[CW] Iambic contact gap settings

Wed, 19 Nov 2003 17:53:18 -0500

The reason that the vertical play is an adjustment and not just a limiting
factor is that some keys - notably the Vibroplex have an adjustment for
this.  This adjustment primarily affects the vertical play in the key, but
as the socket comes out of the cup in the pivot, it introduces horizontal
play also.  This can result in contact misalignment and general "slop" in
the key!

73

DR
----- Original Message -----
From: "David J. Ring, Jr." <[email protected]>
To: "Bill Brannick" <[email protected]>; <[email protected]>
Sent: Wednesday, November 19, 2003 5:46 PM
Subject: Re: [CW] Iambic contact gap settings

> Actually the "close spacing" is a critical adjustment of three things:
>
> 1.)    Minimum contact spacing so that the contact does NOT false.
> 2.)    Lever throw.
> 3.)    Vertical play and horizontal play of the pivot of the key.
>
> If the levers were arranged so that a very small movement of the lever
made
> a huge movement of the contacts, most people would say that the key is
> adjusted for close spacing.
>
> Unfortunately, the mechanical tollerances and size of the key are the
> limiting factors!
>
> More precise tollerances and avoidance of wiggle in any direction, lack of
> "stickiness" in the bearing (or lack of one) will enable the contact
spacing
> to be minimized.  If there is too much play, the contacts won't align
> consistantly, which will mean that sometimes they will contact, and
> sometimes they won't for a given movement.  If the ability of the pivot to
> move is not consistant, or is restricted, the lever won't move freely and
> consistantly.
>
> A longer lever from the finger piece to the fulcrum of the key will enable
a
> more sensitive throw - It is easier to close the gap with a certain
pressure
> applied.  The mass of the key also changes the way the key behaves.
>
> I am not a mechincal engineer, but I know there is relationship to key
mass
> on the lever.  Large lever keys "seem" easier to use and to have closer
> contacts, however one key with a very short lever - the WBL V22L - has
> perhaps the best touch for high speed.  The lever is so small.  But I
guess
> if you consider the whole paddle in determining the lever size, the lever
is
> very long on the fulcrum to the paddle as opposed to the fulcrum to the
> contact points.
>
> The mass of the lever in this key is very tiny - just a small right angle
> shaped piece of steel.
>
> 73
>
> David Ring
> N1EA
>
>
>
>
> ----- Original Message -----
> From: "Bill Brannick" <[email protected]>
> To: "Ken Lotts" <[email protected]>; <[email protected]>
> Sent: Wednesday, November 19, 2003 1:54 PM
> Subject: Re: [CW] Iambic contact gap settings
>
>
> > At 04:22 11/19/2003, Ken Lotts wrote:
> > >.  but now I am wondering how many
> > >old timers set their contacts (on their iambic paddles) out a ways..
As
> a
> > >side note, I suspect the overall paddle design might have a lot to do
> with
> > >how far the gap setting might end up at because of lever action (paddle
> arm
> > >travel).
> >
> > I had a Bencher for a number of years before switching to one of  K8RA's
> > fine keys.
> > Perhaps some would call it too close, but I have always used a single
> > plastic coated playing card to set the gap.  Obviously far less then
> 1/16".
> >
> > Bill, W6WLB
> >
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> >
>
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