I don't have Solid Works. It's a fairly simple design, most machine shops should have no problem with it.
OK, so I downloaded the free CAD software from emachineshop.com and after a few false starts, was able to recreate both pulleys and export them in .STL format. Emachineshop.com quoted $229 for 10pcs and $281 for 25 pcs (I think 1 pc was $180). The material is spec'd as Acetal which is the generic term for Delrin.
When I had the local machine shop make pulleys, the prices were similar but I sent them a motor so they could dry fit the center bore and dial in the tolerance so the fit was snug but not an interference fit and not sloppy so the pulley would wobble. I don't know if the tolerances indicated in the attached files are adequate or not; maybe if/when someone has pulleys made, they can have that conversation with the shop. The original machine shop that I tried could not keep things concentric. The center bore was done with a boring bar and for the 4mm part, was very small and deflected too easily. The shop that finally did the pulleys used a high speed lathe and removed very small amounts of material at a time.
PN 8900-03-0600 has a 4mm center bore, PN 8901-03-0600 has a 0.25" center bore.
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As mentioned, the datasheet for the motors (well, for the BLWR series) specifies a tolerance of 0.012mm for the shaft diameter. Not sure how that translates to practice, i.e. how much shaft diameters differ in practice between motors.
Ideally, one would do like @Pyramid and have the shop dry fit the part to the exact shaft it will mate to. That is what I intend to do anyway - I've been told that tolerances might need to be adjusted should one opt for a different material.
Ideally, one would do like @Pyramid and have the shop dry fit the part to the exact shaft it will mate to. That is what I intend to do anyway - I've been told that tolerances might need to be adjusted should one opt for a different material.
First and foremost, I would like to thank Bill for all the work he has done and for sharing his designs with the rest of us.
Reading posts in this thread, and other related ones, put me back on a learning path.
Here is some information about my project -
I made replica of a turntable that I owned once upon a time - Micro Seiki RX-5000.
Several changes/improvements, such as stainless platter, stainless bearing housing, machined solid aluminum base, etc were incorporated. At the risk of sounding arrogant, I would say that the replica is every bit as good as the 'real thing'. Photos will follow.
The best drive option I could come up with was DC motor and FG servo control board salvaged from a vintage Pioneer turntable. This motor was design to drive a platter with 200mm hub underneath. I had to tweak the board to increase the speed and machine larger pulley in order to drive 310mm diameter stainless platter weighting in around 20kg.
Needless to say, when I found out about SG4 project, that Bill so generously shared with us, I jumped on it and built a drive for PAPST motor that came out of an EMPIRE 298 turntable. This PAPST motor variety has 4 posts holding two rectangular plates together and I believe this design is superior to other PAPST frame options out there.
SG4/PAPST AC drive works well and it is definitely a big improvement compared to vintage Pioneer FG Servo DC motor. Due to a high speed of the PAPST motor (1800 rpm), fairly small diameter pulley is required. Therefore, contact area between pulley surface and kevlar thread that drives the platter is also very small and rather large tension of the thread is required to avoid slipping. Once the tension of the thread is properly adjusted it takes about 8 seconds to bring 40lb platter from 0 to 33.33 rpm.
PAPST motor is very quiet but I still have to find optimal capacitor value and try two phase connection that would eliminate capacitor.
Out of desperation, I tried modifying Hurst AC motor with very little success. First, I added an oilite bronze sleeve on the bottom of the original housing so that the rotor shaft is supported on both top and bottom. Improvement was negligible and motor was still quite noisy. Next, I machined new solid aluminum motor housing, transplanted Hurst coils and rotor and used ABEC 5 rated ball bearings on top and the bottom. Motor looked like a serious piece of engineering after all this was done. I wanted to believe there was some improvement to justify time I spent, but in all honesty there was none.
Hurst people should consider replacing micrometer in their company logo with a pipe wrench or a sledge hammer. Joking aside, my conclusion is that no level of modification would make Hurst AC motors suitable to drive turntable platter.
Yesterday I purchased two BLWR motors and ordered circuit boards and parts. I can't wait to put it together and try...
Reading posts in this thread, and other related ones, put me back on a learning path.
Here is some information about my project -
I made replica of a turntable that I owned once upon a time - Micro Seiki RX-5000.
Several changes/improvements, such as stainless platter, stainless bearing housing, machined solid aluminum base, etc were incorporated. At the risk of sounding arrogant, I would say that the replica is every bit as good as the 'real thing'. Photos will follow.
The best drive option I could come up with was DC motor and FG servo control board salvaged from a vintage Pioneer turntable. This motor was design to drive a platter with 200mm hub underneath. I had to tweak the board to increase the speed and machine larger pulley in order to drive 310mm diameter stainless platter weighting in around 20kg.
Needless to say, when I found out about SG4 project, that Bill so generously shared with us, I jumped on it and built a drive for PAPST motor that came out of an EMPIRE 298 turntable. This PAPST motor variety has 4 posts holding two rectangular plates together and I believe this design is superior to other PAPST frame options out there.
SG4/PAPST AC drive works well and it is definitely a big improvement compared to vintage Pioneer FG Servo DC motor. Due to a high speed of the PAPST motor (1800 rpm), fairly small diameter pulley is required. Therefore, contact area between pulley surface and kevlar thread that drives the platter is also very small and rather large tension of the thread is required to avoid slipping. Once the tension of the thread is properly adjusted it takes about 8 seconds to bring 40lb platter from 0 to 33.33 rpm.
PAPST motor is very quiet but I still have to find optimal capacitor value and try two phase connection that would eliminate capacitor.
Out of desperation, I tried modifying Hurst AC motor with very little success. First, I added an oilite bronze sleeve on the bottom of the original housing so that the rotor shaft is supported on both top and bottom. Improvement was negligible and motor was still quite noisy. Next, I machined new solid aluminum motor housing, transplanted Hurst coils and rotor and used ABEC 5 rated ball bearings on top and the bottom. Motor looked like a serious piece of engineering after all this was done. I wanted to believe there was some improvement to justify time I spent, but in all honesty there was none.
Hurst people should consider replacing micrometer in their company logo with a pipe wrench or a sledge hammer. Joking aside, my conclusion is that no level of modification would make Hurst AC motors suitable to drive turntable platter.
Yesterday I purchased two BLWR motors and ordered circuit boards and parts. I can't wait to put it together and try...
Precision boring small ID hole is somewhat difficult task. Also, type of material being machined makes a HUGE difference.
Boring bar required is very small and it easily deflects during the cut. The only way to do this right on a regular engine lathe is to remove very small amount of material in a single pass to minimize tool deflection.
Boring/drilling an undersized hole and reaming it to size does not guarantee precision fit. This is simple/cheap operation and shops often employ it.
Absolutely best way would be to drill/bore slightly undersized hole and then grind the ID to a desired size. Grinding tolerances are typically in 0.000x" range but precision grinding is quite expensive.
Don't let my comment discourage you. Difficult doesn't mean impossible if machine shop guys know what they are doing.
Boring bar required is very small and it easily deflects during the cut. The only way to do this right on a regular engine lathe is to remove very small amount of material in a single pass to minimize tool deflection.
Boring/drilling an undersized hole and reaming it to size does not guarantee precision fit. This is simple/cheap operation and shops often employ it.
Absolutely best way would be to drill/bore slightly undersized hole and then grind the ID to a desired size. Grinding tolerances are typically in 0.000x" range but precision grinding is quite expensive.
Don't let my comment discourage you. Difficult doesn't mean impossible if machine shop guys know what they are doing.
What RPM are you looking to run the motor at? 1800 RPM would require 120Hz, which the SG4 will not do. The project is better suited to drive the motor at 600 RPM (40Hz) and drive the rim.
What if someone downloads the old version and makes a bad pulley?
I reposted the file (#29). Can you replace the original with the new file and delete the extra posts?
Hi Bill,
SG4 with class D amp driving PAPST motor with 7.5mm diameter pulley on the shaft works perfectly fine. Frequency is around 46Hz for 33.33rpm and 53Hz for 45rpm. I machined several different pulleys and cut the OD down in order to make motor as quiet as possible. That's why my SG4 frequencies are on a low side.
My platter speed stability, measured using Platter Speed app and 3150Hz test tone on Ultimate Analogue Test LP, is excellent. However, slipping of the kevlar thread can't be avoided with the pulley diameter this small.
Lower motor speed and larger diameter pulley would definitely reduce slipping of the thread.
Original Micro Seiki RY-5500 DC motor speed was 660/900 rpm for 33.33/45rpm so I am looking for motor speed of around 600rpm. Your new BLDC drive with AA motor should be perfect for this task.
Mirko
SG4 with class D amp driving PAPST motor with 7.5mm diameter pulley on the shaft works perfectly fine. Frequency is around 46Hz for 33.33rpm and 53Hz for 45rpm. I machined several different pulleys and cut the OD down in order to make motor as quiet as possible. That's why my SG4 frequencies are on a low side.
My platter speed stability, measured using Platter Speed app and 3150Hz test tone on Ultimate Analogue Test LP, is excellent. However, slipping of the kevlar thread can't be avoided with the pulley diameter this small.
Lower motor speed and larger diameter pulley would definitely reduce slipping of the thread.
Original Micro Seiki RY-5500 DC motor speed was 660/900 rpm for 33.33/45rpm so I am looking for motor speed of around 600rpm. Your new BLDC drive with AA motor should be perfect for this task.
Mirko
![IMG_20170517_190932[1].jpg](/community/data/attachments/568/568557-c9bba40f9362f9e838f8b5db9b404c58.jpg)
@Mirko-You should be fine with that combination. 600 RPM is ideal.
@ george-You would need a new pulley with the BLWS motor. It has a 0.25" shaft and the VPI pulley is 3/16". The BLWS motor should fit in the VPI motor pod.
The BLWR series motor will work with the VPI pulley with the addition of a sleeve to convert its shaft (4mm) to 3/16", but the motor will be too tall for the pod.
@ george-You would need a new pulley with the BLWS motor. It has a 0.25" shaft and the VPI pulley is 3/16". The BLWS motor should fit in the VPI motor pod.
The BLWR series motor will work with the VPI pulley with the addition of a sleeve to convert its shaft (4mm) to 3/16", but the motor will be too tall for the pod.
Granted, it's not easy...However, I think it is possible to do if I make an arbor the size of the original bore, clamp the pulley onto it and bore with a centering drill from the opposite end. I'll have to compare the tolerances of the new motor shaft with my center drill and a test bore. I don't need to bore the pulley to its full depth, as it can be flipped and set screws added to the opposite end. This assumes that VPI made these perfectly concentric to the bore to begin with. I will test the run out of both my arbor and the pulley.
I really have nothing to lose as I have extra pulleys that I don't currently use. If it doesn't work out and it seems like my old Logan lathe isn't up to the task of making the pulley to my expectations then I will have to make a call to one of my friends that has a collection of excellent Swiss watch making lathes.
BLDC motor availabillity from Anaheim Automation
Here is some information regarding BLDC motor availability -
I live 11 miles away from Anaheim Automation so two days ago I drove there to pick up two BLWR motors.
Sales person was friendly and we had conversation while my order was processed. I asked her about availability of BLWR and BLWS models and here is what I heard...
AA does not reorder motors from their overseas manufacturer until the last piece is sold. From that point it typically takes 4-6 weeks to restock.
BLWS motors are sold out and new order has been placed with the manufacturer. ETA is not available yet but those motors are coming.
BLWR motors are almost out of stock and only 11 pieces are currently available. Once those are sold it might take up to 11 weeks until new shipment arrives.
Here is some information regarding BLDC motor availability -
I live 11 miles away from Anaheim Automation so two days ago I drove there to pick up two BLWR motors.
Sales person was friendly and we had conversation while my order was processed. I asked her about availability of BLWR and BLWS models and here is what I heard...
AA does not reorder motors from their overseas manufacturer until the last piece is sold. From that point it typically takes 4-6 weeks to restock.
BLWS motors are sold out and new order has been placed with the manufacturer. ETA is not available yet but those motors are coming.
BLWR motors are almost out of stock and only 11 pieces are currently available. Once those are sold it might take up to 11 weeks until new shipment arrives.
Ordering SG4 uPs
Please don't send a request for the SG4s through the private message system. I can't send a PayPal invoice to the forum. It duplicates requests, generates more messages, and it makes it much harder to keep things straight, especially if I get a private message with only a forum name or just a first name, and later receive a message through my private email with your actual name, and no forum name. I'm having a lot of difficulty matching this stuff up and knowing whether or not a request has been invoiced or not, plus the hassle of more messages.
Please read this and give all required information: I need a request from your private email that is linked to PayPal, to my private email (twystd3 at yahoo dot com). In this email, include the amount you want, your real name, your forum name, and your shipping address. I will then send you a PayPal invoice that will include shipping and PayPal fees. BTW, all the chips I will be sending out are V1.03s, as I returned my remaining stock of V1.02s to pyramid for reprogramming.
Please help me keep this straight.
twystd (Roe)
Please don't send a request for the SG4s through the private message system. I can't send a PayPal invoice to the forum. It duplicates requests, generates more messages, and it makes it much harder to keep things straight, especially if I get a private message with only a forum name or just a first name, and later receive a message through my private email with your actual name, and no forum name. I'm having a lot of difficulty matching this stuff up and knowing whether or not a request has been invoiced or not, plus the hassle of more messages.
Please read this and give all required information: I need a request from your private email that is linked to PayPal, to my private email (twystd3 at yahoo dot com). In this email, include the amount you want, your real name, your forum name, and your shipping address. I will then send you a PayPal invoice that will include shipping and PayPal fees. BTW, all the chips I will be sending out are V1.03s, as I returned my remaining stock of V1.02s to pyramid for reprogramming.
Please help me keep this straight.
twystd (Roe)