[CW] Semi-Automatic Bug adjustment

[David J. Ring, Jr.]

I received a copy of an article which I assume ran in RSGB magazine as it
was sent to me from a station in the United Kingdom.

I hope this excellent article is of some benefit to you.

The only comment that I have is that I've used a drop "teflon" lube at the
pivot point, also lock lubricating graphite oil gives good results - and the
new synthetic bicycle lubes are also excellent.  A drop of WD-20 would work
well too, but I wouldn't be surprised if it evaporated quickly.

Here is the article.

73

DR

CLEANING AND ADJUSTING SEMI-AUTOMATIC ('BUG') KEYS

'DOC' WESCOMBE-DOWN, VK5HY/VK4CMY, believes that a straight hand keys and
bug-keys are the only true Morse senders around - the electronic keyers and
keyboard Morse generators have dehumanised the basic skill of Morse code,
which is the making and spacing of characters, numbers
and symbols correctly by hand".

While I guess that this is today a minority opinion it is true that
"seasoned CW operators take pride in the upkeep and adjustment of both
straight and bug keys, this never being seen as a chore but the key element
in the formation of Morse." In "Amateur Radio", July 1994,
pp l1-12, VK5HY provides detailed innformation on maintaining and adjusting
semi-automatic keys, and the following information has been  abstracted from
his article:

He stresses that no two operators key exactly the same way and that the most
important aspect is correct adjustment of the key for sending well-formed
dots (dits). Again, just as a person's handwriting changes so does the
'feel' of the key change, so that you need to be able to adjust it to suit
your current keying. Fig 12 shows the usual adjustment points of most makes
of semi-automatic keys.

Note that some experimenting with the following adjustments may be needed.

* Adjust both the left and right trunnion screws so that the vibrator arm
(pendulum) lies perfectly straight and butts lightly against the damper
wheel. This sets the initial 'hands off' key position.

* Slide the speed weight(s) on the vibrator arm to the end position giving
the slowest dot speed. Tighten the weight(s) ensuring they do not contact
the damper wheel.

* Hold the flat thumb paddle in the constant dot position and adjust the
left trunnion screw so that the vibrator dot can move to the left about
0.4mm (1164 inch). Use a small scale rule to check. Then tighten the left
trunnion screw.

* Hold the paddle for steady dots and allow the vibrator arm to stop
vibrating. Now adjust the dot contact screw (on the dot post) so that the
contact just makes firm connection with the vibrator dot, giving steady tone
from your monitor. Tighten contact screw and release paddle.

* To check dot adjustment, hold paddle to activate string of dots - there
should be at least 40 dots for each paddle movement, if necessary
repositioning dot contact screw to obtain this. When the vibrator arm stops
oscillating, the vibrator dot should come to rest lightly touching contact
screw.

* With two speed weights, to speed up dot rate, slide the innermost weight
towards the paddle end.  Always keep the outermost weight at the end of
vibrator arm, regulating dot speed with the innermost weight.

* For dash adjustment, position dash contact for a lateral movement of 0.4
to 0.8mm (1 164 to 1/32 inch). Typically, thickness of a sheet of typing
paper or a business card. Movement is a matter of personal prefer- ence, but
the smaller the spacing the better the feel of the key. Adjustment of spring
tensions is a matter of personal preference. Typical about one third of the
tension available. The less tension, the easier the feel. It depends on
whether you have a 'light' or 'heavy' arm action.

* Some users have been seen to use finger touch operation similar to that
preferred by some users of electronic keyers. However, the bug key was
developed to prevent 'glass arm' in protracted operation.  VK5HY suggests
"set the key side on to you (ie vibrator arm longways to the front of your
body) located directly in front of the shoulder of your non-keying arm and
rest the non-keying forearm parallel to the key.  Also rest the keying
forearm flat on desk- top so ycur body weight is taken evenly by both
forearms. The key is now operated by wrist rotation towards (dashes) and
away (dots) from your body front. This posture immobilises whole arm action
and encourages rolling of the wrist - just as with a straight key, wrist
action produces rhythmical Morse, not 'nerve Morse'. Once this basic action
is acquired, the bug can be repositioned to suit individual situations."

On the subject of key maintenace, VK5HY recommends, the pertodic inspection
of the condition of gold or silver contacts. They should be clean and
bright. Place clean typing or copying (bond) paper between the contacts and
pull it through several times to wipe the contacts. Use switch contact
cleaner also but no, repeat no, matchbox striker paper, wet'n'dry paper, or
any abrasive cleaner such as Brasso or Silvo. These should be used only when
attempting to resurrect badly pitted and burned contacts although it is
better to have new contacts or replate old ones. If you do wish to resurrect
pitted contacts use (1) very fine emery paper; (2) very fine wet'n'dry
paper; (3) crocus cloth or toothpaste on a polishing cloth; (4) bond paper.

To remove leftover polishing debris, use cotton buds and rubbing alcohol or
petrol.  Clean the areas thoroughly. Don't use CRC, or sewing machine oil,
etc on a bug as these attract lint and dust. Use tiny dabs of silicone
lubricant at pivot points. When not in use keep the key in a dust cover.

(A few words to explain the drawing which isn't sent with this email - )

NOTES-
The damper wheel is the small wheel that rests against the vibrator arm.
The speed weight is the round or square weights that can be moved on the
vibrator arm.
The dot vibrator is a long rod or thin flat bar on which the speed weights
are placed, which vibrates when properly adjusted.
The Trunnion screws are on the frame of the key, one on the left and one on
the right - they determine the limit of the swing of the vibrator.