Re: [Phono-L] Credenza speed readout needle chatter
WD-40 is not a lubricant. It works good as a cleaner or to displace water, but not as a lubricant. Liquid Bearings works well and has no smell and is synthetic. Steve From: Phono-L on behalf of Robert Wright via Phono-L Sent: Friday, September 13, 2019 12:34 PM To: Antique Phonograph List Cc: Robert Wright Subject: Re: [Phono-L] Credenza speed readout needle chatter Firstly, thank you both for the detailed info! Ron, it looks like your suggestions are aimed at reducing vibration from the governor mech itself, the application of which makes perfect sense. I just may try that on all the motors here, in fact. Thank you! Andrew, it sounds like you're suggesting that once the indicator arbor is in (let's call it) 78rpm position, it is in that specific axis (or axes) where the hole may have become enlarged and/or the arbor's pivot post has become polished -- i.e., there's no chatter at other speeds because the indicator pad is in a different position, placing the posts where the wear has not occurred. This makes perfect sense to me, especially as the indicator chatter happens with at least one other motor here (a spring one, not the electric one I initially wrote about). I'm sure both machines have operated at 78rpm or thereabouts their entire lives, indeed. It also makes sense that adding grease to the pad helps, but only for a few plays -- once it has cleared out of the path, the posts are again in (let's call it) chatter position. In that light, would you think installing a significantly longer leather pad into the arbor would change its rotational position enough to place it into a "fresh" spot? It would also increase the return spring tension slightly, which may help alleviate chatter. Doesn't seem like it would take much, perhaps an additional 16th - 8th of an inch. It might get another 100 years of chatter-free use if so. Thoughts? (I've also used a spritz of WD-40 to lubricate the post holes -- perhaps I'll slather a fingertip of grease on them instead.) I also considered sympathetic resonance, but I don't know how much the math lines up, considering it is a range of speeds (albeit a narrow one) while the 60Hz vibration is more or less constant (I realize the 60Hz vibration and any errant governor vibration are two different things). But the hole wear, in my mind, lines up to that problem range quite well! I say it often in my emails here, but it bears repeating once again: to someone like me who loves phonographs much more than they have technically studied them, this list isn't just a handy resource, it's a lifeline. Thank you, gentlemen. Reporting back soon, Robert PS - In my defense, I never said the source of the chatter was the point of contact between the pad and the flywheel! I only meant to describe the symptom, i.e., where the noise occurred, not the underlying disease that might suggest a cure. I just get in a hurry sometimes. I'll try to be clearer! :-) On Sep 12, 2019, at 3:30 PM, Andrew Baron via Phono-L mailto:phono-l@oldcrank.org>> wrote: Hi Robert. Intriguing problem, and I think I may be able to shed a little light. My supposition could be wrong, but if you look at the physics of the thing, it could point to not one issue (“…obviously the contact point between the leather nib…”), but more likely two issues. You have to raise your perception above where the symptom’s cause would appear to originate, and look at the whole picture. The key to solving your mystery may be directly related to something you conveyed very precisely, that the issue occurs over an extremely narrow band of speeds. So, it appears that we have a primary cause (vibration source at the leather and flywheel), exacerbated or amplified by a secondary condition, which I will assume is marginal wear in the holes that the leather pad arm’s arbor passes through (the first of the two axles), in possible combination with the holes that the speed indicator needle’s arbor passes through, in the indicator frame. Given that the steel arm that the leather pad mounts to is supported on a smaller arbor, and given that this arbor is first in line and thus closer to the governor flywheel where the vibration originates, it’s likely that wear would be more present at those holes and possibly the associated arbor as well, than at the larger holes and arbor of the indicator needle. The same wear on smaller parts will occupy a larger percentage of area, thus having a more noticeable effect. The wear I describe would be very subtle. If for example, the holes that the indicator arbor passes through are normally three-thousandths of an inch larger in diameter than the arbor (just guessing on this — I have not measured it), and it’s known that the arbor touches only a specific portion of the wall of those holes at a specific speed, then you may find that the holes and/or the arbor itself have worn -slightly- out of round. It
Re: [Phono-L] Credenza speed readout needle chatter
Do not grease the pivots of the speed control indicator mechanism. Indeed, Victor recommended that they not be lubricated at all. That mechanism has to be extremely free for it to work correctly. Since it is so sensitive, minute variations in the operation of the governor may not show up in the rotation of the TT due to its flywheel effect. They may show up on the speed control dial though.Having said that, could it be dried lubricants at the 78 position of the indicator causing the problem. Hit the mechanism with carburetor cleaner spray and see if that clears up the problem. Ron L From: Phono-L [mailto:phono-l-boun...@oldcrank.org] On Behalf Of Robert Wright via Phono-L Sent: Friday, September 13, 2019 12:34 PM To: Antique Phonograph List Cc: Robert Wright Subject: Re: [Phono-L] Credenza speed readout needle chatter Firstly, thank you both for the detailed info! Ron, it looks like your suggestions are aimed at reducing vibration from the governor mech itself, the application of which makes perfect sense. I just may try that on all the motors here, in fact. Thank you! Andrew, it sounds like you're suggesting that once the indicator arbor is in (let's call it) 78rpm position, it is in that specific axis (or axes) where the hole may have become enlarged and/or the arbor's pivot post has become polished -- i.e., there's no chatter at other speeds because the indicator pad is in a different position, placing the posts where the wear has not occurred. This makes perfect sense to me, especially as the indicator chatter happens with at least one other motor here (a spring one, not the electric one I initially wrote about). I'm sure both machines have operated at 78rpm or thereabouts their entire lives, indeed. It also makes sense that adding grease to the pad helps, but only for a few plays -- once it has cleared out of the path, the posts are again in (let's call it) chatter position. In that light, would you think installing a significantly longer leather pad into the arbor would change its rotational position enough to place it into a "fresh" spot? It would also increase the return spring tension slightly, which may help alleviate chatter. Doesn't seem like it would take much, perhaps an additional 16th - 8th of an inch. It might get another 100 years of chatter-free use if so. Thoughts? (I've also used a spritz of WD-40 to lubricate the post holes -- perhaps I'll slather a fingertip of grease on them instead.) I also considered sympathetic resonance, but I don't know how much the math lines up, considering it is a range of speeds (albeit a narrow one) while the 60Hz vibration is more or less constant (I realize the 60Hz vibration and any errant governor vibration are two different things). But the hole wear, in my mind, lines up to that problem range quite well! I say it often in my emails here, but it bears repeating once again: to someone like me who loves phonographs much more than they have technically studied them, this list isn't just a handy resource, it's a lifeline. Thank you, gentlemen. Reporting back soon, Robert PS - In my defense, I never said the source of the chatter was the point of contact between the pad and the flywheel! I only meant to describe the symptom, i.e., where the noise occurred, not the underlying disease that might suggest a cure. I just get in a hurry sometimes. I'll try to be clearer! :-) On Sep 12, 2019, at 3:30 PM, Andrew Baron via Phono-L wrote: Hi Robert. Intriguing problem, and I think I may be able to shed a little light. My supposition could be wrong, but if you look at the physics of the thing, it could point to not one issue ( obviously the contact point between the leather nib ), but more likely two issues. You have to raise your perception above where the symptoms cause would appear to originate, and look at the whole picture. The key to solving your mystery may be directly related to something you conveyed very precisely, that the issue occurs over an extremely narrow band of speeds. So, it appears that we have a primary cause (vibration source at the leather and flywheel), exacerbated or amplified by a secondary condition, which I will assume is marginal wear in the holes that the leather pad arms arbor passes through (the first of the two axles), in possible combination with the holes that the speed indicator needles arbor passes through, in the indicator frame. Given that the steel arm that the leather pad mounts to is supported on a smaller arbor, and given that this arbor is first in line and thus closer to the governor flywheel where the vibration originates, its likely that wear would be more present at those holes and possibly the associated arbor as well, than at the larger holes and arbor of the indicator needle. The same wear on smaller parts will occupy a larger percentage of area, thus having a more noticeable effect. The wear I describe would be
Re: [Phono-L] Credenza speed readout needle chatter
Firstly, thank you both for the detailed info! Ron, it looks like your suggestions are aimed at reducing vibration from the governor mech itself, the application of which makes perfect sense. I just may try that on all the motors here, in fact. Thank you! Andrew, it sounds like you're suggesting that once the indicator arbor is in (let's call it) 78rpm position, it is in that specific axis (or axes) where the hole may have become enlarged and/or the arbor's pivot post has become polished -- i.e., there's no chatter at other speeds because the indicator pad is in a different position, placing the posts where the wear has not occurred. This makes perfect sense to me, especially as the indicator chatter happens with at least one other motor here (a spring one, not the electric one I initially wrote about). I'm sure both machines have operated at 78rpm or thereabouts their entire lives, indeed. It also makes sense that adding grease to the pad helps, but only for a few plays -- once it has cleared out of the path, the posts are again in (let's call it) chatter position. In that light, would you think installing a significantly longer leather pad into the arbor would change its rotational position enough to place it into a "fresh" spot? It would also increase the return spring tension slightly, which may help alleviate chatter. Doesn't seem like it would take much, perhaps an additional 16th - 8th of an inch. It might get another 100 years of chatter-free use if so. Thoughts? (I've also used a spritz of WD-40 to lubricate the post holes -- perhaps I'll slather a fingertip of grease on them instead.) I also considered sympathetic resonance, but I don't know how much the math lines up, considering it is a range of speeds (albeit a narrow one) while the 60Hz vibration is more or less constant (I realize the 60Hz vibration and any errant governor vibration are two different things). But the hole wear, in my mind, lines up to that problem range quite well! I say it often in my emails here, but it bears repeating once again: to someone like me who loves phonographs much more than they have technically studied them, this list isn't just a handy resource, it's a lifeline. Thank you, gentlemen. Reporting back soon, Robert PS - In my defense, I never said the source of the chatter was the point of contact between the pad and the flywheel! I only meant to describe the symptom, i.e., where the noise occurred, not the underlying disease that might suggest a cure. I just get in a hurry sometimes. I'll try to be clearer! :-) On Sep 12, 2019, at 3:30 PM, Andrew Baron via Phono-L mailto:phono-l@oldcrank.org>> wrote: Hi Robert. Intriguing problem, and I think I may be able to shed a little light. My supposition could be wrong, but if you look at the physics of the thing, it could point to not one issue (“…obviously the contact point between the leather nib…”), but more likely two issues. You have to raise your perception above where the symptom’s cause would appear to originate, and look at the whole picture. The key to solving your mystery may be directly related to something you conveyed very precisely, that the issue occurs over an extremely narrow band of speeds. So, it appears that we have a primary cause (vibration source at the leather and flywheel), exacerbated or amplified by a secondary condition, which I will assume is marginal wear in the holes that the leather pad arm’s arbor passes through (the first of the two axles), in possible combination with the holes that the speed indicator needle’s arbor passes through, in the indicator frame. Given that the steel arm that the leather pad mounts to is supported on a smaller arbor, and given that this arbor is first in line and thus closer to the governor flywheel where the vibration originates, it’s likely that wear would be more present at those holes and possibly the associated arbor as well, than at the larger holes and arbor of the indicator needle. The same wear on smaller parts will occupy a larger percentage of area, thus having a more noticeable effect. The wear I describe would be very subtle. If for example, the holes that the indicator arbor passes through are normally three-thousandths of an inch larger in diameter than the arbor (just guessing on this — I have not measured it), and it’s known that the arbor touches only a specific portion of the wall of those holes at a specific speed, then you may find that the holes and/or the arbor itself have worn -slightly- out of round. It would be hard to see, but if the holes are normally for example .003” larger than the arbor, and now they’re subtly egg-shaped and .005” in only one direction (out of round), then any vibration whatsoever at the contact point (leather pad & flywheel) would cause the arbor to vibrate in a unidirectional orientation, within its holes. Wear would naturally occur on the associated parts only in the specific
