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Ideas For "Truing Up" A Governor Disc?

Posted: Sun Oct 26, 2014 10:08 am
by FellowCollector
I have found, over the course of many years of collecting, brass governor discs that have become very slightly warped - thus contributing to flutter during playback (IMHO). I've found this condition on both Edison and Columbia cylinder machines and wonder if anyone here has encountered this and, better yet, arrived at a reasonable home solution to true up these brass governor discs. The condition is especially prominent on Columbia cylinder Graphophones for some reason. I have a good number of Columbia cylinder machines in the collection and some have this problem and all of those have a flutter to some extent whereas those with true running governor discs play flawlessly. My guess as to the cause of the warped disc is that one or more of the governor weights had been replaced with one of lesser or greater weight relative to the other weights on the shaft or a given machine had been run for prolonged periods with a missing governor weight thus creating an imbalance during high speed rotation of the governor, and thereby slightly distorting the originally "true" brass disc. Of course, mishandling can be a cause as well. In any case, if anyone has some ideas on truing one these discs up it would be sincerely appreciated.

Doug

Re: Ideas For "Truing Up" A Governor Disc?

Posted: Sun Oct 26, 2014 10:19 am
by phonogfp
I too have encountered this problem - - especially on Qs and Bs.

I'm not touting this as "the answer," but I've had good results from placing the governor disc (stripped of its weights & springs of course) in a vice with the jaws lying across the face of the disc. Try gently tightening it, then loosening it as the disc is revolved a few degrees, repeating this movement perhaps 20-25 times as you turn the disc 360 degrees. Again, there's no need to torque the vice - - just firm it up each time.

Good luck! :)

George P.

Re: Ideas For "Truing Up" A Governor Disc?

Posted: Sun Oct 26, 2014 11:04 am
by FellowCollector
Thanks George! I really appreciate your suggestion. I'll give it a try!

Doug

Re: Ideas For "Truing Up" A Governor Disc?

Posted: Sun Oct 26, 2014 1:10 pm
by Phonofreak
I never knew this. All this time I thought it was either the belt, weights or bearings. Now to start checking these governor disks on my two "problem children"
Harvey Kravitz

Re: Ideas For "Truing Up" A Governor Disc?

Posted: Sun Oct 26, 2014 4:27 pm
by De Soto Frank
Before heading-off to the vise with governor-disc, suggest removing it from the shaft, and making sure it is truly "warped".


One would be mount the disc on a suitable piece of threaded rod, clamping it between two nuts and washers, and slowly spinning it in a drill or lathe, and watching the edge of the disc for "wobble". If you have a dial-indicator, you can use that to check the disc for run-out.

If the bottom surface of the disc is flat ( no "hub" or peening at the center ), it can be placed on a "surface plate" ( a thick piece of "float-glass" or true "plate glass" ) works, and trying to slide feeler gauges or pieces of paper under the edge...


Lastly, make sure the jaws on the vise are parallel and smooth... lots of inexpensive vises have uneven jaws, which might do more harm than good...

Re: Ideas For "Truing Up" A Governor Disc?

Posted: Mon Oct 27, 2014 3:48 pm
by JerryVan
The only way to really true the disc is to put it on a snuggly fitting arbor and to take a cut off the disc face on a metal lathe.

I would suggest that most of them were never made much better when new. Also, be sure it's really the disc that is not true before you do anything. A bent governor shaft pin will also make the disc wobble, especially if the bent pin is at the disc end of the shaft. Loose/worn bearings at the ends of the governor shaft will do the same.

Re: Ideas For "Truing Up" A Governor Disc?

Posted: Mon Oct 27, 2014 4:07 pm
by Chuck
I've seen these warped and wobbly looking governor
disks too. As a matter of fact, the original one that
was in my Edison Standard model D combination 2/4 machine
was fairly badly warped.

That setup sounds warbly, and I never bothered to try and
true up that particular disk.

Instead, I eventually came across some different
governor parts and changed out that disk with a true
one and also at that time swapped out the arrangement
that has the little spring-wire dampener fastened on
via a small setscrew collar on to the shaft.

That new arrangement allowed me to finally get this
machine running smoothly and properly.

I have an idea that some of the governor disk warping
we see now may have been caused by pressing the
start/stop lever too hard against the disk, thus bending
it. They are fairly thin. A good one would be about
twice as thick, in my opinion. I have considered
attempting to make a new one in the lathe, out of brass,
and making it nice and thick.

I don't doubt for a second that warped governor disks
can be straightened out using a vise and lots of patience. Never tried that myself, but it makes
perfect sense.

Chuck

Re: Ideas For "Truing Up" A Governor Disc?

Posted: Tue Oct 28, 2014 4:37 pm
by Ivor-Duncombe
It's difficult to imagine a governor disc "becoming" worn under normal conditions unless the physical set-up is very poor (i.e. the speed control lever can be pushed beyond the limit where the friction pad presses far to hard on the outer edge of the disc face). I would suggest that we all take extreme care not to drop discs, or more particlarly, complete governor shaft assemblies onto a concrete floor when assembling or reassembling a motor. If the weights are fitted to the governor when it is dropped onto a hard floor it is hard to imagine the disc and/or governor shaft not being bent or distorted in some way. This is particularly true when the disc edge is the first part to hit the floor. The g's experienced (especially with gravity acting on the mass of a fully assembled governor shaft)are extremely high.