as the long main springs can cause the dot arm to flop around more on the damper.    Frank W7IS  

 


Popular posts from this blog

Vertical Placement of Vibroplex Style Speed Keys

Image
I've been using speed keys since 1958 but I've never experimented with trying to place them vertically until recently.   The articulated damper assembly of Vibroplex Original keys are designed to be used horizontally.   So it requires a slight modification for vertical operation. Which takes only a few minutes as below:  1.  Lock the articulated damper arm in place by wrapping string or fishing line around the bottom of the damper assembly and around the articulated arm so that the articulated arm is held firmly in place. 2.  Lock the damper ring in place by securing it with its screw. 3.  Place a rubber O ring of the proper size around the damper wheel or replace the metal damper wheel with a rubber wheel of the same size.  Hardware stores have rubber wheels of the type used in faucet repair and you should be able to find the correct diameter needed. See the below picture of the easily modified damper with the rubber O ring. Now, all the dampening of the dot arm will ta
Read more

Speed Key Adjustment Procedures

Image
Over the past 115 years there have been large numbers of different type Speed Keys available.  Some of them are more difficult to adjust for perfect code with a 3 to 1 dot/dash ratio.   But most share the basically the same senario of adjustments-- (Except for the Vibroplex Model X--  The Model X key can be very difficult to adjust due it uses the same contact for both dots and dashes}.    The first speed key I tried adjusting took what seemed like forever until I had it making  reasonably decent code.   But after using speed keys since the 1950's, I can now adjust a speed key for perfect code just by watching and listening to the make and break of the dot contacts.  The secret to adjusting speed keys for perfect code is to place an Analog VOM (on Ohms X1 scale) across keys wire nuts and adjust the spacing of the dot contact for a 50% deflection of the Analog VOM while making dots.   It has to be an Analog VOM using the X1 ohms scale..  (Not a digital VOM).  It will take tweaking o
Read more