Restoring and Improving A Thorens TD-124 MKII - Page 83 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 15th July 2013, 06:20 PM   #821
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Probably need to talk to the help desk about your login issue, no reason I am aware of why your old account should not have worked, I do note that ntesla reports your membership data as 2009.. Perhaps you can request to use your original moniker.

As to the bearing issue, I purchase bushings from sellers who supposed supply them specifically for the TD-124 and they have all been variable in terms of fit.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 17th July 2013, 04:42 AM   #822
diyAudio Member
 
Join Date: Feb 2009
Hi Kevin,

I'm not sure that the name change hassle is worth the trouble, for me or the operator, so I'm just going to let it be.

I guess if I was planning on ordering a bearing, I would ask them to specify the OD and ID, knowing that they both would shrink by a small amount once installed.
  Reply With Quote
Old 20th July 2013, 08:15 PM   #823
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Default Royco, Mobil & Shell turbine oils: any experience with them?

Specifically I'm interested in knowing if anyone has either used one of these synthetic turbine oils in the TD 124 motor, or if they've investigated them and determined they wouldn't be appropriate for this application.

Royco 555 Turbine Oil

Royco 555 Turbine Oil 1 Quart | eBay

Shell Aeroshell Turbine Oil 560

Shell Aeroshell Turbine Oil 560 Manufacturer Lot 6064 | eBay

Mobil Jet Turbine Oil

Mobile Jet 254 Turbine Oil One Quart Can Mil PRF 23699 Synthetic Oil | eBay

I'm still digging into the specs of these, but here's a link to the Royco 555
http://www.qclubricants.com/msds/PDS/Royco555.pdf
  Reply With Quote
Old 20th July 2013, 10:57 PM   #824
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Default TD 124 motor & spindle operating temps?

I'm trying to familiarize myself with some of the military specifications for various turbine oils, and as I've read them, I realize I've not come across much discussion related to the operating temps of the motor (spindle/bushing contact point temp) and the spindle. Clearly the motor runs quite a bit hotter than the spindle and while there's been discussion about just how hot it runs, all I've read has to do with how hot the outside is to the touch.

If anyone's conducted measurements, or feels they know enough about motor operating temperatures in general to hazard a guess as to the temp. range on the bearing surfaces, I'd sure like to hear what you have to say. Likewise for the spindle. I understand the general thinking seems to be that one oil can do both jobs, but I'm just not there yet. Thanks.
  Reply With Quote
Old 21st July 2013, 01:49 PM   #825
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Default Thorens Motor Grommets vs RCA Motor Grommets

Nine New Motor Grommets for RCA 45 RPM Record Player Free Fast Shipping | eBay

I have several Duals I'm working on, so came across this ad while scanning this seller's inventory of Dual parts. While they don't have the top washer, they are advertised as new rubber and the motor they support, while not identical to the e-50, looks like it could be of comparable weight. Perhaps they're completely different dimensions/load capacity than what's currently being offered for the Thorens, but then again, perhaps not. The difference in price is what intrigues me.

Thoughts?
  Reply With Quote
Old 26th July 2013, 12:07 AM   #826
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Default Isoflex PDP 40 in Thorens TD 124 motor?

Still digging into various motor lubrication options and hit on one as a result of my work on various Dual turntables - Isoflex PDP 40. The 1200 series Duals have pretty massive motors with spherical sintered bronze bushings. Specs on the Isoflex PDP 40 indicate it's a synthetic oil intended for a variety of uses, including "synchronous motors." There's a mention of it being suitable for use in turbines as well. The full specs. can be found at the link below. I'm interested in hearing any thoughts on its use in the E-50 motor.

http://www.nonstopsystems.com/radio/...nschreib-K.pdf
  Reply With Quote
Old 26th July 2013, 12:58 AM   #827
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Bear in mind that the E-50 is an induction motor that needs a certain level of drag to assure that it runs within the proper speed range. The original lubricants were selected to assure proper operation over a wide range of conditions. You're essentially second guessing the original designer of the table which is not necessarily a bad thing at all, just be aware that you may have a lot of additional work ahead of you to get it to run correctly with all of the proposed changes.. Good luck!
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 26th July 2013, 03:21 AM   #828
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Quote:
Originally Posted by kevinkr View Post
Bear in mind that the E-50 is an induction motor that needs a certain level of drag to assure that it runs within the proper speed range. The original lubricants were selected to assure proper operation over a wide range of conditions. You're essentially second guessing the original designer of the table which is not necessarily a bad thing at all, just be aware that you may have a lot of additional work ahead of you to get it to run correctly with all of the proposed changes.. Good luck!
Thanks, Kevinkr. Much of this is probably old news to you, but I'm stumbling through it for the first time on my own and despite having read a good deal here and on other forums, I really haven't learned enough, so I'm trying to learn more any way I can.

I understand the Dual and Thorens motors aren't of the same design, but I don't quite follow how the "drag" you're referring to relates to the lubrication used in the motor. Are you suggesting any lubrication characteristics that make it spin more easily would be a problem, or the opposite? Lubrication is a science, one I'm unlikely to ever understand, but I do think it's possible to learn enough to make a proper decision here, or at least that's my goal. Viscosity alone is a lot more complex than I ever thought it was, so of course what you're saying is of great interest to me and I'd like to hear more of your thoughts on the matter.

You mentioned "all of the proposed changes." I'm not looking at making any other modifications to the motor. I did mention some grommets I saw on eBay and asked if anyone knew anything about them, but I don't need them. All the motor grommets were replaced with ones I bought in a kit, although I have to admit I had to take the word of the seller that they were for the Thorens. Now that I know there are other turntables out there that used grommets that look (but might not be) identical, that's something I have to take into consideration. I never did believe the old saying, "parts is parts."

My only planned work on the motor is to install the motor rebuild kit I purchase, the same one most people use. But I've spoken to the seller who tells me the bushings have been saturated with Mobil 1 engine oil. And that complicates things a bit for reasons I'll explain below.

To be clear, my objective isn't to try and second guess the designer, but to figure out just what the designer actually used for lubricating the motor, use that, or something with very similar characteristics, which is hard to do since I have never seen the original Thorens specs for the motor oil.

I understand that if someone is really insistent on using the most appropriate lubrication known for the E-50 motor, they should just buy what Schopper sells. Honestly I'm not 100% sold on that option either - primarily because no specs are given for it - only that it's a "NATO grade turbine oil" that can be used in cruise missiles. Yes, that's what the U.S. distributor gave me for info. on the oil.

Having read up a bit on the milspec for cruise missile turbine oil, I have to say I honestly don't think much of that applies here. One of the main concerns for lubrication in cruise missiles it turns out is idle time, for instance.

Over at VinylEngine I came across a similar discussion related to lubricating the Duals. One post in particular really got my attention. The fellow provided a pretty detailed comparison/contrast of engine oils vs machine oils, why one can't simply be substituted for another. It made a great deal of sense to me.

To summarize what was said there - Engine oils are used in closed lubrication systems with filters, several quarts of circulating lubrication, intended to be drained periodically. These oils contain additives that can, over time, clog sintered bronze and when exposed to water, for instance, become milky. Machine oils are used in much smaller quantities, in environments where they're in direct contact with the atmosphere.

Thus I'm doing the best I can to figure out just what really is the proper oil for this motor and I'll keep looking into it and asking questions until I figure it out. Like a dog with a bone, I suppose.
  Reply With Quote
Old 26th July 2013, 11:13 AM   #829
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Lower viscosity oils will cause the motor to run faster than it should as will sloppy bearings, at a certain point the eddy current brake can no longer be adjusted sufficiently to slow it down. This incidentally applies also to the lubricant in the main bearing well.

The consensus of most who work on these tables is that a 20wt electric motor oil is about as close as you will get to the original. The 3 in One 20wt Electric Motor Oil I recommended earlier in the thread works extremely well. I've rebuilt more than a half dozen of these motors and used this oil to impregnate new motor bearings without issue. The oldest of these motors has run for over 1K hours over the past two years with no need for further attention.

I would recommend checking to see what weight of synthetic was used in your bearings.. Were it me I would heat the bearings to drive out the existing oil and replace with the above 20wt oil.

Automotive oils are best avoided for the reasons you state. IMVLE some turbine oils do not stand up well in the presence of oxygen and I no longer use them for this reason. (Yellow sludge)
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 26th July 2013, 12:45 PM   #830
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Kevinkr - I fully agree with everything you said. My focus is not to find a better alternative to various engine oils or turbine oils (those that are not intended for use in electric motors with sintered bronze bearings), but to determine if there is anything that would be superior to the 3-in-1 electric motor oil, which currently would be my lubrication of choice.

The work you and others have done in this area carries a lot of weight with me. Hearing specific examples of a well-running motor after two years in service and 1k hours does give me more confidence in the 3-in-one. The only other data I've got on turntable electric motor lubrication longevity comes from Dual. The 1200 series motors apparently were expected to run 5k hours before needing lubrication (they also use oil saturated felt washers).

What has given me pause are comments describing the E-50 motor as running hot. Were I to read something attributed to Thorens that confirms the motors ran hot when new, I'd be less concerned. It could well be the motor design, but lubrication can play such an important part in heat buildup (friction, vibration) that I do wonder.

I also wonder what role the selection of lubricant plays in the extensive break-in period that seems so critical to getting rebuilt motors dialed in. Are other factors much more in play here, i.e. tolerance differences compared to the original, spindle wear, minor deformations in old motor casings, more precise methods of motor assembly by the manufacturer? Or did Thorens actually go through a similar tweaking of the motor under load? Understand I'm not suggesting the break-in tweaking under load isn't necessary, just trying to understand exactly why it is necessary and to the extent possible, determine if it is at all related to the lubrication being used today. If a different lubrication were found that reduced motor vibration further, reduced heat buildup further, and all other lubrication characteristics were on par or better than the 3-in-1, then a reduction in initial vibration, a reduction in overall effort necessary to get the motor dialed in would likely translate to less wear on the moving parts over time.

In short, if you were to spec. a better oil than the 3-in-one, how would it differ?


Quote:
Originally Posted by kevinkr View Post
Lower viscosity oils will cause the motor to run faster than it should as will sloppy bearings, at a certain point the eddy current brake can no longer be adjusted sufficiently to slow it down. This incidentally applies also to the lubricant in the main bearing well.

The consensus of most who work on these tables is that a 20wt electric motor oil is about as close as you will get to the original. The 3 in One 20wt Electric Motor Oil I recommended earlier in the thread works extremely well. I've rebuilt more than a half dozen of these motors and used this oil to impregnate new motor bearings without issue. The oldest of these motors has run for over 1K hours over the past two years with no need for further attention.

I would recommend checking to see what weight of synthetic was used in your bearings.. Were it me I would heat the bearings to drive out the existing oil and replace with the above 20wt oil.

Automotive oils are best avoided for the reasons you state. IMVLE some turbine oils do not stand up well in the presence of oxygen and I no longer use them for this reason. (Yellow sludge)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need help with Phono Cartridge for Thorens TD-166-MKII sonictonicmusic Analogue Source 5 24th July 2013 08:43 PM
Thorens TD-124 newbie neil_kaye Analogue Source 6 17th March 2008 02:44 AM
Thorens TD-125 MKII Parts needlenose Analogue Source 9 12th March 2005 10:08 PM
Transformer for Thorens TD-166 MKII Peter Menting Analogue Source 5 30th August 2003 06:15 PM
Thorens TD 124 MKII question louis Analogue Source 3 2nd July 2003 03:27 AM


New To Site? Need Help?

All times are GMT. The time now is 05:51 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2