Have been intrigued by this stiction principle. So in honour of it I found my worst off center lp to try this theory out, have not found a single trace of stiction/sliding of the bearing on glass tube vs rolling as represented. I am as much as anyone very interested in physics and theory but obviously would like to see solutions to a problem. IMHO there is not a problem unless one has built the arm as is and then offered solutions. My apologies if this comes across as crass, but I've been running his for atleast 4 months without even as much as cleaning the tube and it still tracks like a champ 
.
Colin
.Colin
Last Saterday I`ve made a visit to the German AAA-Forum Show at Krefeld.
One of the participants: Clearaudio, with their TT2 tonearm.
One word: Fantastic!!
But the Colin`s sound descriptions are just what I heard at Krefeld.
Chapeau Colin.
Hans.
p.s. http://www.aaanalog.de/index.php?context=page&id=Page:6378#english
p.s.2 check at the end of this week ( google ) for possible foto reports.
One of the participants: Clearaudio, with their TT2 tonearm.
One word: Fantastic!!
But the Colin`s sound descriptions are just what I heard at Krefeld.
Chapeau Colin.
Hans.
p.s. http://www.aaanalog.de/index.php?context=page&id=Page:6378#english
p.s.2 check at the end of this week ( google ) for possible foto reports.
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Why is anyone buying *sealed* bearings??
The seals add friction and are usually used on permanently lubed bearings - the lube installed inside.
They do sell bearings with one side "shielded" if you think you needed that for some reason or another.
Silicone/synthetic oil does not gum up or thicken.
To polish the outside of the bearing I suggest making up an arbor. The arbor needs to hold the bearing between two washers. The washers should just make it to the edge of the outer race. One could use a suitable screw plus a center spacer, then you back the screw up the assembly to clamp the bearing. Now when you spin the bearing on the arbor you do not spin the bearing. One could use clear kitchen wrap (aka "Saran Wrap" in the USA) as a gasket between the washers and the bearing for a better seal.
Do not use "emery" paper, if you were going to use an abrasive you would want to use "wet or dry" Aluminium Oxide. Automotive supply houses sell it in grits down to 2400. If the bearing is pretty smooth already, 2400 grit + oil followed by cleaning (rag is enough) and then polishing compound(s) will give a mirror finish.
I like the ultrasonic cleaner idea.
Don't put your hands in Acetone.
Do not breathe it - or other solvents.
It is a carcinogen.
I know they use it as nail polish remover.
Doesn't change it.
Call back when you are old, you might regret exposure to solvents then...
Most oils will give up when hit with "degreaser spray" those are strong alkaline substances. Water based. You could follow with a water and detergent hot water rinse, and/or repeat this a few times, finally a quick solvent dip if you are concerned about any surface residuals. Hot air (hair dryer?) should pull out any left over liquids.
There are some *waterproof* greases that are really tough to remove. But why did you buy a sealed bearing with grease in it to begin with? Open bearings have a light oil generally speaking. Large industrial open bearings may come packed with some grease, mostly to keep them from rusting on the shelf.
Over speeding these bearings via compressed air with no load should have no negative effect, afaik.
The seals add friction and are usually used on permanently lubed bearings - the lube installed inside.
They do sell bearings with one side "shielded" if you think you needed that for some reason or another.
Silicone/synthetic oil does not gum up or thicken.
To polish the outside of the bearing I suggest making up an arbor. The arbor needs to hold the bearing between two washers. The washers should just make it to the edge of the outer race. One could use a suitable screw plus a center spacer, then you back the screw up the assembly to clamp the bearing. Now when you spin the bearing on the arbor you do not spin the bearing. One could use clear kitchen wrap (aka "Saran Wrap" in the USA) as a gasket between the washers and the bearing for a better seal.
Do not use "emery" paper, if you were going to use an abrasive you would want to use "wet or dry" Aluminium Oxide. Automotive supply houses sell it in grits down to 2400. If the bearing is pretty smooth already, 2400 grit + oil followed by cleaning (rag is enough) and then polishing compound(s) will give a mirror finish.
I like the ultrasonic cleaner idea.
Don't put your hands in Acetone.
Do not breathe it - or other solvents.
It is a carcinogen.
I know they use it as nail polish remover.
Doesn't change it.
Call back when you are old, you might regret exposure to solvents then...
Most oils will give up when hit with "degreaser spray" those are strong alkaline substances. Water based. You could follow with a water and detergent hot water rinse, and/or repeat this a few times, finally a quick solvent dip if you are concerned about any surface residuals. Hot air (hair dryer?) should pull out any left over liquids.
There are some *waterproof* greases that are really tough to remove. But why did you buy a sealed bearing with grease in it to begin with? Open bearings have a light oil generally speaking. Large industrial open bearings may come packed with some grease, mostly to keep them from rusting on the shelf.
Over speeding these bearings via compressed air with no load should have no negative effect, afaik.
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I bought the sealed bearings, cleaned them, used them, they work fine.
Suppose the benefit to keeping them sealed is to keep dust and dirt out.
I've bought another set, and will try them without cleaning.
I've easily over 100 albums on my arm now....its fantastic.
Am thinking of a better TT to put it on.
This is a quick video I've done of my room and equipment.
In it is the tonearm working....please, just critique the arm.
My Room - YouTube
Suppose the benefit to keeping them sealed is to keep dust and dirt out.
I've bought another set, and will try them without cleaning.
I've easily over 100 albums on my arm now....its fantastic.
Am thinking of a better TT to put it on.
This is a quick video I've done of my room and equipment.
In it is the tonearm working....please, just critique the arm.
My Room - YouTube
Hi all !
There's one thing I would like to mention here , which I believe is food for thoughts :
Altough the horizontal movement goes very smooth with the basics as Colin provided us .. the vertical movement of the wand is not as smooth as one would think . I find out about this when setting the VTF with my digital scale .
I can hardly get to a stable and steady value and the force seem to change each time I lift the armwand and let it down on the scale again .
I think HERE is where polishing the bearingedge could be benificial ! so not at all related to horizontal movement . I have seen linear trackers where this issue has been solved by using either knive bearing seats or another bearing construction .
Could someone chime in on this please ? I can imagine others have noticed this too ??
THX
Paul
There's one thing I would like to mention here , which I believe is food for thoughts :
Altough the horizontal movement goes very smooth with the basics as Colin provided us .. the vertical movement of the wand is not as smooth as one would think . I find out about this when setting the VTF with my digital scale .
I can hardly get to a stable and steady value and the force seem to change each time I lift the armwand and let it down on the scale again .
I think HERE is where polishing the bearingedge could be benificial ! so not at all related to horizontal movement . I have seen linear trackers where this issue has been solved by using either knive bearing seats or another bearing construction .
Could someone chime in on this please ? I can imagine others have noticed this too ??
THX
Paul
Altough the horizontal movement goes very smooth with the basics as Colin provided us .. the vertical movement of the wand is not as smooth as one would think . I find out about this when setting the VTF with my digital scale
Could someone chime in on this please ? I can imagine others have noticed this too ??
THX
Paul
I mentioned this in my first post. It is even more pronounced with my heavier wire. VTF would change by upto 0.5 gm depending on how I dressed the cable.
My plan is to chop up an old Lenco arm and V block. I have also destroyed an old Japanese arm and have the vertical bearing but it is a bit heavy. I don't think the bearing needs to be ultra smooth though.
My transfi wire is at the post office so should get it on friday. Too many other jobs around the house as well.
Bear,
I agree with open bearings so far. I bought sealed bearings and even after cleaning and spinning up they still aren't as smooth as the open set. These were expensive too, $9.0 each. Unfortunately I have to buy these online and they turned out to be pressed in metal seals that I can't remove. I have 10 sealed (rubber I hope) ordered from ebay hongkong for $3 coming sometime.
Regards,
Kffern
Hi Paul and others trying to sort out the running of these magnificent linear mechanical tone arms.Hi all !
There's one thing I would like to mention here , which I believe is food for thoughts :
Altough the horizontal movement goes very smooth with the basics as Colin provided us .. the vertical movement of the wand is not as smooth as one would think . I find out about this when setting the VTF with my digital scale .
I can hardly get to a stable and steady value and the force seem to change each time I lift the armwand and let it down on the scale again .
I think HERE is where polishing the bearingedge could be benificial ! so not at all related to horizontal movement . I have seen linear trackers where this issue has been solved by using either knive bearing seats or another bearing construction .
Could someone chime in on this please ? I can imagine others have noticed this too ??
THX
Paul
Here is what I've come up with so far. For starters, go back and reread everything Bo Hansson has written on the subject. IIRC he suggests letting ones ears tell you when the tracking force is correct. For his arms (CANTUS) he never mentions a suggested tracking force. A ball park figure is what I wanted and tried all the tricks in the book to make my LT arm work at some reasonable figure. NO luck, I couldn't measure it. there was always the arm doing what it wanted and not what I thought I was asking it to do. Better results from ignoring the scales and just listening. Then the penny dropped. Never with existing scales and balances will it be possible to measure the vertical tracking force under the dynamic condition of playing a record, especially with the mechanical bearings rolling on the glass tube or rod. But will it be possible to set the counter weight so that when dropping the cartridge from a height that just allows the stylus to graze the recorded track repeatably. I tried it and yes one can achieve this degree of balance. Now take that digital scale you almost threw out and make some little lumps of putty or plasticine that weigh what you are trying to achieve for tracking force. Place a most likely candidate right above the stylus and listen. Once you have seen and heard the results I think you will be amazed at how well your arm tracks with a much lighter weight than you were expecting.
BillG
Fantastic gear and setup you have there PDR!!! And I thought that I was the only person around here that listened to C&W....
Do you have any Zac Brown that you can put up to YouTube???
(not really - just a feeble attempt at humor....)
Hi , a duran 10MM O.D. glass tube , bearings ( open type ) UL 610X-L 23 Switzerland . SMR106 RVS (Inox) minilagers van RMB (Zwitserland)
d=6mm
D=10mm
B=2,5mm
6x10x2,5mm
Aprox. 0,4 Gram deviation !
THX ,
Paul
5MM gap between them .. polished brass shim
I've been trying to upload some photos relevant to the issue of edge-polished bearings on vertical friction, along with explanatory text - and also detailing an alternate construction method for low-weight of the carriage/wand/headshell. The "failure to upload from computer" error has been consistent for many hours now. Previously I'd uploaded photos to this thread - and the current photos are well within parameters for size and resolution.
Anybody got a clue as to what the problem might be? I rebooted my computer several times.
John
p.s. Polished bearing edges seem to have little or no influence on vertical friction with either a polished SS rod or borosilicate glass tubing. Dry Teflon applied to the SS rod seems a very minor help. In both cases friction is very great.
Anybody got a clue as to what the problem might be? I rebooted my computer several times.
John
p.s. Polished bearing edges seem to have little or no influence on vertical friction with either a polished SS rod or borosilicate glass tubing. Dry Teflon applied to the SS rod seems a very minor help. In both cases friction is very great.
just a reminder that from Bo's point of view you want to have very low resistance in the horizontal plane and a high resistance in the vertical so that the arm is stiff in that plane. This is the preferred arrangement over the previous rolling knife edge design which allowed for resonance in the vertical plane. Best regards Moray James.
John,
Sorry, I have no clue as to why you can't upload pics. Perhaps it will resolve.
This friction/stiction business is getting out of hand. I think we need to look at what we are trying to do, and what role friction plays in doing or not doing what needs to be done. For one thing, if an impulse comes along which kicks the arm upward, we don't want the arm to fly up to the limits of its travel. So friction can be a mechanical shock absorber (aka damper). By the same token, we don't want the arm to stay stuck at the top of its travel because the friction won't let it come down. So some friction will help us track a record. The value must allow unimpeded vertical motion of the cartridge to rise and fall with a warp. Intimate contact with the groove must be preserved. Right now I can't follow through on this line of analysis in real time. What I am requesting is that we all think this through to the best of our abilities to determine what is required and how any given parameter will allow our cartridge to meet the requirements. The shotgun in the dark approach may hit the target but we won't know it because we don't know what we are shooting at.
I'm anxious to see your pics.
Rgds,
BillG
Thanks Moray. That in part is one of the things I was driving at.
BG
Sorry, I have no clue as to why you can't upload pics. Perhaps it will resolve.
This friction/stiction business is getting out of hand. I think we need to look at what we are trying to do, and what role friction plays in doing or not doing what needs to be done. For one thing, if an impulse comes along which kicks the arm upward, we don't want the arm to fly up to the limits of its travel. So friction can be a mechanical shock absorber (aka damper). By the same token, we don't want the arm to stay stuck at the top of its travel because the friction won't let it come down. So some friction will help us track a record. The value must allow unimpeded vertical motion of the cartridge to rise and fall with a warp. Intimate contact with the groove must be preserved. Right now I can't follow through on this line of analysis in real time. What I am requesting is that we all think this through to the best of our abilities to determine what is required and how any given parameter will allow our cartridge to meet the requirements. The shotgun in the dark approach may hit the target but we won't know it because we don't know what we are shooting at.
I'm anxious to see your pics.
Rgds,
BillG
Thanks Moray. That in part is one of the things I was driving at.
BG
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BillG & Moray James,
Given what you've both written, then the polished-edge bearings and polished SS rod meet the criteria in spades. As to whether they might provide any added sonic benefit is unclear. I've got 7 photos of an alternate 'low mass' fabrication method, an a whole lot of text explaining the photos. Quite frustrating to get the whole thing written up, and the photos processed, and then no go loading to this thread. Maybe tomorrow - as Gaborbela has written above the problem is in other threads also.
There is a very clear rolling 'sound' difference (at high speed) between the bearings on glass and on polished SS. Much, much nicer on SS than on glass. Probably irrelevant.
Here's the alternate fabrication method teaser, or not as the case may be. My carriage (without cartridge, cartridge clips, wire, or counterweight, etc.) weighs in at 16.7 grams, with a total length of the wand/headshell at 8 3/8" (hence 6" for the counterweight end). I'm thinking, possibly wrongly, that that is pretty low mass - using balsa composite, magnesium, and a section of an Easton aluminum/carbon competition arrow. The bearing axles are 1/8" diameter aluminum tubing. Mostly all glued together. I've followed Colin's 'last testament' as closely as possible for the carriage dimensions.
If ChrisG is reading, do you have another nut underneath the top washer in your mount fixing the threaded rod securely to the washer along with the top nut - or is there only the top nut as seen in your latest photos? The photos don't show the underside of the top washer. Are the 3 leveling screws 'free' on the bottom washer? Thanks in advance if you can answer.
Polishing my (SS) rod [still],
John
Given what you've both written, then the polished-edge bearings and polished SS rod meet the criteria in spades. As to whether they might provide any added sonic benefit is unclear. I've got 7 photos of an alternate 'low mass' fabrication method, an a whole lot of text explaining the photos. Quite frustrating to get the whole thing written up, and the photos processed, and then no go loading to this thread. Maybe tomorrow - as Gaborbela has written above the problem is in other threads also.
There is a very clear rolling 'sound' difference (at high speed) between the bearings on glass and on polished SS. Much, much nicer on SS than on glass. Probably irrelevant.
Here's the alternate fabrication method teaser, or not as the case may be. My carriage (without cartridge, cartridge clips, wire, or counterweight, etc.) weighs in at 16.7 grams, with a total length of the wand/headshell at 8 3/8" (hence 6" for the counterweight end). I'm thinking, possibly wrongly, that that is pretty low mass - using balsa composite, magnesium, and a section of an Easton aluminum/carbon competition arrow. The bearing axles are 1/8" diameter aluminum tubing. Mostly all glued together. I've followed Colin's 'last testament' as closely as possible for the carriage dimensions.
If ChrisG is reading, do you have another nut underneath the top washer in your mount fixing the threaded rod securely to the washer along with the top nut - or is there only the top nut as seen in your latest photos? The photos don't show the underside of the top washer. Are the 3 leveling screws 'free' on the bottom washer? Thanks in advance if you can answer.
Polishing my (SS) rod [still],
John
Hi Colin,
Wondering what ever happened to the experiments with a smaller diameter tube (smaller than 10mm)??
Bob,
Was a no go, 10mm proved best overall and as has been correctly stated, we want horizontal friction low and vertical higher.
To all, on the bearing issues, I've inspected my 9mm bearings and realize they have very little edge to them, almost no bevel which explains alot of why I have had flawless success with them, maybe go for 8mm bearings as they are more common and work almost as well as 9mm. Also, my bearings are 3mm wide, maybe just maybe parts choice is mor important than I thought, as 12mm bearings did not work near as well. As the bearing gets larger I can see a need for degreasing, but not apparently necceassary for the smaller sizes it seems.
Colin
Was a no go, 10mm proved best overall and as has been correctly stated, we want horizontal friction low and vertical higher.
To all, on the bearing issues, I've inspected my 9mm bearings and realize they have very little edge to them, almost no bevel which explains alot of why I have had flawless success with them, maybe go for 8mm bearings as they are more common and work almost as well as 9mm. Also, my bearings are 3mm wide, maybe just maybe parts choice is mor important than I thought, as 12mm bearings did not work near as well. As the bearing gets larger I can see a need for degreasing, but not apparently necceassary for the smaller sizes it seems.
Colin
Another point which hasn't been addressed which I'm sure those who have built the arm can also point out. Any noise contributed by the bearings is dominate by any vinyl noise and to an even larger extent in some cases the noise of the record cutting lathe advancing between tracks. If we were to get very technical we could say potentially bearing noise would be higher with louder cuts with fewer lines per inch engraved but from my findings it's lower than the noise floor of vinyl in which I can't audibly hear with an lp playing. Worst case scenario it would be truly more audible on a runout groove, but, this noise is usually dominated by the rapid advancement of the cutting lathe. One thing that is astounding is just how noisy some lathes are and how easily that gets picked up by the cutterhead.
Colin
Colin