HI,
Has anyone attempted to make a platter bearing with tight allowance and heated the bearing to have prompt and steady RPM regardless the room temperature?.
I was looking for a Ceramic small heater but the temperature range is too big for this application. I think a temp around 30 degree Celsius would be ok.
I read that someone did with fish tank heater, but the normal 5 or 8 watt heater tubular are too long for my application.
If someone has done it, can you kindly provide some information?
Thank you and best regards
Adelmo
Has anyone attempted to make a platter bearing with tight allowance and heated the bearing to have prompt and steady RPM regardless the room temperature?.
I was looking for a Ceramic small heater but the temperature range is too big for this application. I think a temp around 30 degree Celsius would be ok.
I read that someone did with fish tank heater, but the normal 5 or 8 watt heater tubular are too long for my application.
If someone has done it, can you kindly provide some information?
Thank you and best regards
Adelmo
HI,
Brinkmann TT manufacturer do not entirely think as your opinion.
RPM when the bearing allowance is very very precise and due to the different material expansion affect the RPM in cold and warm running.
Of course is possible to have an electronic system that compensate the speed adjustment, but it is following and results are quoted not to be so good.
Rgds
Adelmo
Brinkmann TT manufacturer do not entirely think as your opinion.
RPM when the bearing allowance is very very precise and due to the different material expansion affect the RPM in cold and warm running.
Of course is possible to have an electronic system that compensate the speed adjustment, but it is following and results are quoted not to be so good.
Rgds
Adelmo
Another snake oil theory...
HMT model NH26 lathe had a run out of 2.5 microns at 4000 rpm with a depth of cut of 10 mm in steel.
They used Gamet (French IIRC) bearings of EP2 grade (extra precision) on the head stock.
That is serious accuracy under load, a turntable is an ant in comparison.
HMT is Hindustan Machine Tools, in India.
If you know engineering math, please check the radial and axial allowances on bearings, and check for thermal expansion tolerances, there will be negligible expansion till about 90 degrees Celsius.
The only way a bearing will stick in normal use at room temperature are:
1. Worn out or dry lube.
2. Inner shaft too big or outer housing too tight.
3. Mounted at an angle, in the sense the housing and shaft are not in parallel, not applicable for self aligning bearings.
Check these first.
And instead of a heater, put it in an air conditioned room. Steady temperature.
Another tip: the 7200/300/400 series bearings are thrust ball bearing series with the same dimensions as the 6200/300/400 (metric) ball bearings, that means easy to substitute if you feel like.
And bear in mind that motor cycles use standard ball bearings on the crankshafts, even though that is a reciprocating load at up to 9000 rpm.
In comparison, a turn table is only 78 rpm max....
HMT model NH26 lathe had a run out of 2.5 microns at 4000 rpm with a depth of cut of 10 mm in steel.
They used Gamet (French IIRC) bearings of EP2 grade (extra precision) on the head stock.
That is serious accuracy under load, a turntable is an ant in comparison.
HMT is Hindustan Machine Tools, in India.
If you know engineering math, please check the radial and axial allowances on bearings, and check for thermal expansion tolerances, there will be negligible expansion till about 90 degrees Celsius.
The only way a bearing will stick in normal use at room temperature are:
1. Worn out or dry lube.
2. Inner shaft too big or outer housing too tight.
3. Mounted at an angle, in the sense the housing and shaft are not in parallel, not applicable for self aligning bearings.
Check these first.
And instead of a heater, put it in an air conditioned room. Steady temperature.
Another tip: the 7200/300/400 series bearings are thrust ball bearing series with the same dimensions as the 6200/300/400 (metric) ball bearings, that means easy to substitute if you feel like.
And bear in mind that motor cycles use standard ball bearings on the crankshafts, even though that is a reciprocating load at up to 9000 rpm.
In comparison, a turn table is only 78 rpm max....
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Use a rubber or EVA foam sheet to reduce vibrations.
Also bear in mind that some European makers, who are garage scale operations, try to highlight an arcane aspect of the system to say they are good or best.
Like B&O, most could not face the test of quality and price and are out of business.
Cartier watches were advertised on the back cover of 'Time' magazine in the 90s....turned out they had six workers in the factory and used ETA movements.
Cartier were lucky to sell one watch a day in the entire world...fancy shape with a Swatch movement!
ETA owns Swatch, Omega, Rado and other brands, possibly Rolex too.
But the impression given was that this was a desirable and unique item to purchase.
Could be same for Brinkmann
A bearing in EP2 grade goes for 100 x the regular price, ask Brinkmann what grade bearings they used, from which supplier.
They won't reply if they are still in business.
And ask them why they did not themselves put the speed and temperature regulation system, instead leaving it to the user to do themselves, not everybody is as good at this.
That is taking the customer for granted.
Like not putting buttons on a shirt, the customer will put them by themselves.
If I was their customer, I would never buy such a product.
Also bear in mind that some European makers, who are garage scale operations, try to highlight an arcane aspect of the system to say they are good or best.
Like B&O, most could not face the test of quality and price and are out of business.
Cartier watches were advertised on the back cover of 'Time' magazine in the 90s....turned out they had six workers in the factory and used ETA movements.
Cartier were lucky to sell one watch a day in the entire world...fancy shape with a Swatch movement!
ETA owns Swatch, Omega, Rado and other brands, possibly Rolex too.
But the impression given was that this was a desirable and unique item to purchase.
Could be same for Brinkmann
A bearing in EP2 grade goes for 100 x the regular price, ask Brinkmann what grade bearings they used, from which supplier.
They won't reply if they are still in business.
And ask them why they did not themselves put the speed and temperature regulation system, instead leaving it to the user to do themselves, not everybody is as good at this.
That is taking the customer for granted.
Like not putting buttons on a shirt, the customer will put them by themselves.
If I was their customer, I would never buy such a product.
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Hi,
I respect your opinion but I do not agree with it.
By the way the fly wheel and platter bearing was a sleeves bearing with thrust plate...
High speed bearing and low speed bearing are different as different is the lubricant.
However it is common in hifi turntable that the platter sleeve bearing have some minor difference in rpm when cold or warm, considering that in most cases the bearing shaft is around just 11 to 15mm in diameter or smaller. Certainly it is possible to use a much bigger motor with higher torque, thicker belt to drive the platter, but there might be some short coming in the sound reproduction....
Oil with different viscosity makes some difference in RPM in a turntable
I do not like to compare motorcycle to turntable as there are different issue involved. In motorcycle rumble is not a problem ...... I own myself a Triumph motorcycle
At the present in my room there are 22 centigrade, not to bad temperature, but the motor pod have lower temperature and need about 40 minutes to warm up and get steady RPM. All is freely spinning believe me.
I wrote what I see in my TT that is also supported by others in similar way
Anyhow, tks for the information, have a nice Sunday.
Rgds
Adelmo
I respect your opinion but I do not agree with it.
By the way the fly wheel and platter bearing was a sleeves bearing with thrust plate...
High speed bearing and low speed bearing are different as different is the lubricant.
However it is common in hifi turntable that the platter sleeve bearing have some minor difference in rpm when cold or warm, considering that in most cases the bearing shaft is around just 11 to 15mm in diameter or smaller. Certainly it is possible to use a much bigger motor with higher torque, thicker belt to drive the platter, but there might be some short coming in the sound reproduction....
Oil with different viscosity makes some difference in RPM in a turntable
I do not like to compare motorcycle to turntable as there are different issue involved. In motorcycle rumble is not a problem ...... I own myself a Triumph motorcycle
At the present in my room there are 22 centigrade, not to bad temperature, but the motor pod have lower temperature and need about 40 minutes to warm up and get steady RPM. All is freely spinning believe me.
I wrote what I see in my TT that is also supported by others in similar way
Anyhow, tks for the information, have a nice Sunday.
Rgds
Adelmo
Perhaps the issue is with the motor pod and not the turntable?
I could imagine that, depending on the bearing oil chosen the viscosity of the oil will vary with temperature. But, given that the TT and motor are already at room temp and that your TT bearing was designed and built to offer the lowest possible friction, they're not going to generate much heat no matter how long you run the TT, so the oil is likely to keep room temp viscosity.
But the motor? I could believe that changing performance and warming over a few minutes depending on electronics. Perhaps you need a better speed controller for the motor?
Possibly the belt. It's the contact area and relies on friction to do it's job. Perhaps belt length changes if its temperature rises. But for it to effect a change in the bearing it'd have to significantly change the temperature of the platter, and that's a lot of mass.
Hi,
I use 2 motors for the fly wheel and 3 belts to drive the platter. These motor are the same as the one used to drive the platter only ( without the fly wheel ).
Therefor the single motor drive reach the speed immediately. Therefore I assume that the problem is related to the Fly wheel motor pod unit and in particular to the fly wheel bearing warming up.
oil viscosity may improve somehow the delay time to reach the optimal speed, but I think not that much since the main problem is that the Fly wheel bearing need to reach a certain temp before reach the wanted 33.33 RPM.
Now I am doing some maintenance to the platter s bearing ( replace the thrust plate as I noticed it has 0.5mm sphere mark in it ) after about 15 years of use, when I reassemble it I will change the oil viscosity to check for possible improvement.
I plan to use also Cera Tec additive 6% with the oil of the fly wheel to see if any change for the better.
However I still believe that the bearing heater for the fly wheel is the solution.
Hope I can find a very small Fish tank heater that can work in dry state to try it. Unfortunately my motor pod inside do not have much free space ...... so not easy to find a 8 or 10 Watt heater.
Tks n rgds
Adelmo
I use 2 motors for the fly wheel and 3 belts to drive the platter. These motor are the same as the one used to drive the platter only ( without the fly wheel ).
Therefor the single motor drive reach the speed immediately. Therefore I assume that the problem is related to the Fly wheel motor pod unit and in particular to the fly wheel bearing warming up.
oil viscosity may improve somehow the delay time to reach the optimal speed, but I think not that much since the main problem is that the Fly wheel bearing need to reach a certain temp before reach the wanted 33.33 RPM.
Now I am doing some maintenance to the platter s bearing ( replace the thrust plate as I noticed it has 0.5mm sphere mark in it ) after about 15 years of use, when I reassemble it I will change the oil viscosity to check for possible improvement.
I plan to use also Cera Tec additive 6% with the oil of the fly wheel to see if any change for the better.
However I still believe that the bearing heater for the fly wheel is the solution.
Hope I can find a very small Fish tank heater that can work in dry state to try it. Unfortunately my motor pod inside do not have much free space ...... so not easy to find a 8 or 10 Watt heater.
Tks n rgds
Adelmo
Hi Steven,
Tks for the suggestions.
When I drive only the platter ( without the fly wheel ) I use a single motor.
For the fly wheel motor pod I used 2 motors, they are individually the same as the one i have employed for the single motor unit, but double.
These motors are from a 5.5 Inch floppy disk. They have a good electronic control for 360 RPM and I would say a not too bad torque. For power supply 12V DC I use a PC power supply 550 Watt.
I have chosen the optimal belt round section and length to drive the fly wheel after several belt test ( section is 2.4mm ).
For the platter I use 3 round belts with a section of 1.7mm. I have tried 3 belts with 1.5mm section but they are not running well, perhaps were too long in length but since I am satisfied with the 1.7 mm ones I do not invest in belt anymore. My motor pod can adjust the distance ( belt tension ) so I tested the optimal position. It is pretty heavy therefore do not change its position after set it.
Agree with you that torque of the 2 motors for the fly wheel and platter could be near the limit, but I do not like to add one more motor. Complex to do and not nice looking with 3 motors in this pod. At the present I prefer to improve the friction of the fly wheel and platter in following ways:
Bearing platter:
Change the thrust plate as I noticed a small wear made by the 5mm spindle s sphere. The sphere is still in pretty good condition and since was crimped to the spindle I just keep as it is. I have a ceramic one but too complex to change it and not sure I would improve much.
The bearing s bushes are still in great condition.
Change oil and add the Cera Tec 6% as additive
Fly wheel:
Change the oil and add the Cera Tec 6% as additive
Try to find a small fish tank heater 12V 8 or 10 Watt and test it.
After above I shall take some conclusion.
I do not have an electronic speed regulation that allow to manually change the speed ( increase or lower )
However the motor speed is pretty steady as I checked with a laser speed tachometer.
Tks and rgds
Adelmo
Tks for the suggestions.
When I drive only the platter ( without the fly wheel ) I use a single motor.
For the fly wheel motor pod I used 2 motors, they are individually the same as the one i have employed for the single motor unit, but double.
These motors are from a 5.5 Inch floppy disk. They have a good electronic control for 360 RPM and I would say a not too bad torque. For power supply 12V DC I use a PC power supply 550 Watt.
I have chosen the optimal belt round section and length to drive the fly wheel after several belt test ( section is 2.4mm ).
For the platter I use 3 round belts with a section of 1.7mm. I have tried 3 belts with 1.5mm section but they are not running well, perhaps were too long in length but since I am satisfied with the 1.7 mm ones I do not invest in belt anymore. My motor pod can adjust the distance ( belt tension ) so I tested the optimal position. It is pretty heavy therefore do not change its position after set it.
Agree with you that torque of the 2 motors for the fly wheel and platter could be near the limit, but I do not like to add one more motor. Complex to do and not nice looking with 3 motors in this pod. At the present I prefer to improve the friction of the fly wheel and platter in following ways:
Bearing platter:
Change the thrust plate as I noticed a small wear made by the 5mm spindle s sphere. The sphere is still in pretty good condition and since was crimped to the spindle I just keep as it is. I have a ceramic one but too complex to change it and not sure I would improve much.
The bearing s bushes are still in great condition.
Change oil and add the Cera Tec 6% as additive
Fly wheel:
Change the oil and add the Cera Tec 6% as additive
Try to find a small fish tank heater 12V 8 or 10 Watt and test it.
After above I shall take some conclusion.
I do not have an electronic speed regulation that allow to manually change the speed ( increase or lower )
However the motor speed is pretty steady as I checked with a laser speed tachometer.
Tks and rgds
Adelmo
Attachments
It sounds like a fools errand you are on and I really shouldn't encourage you.
However, any electrical device that consumes energy is a 'heater'.
Incandescent light bulb or resistor come to mind as the most obvious for a low wattage heater.
Perhaps you could locate your turntable above your amplifier and make use of the waste heat?
However, any electrical device that consumes energy is a 'heater'.
Incandescent light bulb or resistor come to mind as the most obvious for a low wattage heater.
Perhaps you could locate your turntable above your amplifier and make use of the waste heat?
That thing looks home made or fabricated.
How or where does Brinkmann come in?
Use a stronger motor with ball bearings, floppy drive motors were not intended for turning such heavy loads.
Belts do wear differently, it is common for one to elongate more than the other, so I would stick to single belts.
Also verify that your speed variation is within that expected for other turn tables of a comparable design, some have a strobe, with manual speed control.
Automatic speed control can be done with an Arduino unit controlling the motors with a feedback from a sensor.
But a consumer unit with such control? I have never heard of one, but my experience is limited.
The platter rests on a thrust bearing at the bottom, what about the top end of the shaft/spindle?
How or where does Brinkmann come in?
Use a stronger motor with ball bearings, floppy drive motors were not intended for turning such heavy loads.
Belts do wear differently, it is common for one to elongate more than the other, so I would stick to single belts.
Also verify that your speed variation is within that expected for other turn tables of a comparable design, some have a strobe, with manual speed control.
Automatic speed control can be done with an Arduino unit controlling the motors with a feedback from a sensor.
But a consumer unit with such control? I have never heard of one, but my experience is limited.
The platter rests on a thrust bearing at the bottom, what about the top end of the shaft/spindle?
So I researched what brinkman is saying about their heated bearing approach. Their only real claim is that the bearing tolerance is so tight that they need to heat the bearing so that it doesn't bind up in the winter time.
It has nothing to do with temperature consistency or precision. They just want to make sure that you don't mar up your bearing if you wake up one cold winters morning and turn on your record player.
It is a quality of life feature more than anything else.
Have you looked into air bearings? They hold very tight and consistent tolerances. You can also diy one if you have the patience and know how.
It has nothing to do with temperature consistency or precision. They just want to make sure that you don't mar up your bearing if you wake up one cold winters morning and turn on your record player.
It is a quality of life feature more than anything else.
Have you looked into air bearings? They hold very tight and consistent tolerances. You can also diy one if you have the patience and know how.
@ 12russel3456
would a ni-chrome wire wrapped around bearing with low voltages work ? However I would not recommend heating without insulation or longterm effects on its surroundings. Also wouldn't it be counter productive if one wants to 'quickly' heat the bearing putting undue metal stress on finely crafted bearing ?
Best would be to let it run for few minutes. And let it get warm itself without any heating element.
Regards.
would a ni-chrome wire wrapped around bearing with low voltages work ? However I would not recommend heating without insulation or longterm effects on its surroundings. Also wouldn't it be counter productive if one wants to 'quickly' heat the bearing putting undue metal stress on finely crafted bearing ?
Best would be to let it run for few minutes. And let it get warm itself without any heating element.
Regards.
Turntable bearings
Hello everyone,
I am getting tired of reading about improvements of existing turntable bearings. Increasing their precision will only make them more expensive.
Please put your thinking caps on and design a turntable bearing that is ultra simple and ultra low cost at the same time! William Firebough designed such a bearing in his turntable design.
I will attempt it myself in 2022.
Sincerely,
Ralf
Hello everyone,
I am getting tired of reading about improvements of existing turntable bearings. Increasing their precision will only make them more expensive.
Please put your thinking caps on and design a turntable bearing that is ultra simple and ultra low cost at the same time! William Firebough designed such a bearing in his turntable design.
I will attempt it myself in 2022.
Sincerely,
Ralf
I've got a relatively non-expensive Kenwood DD linear arm machine.
It's platter/motor bearing is absolutely silent, even if spun at a few hundred RPM.
So all the foolishness about designing a "better bearing" flies right out the window.
Yet, some people are stubborn and obsessed over such things.
Not sure how the motors' speed is synchronised. Are they plugged in the same controller?
I really do believe air bearings are the way to go.
I have spent a lot of time researching bearings. There are a ton of different designs out there in the world, but all of them are designed with 1 purpose in mind. Low friction.
Everyone is focused on better thrust plates, harder ball bearings, better lubrication, and so on.
An air bearing is virtually frictionless, there is no ball bearing, there is no lube, there is no real meaningful contact between the bearing and the platter.
The only other design I have seen that idealizes so many parameters is a torque converter style turntable. But they are kind of messy and hard to make. With some practice, you can make an air bearing fairly easily.
Hi Everyone,
Sounds like week end so I got some post!. Tks.
@ russa: tks for the encouraging.
@ Naresh: see Origami project with floppy disk. Mine is much much bigger and have advantage to use two bearing in their rotor shaft and being brushless with outside rotor similar to Maxon brushless motors. They have built in a sofisticate electronic control. Speed variation under full load is plus minus 0.1 RPM while turning 340 RPM. Not too bad guys!.
@Tj226: steady bearing temperature steady tight allowance, better and steady spinning. Better sound reproduction. However temperature of the bearing should be around 26 to 30 degree therefore shall not compromise the metals and can be kept on all the time for immediate spinning.
@ Hiten: is not a quick warming and temperature is pretty low and I am thinking to keep all the time on due to the low wattage ( 8 or 10 maximum ) and can be low DC such as 5 or 12 taken from my power supply already installed.
@ Straight Tracker: mine is not a high cost and I assume after 15 years of use a good quality too.
@ Wiseoldtech: my bearing need to spin well and suppor over 5 Kg weight. Kindly note. I just high light that my single motor belt drive is running pretty well. Now the double motors with fly wheel ( see VPI ) is aimed to improve the dynamic of the sound tks to the fly wheel.
@ Gigigirl: I may try recording tape in future. The belt at the present is not the problem here. Temp being low ( max 30 degree Celsius ) shall not be a concern for such bearing materials.
@ Analog sa: each motor have its own brushless controller, I have checked their individual speed and they are pretty synchro. They have same PSU unit for the DV voltage.
@ Tj226: air bearing is too complex to make for the fly wheel and the platter bearing. I believe it, but pump has also shortcoming and complexity as well. I would prefer a mag bearing a la Clar Audio.
Tks you all for the support.
I shall keep you posted of the next result as soon as I have replaced the thrust pad.
Rgds
Adelmo
Sounds like week end so I got some post!. Tks.
@ russa: tks for the encouraging.
@ Naresh: see Origami project with floppy disk. Mine is much much bigger and have advantage to use two bearing in their rotor shaft and being brushless with outside rotor similar to Maxon brushless motors. They have built in a sofisticate electronic control. Speed variation under full load is plus minus 0.1 RPM while turning 340 RPM. Not too bad guys!.
@Tj226: steady bearing temperature steady tight allowance, better and steady spinning. Better sound reproduction. However temperature of the bearing should be around 26 to 30 degree therefore shall not compromise the metals and can be kept on all the time for immediate spinning.
@ Hiten: is not a quick warming and temperature is pretty low and I am thinking to keep all the time on due to the low wattage ( 8 or 10 maximum ) and can be low DC such as 5 or 12 taken from my power supply already installed.
@ Straight Tracker: mine is not a high cost and I assume after 15 years of use a good quality too.
@ Wiseoldtech: my bearing need to spin well and suppor over 5 Kg weight. Kindly note. I just high light that my single motor belt drive is running pretty well. Now the double motors with fly wheel ( see VPI ) is aimed to improve the dynamic of the sound tks to the fly wheel.
@ Gigigirl: I may try recording tape in future. The belt at the present is not the problem here. Temp being low ( max 30 degree Celsius ) shall not be a concern for such bearing materials.
@ Analog sa: each motor have its own brushless controller, I have checked their individual speed and they are pretty synchro. They have same PSU unit for the DV voltage.
@ Tj226: air bearing is too complex to make for the fly wheel and the platter bearing. I believe it, but pump has also shortcoming and complexity as well. I would prefer a mag bearing a la Clar Audio.
Tks you all for the support.
I shall keep you posted of the next result as soon as I have replaced the thrust pad.
Rgds
Adelmo
I did think about bearing and probably had posted somewhere few years back. I thought of having a bearing with triangular shape inside where the shaft would press against two fixed planes (as shown in rough diagram attached) and one side will have ball bearings pressed with proper tension hard springs with screw to adjust the pressure. Tightest tolerance possible ? We can make it even more robust by having a plate pressing against the bearing shaft (2nd image).
regards
