[CW] Bug differences affecting Speed

[D.J.J. Ring, Jr.]

The oldest of the Vibroplex Originals had thinner springs which implies the
springs were weaker and thus slower.

K4MSG says in his eham review of Alberto Frattini's J-36 semiautomatic key:

Much lower minimum speed range than my Lionel J-36. I did a rough
measurement and it’s in the neighborhood of 15 wpm minimum with a “high
end” capability well above 35 wpm. This is due to the much-thinner
mainspring, i.e., 0.0123” on the Frattini J36 as compared to 0.0165” on my
1944 Lionel J-36.

KC4TXR observes Vibroplex bugs made since around January 2001 have a
thinner mainspring than those made in 1999, he replaced the mainspring in
his 1999 Vibroplex Original with Blue Racer finish and reports that with
the weights he has and the longer pendulum length used in all Originals he
achieved a slow speed of 16 to 18 wpm with the thinner mainspring used
after 1999.

I don't know what Vibroplex Originals use now. The thinness and length of
the mainspring make for slower dots as does more weight on the vibrator
rod, or any devices that add length to the vibrator rod such as Franklin
Geisel, W7IS produced under the "extendadot" name as shown here
https://youtu.be/bSexPcF90VA?si=ACt7tKUAW-ZoP1iK

Perhaps a search of the archives of morsecode and cw email lists on qsl.net
will show historical discussions on mainspring thinness measurements of
various Vibroplex semiautomatic keys throughout the years.

73
DR









On Sat, Jun 8, 2024, 8:35 PM Richard Knoppow <1oldlens1 at ix.netcom.com>
wrote:

>     I am not sure which list the recent discussion of bug differences
> was in. Can't find it so will post here as a likely place.
>     Part of the discussion was of the main spring, i.e. the spring on
> which the pendulum oscillates. I found on three or four they were about
> the same in dimensions and thickness. However, I got curious about the
> length of the pendulum from what I will call the hinge point of the
> spring to the damper contact and the maximum length from the hinge to
> the weight or weights. I am calling the end of the spring that is
> clamped to the non-moving lever arm the hinge point, since that seems to
> be where the movement originates. Well, found the distance was not the
> same. The Original and my Bunnell J-36, of the "Flash Key" type are just
> about the same at 3.3 inches while the Lionel J-36 is 3.6 inches. Now,
> the curious thing is that the Bunnell key is significantly faster than
> the other two. The Bunnell key is not exactly a Flash key but bears some
> similarity having a lower frame but has a flat pendulum like the
> Lightening Bug and Lionel J-36.  The slowest of these three is the
> Original but its also by far the oldest, 1920, and the spring likely is
> fatigued. It goes down to about 20 WPM. The Lionel J-36 goes down to
> maybe 25 WPM and the Bunnell J-36 to about 30 WPM. I have a couple of
> other Originals, much newer, which go down to maybe 25 WPM and I suspect
> this is the design intent. In any case I will make more measurements.
> While the distances look the same on casual examination they are not.
> How much, if any, effect this has on speed is yet to be determined.
>     I hope this is of some interest.
>     I used a vernier caliper of good quality to make the measurements.
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> SKCC 19998
> ______________________________________________________________
> CW mailing list
> Home: http://mailman.qth.net/mailman/listinfo/cw
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:CW at mailman.qth.net
> CW List ARCHIVES: http://mailman.qth.net/pipermail/cw/
> Unsubcribe send email to
> cw-unsubscribe at mailman.qth.net
> Subscribe send email to cw-subscribe at mailman.qth.net
> Support this email list: http://www.qsl.net/donate.html
>
> =30=
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/cw/attachments/20240608/2566addc/attachment.html>