How best to eliminate LP warps

@piaudiol The use of an environment using the available Ambient Heat and not using heat applied as a point source or forced heat, is as said earlier, a low risk way to accelerate the reforming of the Vinyl Disc.

Sunlight Directly behind glass can reach 60 Celsius, so a Thermometer used to select a position that is creating a Temperature between 20-40 Celsius will be a lower risk method. 

Your success with creating the wanted reforming of the Vinyl Disc within a short timescale is good news and should serve as a guideline for methods that will create an ambient heat to assist with the reshaping.  

A Vinyl LP is Thermoformed and the composition of the material will react to heat and deform, as well as conditions that are applying force to a degree that can cause it to deform in shape.

Methods to correct a deform in shape can utilise both of the above influences, the use of Heat and Force are the common methods chosen. The not so common method chosen is Force only and relying on a ambient temperature as the heat source. 

Methods to flatten a Warped LP are around for a very long time, and were probably presented as a method from an era, when a LP that was deemed as a damaged and very easily replaceable due to the LP as a commodity being readily available,                the Flattening Devices in their earliest concepts were one of many other marketable product, offered as a ancillary device, most likely to be purchased by individuals with a desire to 'make do and mend'.

The times have changed and the Vinyl LP is not so readily available, and the need to 'make do and mend' is a genuine consideration. The LP as a commodity today is for certain Albums a thing of rarity. If such a rarity is to receive a corrective treatment, the rarity, put a new emphasis on the considerations that are required to ensure the correction is not detrimental to the LP in general.

The only real concern that should be in place, is whether the outcome of a Groove having deformed and them being deformed once more, to be returned to an earlier shape, will have incurred an unavoidable change to its form produced at the time of the pressing being new.     

A Thread on another Forum has covered this subject and has suggested a variety of methods using Polished Edge Glass Sheets as the press to supply the force.

The Methods are all reported on as being successful, but in my mind some are carrying more risk than others and there are not guarantees, one method using force applied heat can be replicated in another set up.  

One individual used the Glass Sheet Press with a added Weight only, and had reported that the LP was flattened within a month.

This as a method, in my mind is the method that presents the least risk for the LP, as there is not a force heated environment being created, where forced heat or point source heat is presenting an additional risk.

The time required using the Press/Force only method, could probably be decreased if the materials were placed into a smaller environment with an increased Temperature set with a range between 25 - 40 Degrees Celsius, with 40 as the maximum.

In my mind the temperature should be ambient and not created by forcing or applying heat directly to a press material that is being used, as this could create a point source for the heat, and the LP could be detrimentally impacted on as a result. 

A method to control the temperature to a chosen level of heat, could be achieved at e very cost effective outlay.

A Polystyrene Box used for Temperature Controlled Transportation, with a Herpetologist's Heat Mat placed inside will be a very suitable method.

A Heat Mat produces a uniform heat over the mats surface, so a hot spot is not radiated, creating an intensely heated zone, using the Heat Mat with a Thermostat  will be ideal for producing a very cost effective method for controlling the Box's evenly distributed Temperature with a low voltage heating device.

I had a unwanted experience once when using a Oven to be the source of heat. , When trying to make a form in a foam material, the Foam was placed and concealed,  between two heavy metal plates and the Fan Oven set to a low Temp'. The low Temp' was still able to create a Hot Spot, which caused the foam edge to deform to a non correctable condition.

I don't recommend using an Oven as a method for rare vinyl LP's, I don't see how a condition can be created that is reliable and consistent for all adopters of the method, unforeseen risks seem inevitable.

For the DIY Method and not using purpose produced devices, the Ambient Room Temp and Press with applied weight, with an allowance for the time needed to complete the reforming of the original shape, is looking like the best place to begin.

If a version of this method is then wanted which can potentially produce a decreased time requirement for the process. The method to produce a space with an increased ambient Temperature being present, seems to be the next method that has the least risk attached.          

If a research is done into using a Peripheral Ring, it soon becomes apparent that additional to the intended benefits of the increased inertia, the impact of the weight on the LP, and the reduction of the warped form around the rim, has shown, if the reports are accurate that new levels of quietness are achievable during the playback when the Peripheral Ring is present. 

Not all TT's can utilise a common design of a Peripheral Ring, so it is always best to check if the TT is compatible with the design being selected. One such design change could be the need for a shallower depth weight or a chamfered edge to a weight.

 

@drbond In relation to your inquiry about eccentric rotation, the Link might prove to be latest commercial device on offer to confirm the amount of Off Axis eccentricity being produced.

It would be good to know if this device is also able to measure the Spindle being rotated in a Off Axis Rotation.

 https://ds-audio-w.biz/products/563/?fbclid=IwAR041VevFGPZEx1e_igdoMNhhEUbOFKiQvBaK3ktZM-ocM63_X6sAnehJ98  

@mijostyn A spindle within a Bearing Housing and rotating being guided by Bush Parts with excessive wear on the inner walls will allow for the Spindle to take on a eccentric 'off axis ' rotation.

As said it would be good to know if the device was able to detect this being present.    

At no time have I made it seem like it is going to be a common discovery to encounter a TT, that has a Platter Spindle housed with Interface materials that are showing excessive signs of wear and the most likely cause being, the interface parts are doing, 'as said on the tin' and having a service life associated with being sacrificial and expected to yield in their soundness by design.

The fact is that it does occur, an interest in the subject can easily show cases where discoveries have been made.  I have hands on experience of these unwanted conditions having occurred and through discussions with others face to face and through using a forum as communication channel, knowledge becomes available of unwanted conditions that have been discovered within a TT's Platter Spindle Bearing Housing.

I have no beef with anybody who does not care for the subject, but as there are many who visit forums, and somehow end up with a desire to buy into a Vintage TT, it is no harm in informing them of a condition that they might inherit as part of their purchase. It is for these reasons only that I keep the subject live.

I have been instrumental without making any profit, in helping some Vintage TT owners acquire a necessary part to overcome a condition that has been wanted to be remediated. The conditions have not been fantastical as seems to be suggested by a few members on here recently, but quite real and enough of a concern for the TT owners to seek guidance to correct the condition.  

A Individual who is buying TT that has been a model available in the used market for a very long time and especially the Vintage Period, can be supplied a TT that has a condition in a Bearing Housing that might need a rethink and corrective measures used to make an improvement. It is best to identify with this being a Possibility prior to going down the rabbit hole, not all users of TT's are settled with the idea of carrying out surgery on them, the very idea, might make them feel quite queasy. 

I know a individual who has a well respected Japanese Vintage TT, one that quite a few would aspire to own. This individual has been quite proud of their TT and had made it known on a few occasions, how they would be happy to have it used in a Line Up at a Bake Off.

This same individual when stumbling on a discussion about Bearing Condition on another forum, was to become a vehement adversary to the notion their TT could be in need of a overhaul of the Bearing.

At a later date a Off Board Key Strobe was used and a discovery was made that encouraged the individual to suspect something was amiss. The investigation lead to the Bearing Assembly, and the result of the investigation was such that the Bushes were showing signs of excess wear and the Interference fit Ball was with a  scribed surface.

This individual was aware of the work was having done on a identical model TT, and inquired if they could queue Jump, as they were not wanting to use their TT, in the condition it would be in if reassembled using the Vintage OEM Parts.

I agreed to let the other TT have the work carried out in advance of my own one.

The Engineer tied up and the work run on longer than planned, the TT owner waiting for their bearing parts to be produced, bought in another identical model TT, to use as a stop gap. The having the possession of two TT's got their thoughts going and two identical Plinths were produced from the materials of choice.

The Identical Plinths and Same Model TT's was now in a position where both versions could be A/B compared using the same Tonearm and Sub Plinth Structure.

The outcome of the A/B testing was quite a revelation, the Original Parts TT, did not survive the whole of the selected tracks to be used during the comparisons.

The TT with the Bearing Parts using a modern approach and modern materials was the much preferred, they claimed it was like two different TT's.

The Vehement Adversary to the notion, was now making appraisals for the changes that were not present prior to the first experience of the new design bearing assembly.

There are now in place other additional methods that have been adopted for use by this individual, they are convinced that looking after the bearing assembly and housing are key to creating a valuable improvement. There is now a method produced to rigidly fasten the Bearing Housing. The curiosity has not stopped there, there is also one of the TT's with a Lignum Vitae Bush and Thrust Pad produced, that is yet to be A/B demonstrated between the two modified TT's.         

A Worn Thrust Pad is the most likely to be expected, many that are inspected for wear will usually show some form of indentation.

It is quite common to see a Thrust Pad that is interfaced with an interference fit ball in the base of the spindle, to have shown an ellipse shape as the wear seen formed at the indentation on the Thrust Pad. This condition serves as an indicator, and suggests the Spindle Rotates of Axis.

Another condition reported on, is a flattening of a Steel Ball and another much more unwanted condition, being a scribing on the surface of the Steel Ball, I have been shown these conditions first hand and have seen it presented as an item needing to be corrected on other forums. It has also been a subject shown by a respected service engineer, who is referred to on this forum regularly. This is not a fantastical idea, it is real and it occurs.

The Bushes are probably the hardest item to think of as showing a Wear, but again they do. When the condition is present, an eccentric rotation is most likely to occur, the longer the period of rotations, the longer the exposure to operating conditions that can increase the wear, resulting in increased Bush Wear and an increased eccentric rotation. I have had my fingers on Spindles that have been able to produce a Tapping Noise when gentle finger pressure is applied. I know of others who have been able to produce a Tapping noise as well, using similar lightly applied finger pressure. It is not a fantastical idea, it occurs. 

I like to think that when a individual has a TT in use with an unknown usage history, they are fully confident about the condition of the TT's Bearing Assembly and that is is functioning to a standard that is mechanically sound.

The idea of a very expensive Stylus interfacing with an LP Groove that is most likely eccentric in rotation due the pressing of the LP, and then this being amplified further by the Off Axis rotation of the Spindle, is a condition I wish to avoid.

I have taken a few steps to overcome across many years, and have had Bearings Overhauled by a Specialist Service, or alternatively Supplied as a New Design to be used on a Vintage TT. 

As always 'each to their own'.

If there are individuals not wanting to concern themselves with the the possibility for mechanical issue being present, that may be a concern, within the assembly of the Bearing Housing, that is fine. At no time have I made it seem the enjoyment of music is not to be had on any condition of a Bearing Assemblies Parts.

Alternatively there might be an individual who is aware of something that is a concern to them, then stumbling on these types of post's might be enough to motivate them to learn more, there can be no harm in that happening.    

Then there are the types that like to think the Bearing Assembly is able to be  brought up to a very high specification and has exchange materials in use that are modern and fit for the purpose of the role they are selected for, I'm sure those types really enjoy stumbling on Post's that cover the subject of carrying out such work.   

 

Tea Total is the Key, no fantastical stuff, followed by just a pure curiosity to learn a little about the what would be the best for the Vinyl Source.

For me it lead to the best environment that a Stylus can be functioning in.

In a very layman description, Vinyl Condition and Cleanliness/Purification within the Groove, Operational Energies Transferred to the Styli, Energies Transferred from the Styli.

I am fortunate to be able to have a support form very adept individuals, who are known for being able to produce methods or carry out work that reduces the effects of the above.

To receive a demonstration of a Vintage TT, with a modified bearing housing, using Modern Materials machined to be a best fit and have a lubrication that is hydrodynamic, is something when encountered is quite indelible, it is as memorable as the song 'Summertime', and has a similar impact, as once heard, one is happy to hear more. 

I have a friend who took these ideas, to a further level and had a Spindle Produced that has a Steel section within the Bearing Housing and a option to use a Variety of Materials that are in contact with the Platter, there material of choice when I was demonstrated this design was Ebony. 

My interest in the subject is no different to a savvy Modern Turntable Producer, they are looking at the similar materials and choosing these to work with their own dimensional tolerances for the materials to interface, this will then allow for their selection of lubrication that best suits those chosen materials and selected dimension tolerances.   

On the subject of a Warp, I have tried out a AT-666 Vacuum Mat and was not satisfied with the sonic trait and how it was perceived as influencing the SQ during the replay.

I do intend on owning a AT-666 and trying it with different materials under it and upon it the LP, to see if the sonic trait can be altered to one that is being perceived as more to my preference. As usual these outcomes are all subjective, and the usual undertaking of later arranged group demonstration, along with the variety of  listening sensitivities that comes with a mixed group,  could easily produce a host of mixed assessments, that are the antithesis of ones own. 

Not being Selfish, the final choice, does belong to the end user, but sometimes the comments made from others, does help with pinpointing traits that one may have been overlooking during their own evaluations. 

 

    

@lewm On this forums analogue section there are very few posts from a small selection members, which can appear when an individual beats the drum on a subject, that it is something that is ubiquitous and all are needing to heed the concerns raised.

That is not the case, I am only offering an account of my experiences encountered and nothing else, as said I have been touching base on this subject for many years and have latched onto various information that is in keeping with it as and when discovered.

My earliest experience, where I have shown concern for a bearing condition prior to having modification carried out is when I cleaned out and decontaminated a Bearing, to allow for a Lubrication oil change on a Belt Drive TT, but I would not align that sort of activity with a Bearing Modification.  

As said, I have been interested in the condition of a bearing housing on a owned TT for more than 20 years, this interest started with a Garrard 401, that was sent to a engineer renowned at the time for their work who modified the assembly.

It was this experience that left such a good impression, that made myself be more concerned for a Bearing on a TT, than I would suggest is the common level of concern met, in recent years.

This same type of level of concern has been made toward the Tonearm, and I no longer use certain Tonearms, as I have a arm that has been overhauled, using modern materials and machining tolerances that suit these materials, once more the experience of such design when encountered is a compelling attractor and indelible, especially enough to not want to continue with the other owned Tonearms.

In relation to a TT Bearing, my interest commenced more than 20 years past and during this period, the interest was ignited on a few occasions, but especially through the forum Lenco Heaven.

Through LH, I have been both observing others work and meeting with individuals involved with the forum, who have been working with improving Bearings on the TT's, this work has been observed from many areas and methods used have been duplicated by others.

The Lenco and the Garrard TT's are now able to have Bearing assemblies supplied as Commercially Available Products as an exchange part, that are using the basic principles for the designs produced by the forum members enthusiasts.

The general ideas for the designs are to remove Metal to Metal Contact.

The use of Non Metal Modern Materials used for the role for replacing the originally used metal sacrificial parts, along with a design intent, that  is creating a interface with a accurate/consistent dimensions for the tolerances between the moving an passive parts has been a method that has become quite common in todays bearing assembly designs.

I have been invited in the past to take part in assessing the differences between a bearing assembly on a Idler Drive TT.

Three Bearing were available that are quite easy to swap out, the TT's Chassis had been specially treated to minimise Flexion occurring and effecting the Bearing Spindle.

One Bearing was original with an added lubrication only to a Bearing Housing.   Another version was a overhauled Bearing Assembly, based around the original. The other version was a Modern Material designed Exchange Bearing with a Composite Spindle and where Hydrodynamic Lubrication was claimed to have also been achieved and the flexion that can occur to a Bearing Housing was substantially reduced.

All the above demonstrations took place on the same TT > Tonearm > Cart' and Mounting Method and the attraction toward the Modern Material Exchange Bearing, with a attention to the Lubrication Method and Reduced Flexion, is a version when encountered is quite compelling, it is an indelible experience, needing to be experienced for longer than the alternative versions. 

What I can suggest without reservation, is that a change of Lubrication Only within the Bearing Housing, is a method I will am not recommending, it the TT is to be used extensively.

To fall into the mindset that a oil change only on a TT that is with a unknown history of usage and the present owner not having any knowledge of the quantity of rotations and the conditions those rotations have occurred in, is a situation that is enough to warrant the notion that a further investigation of the Bearing Assembly would be a good practice. Caution is a best practice to be used, if improveing on the condition within the Bering Housing is wanted to be pursued, a skilled individual in such practices may be best consulted with to be a reassuring support.

When I transferred over from Idler Drives to Vintage DD TT's, I acquired TT's in the usual manner, as I viewed these as projects and purchased at a project value.  To have made a purchase of TT's that have shown a excessive movement from the Spindle was not intended or even considered as the condition that would be most concerning, especially when the play detected is the worse movement I have detected from any spindle bearing I have handled.

It has been this experience that has encouraged myself to make it known that when considering a Vintage Japanese DD TT, that not only the Electronics might present an issue that is a concern.

During my broadening of the discussions on the subject of discovering an unwanted Spindle Movement on DD TT, there has been others come forward and make it known that there has also been similar finding on their owned Vintage DD TT's. On the subject of detecting a play on a Spindle within the Bearing Housing I am not alone, having a few Compadre from across the Globe reporting on a similar finding. 

Again, at no time have I suggested there is a ubiquitous issue with a Vintage Japanese DD TT. 

I happily receive comments from TT owners who are not detecting anything concerning on their owned TT's Spindle, this is the best scenario and is the one I wish for all to encounter.

I happily spend 'some of my time' learning about the overall requirements to get the best from a Vinyl Source, Mechanics, runs parallel with Geometry and Electronics, I am quite balanced across all the necessary disciplines to be understood, and choose the parameters that are the most attractive to myself.  

I share my experiences and reference the experiences of others, for the individual leaning toward the idea of purchasing a Vintage Japanese DD TT. It is for the best, if they go into it with their eyes wide open, using the knowledge that is available to them. It is no harm for a wannabe purchaser, or owner of a TT, to be aware that a Bearing Assembly might come with or have a condition that is not ideal, and is another to be  added to the usual concerns seen for the condition of the Electronics.

As always we really want the supplied product to be one with a minimum of markings on a almost pristine Aesthetic, as the only bug bear, but wants and realisation are quite different when it comes to Vintage.   

 

@poorguy I never learnt what the metal was that is used on the AT-666.

I know others use this mat on this forum, and it might be possible to learn which metal is used if a wider inquiry is made.

I also know through this forum, it has been used without a Vacuum and has been rated as an attractive method, I have not heard the mat used in such a way, but would try it out in the near future, as I will be visiting the owner of the one I have tried out.

Again there are AT 666 owners on here who can offer a description with almost immediacy if willing to help.

The AT 666 is not always going to be able to successfully hold a Vacuum for a full period of a side of a LP, their age is contributory to this, the length of time the Vacuum is in place is a unknown, some do not produce a Vacuum anymore.

With the above in mind, it does suggest careful selection is required, when purchasing,  if a Vacuum is the important function for the mat.