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LCWO Discussion Forum [Atom LCWO Forum Feed]

This is a simple discussion forum for LCWO users. Feel free to use it for any kind of discussion related to this website.

Thread: Contact Points on Straight Keys

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AuthorText


Posted: 2021-10-26 14:22
What is necessary for the contact points of a Straight Key to work efficiently.
Can "contact points" be purchased or improvised or otherwise acquired or made? This is in regard to the repair of an older straight key recently purchased.
Can contact points be improved with a thin coating of solder?


Posted: 2021-10-26 15:40

Apart from the obvious - contacts have to line up and actually come close enough to meet . . .

. . . contact issues may be corrosion/oxide/dirt/paint/grease etc on one or more of the contact surfaces
or
lack of connectivity somewhere within the key wiring or cable terminals.

Before using an abrasive (paper is often enough) to clean the key contact surfaces, test from the the cable ends with an ohmmeter
to the base of each contact, or back along until you find a circuit.

Contact surfaces are best made of silver or some such metal which won't form oxides etc so easily.
Begali will supply gold contacts.

Various manufacturers sell spares . . .

http://www.kent-engineers.com/handkeyspares.htm
http://www.vibroplex.com/contents/en-us/d9153.html
https://www.morsex.com/ameco/keys.htm
Probably begali also

Sometimes contacts come up on ebay - but I couldn't recommend any.

Solder is unlikely to be better than silver . .

What sort of key did you buy ? or is it a secret ?

cb


Posted: 2021-10-26 16:26
Thanks Chris. I have several keys, J-37, J-38 and another od uncertain make, that looks like the MFJ key sold with the 557 Oscillator, but is made of Brass. Then I have one great big fat KENT key, the KENPRO KK-50 which is my "baby". This is TOP SECRET. Do not share this information with anyone.


Posted: 2021-10-26 17:29
BrucerDucer1:
Thanks Chris. I have several keys, J-37, J-38 and another od uncertain make, that looks like the MFJ key sold with the 557 Oscillator, but is made of Brass. Then I have one great big fat KENT key, the KENPRO KK-50 which is my "baby". This is TOP SECRET. Do not share this information with anyone.


All good stuff . .

The KK-50 was made 1980-90-ish by KENPRO KOGYO of Tokyo, now part of Yaesu

not Kent (-engineers) keys - so don't buy any spare Kent contacts for that one . . .

cb


Posted: 2021-10-26 19:11
Thanks Chris, that is very helpful. So does not Yaesu make the keys. I have trouble figuring out who makes quality keys, though I know there are still custom makers making expensive keys.


Posted: 2021-10-26 21:19


A quality key is one you like ( - also maybe one that doesn't break ).


If you aren't pounding for 3 hours at a stretch every day in ship, you maybe can have lower criteria . . .



That MFJ is a $20 cheap training key - but perfectly good if you like it . . . see :-
https://youtu.be/HPwxgH-BE10?t=175

Burt goes 20wpm he says . .
https://youtu.be/HPwxgH-BE10?t=383 , so maybe that's it.

I think this guy is using a $30-ish chinese K4 key:-
https://www.youtube.com/watch?v=i8Ed0TSp0gs&t=38s
like
https://www.aliexpress.com/i/1005002688348384.html

Good keys for them . . . YMMV etc

cb


Posted: 2021-10-26 22:43
You might want to seek advice from key collectors/restorers on qrz.com/cw forum or brasspounders.net. The silver/gold on keys and relay contacts is quite thin - beware or cowboys recommending nail files and common sandpaper. Once you do the wrong thing, reversal is not an option.
Also their are some "approved" chemical treatments if more than a piece of paper of "dollar bill" don't work (US dollar is not plain paper).

bill


Posted: 2021-10-27 12:54
Thanks Bill. Here is a question. Can I solder a contacts with pure silver or partial silver? Is there a specific solder that has part silver in it?


Posted: 2021-10-28 05:16
Not that I have ever done silver soldering, but sure that exists. Its what jewelers would do. Keep in mind a jeweler is NOT looking for two surfaces perfectly parallel. Usually silver soldering is done with a torch, an iron would have to likely be quite hot. Then there would be the precision filing to get a nice surface. Of course contacts on relay and likely keys is done with some electro plating process which is slow and very thin.

I think you will end up spending a lot of time and money going down this path. If you were restoring the key from the Titanic or something it would be worth it LOL. Probably hunting for replacements parts is a better approach. I'll private message you a long time key collector who will have much better info than me.

I think all of this is well beyond the realm of an MFJ/Radio Shack/Heathkit etc type key.

Good Luck
73 Bill


Posted: 2021-10-29 10:02
Okay Bill, thanks for the caution about repairing or maintaining some of the keys. I am thinking at times about purchasing a new, quality straight key.
Are there sources for parts for keys?

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