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 Post subject: HMV pre-1921 two spring motor
PostPosted: Tue Aug 27, 2019 4:42 pm 
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Victor II
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Keep'em well oiled
Joined: Mon Dec 18, 2017 2:51 am
Posts: 378
Location: Madrid, Spain
I have a question about this type of motor...
Attachment:
File comment: Motor. Side view.
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Attachment:
File comment: The motor prior to disassemble
IMG_20190704_201931.jpg
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Attachment:
File comment: The spring barrels, cleaned externally.
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IMG_20190827_213829.jpg [ 1.82 MiB | Viewed 325 times ]

These two barrels seem to have the springs installed in the same direction, and they rotate independently one from the other, attached to the common axis. But if they are not engaged between them by the barrels, how do they work? It seems that the arbor loads only the spring attached to the bull gear, and the second spring...? I haven't studied the motor running when assembled, and I can't realize how the two springs work... Can any of you explain it to me or point me to a video where this can be seen?

Thinking about it... (I've not yet arrived to open the spring barrels) I guess it's a matter of sleeves installed on the axis, and the first loaded barrel engages a sleeve in the second barrel attached to the center of the second spring, or something alike?

Thanks,
Inigo


Last edited by Inigo on Wed Aug 28, 2019 5:11 pm, edited 1 time in total.

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 Post subject: Re: HMV pre-1921 two spring motor
PostPosted: Wed Aug 28, 2019 5:10 pm 
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Victor II
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Keep'em well oiled
Joined: Mon Dec 18, 2017 2:51 am
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Location: Madrid, Spain
Don't needed. Solved. Thanks.
A clever system; the first spring is loaded by the arbor at its center, and its barrel is solidary with the center hub of the second spring, which protrudes from the barrel bottom. The second barrel has the bull gear at its edge and feeds the spindle worm.
Also thanks to others in this forum who have explained how to extract the barrel lids, installed by pressure. Kicking the arbor, it directly transmits the force to the center of the second lid. The first one is extracted the same way, but kicking the first barrel, now empty , solidary of the second central hub.
The motor and springs are now clean, waiting to be assembled again with new oiling. Thanks also to many colleagues at the forum which have advised WD40 for grease removal. It works wonders. I cleaned every part with that, a bit of mechanical action using old toothbrushes and a brass thread brush, a dab of 0000 steel wool, and lots of paper towels. It cleaned easily and fine.

Resuming old threads, I don't know which grease to use for the springs...?. Molykote doesn't work. My own mixture of lithium grease and graphite powder neither works after some time.
I'm nuts about this.
Any advice?
I've seen one video in yt where the colleague ads a red grease to the springs... What is that product?
Thanks anyway.
Inigo


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 Post subject: Re: HMV pre-1921 two spring motor
PostPosted: Wed Aug 28, 2019 7:01 pm 
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Victor III
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Joined: Thu Jan 15, 2009 9:51 pm
Posts: 567
Location: USA
Inigo wrote:
I've seen one video in yt where the colleague ads a red grease to the springs... What is that product?

Mobil 1 Synthetic Wheel Bearing Grease. I've used it in spring barrels for my Victrolas and Gramophones for many years.
Best regards ... AZ*


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 Post subject: Re: HMV pre-1921 two spring motor
PostPosted: Thu Aug 29, 2019 2:02 am 
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Victor III
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 823
Location: Italy
Inigo wrote:
Resuming old threads, I don't know which grease to use for the springs...?. Molykote doesn't work. My own mixture of lithium grease and graphite powder neither works after some time.
I'm nuts about this.


70% molybdenum grease (I use Valvoline, but of course many others would do) and 30% graphite paste mixture. Do not add oil.

I believe that Molykote, despite the name, offers a range of products that don't necessarily contain molybdenum. If you choose Molykote make sure that it is a real molybdenum grease.


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 Post subject: Re: HMV pre-1921 two spring motor
PostPosted: Thu Aug 29, 2019 11:41 am 
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Victor II
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Keep'em well oiled
Joined: Mon Dec 18, 2017 2:51 am
Posts: 378
Location: Madrid, Spain
Thanks for your tips.
Molykote is a molybdenum grease, but I've used it on springs, and I believe it sticks too much, difficult the spring work. Maybe I added too much of the product.
I've bought one graphite cream used for locks and the like, but I haven't tested it yet.
I'm tempted to try the mobil 1. But I don't know where to buy it. It's an automotive product? May they have it for sale in car repair shops or gas stations?
Thanks,
Inigo


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 Post subject: Re: HMV pre-1921 two spring motor
PostPosted: Thu Aug 29, 2019 1:25 pm 
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Victor II
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Keep'em well oiled
Joined: Mon Dec 18, 2017 2:51 am
Posts: 378
Location: Madrid, Spain
Now I remember that I overhauled an hmv 130 for a friend, and for the springs I used a modern grease with teflon micro-balls, and it worked fine. It was one of those modern products that come on a spray can, white coloured.
Do you know about that? Have anyone ever used that kind of modern grease?
This might be the solution, being greasy, moderately viscous, while the teflon balls, being one of the materials with the smallest sliding coefficient known, help the coils sliding, and avoid them sticking to the next one, which causes the spring unwinding resistance. The viscous grease sometimes tend to stick the coils, kind of vacuum effect, which I suspect is no good for the motor efficiency.
Inigo


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 Post subject: Re: HMV pre-1921 two spring motor
PostPosted: Fri Aug 30, 2019 2:46 am 
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Victor III
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 823
Location: Italy
I used Teflon grease extensively in the 90's - although not on gramophones, mostly tape recorders and alike - it's very good at first but the base dries up quite quickly (too quickly for my taste) and gets sticky which is exactly the opposite of what a good grease should do in my opinion, and I already had to rehaul all machines that I lubricated with it. The product may have been improved recently with synthetic bases, but I never really had the will to go back to it and try it again.

As said here and elsewhere, at present time my preference goes for molybdenum grease (for all applications) mixed with 30% pure graphite paste when it comes to gramophone springs. Both molybdenum and graphite are good lubricants even when completely dried up, and the mixture very closely remembers what was originally used in gramophone spring barrels. The only questionable side of molybdenum grease - if we may say so - is its black colour that looks "dirty", but on the other hand that's exactly what makes it so suitable for spring barrels.

The "vacuum effect", as you call it, is the reason why oil shouldn't be added to the coil lubricant mixture: it tends to stick coil spirals one to another, they can slip but not separate. However, I've also read comments of people adding it and being happy with the results, so possibly it also depends on which grease one mixes with which oil. In any case, personally I see no reason for adding any oil, as on one side it's not necessary, and may give problems on the other.

I really don't think that too much grease could cause any problem at all, actually the barrel should be completely packed with grease so that it will be squeezed everywhere when winding. Perhaps you put too few, instead?

I believe Mobil1 is specific for ball bearings, so you should be able to find it in shops specialised in tooling and mechanics and also in very large automotive spares shops.


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 Post subject: Re: HMV pre-1921 two spring motor
PostPosted: Tue Sep 10, 2019 3:36 pm 
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Victor II
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Keep'em well oiled
Joined: Mon Dec 18, 2017 2:51 am
Posts: 378
Location: Madrid, Spain
Thanks. Will consider all your inputs... Maybe I'll do what I never did before: mix the Molykote with graphite powder... Last chance for products already at home! I left the springs with the WD40 alone and they seem to work, although there's some thumping when winding, not when unwinding... But I hate the metallic noises the empty barrels do when winding, and I think this situation may scratch the spring surfaces. I won't play anymore records on that machine until I take out the springs again and reverse with that mixture. A lot of work, but it must be done!
Inigo


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 Post subject: Re: HMV pre-1921 two spring motor
PostPosted: Wed Sep 11, 2019 4:17 am 
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Victor III
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F. Depero, "Grammofono", 1923.
Joined: Thu Feb 24, 2011 4:19 am
Posts: 823
Location: Italy
If you indeed have graphite powder rather than paste, I suggest you add a lower percentage, perhaps 15-20%, or the mixture might result too thick.


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