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Author Topic: BALL BEARINGS VERSUS TRUNION  (Read 14404 times)

Posts: 37

« on: November 19, 2013, 02:30:21 PM »

Being new to CW, and keys, I was wondering if BB's actually have an advantage over trunnion bearings.  Being a newbie to the feeling of
keys, I have not developed the subtle ability to feel any difference, especially since I set the contact spacing so close that I cannot feel the iambic levers moving.  As far as life of the two bearing types, even at 60 WPM (no not me) so long as the trunnion is cleaned and lubricated periodically,it should last as long as the BB.  BB's are the sealed type, but even they will eventually get exposed to air,dust, moisture and temperature changes causing the lubrication to thicken.  The speed of each I suppose could be a factor at Very High Speed
CW with the BB (Huh) getting the choice, as well as side to side rocking motion, but there are differing opinions on that.
I would appreciate a solid discussion on the subject, as well as springs versus magnets for tension.

I am guessing that it is a moot point, since it is probably based on what you like anyway !!   

Posts: 3289

« Reply #1 on: November 19, 2013, 03:31:11 PM »

I was advised as a Novice to only buy keys with ball bearings because they had lower friction and would not wear down like a trunnion.   Thirty plus  years on, I don't see any difference. 

I have keys that are over 70 years old which are well worn and still soldier on in fine fashion.

Keys are like wives.  Get what suits your fancy.  The next guy's opinion matters not.  Smiley

Posts: 2100

« Reply #2 on: November 19, 2013, 03:41:45 PM »

Based on what you like is correct. As you say ball bearings can stick at times and create flat spots not to mention falling out depending on quality causing problems. As for the trunnion type a lot depends on age and quality of key i.e. my two main keys are my great grand dad's original 1890s Signal Electrics with original springs still working as new but not at 60 wpm. I would suspect that most any type trunnion key built after WWII would not be built to the same standards and quality material at least for some of the ones I've seen and tried. My take on magnets, tried them, no thanks.

Posts: 374

« Reply #3 on: November 19, 2013, 08:01:36 PM »

I would appreciate a solid discussion on the [ball bearings v. trunions], as well as springs versus magnets for tension.  

Yes, we all have opinions.  For mine, I bought an early Begali Signature (sealed ball bearings and magnets), serial number 042, and could not be more pleased.  I prefer a near-motionless setting and this paddle fills that bill!  A little pricey, but if you can afford it, give a Begali a try. 


Posts: 1000

« Reply #4 on: November 20, 2013, 03:06:12 AM »

Lever arms in keys don't move far enough to benefit from ball bearings.  Makes good ad copy though.  It sounds like it should work well.  That said, there likely is no disadvantage either, other than perhaps raising the  cost of key somewhat.  A well engineered key can employ either type of bearing to good advantage.
« Last Edit: November 20, 2013, 03:08:59 AM by K0RS » Logged

Posts: 2100

« Reply #5 on: November 20, 2013, 05:07:25 AM »

This may be of interest to some: On my 100 plus year old keys the cross arm pivot points consist of some type of fused on silver type looking alloy and the trunnion pivot holes themselves are lined with some type of thin gray looking lead alloy babbitt material.To date no signs of wear, sticking or wobble on any axis. I am curious if any of the high end manufacturers of today do anything like this on their straight keys.

Posts: 6764

« Reply #6 on: November 20, 2013, 08:35:00 AM »

Trunion bearings consists of a pointed "rod" setting in a "V".  This arrangement makes the bearing surface much greater than the round edge of a ball creating more resistance or drag.  If the point is the only thing that touches the bottom of the V, then the pressure on that point must be increased to prevent wobble of the point in the V.  This also equals resistance and drag.

This, in my opinion, has been a "selling point" for the ball bearing keys.  However, the friction points in relation to the size of the key and the sensitivity of a person's fingers is so minuscule that I have serious doubts if 99% of the CW operators can tell one from the other.

It is also my opinion that a person should buy what he/she thinks is the best.  This provides self satisfaction and enjoyment.  However, it's also best not to brag and blow or get into an argument with another about it unless you wish to risk having your satisfaction and enjoyment destroyed!   Grin

Al - K8AXW

A Pessimist is Never Disappointed!

Posts: 404

« Reply #7 on: November 20, 2013, 02:19:17 PM »


Ball bearings don't have adjustable side play, such like trunnions have.

Read this part of a story written around 1979:

While I write like a doctor, I can send with a hand key as long as I want to—with very few errors. And with a Bug, and with any solid state keyer.

I had a buddy once, who got himself a glass arm. He could not send even one word with his right hand, so he switched over and relearned to telegraph with his left. It was just a matter of time before the left went too, but he got himself promoted and didn't have to telegraph any more. So there is a remedy, but avoidance is the best policy.

And this is easy. The secret is in the key adjustments—you loosen the “trunnions,” or the tightness of the needle-and-cone bearings on each side of the key, until you can shake the key lever from side to side. There must be as much side-play in the lever as there is up-and-down motion between the key contacts. That's all there is to it.

You won't believe this. That's all right; I didn't believe it either, until I proved it through experiment. The dollar key I mentioned earlier has no side adjustment. Either it has cylindrical ears that poke through holes in the U-shaped mounting bracket, or it has conical ears which should be ground into cylinders. Never mind the sloppy feel; your arm is more important than anyone's opinion. You need that slop, whatever key you use.

Probably you have a good solid brass key with side adjustments. Well then, unscrew the side screws and lock them at the point that you can move the lever sideways the same amount that you pump it up and down.

It will feel “funny,” but send a few minutes—at least a paragraph. If you can keep going, do so.

Now adjust the key up snug. Not to binding, or with noticeable friction; just barely enough to prevent side-motion. Now send, and see how your arm feels. Does it begin to tighten up, and do you begin to make errors?

Loosen the key. You may need a couple of sessions to convince you, if you are on the stubborn side, so there is no need to risk your arm while you decide. But the arm, and how it feels, tells the story. Stubborn or no, I know how that key adjustment will wind up! You will never send with a tight key again.

So much for the practice, now for the theory: Our grandparents used to explain any number of things as being the result of “nerves.” The trouble with one word explanations is that they don't lay it out for you. In this case, though telegraphers and doctors alike knew perfectly well that Telegrapher's Paralysis was a nervous condition, only the more observing saw any connection with a tight key and a glass arm. And even they hadn't the least notion how such connection might work.

The first clue came from the work of H. S. Black, of the Bell Telephone Labs, who invented negative feedback amplifiers in the thirties. To him the invention meant stable telephone repeaters, and high fidelity at less cost. But to physiologists, experimental psychologists, and other researchers into the living body and its operation, it offered an explanation that had been lacking before. When you put your hand out to touch something, how did the hand stop where you wanted it to? Feedback, by various paths, was a concept that fitted all the observed facts. It simplified explanations; it predicted results. The idea that something caused by the original action that opposed and controlled it was new and exciting.

I have two pocket calculators. One has a keyboard that clicks under finger pressure, like a typewriter key. The other keyboard has keys of the conductive plastic foam type. And be it ever so bounceless, I don't like it, because it feels just like stepping in a cow-clap. It is just mushy; the other keyboard lets my fingers know when to stop pressing, with a click that is felt as a vibration. Expecting this, I actually cracked the circuit board on which the mushy keys were mounted, trying to make them react as expected. I had to cement another board onto it to prevent breaking the printed connections.

Also, I worked for a time at a broadcasting station as a transmitter operator. The on-off buttons controlling the circuit breaker for the high voltage were of the industrial type. They were spring-loaded and all that, but had absolutely no follow at all. Everybody hated them—you couldn't tell anything by feel. They gave a disconcerting impression of anticipating you, as if they operated while you were only thinking about pushing them.

Ask any target shooter what a bad trigger pull will do to his scores.

The fact is that most of us are confused and uneasy when something doesn't “feel right.” This applies to telegraph keys, too. The rigidity of the side-adjustment, the absence of side-play, dulls and reduces the feedback that monitors what flows out of our brain, down the arm to the fingers, and into the key. This is my theory. No one else has ever said that this is true, so far as I can find out—and I've tried!—if only because telegrapher's paralysis is as dead as its victims, for the most part. It is one of the rarest of diseases, so far as telegraphing goes, but it has other manifestations, and should, by all means, be understood.

We have to have feedback, lest the nerves rebel through confusion. I have seen a man standing, back arched, face contorted, arm stiff, trying to telegraph by tapping. I didn't laugh. Telegraphing was part of his job, and for him it was torture. Of course, he could send like a streak with a bug. If you check the old ads, you will see that they claimed “ease” and “speed” as selling points. But bugs were and are very expensive—aside from a few a few broker operators, most sales were to telegraphers who had glass arms. They were as helpless without their bugs as a present day grammar school student without his pocket calculator.

Lyall Watson, in his book Super Nature, has some interesting things to say. He tells of experiments in 1946 in which Grey Walter and his colleagues used flashing lights during brain wave tests and their patients went into convulsions. Other workers have had similar results when the rate of flashing coincided with certain brain wave patterns. The most consistent seizures occurred when the brain waves themselves were made to trigger the light, something like a buzzer of multivibrator action. Under this arrangement, half of the patients had spasms. And they had no history of epilepsy! Watson also mentions a bicyclist who blacked out while riding down a lane with trees along its sides. When the sun was low enough, the flickering produced
      by riding past the line of trees was enough to cause blackout—not just once but several times. How many mysterious automobile accidents, do you suppose, are caused by something like this?

In 1927 I went to work for AT&T. I knew a little International Morse, not much, and I discovered that Morse was quite a lot different. It was faster, too, once you learned to read spaces between clicks instead of tone pulses.

There was a full telegraph department with a few printer circuits, but mostly hand-operated Morse. In the test room, where I worked, there were at least a dozen “test wires.” These were simple Morse circuits with a sunder mounted high, well above the jack-fields, next to the carvings of “Nekkid Wimmen” which were standard decoration in those days. Now we got plastic strips. Down on the keyshelf in a clutter of switch-keys and cord-circuits and such, dwelt the telegraph keys. The clutter was not conducive to good sending, but we had men who could do it. For one thing, telephony was just something added to their Morse experience. They were operators; that is how they got their jobs. They learned how to operate a Wheatstone Bridge, and gain a repeater, and that was about it. The test wires were used for communication between offices.

In those days, a telephone route between cities was likely to have just one standard 40 wire line. Open wire, not cable. That meant 20 side circuits, ten phantoms, thirty phone circuits in all. The side circuits were all composited (a composite set was a low pass filter) and a telegraph wire—nearly always half-duplex—could be connected to each wire, giving forty telegraph wires, two way. That is where the name “and Telegraph” comes from. These did not carry public messages, by agreement with Western Union they were all either leased wires, or test wires.

You had to be conscious of your own office call; when you heard it, you interrupted the circuit to “break” the distant operator. When you heard the wire close, you said “I” and listened to his first words. Invariably he wanted something simple, and, while he was telling you, you walked away and did the job, listening all the while. Then you came back a few seconds later and said OK. The most convenient system you ever saw; it took a lot of effort and determination for the High Brass to kill it. We liked it. Radio Traffic men ar3e aiming at such operation with their “break-in.”

I was just a kid then; my co-workers were 30 to 60 years old. The older men got bored when work was light and they weren't kidding me. Then they resorted to horse-play. A favorite gambit was to loosen the trunnions to the critical point so that when the key was touched, the lever would explode out of it like a mousetrap and the spring would be lost. The victim had to try sending with the switch-lever, by which the circuit was kept closed while idle. This is like telegraphing with a knife-switch, and he would swear loudly to the delight of the perpetrators.

As I say, I was young. This did not suit my sense of propriety. Besides, I had noticed that, even when in working condition, the adjustment was very sloppy. So to be helpful I would tighten them to what I thought was the “proper” adjustment. In other words, I was a wise guy, just as the kids are today, and for the same reason: ignorance.

My “adjustment” never lasted long, so one day I took a pair of gas-pliers and tightened all the lock nuts.
      And then it really hit the fan. Grown men running up and down and cursing and threatening mayhem and worse for the unspeakable scoundrel who not only messed up all the key adjustments but had the unutterable gall to LOCK them that way! I watched them searching behind the test-board and under the duplex tables and even up on the cable racks for the dastard, whoever he might be, while I was in plain sight and feeling a little exposed. I knew who it was, all right. It was me. I was dimly aware that I was being taught something, and with more tact and good humor than I deserved. Later I, too, put on a show of rage and incipient insanity when as a chief, I had to make a point. You can't do it often, but it works, it works! The difficulty is in keeping your face straight.

I asked one of the older men, who had been patient with me, what it was all about. “Don't you know? Send on a key without side-play and you get a glass arm!”

My informant was one of the few, even in that office at that time, who knew what caused Telegrapher's Paralysis; he knew that it was due to bad key adjustment and “nerves,” and that was as much as anyone knew. In the years since, I have asked questions at every opportunity and so far have not one answer that means anything. I have puzzled over it for those same years, and the work of Norbert Weiner and others gave my first clue. It is entirely possible that I am the only man alive who actually does know; I hope not, and would be delighted to hear from anyone else who does. But I am afraid that, until now, I have been the torch bearer.

This story will undoubtedly be classified under Dewey Decimal System in some library or other, and will still be obscure. However, it will be in print, and not locked up in the heads of dead men. The knowledge, aside from help to key men, might even furnish an important clue to the psychologists and other workers in the field.

Be that as it may, you have no excuse for acquiring a glass arm. You know better.

73 Wim PA0WV
« Last Edit: November 20, 2013, 02:26:51 PM by PA0WV » Logged


Posts: 138

« Reply #8 on: November 20, 2013, 02:58:56 PM »

I figure that ball bearings might be a little longer lasting but as many have already stated here that trunion never wear out. I guess is 6 of one half dozen of the other.

The same with springs or magnets. I own two N3ZN top of the line paddles and a Vibroplex Square Warrior all with magnets. I also own another 13 paddles; you name it, Begali, Kent, Bencher, Vibroplex Iambic, Vibrokeyer and Brown Brothers. There might be something wrong with me but I can't tell the difference between magnet and springs. They all feel fine to me.

Posts: 502


« Reply #9 on: November 21, 2013, 09:29:07 AM »

I built two straight keys this year inspired by the designs of Rich (WB9LPU).  One with a trunion bearing and one with ball bearings.  I can tell almost NO difference between the two.  Both have a great feel and work smoothly.  Before the build I would have sworn ball bearings would have been better but learned differently.  Regards - Joe N3Hee

CW Academy Advisor (Level II)
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