The choice to make the pulley out of brass was not mine. In fact I made several out of aluminum (some for me and some for a few in the GB who wanted them). The aluminum is much cheaper than brass as well as being lighter. Also it does not tarnish the way brass does.
About the through hole. This is possible, but making it double sided is definitely not advisable. Trying to bore a hole .5" deep with a .0005" tolerance is hard enough let alone over an inch (the tool we used had a .6" max depth). I would stick with single side mounting and add a hole to the top side that would allow for press removal.
Now keep in mind that my original design was cut in a single setup. Once the stock was set in the collet, all cutting was done. As a result the concentricity of the bore to the outside diameter is essentially perfect. Trying to make this double sided will add a second setup to the part, increasing cost dramatically and making the second bore's concentricity subject to chucking.
The top cut was made for a belt or string. They design you have won't work for a belt if that is wanted. The upper shoulders are not necessary. The hard transition from the string portion to the mylar portion and the base will leave a sharp burr. The small flat was there simply to make the parts so that there was minimal filing and sanding necessary.
The lower one was intended to give the option of adding a set screw. I tested each pulley and they all slid on tight to the shaft of my motor, but would need some kind of adhesive to keep it in place. I plan to put setscrews in my pulley so that I don't have to worry about the pulling damaging the motor bearings.
My final design was trying to be everything to everyone. Some compromises were made for cost and the desires of everyone in the GB. In the end I think it was fine. Personally I never heard any complaints about the weight or size of them. Personally I think that the added mass of the brass is a good thing as long as the motor bearing can handle it. Having a heavy pulley with a high rpm will achieve a good level of centripetal momentum and will help stabilize platter speed. That is what all of this is about in the first place.
I will probably turn the top off of my pulley and only use the mylar belt. I also made 3 for myself with the intention of making 3 main bearings. One for the platter and 2 for the idler pulleys that will ensure even pressure on the main bearing.
DaveM
About the through hole. This is possible, but making it double sided is definitely not advisable. Trying to bore a hole .5" deep with a .0005" tolerance is hard enough let alone over an inch (the tool we used had a .6" max depth). I would stick with single side mounting and add a hole to the top side that would allow for press removal.
Now keep in mind that my original design was cut in a single setup. Once the stock was set in the collet, all cutting was done. As a result the concentricity of the bore to the outside diameter is essentially perfect. Trying to make this double sided will add a second setup to the part, increasing cost dramatically and making the second bore's concentricity subject to chucking.
The top cut was made for a belt or string. They design you have won't work for a belt if that is wanted. The upper shoulders are not necessary. The hard transition from the string portion to the mylar portion and the base will leave a sharp burr. The small flat was there simply to make the parts so that there was minimal filing and sanding necessary.
The lower one was intended to give the option of adding a set screw. I tested each pulley and they all slid on tight to the shaft of my motor, but would need some kind of adhesive to keep it in place. I plan to put setscrews in my pulley so that I don't have to worry about the pulling damaging the motor bearings.
My final design was trying to be everything to everyone. Some compromises were made for cost and the desires of everyone in the GB. In the end I think it was fine. Personally I never heard any complaints about the weight or size of them. Personally I think that the added mass of the brass is a good thing as long as the motor bearing can handle it. Having a heavy pulley with a high rpm will achieve a good level of centripetal momentum and will help stabilize platter speed. That is what all of this is about in the first place.
I will probably turn the top off of my pulley and only use the mylar belt. I also made 3 for myself with the intention of making 3 main bearings. One for the platter and 2 for the idler pulleys that will ensure even pressure on the main bearing.
DaveM
If this pulley is a go, I would rather wait and get this pulley in lieu of the Teres and Bix. The idler pulley idea sounds interesting as well.
Rotating mass is an issue if you are trying to decrease losses in HP. Centrifugal forces multiply the weight of the rotating mass (MOI). Lighter pulleys will be easier to accelerate but requires more power to maintain speed. However, this is not what we are trying to achieve. I don't think the weight of the pulley will make a difference one way or the other, considering the RPMs and tolerances we are talking about.
Personally, I would do away with the string and just use tape. I would go with MK's recommendation of 17mm. This is best ratio for his design to maintain speed. Morever, 17mm is more pulley area for the belt to grip. I think we should look into materials that would address the issue of belt creep.
Rotating mass is an issue if you are trying to decrease losses in HP. Centrifugal forces multiply the weight of the rotating mass (MOI). Lighter pulleys will be easier to accelerate but requires more power to maintain speed. However, this is not what we are trying to achieve. I don't think the weight of the pulley will make a difference one way or the other, considering the RPMs and tolerances we are talking about.
Personally, I would do away with the string and just use tape. I would go with MK's recommendation of 17mm. This is best ratio for his design to maintain speed. Morever, 17mm is more pulley area for the belt to grip. I think we should look into materials that would address the issue of belt creep.
Thanks DaveM for your comments. As we can see, your original design was well tough by a knowlegable guy, which I'm not in that matter 😉
I was just proposing things to start a discussion. I can see what were the original ideas behind your design. Designing a part is not just making a nice drawing, it is also to make sure it can be done with the tools in the shop 😎 in an economical matter.
What was the reason for the small curvature on the tape section? Is it what it is called "to crown" the pulley?
Is the platter mass more responsible for the speed stability than the small pulley mass?
Indeed thru hole seems impossible to acheive, just a though again.
Your approach seems to be much better and the right one. I read once that to use two set screws is better than just one. What dimension of set screw do you recommend, 2-56 probably?
I was just proposing things to start a discussion. I can see what were the original ideas behind your design. Designing a part is not just making a nice drawing, it is also to make sure it can be done with the tools in the shop 😎 in an economical matter.
What was the reason for the small curvature on the tape section? Is it what it is called "to crown" the pulley?
Is the platter mass more responsible for the speed stability than the small pulley mass?
Indeed thru hole seems impossible to acheive, just a though again.
Your approach seems to be much better and the right one. I read once that to use two set screws is better than just one. What dimension of set screw do you recommend, 2-56 probably?
The crown of the pulley was suggested by someone other than me. To be honest I just followed the suggestions on that one. From the little feedback I did get from them, the crown was a bit too much. It stretched the VHS tape that was being used a little in the middle and it ended up cupping on the platter. The intent of it was to keep the tape centered on the pulley. I believe it was successful on that front, but the diameter of the crown should probably be increased.
I don't think the mass of the pulley plays largely into the whole system, but every little bit counts. I think Secips was right about that.
About the through hole. it is definitely possible, but the parts need to be touched again. Without it, the whole part is turned and then cut off without ever being handled. There was some facing off to clean things on the cutoff that was necessary, so it could be done at that point fairly easily, but the drilled hole would be only for removal and not for mounting.
I had not fully thought out the setscrews. My first idea was to use 3 setscrew. With that, I don't know how that would effect the bore. Also I think that if the bore is done right, one setscrew is plenty.
DaveM
I don't think the mass of the pulley plays largely into the whole system, but every little bit counts. I think Secips was right about that.
About the through hole. it is definitely possible, but the parts need to be touched again. Without it, the whole part is turned and then cut off without ever being handled. There was some facing off to clean things on the cutoff that was necessary, so it could be done at that point fairly easily, but the drilled hole would be only for removal and not for mounting.
I had not fully thought out the setscrews. My first idea was to use 3 setscrew. With that, I don't know how that would effect the bore. Also I think that if the bore is done right, one setscrew is plenty.
DaveM
If this hasen't been mention yet
I'm not participating in this GB but here are my 2 cents:
If you decide to use aluminum for the pulley I would suggest using a T6 treated material. Non treated bars are way to soft for the aplication and you will also end with a black fine tarnish (oxides) over the belt or string which will also adere to the platter rim.
Of course if you plan to anodize thats diferent and will not happen what I described above. Also anodized surface will provide a higher coeficient of friction to the pulley wich is good for the application. 🙂
BTW, I don't think the mass of the pulley is an issue here.
I also agree with Dave, one setscrew is enough. You might do even without a screw if the pulley is pressfit to the shaft degreesing both contact surfaces prior to the instalation
I'm not participating in this GB but here are my 2 cents:
If you decide to use aluminum for the pulley I would suggest using a T6 treated material. Non treated bars are way to soft for the aplication and you will also end with a black fine tarnish (oxides) over the belt or string which will also adere to the platter rim.
Of course if you plan to anodize thats diferent and will not happen what I described above. Also anodized surface will provide a higher coeficient of friction to the pulley wich is good for the application. 🙂
BTW, I don't think the mass of the pulley is an issue here.
I also agree with Dave, one setscrew is enough. You might do even without a screw if the pulley is pressfit to the shaft degreesing both contact surfaces prior to the instalation
This was my experience with the first MK pulley group buy. I mounted the brass pulley with a loctite drop and the motor in a heavy pod, It made turn a 4kg. alluminium platter. It worked beautifully and I used it a lot. Two months ago a problem started, music wasn't what it used to be, I noticed the tape in pulley proximity was wavering and the maxon was noiser than what it used to be. I cecked level pulley and turntable, speed but I couldn't solve anything. I worked around it for weeks until I definitly damaged the motor trying to take off the pulley. So my conclusion was: the pulley was too heavy.
I just want to add, with all the effort Algar_EMI has already put into this GB, I'm surprised he's still up to the task. Kudos!
I only know enough to be dangerous! So, proceed with caution. I am deriving my ASSUMPTIONS from the little experience I have with cars. Mind you, that I never made a cent. In fact, its a money pit AKA hobby 🙂. So, I'm just throwing out ideas. Hope it helps. My thoughts are as follows:
The pulley crown is self centering and allows for misalignment.
Alignment is critical using a flat belt. If platter is heavy, a minute misalignment will put a enormous strain on the motor bearing. Belt slippage will increase. A round belt will also allow for misalignment.
Belt tension is critical. Too much pressure will cause undue stress on drive components. Engines all have specs on belt deflection/play. Some have builtin belt tensioners. Maxon motor specs?
How flexible is mylar?
Straight pulley? This forces us to perfectly align the belt.
Idler pulleys will help distributing the pressure. On turntable and motor bearing. It will reduce the contact between platter and belt.
Multiple round belts?
A lighter pulley will reduce the workload on motor and motor bearing.
Make pulley. Get any pulley with a 3mm bore and file it down to whatever you want. There are timing belt pulleys, with teeth that can be filed down. They come in aluminum, acetal, nylon, etc. It's a hobby 🙂.
I only know enough to be dangerous! So, proceed with caution. I am deriving my ASSUMPTIONS from the little experience I have with cars. Mind you, that I never made a cent. In fact, its a money pit AKA hobby 🙂. So, I'm just throwing out ideas. Hope it helps. My thoughts are as follows:
The pulley crown is self centering and allows for misalignment.
Alignment is critical using a flat belt. If platter is heavy, a minute misalignment will put a enormous strain on the motor bearing. Belt slippage will increase. A round belt will also allow for misalignment.
Belt tension is critical. Too much pressure will cause undue stress on drive components. Engines all have specs on belt deflection/play. Some have builtin belt tensioners. Maxon motor specs?
How flexible is mylar?
Straight pulley? This forces us to perfectly align the belt.
Idler pulleys will help distributing the pressure. On turntable and motor bearing. It will reduce the contact between platter and belt.
Multiple round belts?
A lighter pulley will reduce the workload on motor and motor bearing.
Make pulley. Get any pulley with a 3mm bore and file it down to whatever you want. There are timing belt pulleys, with teeth that can be filed down. They come in aluminum, acetal, nylon, etc. It's a hobby 🙂.
Just paid for 9 BIX Pods, 5 Black & 4 Silver. I cost 152U$ in shipping (Fedex). My original shipping estimate was 10$ per pod. Shipping cost per pod was 152$/9 = $16.88 each, so I'm already short of 6.88 per pod for this order. I'll add this amount at the end.
I still need to order 6 silver pods to complete the order. I'll wait until they are back in stock.
I got all the pods color choice. Thanks.
I still need to order 6 silver pods to complete the order. I'll wait until they are back in stock.
I got all the pods color choice. Thanks.
Scepis,
I appreciate the tenacity you show in thinking of hand filing teeth off of a cogged pulley, but I think you would not be happy with the results. A lathe is the only way to get close enough to not create wow and speed variation.
Patriz - I'm very sorry that happened to your rig. My preference was towards aluminum myself. The group think ended up settling on brass. I guess we should have though about the weight and how it would effect the motor bearings.
I wonder if it would be worthwhile contacting the people on the first GB who got brass to see if they want to pony up for a new aluminum pulley. The brass pulley weighed 80 grams, while in aluminum they weigh 25 grams. With the top taken off, the pulley could weigh less than 18 grams. The simpler lighter pulley would possibly save a bunch of people a big headache.
Maybe we someone to take on a separate GB to alleviate Algar emi some work. Getting the others involved would help get the numbers needed to make this a bit more cost effective.
I don't know, but those are just some thoughts.
DaveM
I appreciate the tenacity you show in thinking of hand filing teeth off of a cogged pulley, but I think you would not be happy with the results. A lathe is the only way to get close enough to not create wow and speed variation.
Patriz - I'm very sorry that happened to your rig. My preference was towards aluminum myself. The group think ended up settling on brass. I guess we should have though about the weight and how it would effect the motor bearings.
I wonder if it would be worthwhile contacting the people on the first GB who got brass to see if they want to pony up for a new aluminum pulley. The brass pulley weighed 80 grams, while in aluminum they weigh 25 grams. With the top taken off, the pulley could weigh less than 18 grams. The simpler lighter pulley would possibly save a bunch of people a big headache.
Maybe we someone to take on a separate GB to alleviate Algar emi some work. Getting the others involved would help get the numbers needed to make this a bit more cost effective.
I don't know, but those are just some thoughts.
DaveM
I have the brass pulley from the first group buy and though the quality is fine, it does seem heavy, so I would buy an aluminum pulley as a replacement.
Rick
Rick
Indeed, I would like to pulley to be split from this group buy.
However, it means sending money back. I can do it, but I won't pay for the 3% PayPal fee.
First, we need to now if the Teres pulley is working fine with 33-1/3.
If Yes, there is possibility that some will still buy the Teres and the BIX for their application. Just a thought...
Got the Hammond enclosure today. I did the last small modification to the PCB. I'll send it tomorrow for production.
I'll order the motors tomorrow also.
However, it means sending money back. I can do it, but I won't pay for the 3% PayPal fee.
First, we need to now if the Teres pulley is working fine with 33-1/3.
If Yes, there is possibility that some will still buy the Teres and the BIX for their application. Just a thought...
Got the Hammond enclosure today. I did the last small modification to the PCB. I'll send it tomorrow for production.
I'll order the motors tomorrow also.
I'm not an expert so this is just an idea, what you think about making the pulley out of non metallic material?
Delrin or something similar hard plastic material?
Delrin or something similar hard plastic material?
If the pulley was made of Delrin without the belt section, the mass would be about 9 grams. With the belt section it would be 13 grams.
This would be an option. I'm not sure how the surface finish would be for the tape. It would be very finicky. To cut the crown we needed to cut the bottom and then cut the top and taper the two cuts together. With Delrin the tooling marks might require some hand sanding to get a smooth surface.
For mounting the bore could have a taper cut into it so that at .4 inches it would taper down to 2.8 mm and then there would be no need for a set screw or threadlock. simply gently press on and use friction. hmmmm....
DaveM
This would be an option. I'm not sure how the surface finish would be for the tape. It would be very finicky. To cut the crown we needed to cut the bottom and then cut the top and taper the two cuts together. With Delrin the tooling marks might require some hand sanding to get a smooth surface.
For mounting the bore could have a taper cut into it so that at .4 inches it would taper down to 2.8 mm and then there would be no need for a set screw or threadlock. simply gently press on and use friction. hmmmm....
DaveM
I will most likely stay with the Teres pulley if Algar_emi is not pushing through with the custom pulley. I'll nix the Bix and call it even to cover whatever out-of-pocket expenses. Tape seems to be the way to go. The smaller diameter allows me to play with different materials available, such as the Mylar shrink tube. Mylar is very grippy, they use it to line heavy bags such as dry dogfood, because of its high cf. Lastly, I will drill a hole to facilate removal for the custom pulley v.2.
We have to define our design objectives for the pulley. I think that we should concentrate on making a good tape or flat belt pulley, lightweight, high cf material, removable.
Instead set screws, could we use collets? They use it to mount props on model planes. Here's one for a 3mm shaft.
Could we modify this? Could we make parts to adapt it for our purposes?
We have to define our design objectives for the pulley. I think that we should concentrate on making a good tape or flat belt pulley, lightweight, high cf material, removable.
Instead set screws, could we use collets? They use it to mount props on model planes. Here's one for a 3mm shaft.
Could we modify this? Could we make parts to adapt it for our purposes?
Secips said:
I think it is a good idea to define the pulley as well to get it moving. My vote is either custom or Teres as well, tape only. I personally do not need 45rpm if it goes Teres and removable (custom) only if it does not undermine its purpose.
Hi, Alger_emi
I would like to order 5 motor+5 PCB (33/45). Sending to Taiwan.
Please contact me back if you still have.
Thanks
I would like to order 5 motor+5 PCB (33/45). Sending to Taiwan.
Please contact me back if you still have.
Thanks