Gareth's Downstairs Computer wrote on 11/16/2017 4:01 PM:
On 16/11/2017 20:04, rickman wrote:
Gareth's Downstairs Computer wrote on 11/16/2017 12:55 PM:
On 16/11/2017 17:07, rickman wrote:
Bob Wilson wrote on 11/7/2017 9:47 PM:
On 11/4/2017 5:42 AM, Gareth's Kitchen Komputer wrote:
On Mon, 21 Dec 2015 23:33:17 +0000, gareth wrote:

For those who make their own Morse Keys, what do you use for the
contacts,
for
I have found the phosphor bronze pillar for the dot contact on my ersatz
Vibroplex
to be very noisy and scratchy?

I'm fairly sure that I asked this question before, but it has been a
habit
of never put off till
tomorrow what you can put off till the day after.

I chose phosphor bronze because in the days of making one's own
electronic
organs, phosphor bronze was suggested as a suitable keying matreial for
the
keyboards.






If a question's worth asking, Gareth...







I have not made lots of keys, but when I do I use contacts from old
relays.
I still have some relays I bought as WWII surplus when I was in my teens,
back in the 1950's. They have strange coil parameters, weird mounting
arrangements, etc., but nice little silver contacts.
Bob W, WA9D

Why use a mechanical switch? There are magnetic hall effect switches
around. Or a mercury wetted switch can be operated by a magnet. Are the
magnetic switches too sloppy?


Perhaps you confuse mercury wetted with reed relays?

I am thinking of reed relays, so I guess I used the wrong name, but aren't
they wetted with mercury to prevent corrosion building up?


In the closed atmosphere of the glass tube, there should not be any
corrosion, I think. ISTR some gas in there, but don't know about
mercury wetting.

Call it what you want, corrosion, oxidation, just plain pitting. The point
is a solid surface will wear from the arcing that happens when contacts
break connections (which also happens on initiating connection because of
switch bounce). Mercury doesn't have this problem as it is a liquid and
reforms the layer every time it is "pitted".

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998