Hi,
I like where you are going with your post. I think you are referring to me when you talk about converting VPI to a direct drive.
I went through your same path. I thought that Hurst motors were too cheap to be used for a TT application, so I researched for days on this topic but, like you, I didn't find ANYTHING better.
This suggested me that Hurst Motors might not be as bad as I though. Again I would like to find a better quality dedicated AC motor and if anybody has an idea, please let me know.
Regarding the 24V motor, I have at home a 115V 300RPM and 115V 600RPM and now 24V 300RPM and the vibration difference from the 115V to the 24V version is noticeable.
Especially driving it with dual phase and trimming the phase shift for best performance really improves the situation.
However, if you hold the motor in your hand, it will make some vibration, but if you put it against a flat surface, the vibration goes almost away.
Have it installed on my TT, the only thing I notices, is some little noise coming from the shaft when it rotates (I thought it was the rubbing of the belt against the pulley, but removing the belt and letting only the motor spin, I was able to detect that the noise comes from the shaft rubbing against something inside the motor I guess).
It is a saddle noise, nevertheless, I am sure that if it pulley goes in contact with the platter although through a silicon O-ring, the noise/vibration I am hearing will be picked up by the needle for sure.
Maybe this problem is correlated to what you are talking about. All I know is that, at least, these motors don’t use ball bearings but rather sleeves (don’t know what material, which are supposedly quieter than bearings of course.
I don’t know what you want to modify on the motor but I can try since I have 3 Hurst motors on my hand.
I have no clue what is all involved, but if we can find a way to make this motor quieter and suitable for RIM drive I am on for it.
Maybe, would it be worth it to open a dedicated topic for this?
I like where you are going with your post. I think you are referring to me when you talk about converting VPI to a direct drive.
I went through your same path. I thought that Hurst motors were too cheap to be used for a TT application, so I researched for days on this topic but, like you, I didn't find ANYTHING better.
This suggested me that Hurst Motors might not be as bad as I though. Again I would like to find a better quality dedicated AC motor and if anybody has an idea, please let me know.
Regarding the 24V motor, I have at home a 115V 300RPM and 115V 600RPM and now 24V 300RPM and the vibration difference from the 115V to the 24V version is noticeable.
Especially driving it with dual phase and trimming the phase shift for best performance really improves the situation.
However, if you hold the motor in your hand, it will make some vibration, but if you put it against a flat surface, the vibration goes almost away.
Have it installed on my TT, the only thing I notices, is some little noise coming from the shaft when it rotates (I thought it was the rubbing of the belt against the pulley, but removing the belt and letting only the motor spin, I was able to detect that the noise comes from the shaft rubbing against something inside the motor I guess).
It is a saddle noise, nevertheless, I am sure that if it pulley goes in contact with the platter although through a silicon O-ring, the noise/vibration I am hearing will be picked up by the needle for sure.
Maybe this problem is correlated to what you are talking about. All I know is that, at least, these motors don’t use ball bearings but rather sleeves (don’t know what material, which are supposedly quieter than bearings of course.
I don’t know what you want to modify on the motor but I can try since I have 3 Hurst motors on my hand.
I have no clue what is all involved, but if we can find a way to make this motor quieter and suitable for RIM drive I am on for it.
Maybe, would it be worth it to open a dedicated topic for this?
Yes, that makes sense, but I thought the OP was interested in building a rim drive which needs more torque and better bearings regardless of the VFD power supply?
I'd certainly be interested in being able to get or make a good affordable VFD. The OP spent a ton of money on the VPI and could buy a good VFD even from VPI for more money, but so far regardless of budget I can't find a good motor even for belt drive, much less for the OP's rim drive mod. Is a VFD really answering the OP's initial question?
Don't we need a good motor to make the VFD useful?
I'd certainly be interested in being able to get or make a good affordable VFD. The OP spent a ton of money on the VPI and could buy a good VFD even from VPI for more money, but so far regardless of budget I can't find a good motor even for belt drive, much less for the OP's rim drive mod. Is a VFD really answering the OP's initial question?
Don't we need a good motor to make the VFD useful?
Can you not use these shorts? ahahah!! I don't understand what you mean by that.
I have the SDS as well!!!
A good motor is needed for both RIM , Direct and Belt.
the only other option is a DC motor, but then you lose in stability of rotation which is far more important than other things IMHO.
Also, as you know already, apparently there is no better motor than Hurst (sad to say!), so if we can improve this which is probably the most widely used, it would be beneficial for a lot of people.
Do we want to look into that? Do you want to open a new thread?
I have the SDS as well!!!
A good motor is needed for both RIM , Direct and Belt.
the only other option is a DC motor, but then you lose in stability of rotation which is far more important than other things IMHO.
Also, as you know already, apparently there is no better motor than Hurst (sad to say!), so if we can improve this which is probably the most widely used, it would be beneficial for a lot of people.
Do we want to look into that? Do you want to open a new thread?
Stefano,
I really think that noise is the bronze bushing in the Hurst motor, I noticed it the minute I plugged in a new SAMA motor from VPI. The SAMA is a stand alone module motor upgrade. It's really just the Hurst motor in a little metal case. Like you, I don't really think they are bad, they may be perfect. But, I don't think that bushing is so nice. I'd like to use a heavy platter and I think a more powerful motor would be better and I'm curious about the RA family of motors. Hurst is really great to deal with, they have good documentation on the website and you can order motors right from the factory website and customer service follows up really well, and they're not expensive so think they're a good motor to mod.
I think teflon bushings like the Iglide J would really help. I think the difficult will be to try to remove the press fit bushings from the Hurst and then finding a replacement bushing that will press back into the same hole. Igus has 100's of different size bushings in both metric and english sizes, so I think there's a chance. There are also companies on the web who will machine small teflon parts to order, so it's doable to have a sleeve made to fit.
I was also thinking in the Hurst motors that offer both a ball bearing bushing and a bronze sleeve bushing that it might be easier to remove and replace the ball bearing bushings. But, maybe the bearing races are also press fit.
Also notice how the RA motor has an option for two ended shafts. The two ended shaft might be easier to replace both bushes.
Jamie
I really think that noise is the bronze bushing in the Hurst motor, I noticed it the minute I plugged in a new SAMA motor from VPI. The SAMA is a stand alone module motor upgrade. It's really just the Hurst motor in a little metal case. Like you, I don't really think they are bad, they may be perfect. But, I don't think that bushing is so nice. I'd like to use a heavy platter and I think a more powerful motor would be better and I'm curious about the RA family of motors. Hurst is really great to deal with, they have good documentation on the website and you can order motors right from the factory website and customer service follows up really well, and they're not expensive so think they're a good motor to mod.
I think teflon bushings like the Iglide J would really help. I think the difficult will be to try to remove the press fit bushings from the Hurst and then finding a replacement bushing that will press back into the same hole. Igus has 100's of different size bushings in both metric and english sizes, so I think there's a chance. There are also companies on the web who will machine small teflon parts to order, so it's doable to have a sleeve made to fit.
I was also thinking in the Hurst motors that offer both a ball bearing bushing and a bronze sleeve bushing that it might be easier to remove and replace the ball bearing bushings. But, maybe the bearing races are also press fit.
Also notice how the RA motor has an option for two ended shafts. The two ended shaft might be easier to replace both bushes.
Jamie
Yeah, we can open a new thread. I've got some spare Hurst motors also that I could take apart and try to swap out bushes and stuff. I don't know the electronics very well, but I can take (break) stuff apart.
just so you know, the higher the torque the noisier the motor (at least in my little knowledge).
When you have a platter with high mass you don't need a high torque to maintain the speed nor to counteract the groove's interaction.
The PA motor has enough torque to be able to handle the task properly and if you have to replace the motor on existing TT, it is very hard to fit something else. The thing that would make the most sense is to find, if there is, a way to improve the existing 300/600 PA/PB Hurst motor that is used on many application.
I didn’t know SAMA was an upgrade with better enclosure, I wonder if it performs any better.
If we open up a post, maybe some experts on the “field” might be interested to step in and give a valuable contribution to the thread.
When you have a platter with high mass you don't need a high torque to maintain the speed nor to counteract the groove's interaction.
The PA motor has enough torque to be able to handle the task properly and if you have to replace the motor on existing TT, it is very hard to fit something else. The thing that would make the most sense is to find, if there is, a way to improve the existing 300/600 PA/PB Hurst motor that is used on many application.
I didn’t know SAMA was an upgrade with better enclosure, I wonder if it performs any better.
If we open up a post, maybe some experts on the “field” might be interested to step in and give a valuable contribution to the thread.
I start thinking that the best solution/compromise to the pros of a belt drive and Idle/direct drive would be to have a very low noise 24V AC motor with dual phase control and phase shift optimization (the one from Pyramid is the absolute best), on a separate pod (like the SAMA motor) and connected with Holographic Mylar tape (check this subject out).
Motor installed on a separate shelf right by TT.
This way, most of the unwanted vibrations should be reasonably kept away from the sylus while the rotation should be very comparable to a direct drive due to the lack of stretching properties and perfect grip of holographic Mylar.
Any thought on this?
Motor installed on a separate shelf right by TT.
This way, most of the unwanted vibrations should be reasonably kept away from the sylus while the rotation should be very comparable to a direct drive due to the lack of stretching properties and perfect grip of holographic Mylar.
Any thought on this?
Stefano,
I think the SAMA was an upgrade to something like the HW19 since the Stand Alone Motor Assembly (SAMA) was not mounted to the same plinth as the platter and tonearm. I think it's really the same motor and electronics just in a heavy enough metal enclosure to sit by itself and not touch the plinth and since it's typically driving through a rubber band all the vibration is isolated.
You really started this thread, and your question is still the same, without an answer, so I'm not sure you should need to start a new thread.
I'm heading in the direction of heavy platter, heavy plinth, more powerful motor, for no good reason. I think the bearings of the platter and motors can be improved and maybe just going heavy will help things a bit.
I believe that with a belt drive and/or AC motor, that there will always be some kind of "belt flutter" as a result of the spring of the belt. Mechanically the belt is a spring with a spring rate and damping factor. The motor also operates like a spring. Regardless of how perfectly the variable frequency drives holds the absolute speed of the signal and long term speed of the motor, the motor, belt, and platter system will oscillate in some way depending on the hysteresis of the system. When the platter slows, the belt will stretch then bounce back. The motor will lag, then catchup. AC motor cogging is a form of this lagging, catching back up. I think most implementations end up with the belt stretch as the worst source of problems and the other stuff not so bad.
I think the design approach is all about moving the mechanical and electrical system oscillation frequencies into inaudible ranges. For example if AC motor cogging might be eliminated by the "spring" of the belt, but then the belt may induce lower frequency oscillation of speed, can it be move low enough not to matter or moved up and damped away? I don't think there are any absolute solutions to this like a higher torque or lower torque motor. A stiffer belt or softer belt. The system would need to be modeled with the mass of the platter, the bearing frictions, and the spring rates of the belt and motor. Impossible to do, so then we are left guessing and experimenting to find the right matching fit of spring rates and damping factors.
The first question really becomes, how do we measure the speed variation. I have a friend who says that it's impossible and only listening can tell. Uggggh.....which does not help me much. He also says belts suck. O'well....what to do if I want to build something from new parts instead of digging in the salvage bin.
This makes my head hurt.
I think the SAMA was an upgrade to something like the HW19 since the Stand Alone Motor Assembly (SAMA) was not mounted to the same plinth as the platter and tonearm. I think it's really the same motor and electronics just in a heavy enough metal enclosure to sit by itself and not touch the plinth and since it's typically driving through a rubber band all the vibration is isolated.
You really started this thread, and your question is still the same, without an answer, so I'm not sure you should need to start a new thread.
I'm heading in the direction of heavy platter, heavy plinth, more powerful motor, for no good reason. I think the bearings of the platter and motors can be improved and maybe just going heavy will help things a bit.
I believe that with a belt drive and/or AC motor, that there will always be some kind of "belt flutter" as a result of the spring of the belt. Mechanically the belt is a spring with a spring rate and damping factor. The motor also operates like a spring. Regardless of how perfectly the variable frequency drives holds the absolute speed of the signal and long term speed of the motor, the motor, belt, and platter system will oscillate in some way depending on the hysteresis of the system. When the platter slows, the belt will stretch then bounce back. The motor will lag, then catchup. AC motor cogging is a form of this lagging, catching back up. I think most implementations end up with the belt stretch as the worst source of problems and the other stuff not so bad.
I think the design approach is all about moving the mechanical and electrical system oscillation frequencies into inaudible ranges. For example if AC motor cogging might be eliminated by the "spring" of the belt, but then the belt may induce lower frequency oscillation of speed, can it be move low enough not to matter or moved up and damped away? I don't think there are any absolute solutions to this like a higher torque or lower torque motor. A stiffer belt or softer belt. The system would need to be modeled with the mass of the platter, the bearing frictions, and the spring rates of the belt and motor. Impossible to do, so then we are left guessing and experimenting to find the right matching fit of spring rates and damping factors.
The first question really becomes, how do we measure the speed variation. I have a friend who says that it's impossible and only listening can tell. Uggggh.....which does not help me much. He also says belts suck. O'well....what to do if I want to build something from new parts instead of digging in the salvage bin.
This makes my head hurt.
just for everybody's information...here is the link to the new post on the motor...if anybody is interested in following it
http://www.diyaudio.com/forums/analogue-source/250340-hurst-ac-motor-lets-upgrade.html#post3800513
http://www.diyaudio.com/forums/analogue-source/250340-hurst-ac-motor-lets-upgrade.html#post3800513
funny enough...believe it or not...I didn't realize I had started this thread....ahahahaha...but yes you are right....I already posted a new and specific thread on the motor....at this point I will leave it there if anybody is interested.
For the platter....high mass on the platter will definitely help...no questions there....
For the separate pods and the SAMA motor. I think that having a separate pad will definitely improve vibration. If this motor can be bolted to a separate shelf then you avoid any possible micro random motion that comes from having a separate motor (that is was driven VPI on their new classic designs) but at the time time, being on a different shelf and isolated from the plinth there is no vibration going through there.
Another firm point seems to be a mylar tape as a option to the stretchy belt.
So combining these options makes up for an isolated low noise motor on an isolated pad connected with mylar tape.
This, to me, seems to be the best compromise on a high mass platter.
Regarding speed, it can be measured, with Pyramid system, however you can't detect instantaneous speed which is what drives your hear and frequency distortions.
Obviously you can notice that on a very high end system and good ears.
Definitely, if there is one thing I have learned, is to drive away from belt driven system if you want to play serious stuff.
I personally think that instead of driving yourself nut....which I went through the same thing in order to try to figure out a better motor for my system, why not instead improving the motor we have which is already a good start, and build a separate pod for it and try to have a more rigid connection with tape which is definitely better than rubber belt?
I mean taking it by step will help. i.e.
1) improve existing motor
2) build a suitable external pad for the motor
3) build suitable Holographic mylar tape for the system
😎
For the platter....high mass on the platter will definitely help...no questions there....
For the separate pods and the SAMA motor. I think that having a separate pad will definitely improve vibration. If this motor can be bolted to a separate shelf then you avoid any possible micro random motion that comes from having a separate motor (that is was driven VPI on their new classic designs) but at the time time, being on a different shelf and isolated from the plinth there is no vibration going through there.
Another firm point seems to be a mylar tape as a option to the stretchy belt.
So combining these options makes up for an isolated low noise motor on an isolated pad connected with mylar tape.
This, to me, seems to be the best compromise on a high mass platter.
Regarding speed, it can be measured, with Pyramid system, however you can't detect instantaneous speed which is what drives your hear and frequency distortions.
Obviously you can notice that on a very high end system and good ears.
Definitely, if there is one thing I have learned, is to drive away from belt driven system if you want to play serious stuff.
I personally think that instead of driving yourself nut....which I went through the same thing in order to try to figure out a better motor for my system, why not instead improving the motor we have which is already a good start, and build a separate pod for it and try to have a more rigid connection with tape which is definitely better than rubber belt?
I mean taking it by step will help. i.e.
1) improve existing motor
2) build a suitable external pad for the motor
3) build suitable Holographic mylar tape for the system
😎
Stefanoo,
I like where you are headed, sounds good to me.
I like the idea of the mylar or other material belt. They're must be a reason for the rubber belt, but there a so many materials with a range of spring rate and dampening that could modify the behaviour of the belt and maybe get rid of the bad bass response of belt drives.
I do like the 115V motors though, just to make it easier to source the power supply and for testing it's a simple circuit to go into the wall supply. Swapping out the capacitor can optimize the phase angle without a lot of other circuitry then if it works just get a nice variable frequency drive.
Also, I'm already in progress of making a heavy cast iron plinth and I'm interested in mounting the motor directly to the plinth. Oh, yes I agree some vibration of the motor goes into the plinth, but so many of these turntables are really flimsy, even very expensive ones.
All other things equal I think Newton's First Law of motion can do a lot for turntables. And I can always mount the motor to the heavy plinth using Sorbothane mounts. I'll put the entire heavy plinth and platter on Sorbothane feet. The idea would be that no special shelf is necessary and all of the problem is taken care of by the massive plinth and platter.
Sorbothane is really a special material. Regular rubber is like a spring with no shock absorber or dampening. Being viscoelastic, Sorbothane dampens well across the full spectrum of sound and by sizing the feet correctly can have a natural frequency below 20hz.
This really gets me into bearings though. So many turntables have these simple bronze bushing bearings, a silicon carbide ball and then a metal thrust plate. I plan to use a polished steel shaft or hard anodized aluminum shaft, the igus iglide J bushing, a silicon carbide ball thrust bearing and a Hylon thrust plate. Hylon is nylon that is cast with lubricant, it's coefficient of friction is much less than nylon and it is lubricated for life. It is relatively hard like delrin such that the silicon carbide ball will not deform the thrust plate so much, but soft enough that the SiNi ball will wear into it's own seat.
Maybe most turntables do not have higher frequency noise from the bearing, but I don't like all these metal to metal interfaces between moving objects and you can see all these turntable mfg's have to get fancy with the bearing lubricant because the tolerances of the bearings are so bad and the lubricant needs to cushion the bearing or it has to be thin so the bearing doesn't seize up. I just don't think they are using modern materials appropriately.
I plan to use a 300 rpm Hurst Motor, about the same as the SAMA although it might be 600 rpm. I want to use a 300 rpm motor so that the drive pulley can be larger and have more options with pulley and belt. A larger pulley will be easier to machine to good tolerance, etc.
I am thinking that if the platter is heavy enough my speed problems will not be so fast (First law again) and that maybe traditional wow and flutter measurement will also work. An old wow and flutter meter isn't very expensive used on e-bay.
Don't worry, I won't get too crazy. I'm convinced that I can make a turntable at least as good as a VPI with a SAMA like motor, because I can just use the same motor at least🙂
I need to learn about the Pyramid system, but first I really want to build something and see what I can hear. I'll keep you in the loop to see how it goes.
Cheers,
Jamie
I like where you are headed, sounds good to me.
I like the idea of the mylar or other material belt. They're must be a reason for the rubber belt, but there a so many materials with a range of spring rate and dampening that could modify the behaviour of the belt and maybe get rid of the bad bass response of belt drives.
I do like the 115V motors though, just to make it easier to source the power supply and for testing it's a simple circuit to go into the wall supply. Swapping out the capacitor can optimize the phase angle without a lot of other circuitry then if it works just get a nice variable frequency drive.
Also, I'm already in progress of making a heavy cast iron plinth and I'm interested in mounting the motor directly to the plinth. Oh, yes I agree some vibration of the motor goes into the plinth, but so many of these turntables are really flimsy, even very expensive ones.
All other things equal I think Newton's First Law of motion can do a lot for turntables. And I can always mount the motor to the heavy plinth using Sorbothane mounts. I'll put the entire heavy plinth and platter on Sorbothane feet. The idea would be that no special shelf is necessary and all of the problem is taken care of by the massive plinth and platter.
Sorbothane is really a special material. Regular rubber is like a spring with no shock absorber or dampening. Being viscoelastic, Sorbothane dampens well across the full spectrum of sound and by sizing the feet correctly can have a natural frequency below 20hz.
This really gets me into bearings though. So many turntables have these simple bronze bushing bearings, a silicon carbide ball and then a metal thrust plate. I plan to use a polished steel shaft or hard anodized aluminum shaft, the igus iglide J bushing, a silicon carbide ball thrust bearing and a Hylon thrust plate. Hylon is nylon that is cast with lubricant, it's coefficient of friction is much less than nylon and it is lubricated for life. It is relatively hard like delrin such that the silicon carbide ball will not deform the thrust plate so much, but soft enough that the SiNi ball will wear into it's own seat.
Maybe most turntables do not have higher frequency noise from the bearing, but I don't like all these metal to metal interfaces between moving objects and you can see all these turntable mfg's have to get fancy with the bearing lubricant because the tolerances of the bearings are so bad and the lubricant needs to cushion the bearing or it has to be thin so the bearing doesn't seize up. I just don't think they are using modern materials appropriately.
I plan to use a 300 rpm Hurst Motor, about the same as the SAMA although it might be 600 rpm. I want to use a 300 rpm motor so that the drive pulley can be larger and have more options with pulley and belt. A larger pulley will be easier to machine to good tolerance, etc.
I am thinking that if the platter is heavy enough my speed problems will not be so fast (First law again) and that maybe traditional wow and flutter measurement will also work. An old wow and flutter meter isn't very expensive used on e-bay.
Don't worry, I won't get too crazy. I'm convinced that I can make a turntable at least as good as a VPI with a SAMA like motor, because I can just use the same motor at least🙂
I need to learn about the Pyramid system, but first I really want to build something and see what I can hear. I'll keep you in the loop to see how it goes.
Cheers,
Jamie
Jnoneiliv1-
I agree with you guys 100%. I think the best cure for W&F is platter mass, trying to do it with direct drive introduces a coloration of its own and is impractical with belt drive.
I originally didn't intend to control the speed with the tach; I built the tach because I couldn't find any measurement instruments with enough resolution to monitor the effects of tweaking the power supply. I figured the mass of the platter would mitigate any speed changes over one rev and the accuracy of the PSU would provide stability over many revs. What I noticed though, was no matter how accurate the supply, my belt drive table would slowly drift upwards in speed (several minutes). That's when the idea occurred to me to feedback the tach reading to the PSU to provide long term stability, the 3rd piece of the puzzle.
I agree with you guys 100%. I think the best cure for W&F is platter mass, trying to do it with direct drive introduces a coloration of its own and is impractical with belt drive.
I originally didn't intend to control the speed with the tach; I built the tach because I couldn't find any measurement instruments with enough resolution to monitor the effects of tweaking the power supply. I figured the mass of the platter would mitigate any speed changes over one rev and the accuracy of the PSU would provide stability over many revs. What I noticed though, was no matter how accurate the supply, my belt drive table would slowly drift upwards in speed (several minutes). That's when the idea occurred to me to feedback the tach reading to the PSU to provide long term stability, the 3rd piece of the puzzle.
does it mean that you will try to modify the hurst motor? I would be really interested to know what your findings are on that.
Please post on the new thread as well if you would like to.
One more question, maybe you have some ideas: where could I have a pulley machined?
I am thinking that the existing pulley I have would be too narrow to have 1/2'' tape going through.
I think I will start moving toward a separate pod with the 24V Motor the dual phase control controller and the mylar tape.
I am thinking that the existing pulley I have would be too narrow to have 1/2'' tape going through.
I think I will start moving toward a separate pod with the 24V Motor the dual phase control controller and the mylar tape.
Jnonelliv1 & others
The best shaft for a turntable bearing is tungsten carbide. Take a look on ebay under " carbide blank " and look for a polished piece about .5" diameter and as close to the length you need and you are set. It has a Rockwell of 90+ and ground to very close tolerance.
The only problem is it is so hard you need diamond tooling to machine it. You can braze to it if needed.
Joe
The best shaft for a turntable bearing is tungsten carbide. Take a look on ebay under " carbide blank " and look for a polished piece about .5" diameter and as close to the length you need and you are set. It has a Rockwell of 90+ and ground to very close tolerance.
The only problem is it is so hard you need diamond tooling to machine it. You can braze to it if needed.
Joe
interesting, but is doable to use this material to modify the motor? If it can't be machined so easily?
stefanoo:
I mentioned the use of tungsten carbide only because Jnonelliv1 was talking about making a DIY turntable.
Joe
I mentioned the use of tungsten carbide only because Jnonelliv1 was talking about making a DIY turntable.
Joe
Pyramid,
Thanks for that feedback, it makes me feel better about some assumptions and I've been worried about measurement. I'm looking forward to learning more about your device.
Regarding the Hurst motor, I cracked one open earlier today. Bad news, I think it would be hard to hot rod. But, good news is maybe it really doesn't need it. The bronze bushing that you can partially see at the shaft end extends a long way down the shaft. The shaft is only supported by the one length of bushing, but it's about 3/4" long. I also think I know where the noise comes from. The shaft is held in place by a one way washer, or what you might call a spring clip. It's that clip that ends up rubbing in the bushing mount. It may just require a little rap every now and then, but otherwise fundamentally sound.
In any case I'll post a series of images of the "cracked" open motor for inspection.
hattatto, thanks for the tip about the bearing shaft. But, I'm not sure why the shaft should need to be so hard, and like you say, then it's hard to machine. Igus provides hard anodized aluminum shafts to match their bushings. The coefficient of friction of the igus iglide bearing and the hard anodized shaft is nearly the same as with a ground steel shaft. I'll need to machine the end of the shaft to accept the silicon nitride thrust ball bearing so I might like to have the easier to machine aluminum shaft, but steel would work also.
In any case, I'll post up a full set of images of cracked motor in case anyone is interested. It's pretty cool.
Cheers,
Jamie
Thanks for that feedback, it makes me feel better about some assumptions and I've been worried about measurement. I'm looking forward to learning more about your device.
Regarding the Hurst motor, I cracked one open earlier today. Bad news, I think it would be hard to hot rod. But, good news is maybe it really doesn't need it. The bronze bushing that you can partially see at the shaft end extends a long way down the shaft. The shaft is only supported by the one length of bushing, but it's about 3/4" long. I also think I know where the noise comes from. The shaft is held in place by a one way washer, or what you might call a spring clip. It's that clip that ends up rubbing in the bushing mount. It may just require a little rap every now and then, but otherwise fundamentally sound.
In any case I'll post a series of images of the "cracked" open motor for inspection.
hattatto, thanks for the tip about the bearing shaft. But, I'm not sure why the shaft should need to be so hard, and like you say, then it's hard to machine. Igus provides hard anodized aluminum shafts to match their bushings. The coefficient of friction of the igus iglide bearing and the hard anodized shaft is nearly the same as with a ground steel shaft. I'll need to machine the end of the shaft to accept the silicon nitride thrust ball bearing so I might like to have the easier to machine aluminum shaft, but steel would work also.
In any case, I'll post up a full set of images of cracked motor in case anyone is interested. It's pretty cool.
Cheers,
Jamie
I have swapped a bend motor shaft with a carbide rod of the same diameter in a Philips synchronous motor, it works.