Proper Gear Mesh, How Do You Determine Adjustment

[Django]

I have been working on a few early Victor motors, (spur and bevel gear types). I have heard some of these motors on YouTube and most were very loud. Mine have turned out to be fairly quiet and I was wondering how people are determining their gear center to center distances.

I had posted a short instruction document regarding my process and some information regarding properly meshing gears, but I removed it because I felt that some may feel that it was condescending. I am sure that some members here have more experience with these motors than I do. My background comes more from being a Tool and Die Maker and later a Mechanical Engineer.

I have my own method, but I was wondering how others determine the proper adjustment of their gear trains. It might be helpful to others, (including myself), to know how to make these motors run at their best, especially since a poorly adjusted motor will eventually eat itself.

[JerryVan]

I am sorry that you removed your document. It was spot-on and helped to describe the action of one of the most misunderstood elements of our hobby: Gears. It was no more "condescending" than the postings, by others, of acoustic analysis of various reproducers. That is to say, not condescending at all! Some may not have fully understood what you posted, (the same as me, finding myself completely lost with the acoustic analysis stuff I mentioned), but then we are all here to learn and to teach.

[Django]

I am sorry that you removed your document. It was spot-on and helped to describe the action of one of the most misunderstood elements of our hobby: Gears. It was no more "condescending" than the postings, by others, of acoustic analysis of various reproducers. That is to say, not condescending at all! Some may not have fully understood what you posted, (the same as me, finding myself completely lost with the acoustic analysis stuff I mentioned), but then we are all here to learn and to teach.

I appreciate your comment. Here is the attachment. I hope that it of some use.

[JerryVan]

I'll add my 2 cents about gear mesh as well...

When new gears are installed in new devices, there is a precise locational relationship between mating gears. Any deviation from those locations results in gear wear and noise. Ideally, the form and curvature of each gear tooth should cause it to roll across the face of its mate, with no sliding, rubbing, friction or mechanical interference. Notice, I said "new" gears in "new" devices. At best, in our hobby, we may have new gears, in old devices. Achieving a reasonable quiet gear train then becomes a trial & error affair. The form & curvature of the gear teeth have been deviated from by wear. The location of each gear, (gear spacing), has also been modified by wear. What to do?

1. Realize that gears that have been running together for 100 years have worn to the extent that their shapes now compliment each other. (Like a well-worn shoe that has conformed to the shape of your foot after years of wear.) While the shape of the gear teeth and their spatial relationship may be very "incorrect", they may still operate rather well. As long as each gear still has some substantial amount of material remaining in its teeth, (meaning it's not about to strip), this can be an okay situation. In these cases, if the gears are to be removed for cleaning, great care must be taken to re-align them exactly as they were. It sometimes requires a fair amount of trial-and-error to find the "sweet spot".

2. Replace a worn out or stripped gear, either with a used one, or a new one? Keeping in mind the above, any "foreign" gear, new or used, that is mated to another used/worn gear, in a worn device, can ultimately produce noise. With the analogy of the well-worn shoe, recognize that while the shoe has conformed to your foot, so too did your foot conform to the shoe! Think of the discomfort of a new pair of shoes. All we can do with our replacement gear, is to adjust their alignment as best we can, (assuming the motor even allows for that). Time and use may quiet things somewhat... or possibly not. Take some confidence however, that when we use gears in decent condition, we at least know that they are strong and not about to strip and do huge damage. The noise may be irritating, but even though it signifies an improper mesh, it will take most of whatever lifetime we have left before it even begins to be an issue. These are not like cars that we drive 30K miles per year.

3. Replace both gears of a mating pair with new gears? This is a better option. Along with repairing the motor housings and/or bearings to re-establish proper gear spacing. In other words, rebuild the motor. Really, while this is sometimes necessary, it is also extreme and costly if you can't do the work yourself. With most pairs of mating gears, one gear, (the one with fewer teeth), gets the lion's share of wear. Replacing only that gear is usually sufficient. Note also, that for the most part, phonograph motor gears are very slow turning. The exception being, some governor gears. Slow turning gears have a very low potential of producing noise, no matter how bad they are. Those gears need only to be strong enough to not pose a risk of damage due to complete failure, i.e., stripping.

Anyway, I know I have restated some of Django's points. It simply means I agree with him Also, these are my thoughts and approaches to phonograph motors & gears. Yours may vary and mine are not intended to be the only way to approach the challenges of phono motor repairs and restoration.

[howardpgh]

I'm not very experienced with machine work, but here is my 2 cents worth.
If you take apart a mating set of old gears, mark their positions on the shaft and match mark their position relative to each other. Since things wear unevenly, marking them may save some headache.

[Inigo]

I've also noticed that some motors that run well and silent, turn noisy when you disassemble, clean thoroughly and reassemble them. Pity I did that to my early machines.. Since a certain point I decided not to touch motors that worked well... Even the dried old grease could be filling certain rude spots that, when cleaning down to the metal, they become noisier!
When i acquired my 194, cleaned it completely and it works very well, except for the winding gear and ratchet pawl. I never got them to work as silent as they were before the cleaning... I spoiled something, and since then, the winding action roars like a coffee grinder! I've never been able to cure that in 20 years!

[Django]

I've also noticed that some motors that run well and silent, turn noisy when you disassemble, clean thoroughly and reassemble them. Pity I did that to my early machines.. Since a certain point I decided not to touch motors that worked well... Even the dried old grease could be filling certain rude spots that, when cleaning down to the metal, they become noisier!
When i acquired my 194, cleaned it completely and it works very well, except for the winding gear and ratchet pawl. I never got them to work as silent as they were before the cleaning... I spoiled something, and since then, the winding action roars like a coffee grinder! I've never been able to cure that in 20 years!

As Jerry pointed out, the teeth of a proper gear that is properly adjusted roll along each other. Another benefit of this ingenious invention is that if everything is working properly, relative speed is constant, (no fluctuation).

Old, thick grease can dampen and hide motor noise. Contaminants suspended within the “paste” will cause wear and increase friction which will wear the entire motor. Clean gears and a high pressure tenacious grease will reduce friction and wear.

The driven governor gear is often the cause of excessive noise, especially when it is a spur gear. You can isolate the culprit by assembling the motor one part at a time.

[Django]

I should add that this thread was only referring to the adjustment of gears. Additionally, I check the entire motor for damage and wear, and tight or irregular spots, check the shafts for run out, inspect the bearing surfaces of the casting and do a thorough inspection, cleaning and lube.

[Django]

The video is my D playing I’ll Take You Home Again Kathleen. The motor has been serviced and for this type of motor, it’s fairly quiet and runs smooth and strong.

https://www.youtube.com/watch?v=pGal3Hnr2ek

This is another Victor D from YouTube. Motors like this one were my reason for starting this thread. Hearing motors like this made me concerned for the longevity of these machines.

https://www.youtube.com/watch?v=CrXlrOU0zaQ

[JerryVan]

The video is my D playing I’ll Take You Home Again Kathleen. The motor has been serviced and for this type of motor, it’s fairly quiet and runs smooth and strong.

https://www.youtube.com/watch?v=W_c9prlcNbs

This is another Victor D from YouTube. Motors like this one were my reason for starting this thread. Hearing motors like this made me concerned for the longevity of these machines.

https://www.youtube.com/watch?v=CrXlrOU0zaQ

Your "D" runs exceptionally smooth! My MS is somewhere in between your D and the noisy D from Youtube. You've clearly put some time & care into making yours purr so nicely!