Hello nocdplz, working means you intalled it on a turntable, and played LPs with it?
Of course, otherwise i'would not post - i've done this design hoping someone will replicate with little effort - Photos in action not yet done (TT must be moved in another room)
All bearings are made with ball pen tips rotating against a brass concave grain You'll find lots of examples in this and other's threads (epsecially used for unipivots)
Skating force, as you and others have taught us, will be there. Refer to graphic made for the Rabbit which has similar geometry.
carlo
Of course, otherwise i'would not post - i've done this design hoping someone will replicate with little effort - Photos in action not yet done (TT must be moved in another room)
All bearings are made with ball pen tips rotating against a brass concave grain You'll find lots of examples in this and other's threads (epsecially used for unipivots)
Skating force, as you and others have taught us, will be there. Refer to graphic made for the Rabbit which has similar geometry.
carlo
Sorry, Billshury: here we are diyers, not buyers. (nor sellers!)
So, first study carefully the project, take those STL files and get them properly printed.
Back home do all the rest of the work, refinishing the parts, mod the grains for the articulations, drill the shaft and so on. Finally assemble it all . & have fun!
carlo
advice: absolutelely avoid electric tools, or you'll have to reprint many parts
So, first study carefully the project, take those STL files and get them properly printed.
Back home do all the rest of the work, refinishing the parts, mod the grains for the articulations, drill the shaft and so on. Finally assemble it all . & have fun!
carlo
advice: absolutelely avoid electric tools, or you'll have to reprint many parts
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Hi, Carlo
Again, you do beautiful work!
Perhaps there is an opportunity to answer a question I have had about Moving-Mount designs like the Birch and Schroeder types. The question goes back to Archie Coppleman's patent (US2522997).
It is this:
The previous lowest-frequency disturbance in an arm was the 0.55Hz of off-balance (or eccentric) records in some turntables. Now we have the Rabbit achievement and its "disturbance" is only about 20mm per side. This takes the variable-length wand idea to a whole new area of "don't care," a stunning achievement if it doesn't have any negative consequences. My question is then, "Is this true?" And does the Dynavector arm deserve more attention than it is getting?
I hope I'm being clear about this. My interest is in more conventional Articulated-Head designs, but the talent being brought to bear on the Birch children is very impressive, and you are one of the central figures (along with dtut).
The choice is no longer "tangential vs fixed vs SLT" but may now include the moving-mount. Actually, you people get naming privileges; I don't.
Admiringly,
Andy
Again, you do beautiful work!
Perhaps there is an opportunity to answer a question I have had about Moving-Mount designs like the Birch and Schroeder types. The question goes back to Archie Coppleman's patent (US2522997).
It is this:
The previous lowest-frequency disturbance in an arm was the 0.55Hz of off-balance (or eccentric) records in some turntables. Now we have the Rabbit achievement and its "disturbance" is only about 20mm per side. This takes the variable-length wand idea to a whole new area of "don't care," a stunning achievement if it doesn't have any negative consequences. My question is then, "Is this true?" And does the Dynavector arm deserve more attention than it is getting?
I hope I'm being clear about this. My interest is in more conventional Articulated-Head designs, but the talent being brought to bear on the Birch children is very impressive, and you are one of the central figures (along with dtut).
The choice is no longer "tangential vs fixed vs SLT" but may now include the moving-mount. Actually, you people get naming privileges; I don't.
Admiringly,
Andy
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Sorry, Andy - I'm not able to answer, I can not understand the reasoning.
Patent (US2522997). looks like a polygon type, ancestor of the Garrard zero = zero offset, but variable overhang error, greater than the traditional arms.
Dynavector is an arm with traditional (Baerwald and others) offset, but with separate hor. and vert. pivots. It has some innovative merits, but not a different geometry.
You mention the "lowest-frequency disturbance" due to the RIAA eccentricity (0.050" - 1,27 mm) tolerance, and say that the Rabbit and the Birch would have one of 20mm. Related to what?
As you know the Thales circle determines the condition of orthogonality of the cantilever to the radius of the disk = 0 offset, 0 tracking error. If also the guiding could be aligned to the Hor. pivot there would be 0 skating force too. But since a true Thales with extensible arm (cathetus) seems really hard to build (I know something, with my wrong Syrinx PLT), the Birch geometry tries to follow that Thales circle, aligning the cantilever to the (now virtual) Thales pivot. With some tolerances, well discussed in the past.
Where lays the "disturbance" you are talking about? Really, without a graph I do not understand
ciao - Carlo
PS - I confess: do not like Birch type TA, because the driving force is completely off-axis. But with the small tracking forces available maybe they are the only ones able to move without an active servo.
Patent (US2522997). looks like a polygon type, ancestor of the Garrard zero = zero offset, but variable overhang error, greater than the traditional arms.
Dynavector is an arm with traditional (Baerwald and others) offset, but with separate hor. and vert. pivots. It has some innovative merits, but not a different geometry.
You mention the "lowest-frequency disturbance" due to the RIAA eccentricity (0.050" - 1,27 mm) tolerance, and say that the Rabbit and the Birch would have one of 20mm. Related to what?
As you know the Thales circle determines the condition of orthogonality of the cantilever to the radius of the disk = 0 offset, 0 tracking error. If also the guiding could be aligned to the Hor. pivot there would be 0 skating force too. But since a true Thales with extensible arm (cathetus) seems really hard to build (I know something, with my wrong Syrinx PLT), the Birch geometry tries to follow that Thales circle, aligning the cantilever to the (now virtual) Thales pivot. With some tolerances, well discussed in the past.
Where lays the "disturbance" you are talking about? Really, without a graph I do not understand
ciao - Carlo
PS - I confess: do not like Birch type TA, because the driving force is completely off-axis. But with the small tracking forces available maybe they are the only ones able to move without an active servo.
The rabbit owes much to the Dynavector and Birch arms.
The Rabbit is my variant of a Birch, driven by the relationship between angles at the two real pivots (belt + pulleys). For the Dynavector, I do not see anything to do with: tha Rabbit has no offset, no split pivots, no damping etc.
The new 3DTOY uses, in a compact design that avoids ball bearings, the double-arms Birch variant invented by Doug years ago.
The reason to design a 3D printable version is not altruism (thanks Walter), nor even the love for the Birch types with all their faults: is that after 1850 posts to count the real arms built in this thread with just one hand is really sad.
It would be time for many to put the hands on their ideas and show us the results. Science needs theories, but theories need experimentation - even for the small problems of our beloved tonearms
carlo
The Rabbit is my variant of a Birch, driven by the relationship between angles at the two real pivots (belt + pulleys). For the Dynavector, I do not see anything to do with: tha Rabbit has no offset, no split pivots, no damping etc.
The new 3DTOY uses, in a compact design that avoids ball bearings, the double-arms Birch variant invented by Doug years ago.
The reason to design a 3D printable version is not altruism (thanks Walter), nor even the love for the Birch types with all their faults: is that after 1850 posts to count the real arms built in this thread with just one hand is really sad.
It would be time for many to put the hands on their ideas and show us the results. Science needs theories, but theories need experimentation - even for the small problems of our beloved tonearms
carlo
Me too, Doug- it's cute, but not serious: just to say "expensive? yes, only a bit cheaper than the famous golf-ball arm"
A trial to understand at what point the finish could be improved: unfortunately the acrylic coating weakens the PLA.
Here something more serious, (hope so): a 3d Rabbit in progress - with ballpen tips, that worked very well. (note your belt-stoppers - any advice?)
carlo
is 3d printing still DIY? is getting too easy..
A trial to understand at what point the finish could be improved: unfortunately the acrylic coating weakens the PLA.
Here something more serious, (hope so): a 3d Rabbit in progress - with ballpen tips, that worked very well. (note your belt-stoppers - any advice?)
carlo
is 3d printing still DIY? is getting too easy..
Attachments
Carlo,
3D printing, point and cup bearings, and a lot of interesting new details - a lot to understand there. I'm very curious about how well the bearings work.
The belt stoppers on my arm had to be offset from each other so they didn't interfere with the belt's main function. From the top, the small pulley clamp is at about 1 o'clock and the large pulley pin is at about 7 o'clock when the headshell is at the lead in grooves.
I'll be out of town for a few days. More when I get back.
3D printing, point and cup bearings, and a lot of interesting new details - a lot to understand there. I'm very curious about how well the bearings work.
The belt stoppers on my arm had to be offset from each other so they didn't interfere with the belt's main function. From the top, the small pulley clamp is at about 1 o'clock and the large pulley pin is at about 7 o'clock when the headshell is at the lead in grooves.
I'll be out of town for a few days. More when I get back.
hi Doug - Ball pen tips bearings work beautifully on 3DTOY, with a friction similar to an honest traditional pivoted: the elasticity of plastic gives them the proper contact, with no chattering. Here we have 4 bearings instead of 8, but putting the belt on top will hopefully reduce the cantilever effect.
As i said, the honeycomb structure of printed parts reduces surprisingly the resonances, so 3d prints seems much better than could be thought - think something like a very rigid balsa (or samba) wood.
Hope that these printed arms will increase the number of experimenters (only 2, always the same, are boring). Designing a real, really working and right sounding PLT is not a joke, and not the joke that can be imagined in theory
carlo
Thanks for the hints for the belt stoppers, I 'd seen the problem when glueing it to pulleys on the Bunny. I'll change the positions
As i said, the honeycomb structure of printed parts reduces surprisingly the resonances, so 3d prints seems much better than could be thought - think something like a very rigid balsa (or samba) wood.
Hope that these printed arms will increase the number of experimenters (only 2, always the same, are boring). Designing a real, really working and right sounding PLT is not a joke, and not the joke that can be imagined in theory
carlo
Thanks for the hints for the belt stoppers, I 'd seen the problem when glueing it to pulleys on the Bunny. I'll change the positions
Moving from ball race bearings to pin bearings resulted in a big improvement in sound quality in my arm, a linear tracker. I think that this was partially due to the much lower friction but largely due to the elimination of chatter and mainly due to improved mechanical grounding (the reason why unipivots work so well). I eventually upgraded to sapphire vee and tungsten carbide pivots which made a further worthwhile improvement. Although expensive I would highly recommend jewelled bearings for your final design. Of course the ball point pen tips are great for development purposes. I love the look of the orange arm. The use of the internal honeycomb will maximize the rigidity to mass ratio and will push the resonant frequency of each component higher and reduce stored energy, both desirable traits.
I look forward to seeing further development.
Niffy
I look forward to seeing further development.
Niffy
Quote all you say, Niffy - which is one of the reasons to draw these arms: experience led me to think that arms and ball bearings hate working together.
The jewels are fascinating, but even if the 3DTOY of a toy has only the color, I do not think they are suitable. First because jewels are high precision mechanisms and here instead loads are not in axis, and second because when the arm is handled the stresses can be harsh.
In this new arm I use a threaded rivet as seat of the cup grain, and this because threaded plastic can not withstand continuous adjustments (normally unuseful, just set up the grain and brake it with a drop of loctite)
Hollow infill is introduced by the "slicer" program (eg CURA or SLIC3R) for printing - different shapes and densities can be set - Maybe the effect is to split resonances in thousands different frequencies.
carlo
I look forward to seeing further development. - join us for that, please, your skill & experience will be precious
The jewels are fascinating, but even if the 3DTOY of a toy has only the color, I do not think they are suitable. First because jewels are high precision mechanisms and here instead loads are not in axis, and second because when the arm is handled the stresses can be harsh.
In this new arm I use a threaded rivet as seat of the cup grain, and this because threaded plastic can not withstand continuous adjustments (normally unuseful, just set up the grain and brake it with a drop of loctite)
Hollow infill is introduced by the "slicer" program (eg CURA or SLIC3R) for printing - different shapes and densities can be set - Maybe the effect is to split resonances in thousands different frequencies.
carlo
I look forward to seeing further development. - join us for that, please, your skill & experience will be precious
For my application, I was able to find Tungsten Carbide endmill blanks from a local company, they then put me in contact with a toolmaker that can grind a 1mm radius on the end and then it goes back to the supplier to be polished.
I found sapphire ring stones for a very good price in China, shipping cost more than the ring stones.
This all costs about 10% what the jewel bearing companies wanted to charge me.
I found sapphire ring stones for a very good price in China, shipping cost more than the ring stones.
This all costs about 10% what the jewel bearing companies wanted to charge me.
Hey friends: keep it simple. please -
3DTOY is not born to be the best arm in the world (I read it so often that i can't help laughing) but only a simple way to see a PLT in action, facing the real problems of these geometries.
From what I know (I have handled some inside a big Sinar-Copal shutter of my view cameras) jewel bearings need precise alignment, axial loads and near 0 tolerances. Here instead ballpen refills (here a chinese pack of 10 sells for 1 euro) are just fine. To make the brass cup grains (the trickyest work of this arm) drill and thread an iron block to guide a center drill and make the conical seat, then polished with a small dremel tip.
Jewell bearings on a plastic tonearm seems like a 12-cylinder Ferrari on a Smart, imho.
carlo
3DTOY is not born to be the best arm in the world (I read it so often that i can't help laughing) but only a simple way to see a PLT in action, facing the real problems of these geometries.
From what I know (I have handled some inside a big Sinar-Copal shutter of my view cameras) jewel bearings need precise alignment, axial loads and near 0 tolerances. Here instead ballpen refills (here a chinese pack of 10 sells for 1 euro) are just fine. To make the brass cup grains (the trickyest work of this arm) drill and thread an iron block to guide a center drill and make the conical seat, then polished with a small dremel tip.
Jewell bearings on a plastic tonearm seems like a 12-cylinder Ferrari on a Smart, imho.
carlo