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 Post subject: Does the weight of an Electrola changer platter matter?
PostPosted: Mon Mar 25, 2019 3:31 pm 
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Victor III
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Location: Florida
I currently am working on three complete VE 9-55 Electrolas and the platters for these are fine. However I see that the platters I have for my three VE 10-70 Electrolas, that I will eventually be working on, are wobbly. After taking these three wobbly ones to a machine shop to examine, it was determined there’s really nothing that can be done to resolve that. So now I’m looking at having some made from aluminum. The original type-1 changer’s platter weighs 3 lbs 9 oz and the type-2 changer platter weighs 5 lbs 13 oz. Though I suspect all my platters in the VE 9-54s and VE 10-35s (that I’ll be working on even more later) are ok, I see that if I had extra platters made, the differences in design between the type-1 and type-2 would come from the final machining process... other than the weight differences.

Questions:
1. Do you think an aluminum platter would work in either or both changer types?

2. Does anyone have a need for a new platter for their changer phonograph?


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Mon Mar 25, 2019 3:44 pm 
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Victor V
Joined: Tue Jan 21, 2014 12:55 am
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Location: Eugene/ Springfield Oregon USA
Just a guess, but I'd think that the weight would be important from a flywheel standpoint for smooth operation- less wow and flutter.


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Mon Mar 25, 2019 11:28 pm 
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Victor III
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Joined: Fri Aug 20, 2010 7:48 am
Posts: 544
Location: New Hampshire
I would think a machinist could drill a larger straight hole, press fit a rod, and re-drill. I would hate to see good original turntables replaced with copies unnecessarily. I hope keeping the original parts for any new owners would be part of the process. That has not always been the case for machines I've purchased from others. Doing what you want to a machine you own is understandable. They are our own personal property. "Since you were asking questions." Buying every machines that comes on the market and performing ones personal restoration practices every machine that is kind of disturbing. I guess there will be some original machines out there. I would rather tolerate a little wobble, after all it is over 90 years old. BTW, If to maintain momentum is the goal, which makes perfect sense, it is not the total weight but the weight distribution. I know we all have our opinions and I felt it was time to share mine. 58


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Tue Mar 26, 2019 12:05 am 
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Victor III
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Location: Florida
Skihawx,

Some time ago, I already had the machinist do what you suggest on a platter that had a hole in the center that was previously improperly drilled out. This solution fixed that particular wobble problem. These other 3 platters have a warp disk area and that suggested fix would unfortunately do nothing to solve the problem, as the machinist demonstrated and stated. My intention is to of course to keep these 3 original platters with their respective machines. The platters I suggest making will go with each machine in addition. The warped platters don’t seem to be an issue during playing the records, other than visually. However, it does make a difference in a smooth looking reject, it’s not quite a swish through the record slot.

I asked for quotes today to have these made of stainless steel or of mild steel. I expect to get the price estimates tomorrow and hope to get the weight estimates as well. I have additional spare changers that don’t have any platters at all and this endeavor would benefit those and hence, benefit any empty cabinets that might come my way or possibly for someone else in need.

My goal is to have these changer machines operate properly. I don’t feel I’m doing a bad thing in providing a perfect operating platter (when necessary), just as I have provided aluminum replacements for bad pot metal changer parts and aluminum replacement antenna arm gears. I respect where you are coming from, but what I’m doing has got to be better than an all complete original machine with disfunctional parts.


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Tue Mar 26, 2019 7:55 pm 
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Victor III
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Location: New Hampshire’s West Coast
How much wobble is there? A warp can be caused by stress or damage. If all of one type are warped, I would suspect stress. They may have been this way from the factory. A heat treater could stress relieve your parts, but that doesn’t mean that they would become flat, but they would then be stable. Unless they are cast, a skilled metalworker should be able to straighten them.

If they are only slightly warped, a good machinist should be able bore and bush the hub, chuck it and average out the highs and lows, then bore the hub true to the plane of the face, (averaged). The hub itself would have a very slight wobble, but at 78 rpm and being close to the center, it should be nearly undectable.

I have never seen one of these platters up close, so please take my comments with a grain of salt.


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Tue Mar 26, 2019 9:49 pm 
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Victor III
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Posts: 608
Location: Florida
Django,

Thank you and everyone for the input. There is a very significant wooble in these 3 particular platters. They are the last 3 type-1 changer platters of a total of 17 machines (just finished my 14th complete changer functional restoration last night). The reject mode is not successfully executed when such wobble exist. These are cast platters and I believe are a slightly better type of pot metal than the 5 notoriously bad pot metal changer parts and gears that cause these changers to stop functioning. The platters don’t crumble like the 5 changer parts and gears do, but they certainly can swell and get warped, though not all of them. I haven’t got my estimate for the heavy metal new platters yet but I’m sure it will be worth it. I plan to leave addressing the wobble to future owners, and will not persue these any further at the advice of my machinist. I plan to have made platters that not only will be perfectly flat and look like the original, but should last hundreds of years . My weight concern and question is no longer of issue since I have ruled out using aluminum. Though I have not worked on them yet, I really don’t believe this is an issue for the type-2 changer platters (VE 9-54, 10-35, 10-69) since they are thicker and heavier (maybe made of steel).


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Wed Mar 27, 2019 12:44 pm 
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Victor IV
Edison, Columbia, Victor, Pathé...and oddball makes
Joined: Sun Jul 08, 2012 1:06 pm
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My 10-50's original platter, seemingly made of pot metal, is noticeably warped. Rather than fiddle around with trying to remedy that, I elected to make a new one. I used to know a retired master machinist, long since gone to that great machine shop in the sky, so I gave him the old platter and scared up a nice block of aluminum at a junkyard. He had a small shop in the corner of another friend's auto repair shop, and machined stuff in retirement for fun and pin money. He was retired from the Lawrence Berkeley Lab and in his late 70s or 80s at the time, and he really knew what he was doing - and the shop owner had a virtually instant resource to make otherwise unobtainable parts for the early Ferraris he repairs/restores.

The plan was to duplicate the diameter and thickness and tapered spindle hole etc, and then hollow out the underside like the original until the weights of the original and the new matched. But it turned out the last step wasn't necessary, because the full new aluminum part weighs about the same as the original cast one.

It's so beautiful that I have never had the heart to glue felt onto it, which makes no difference in operation. Pretty sure it's made to some extraordinary nuclear quality spec, because that's how Bob rolled.

I'll see if I can post some pix later.

Years ago I could have made comparative calculations about angular momentum and inertia and all that other stuff I learned-and-forgot in engineering school, but the bottom line is that it works like a champ.


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Thu Mar 28, 2019 9:39 am 
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Victor III
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Location: New Hampshire’s West Coast
Good luck with your project. Please update us on your progress.

Years ago in the tool and die trade, we would use O-1 tool steel for producing dies and the plates would warp from heat treat and annealing. Before surface grinding we would tap on the concave areas, (the inside of the curve, tapping, not banging), with a piece of brass to relieve some of the stress. We were not bending the piece, just relieving a little stress to allow the part to flatten back out naturally. We had varying amounts of success, but it may be worth a try. Years ago, castings would also be allowed to stabilize over time and castings for machine tools were often left un-machined for a number of years. Even now, extremely precise parts are often roughed out, then stress relieved before finish machining.


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Thu Apr 04, 2019 11:37 pm 
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Victor III
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Joined: Mon Oct 21, 2013 9:58 am
Posts: 608
Location: Florida
Finally got the quotes to make the platters from mild and stainless steel They are through the roof and therefore not an option. Plus the warping concerns of steel that Django mentioned, this route is just not the way to go.

So... now I may be back to aluminum. To determine the weight of the platter in aluminum I would use the formula πr2Δx, where Δx is the height, to determine its volume in cubic inches (c.i.) first. Roughly speaking the platter consists of a ½” high 8” round disk sitting upon a ½” high 1.5” round disk. Since the thickness is roughly ½”, the formula becomes simply π multiplied by the radius. That would be about 13 c.i. and 2 c.i. for the two parts, or 15 c.i. total. So with aluminum being 1.57 ounces per c.i., the approximate weight of the patter would be just under 1.5 pounds, which is half of what it should be.

So... considering what PeterF stated, I think I’m going to get a prototype made up from aluminum and test it out.


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 Post subject: Re: Does the weight of an Electrola changer platter matter?
PostPosted: Thu Apr 04, 2019 11:59 pm 
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Victor IV
Edison, Columbia, Victor, Pathé...and oddball makes
Joined: Sun Jul 08, 2012 1:06 pm
Posts: 1347
Since making my aluminum replacement, I have acquired an accurate digital postal scale. I can thus weigh both the original and new ones accurately. I'll post the results, and pix, here.


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