you are not the only one thinking along these lines
I've been exploring the possibility of using a single pair of concave bearings on a solid glass rod. Planning to try this out on my ROK table as soon as the re-plinth is completed. I'm also planning to try the cantus style inside the tube too. My main reason to try the bicycle bearing arrangement on the single glass tube is that I want to keep the pivot level with the platter, and still keep the arm as short ( and light ) as possible....
John
I also like the polish on the bearing surfaces idea too....
I've been exploring the possibility of using a single pair of concave bearings on a solid glass rod. Planning to try this out on my ROK table as soon as the re-plinth is completed. I'm also planning to try the cantus style inside the tube too. My main reason to try the bicycle bearing arrangement on the single glass tube is that I want to keep the pivot level with the platter, and still keep the arm as short ( and light ) as possible....
John
I also like the polish on the bearing surfaces idea too....
Golana,
Four bearings aren't hard to align, especially considering the way I have configured it see prior thread. The easiest way to the proof is to build it, I have offered a free idea to an exceptional performer, and this is my first real foray into the analog pickup front end and the proof is in the pudding, just build it as it is cheap with nothing to lose
. It's not a 100 percent original idea but I must iterate that the success lies in the specific execution, tbh.Colin
Hi,
I am a long time lurker and first time poster.
I am a hobby machinist and long time audiophile and have been reading this thread with great interest. Having a surface plate reveals many things about the glass rods/tubes mentioned here---- none are round or straight. Now to what degree performance will be degraded is another matter. I totally agree with vynuhl addict about making this arm as cheaply and precise as possible. However for those who feel they have a good working model may want to use a solid ground and polished tungsten carbide rod. I bought a 1/2" diameter tungsten carbide rod 12" long off ebay for $70. This is somewhat expensive but fits the bill of being super ( 90+ Rockwell ) hard,round and slick. The carriage will move with ease. You can get carbide rods in all diameters. Just my 2 cents.
Joe
I am a long time lurker and first time poster.
I am a hobby machinist and long time audiophile and have been reading this thread with great interest. Having a surface plate reveals many things about the glass rods/tubes mentioned here---- none are round or straight. Now to what degree performance will be degraded is another matter. I totally agree with vynuhl addict about making this arm as cheaply and precise as possible. However for those who feel they have a good working model may want to use a solid ground and polished tungsten carbide rod. I bought a 1/2" diameter tungsten carbide rod 12" long off ebay for $70. This is somewhat expensive but fits the bill of being super ( 90+ Rockwell ) hard,round and slick. The carriage will move with ease. You can get carbide rods in all diameters. Just my 2 cents.
Joe
I did wonder myself about the dimensional accuracy of glass tubes.
Here's a suggestion - computer printers contain steel rods for the printhead to slide on that are both round and straight to pretty decent tolerances. I scrounge dead printers just to break them up for those rods. The printheads also contain what I think are oilite bearings sized very closely to the rods.
Way too much friction for a tonearm, but very useful for other purposes.
I asked a fellow professional machinist if he can get me something like that... Hopefully he can get me something for a fair price for my tests...
Hi,
The cheapest place to get carbide rod is on ebay because the sellers are looking to get rid of pieces not needed or left overs from a previous job. I you purchase from a carbide supply house you will pay big money. Put " carbide blanks " in ebay, there is a 7/16" diameter x 12" long on there now for $ 70. Hope this helps.
Joe
The cheapest place to get carbide rod is on ebay because the sellers are looking to get rid of pieces not needed or left overs from a previous job. I you purchase from a carbide supply house you will pay big money. Put " carbide blanks " in ebay, there is a 7/16" diameter x 12" long on there now for $ 70. Hope this helps.
Joe
good point
Bo did on a number of occasions demonstrate with blind comparison of Opus3 master tapes played on the very machine that the tapes had been recorded upon with his Opu3 vinyl records played back on his Continuo record deck fitted with a Cantus tone arm with most listeners being unable to distinguish one from the other. These demonstrations were made to members of the Audio Press. Bo's point was that this proved that neither his deck nor his arm needed further refinement if it was not possible to tell the original master tape from the vinyl playback. Indeed that is a very strong argument. Best regards Moray James.
And how about the dimensional accuracy of the record you are going to play?
Bo did on a number of occasions demonstrate with blind comparison of Opus3 master tapes played on the very machine that the tapes had been recorded upon with his Opu3 vinyl records played back on his Continuo record deck fitted with a Cantus tone arm with most listeners being unable to distinguish one from the other. These demonstrations were made to members of the Audio Press. Bo's point was that this proved that neither his deck nor his arm needed further refinement if it was not possible to tell the original master tape from the vinyl playback. Indeed that is a very strong argument. Best regards Moray James.
From the glass tube aspect I've not noticed dimensional issues, but were clearly talking microscopic that is not clear to even the finest naked eye. If there are any microscopic variations this is taken up the way I've arranged the bearings. I've made a few alternate attempts at different systems but always find myself coming back to the spacer and looser fitting bearings on the 10mm tube since this has without fail provided the lowest friction. It may appear sloppy, but as a whole it works as a solid system. It's just my opinio, but I do think that lab grade glass is more than sufficient for this application and there is little to nothing to be gained by carbide rod except expense. The clearaudio line is from 2-10000$ plus, and use quartz or glass, I don't think price is an issue there.
Colin
Colin
Hi,
I only mentioned the use of carbide rod for the qualities needed for this project which are;
1 near perfect in dimension + or -.0005 in of a specified size
2 super hard with micro inch finish
3 can be had in all metric and English sizes
4 guarantees a smooth and consistent ride for the carriage for the entire length
These traits eliminate the need for any further thoughts or questions about the carriage support and allows folks to concentrate on bearings, carriage design etc.
We all know that records are far from perfect, however using a near " perfect" support " may " help the cartridge track the grooves better. I am only trying to cut out one variable.
Again, this is an excellent project that can be completed by people with different skill levels with good results. Keep up the good work.
Joe
I only mentioned the use of carbide rod for the qualities needed for this project which are;
1 near perfect in dimension + or -.0005 in of a specified size
2 super hard with micro inch finish
3 can be had in all metric and English sizes
4 guarantees a smooth and consistent ride for the carriage for the entire length
These traits eliminate the need for any further thoughts or questions about the carriage support and allows folks to concentrate on bearings, carriage design etc.
We all know that records are far from perfect, however using a near " perfect" support " may " help the cartridge track the grooves better. I am only trying to cut out one variable.
Again, this is an excellent project that can be completed by people with different skill levels with good results. Keep up the good work.
Joe
I've read this entire thread, and now I'm getting the itch to build something... I looked at those bearings with the concave surface, and wonder about running a pair of them along a knife-edge. That feels like a good, low-friction vertical bearing as well as a lower-friction lateral bearing, too.
Comments?
Comments?
And how about the dimensional accuracy of the record you are going to play?
A very, very good point. But the vinyl isn't anything you can do about.
The properties of the rod which the arm rides on are in your grasp however.
But I have never built a tangential tonearm, I'm just going off general engineering principles ( I'm a machinist ). If people are getting good results from their glass tubes I'm certainly not going to argue because real world experience is ( almost always ) what counts IMO.
The dimensional inaccuracy of the record is not an excuse to use a sub-optimal rod/tube. Just saying this for the sake of the argument, I do not consider the glass type used by Colin to be suboptimal by any means. But those imperfections are just another reason why we should use the best we can. The less the friction on the rod, the better the carriage will track the record, despite its imperfections.
Wow....That seems to kill about 7 birds with one stone. You would only need 2 bearings and instead of sliding vertically on a tube with a warp, you would rock on the knife edge. Would ceramic bearings have any benefit?
I'd like to hear some comments by thems thats smarter than me as well.
Btw Colin..this has been one of the most interesting threads I've read.
I'm already collecting my pieces, many thanks for sharing.
Hi,
Siddley & dimkasta
Thanks for helping me make my point. I am lucky enough to own an older Dynavector and a Graham tonearms. For several years I used a Sowther linear tracking tonearm and I used it until the hair thin cartridge wires broke. I liked that arm. I always believed a linear tracking arm is the way to go since it mimics the way the master was cut on the
lathe.
Some observations about some of the glass rods/ceramic tubes /precision dom aluminum tubing I have on hand.
1. Boiler site glass tubing ( 3 samples ) does not roll well at all on a surface plate. A dial indicator shows run out of .012 !!!! inches in certain spots and varied along the length of the tube. This tubing has no need to be precise for its intended use.
2 solid ceramic sharpening stick 1/2" diameter. Again, will not roll well on surface plate. Bad run out.
3. Precision dom aluminum tubing. This was the best with .002 to .004 run out. However this to soft for this tonearm application.
4. 1/2" ground carbide rod. Near perfect, I could not measure any run out and rolled perfectly on the surface plate.
A tip to those using glass/ceramic tubes. Obtain several pieces if possible and roll them on a mirror by tilting one side up and pick the one that rolls most freely and with least amount of imperfection.
Let me say one more time. My post here is not to discourage anyone from making this tonearm, as a matter of fact the opposite is true. For those people on a tight budget use what you have and do your best to make it work. For those who want to make a great tonearm and can spend a little more money, go for the best possible parts possible as it will not cost much more. With good workmanship and good parts I feel you can rival the performance of tonearms that cost $$$$$$$$$.
My gut tells that the easier and more precise ride the carriage has the longer the suspension in the cartridge will last. Just a feeling.
Joe
My gut feeling is that the better
Siddley & dimkasta
Thanks for helping me make my point. I am lucky enough to own an older Dynavector and a Graham tonearms. For several years I used a Sowther linear tracking tonearm and I used it until the hair thin cartridge wires broke. I liked that arm. I always believed a linear tracking arm is the way to go since it mimics the way the master was cut on the
lathe.
Some observations about some of the glass rods/ceramic tubes /precision dom aluminum tubing I have on hand.
1. Boiler site glass tubing ( 3 samples ) does not roll well at all on a surface plate. A dial indicator shows run out of .012 !!!! inches in certain spots and varied along the length of the tube. This tubing has no need to be precise for its intended use.
2 solid ceramic sharpening stick 1/2" diameter. Again, will not roll well on surface plate. Bad run out.
3. Precision dom aluminum tubing. This was the best with .002 to .004 run out. However this to soft for this tonearm application.
4. 1/2" ground carbide rod. Near perfect, I could not measure any run out and rolled perfectly on the surface plate.
A tip to those using glass/ceramic tubes. Obtain several pieces if possible and roll them on a mirror by tilting one side up and pick the one that rolls most freely and with least amount of imperfection.
Let me say one more time. My post here is not to discourage anyone from making this tonearm, as a matter of fact the opposite is true. For those people on a tight budget use what you have and do your best to make it work. For those who want to make a great tonearm and can spend a little more money, go for the best possible parts possible as it will not cost much more. With good workmanship and good parts I feel you can rival the performance of tonearms that cost $$$$$$$$$.
My gut tells that the easier and more precise ride the carriage has the longer the suspension in the cartridge will last. Just a feeling.
Joe
My gut feeling is that the better
I'd be interested to know how the carbide rod works out, I agree we must strive for a certain amount of perfection. Just spun led zeppelin II original red label pressing, wow!, comparing this arm and at120e to its cd equivalent makes the cd sound like an mp3 equivalent, it's that good!. The sound is what it should be, true to the source and involving!.
Colin
Colin
perhaps
you should read the Cantus thread. Bo's first version of his design was a rolling knife edge which is great if you want to play warped records but was left behind for a much improved version with two bearing and four contact points. no point trying to re invent the wheel. Best regards Moray James.
you should read the Cantus thread. Bo's first version of his design was a rolling knife edge which is great if you want to play warped records but was left behind for a much improved version with two bearing and four contact points. no point trying to re invent the wheel. Best regards Moray James.
My friend/machinist said he cannot do this on his own shop. The tungsten rods he has are just turned and to achieve the kind of perfection needed requires big and expensive tools he does not have.
so...
Anyway, I was thinking about Joe's post and his testing on a mirror and the run-out measurements.
My thought was that minor diameter imperfections are not that a big deal since on glass the diameter changes should be smooth and rather gradual, so they would not affect the rolling power of the light carriage significantly.
I m thinking that the bearing's outer perfection is much more significant.
One other thing that came to me while I was writing this, is that bigger bearing diameter should also reduce the significance of rod imperfections. Like in cars. Bigger cars with large wheels are less sensitive to road bumps than let s say a small fiat with 13" wheels... I do not know how this might affect the friction inside it, but this should be quite calculated in its design. the extra weight... I don t know...
so...
Anyway, I was thinking about Joe's post and his testing on a mirror and the run-out measurements.
My thought was that minor diameter imperfections are not that a big deal since on glass the diameter changes should be smooth and rather gradual, so they would not affect the rolling power of the light carriage significantly.
I m thinking that the bearing's outer perfection is much more significant.
One other thing that came to me while I was writing this, is that bigger bearing diameter should also reduce the significance of rod imperfections. Like in cars. Bigger cars with large wheels are less sensitive to road bumps than let s say a small fiat with 13" wheels... I do not know how this might affect the friction inside it, but this should be quite calculated in its design. the extra weight... I don t know...