OK, I stuck at it and its running - kind of.
It works and all, but like someone else I read here back up a bit, the stylus is hunting too much at the moment. This means that although it doesn't skip (I think), as it plays, the carriage is moving forwards in "jerks". I've been studying it in motion, and I don't know if a 90 deg angle is the best way forward. I also think my bearings could be freer too. I might adjust the glass tracks a bit and make that angle a little more shallow and then also wash out the bearings again. It makes me think that the original design with the glass tube was clever enough.
Fran
It works and all, but like someone else I read here back up a bit, the stylus is hunting too much at the moment. This means that although it doesn't skip (I think), as it plays, the carriage is moving forwards in "jerks". I've been studying it in motion, and I don't know if a 90 deg angle is the best way forward. I also think my bearings could be freer too. I might adjust the glass tracks a bit and make that angle a little more shallow and then also wash out the bearings again. It makes me think that the original design with the glass tube was clever enough.
Fran
Trying again, slow typist.
Hi Fran,
Great you have something working. I think you will find a deep cleaning of the bearings will solve your problem. Use a good solvent, mineral spirits followed by lacquer thinner and compressed air. Use the air to spin the bearing up and let it run in for a while. Also make sure your wires from the cartridge are free and flexible. Keep us informed.
BillG
Hi Fran,
Great you have something working. I think you will find a deep cleaning of the bearings will solve your problem. Use a good solvent, mineral spirits followed by lacquer thinner and compressed air. Use the air to spin the bearing up and let it run in for a while. Also make sure your wires from the cartridge are free and flexible. Keep us informed.
BillG
So I went back and washed out the bearings again, finishing with an acetone wash. I then squirted in a little ultraglide (PTFE spray) and then spun them at high speed using the compressor/airline. I also polished the outside of the bearings (shiny now) and cleaned the glass slips with acetone too. They spun quite freely, but not as free as I thought they might. Mounted it all back up on the TT - but still the same effect. You can see it very clearly on a record with a long lead out groove - when the arm needs to move fast it kinda "jerks" across the lead out. I just don't think its frictionless enough to be good.
Now, what I don't know is whether this is just the bearings I have (no name ones 5mm ID/14mm OD) that were expensive enough (€12 each). Maybe some better/alt ones, even ceramics would be better. I though maybe the carriage was too heavy, but I used my cartridge scales to weigh it, it comes in at 46g - incl the cart and counterweight. I could shave another gram or 2 tops off that, but not much more.
I'm going back and forth between this arm and my schroder clone!! Its arm city here at the moment.
fran
Now, what I don't know is whether this is just the bearings I have (no name ones 5mm ID/14mm OD) that were expensive enough (€12 each). Maybe some better/alt ones, even ceramics would be better. I though maybe the carriage was too heavy, but I used my cartridge scales to weigh it, it comes in at 46g - incl the cart and counterweight. I could shave another gram or 2 tops off that, but not much more.
I'm going back and forth between this arm and my schroder clone!! Its arm city here at the moment.
fran
some possibilities
Fran,
Sorry you are having problems. I'm not familiar with PTFE spray but the general consensus is that the bearings must be run dry, that is with no lubrication or any thing other than air. While more Americans breathe U.S. Air than any other brand I'm sure that Dublin Air will qualify. Unless you live on the bus 7 route. I had problems not unlike yours until I got the bearings pristine clean and dry. Since then, no problems at all. It just runs smoothly. I mentioned the wires needing to follow the carriage unimpeded. It took me a while to get that right. Any drag, too heavy or stiff etc. will do bad things. I had the wires draped for nice loose motion with long radius curves and still had problems. Then I noticed that at one position of the carriage it was applying force straight into the end of the wire. (Force applied parallel to lead). Eliminated that and all beautiful since, and that was several months ago. Very early in my experiments with a real jury rig there was a problem that was from the two bearings not being truly parallel. Picture a car with a bad frame alignment running crab track down the road. I have just ordered some 5X10X5 hybrid ceramic bearings of the same brand that DTUT has just installed. were 7.99USD free shipping anywhere in the world. Try the Aceracer web site. The quality of your bearings should be fine at the price you paid. Keep us informed Fran.
DTUT. The ceramics I bought come oiled with a very light weight synthetic lube. I'll try them before cleaning, just to see how well they work. Earlier on I did try lubing with 5 wgt Nano-oil, the ultimate clock oil. after lubing and running them in a bit, I blew them out with the air hose so only the thinest possible film of nanoparticles would remain. Performance was not as good as the clean, dry bearing. Doug, do you use the ceramics with the as shipped lube, or did you flush them out.
Rgds to all,
BillG
Fran,
Sorry you are having problems. I'm not familiar with PTFE spray but the general consensus is that the bearings must be run dry, that is with no lubrication or any thing other than air. While more Americans breathe U.S. Air than any other brand I'm sure that Dublin Air will qualify. Unless you live on the bus 7 route. I had problems not unlike yours until I got the bearings pristine clean and dry. Since then, no problems at all. It just runs smoothly. I mentioned the wires needing to follow the carriage unimpeded. It took me a while to get that right. Any drag, too heavy or stiff etc. will do bad things. I had the wires draped for nice loose motion with long radius curves and still had problems. Then I noticed that at one position of the carriage it was applying force straight into the end of the wire. (Force applied parallel to lead). Eliminated that and all beautiful since, and that was several months ago. Very early in my experiments with a real jury rig there was a problem that was from the two bearings not being truly parallel. Picture a car with a bad frame alignment running crab track down the road. I have just ordered some 5X10X5 hybrid ceramic bearings of the same brand that DTUT has just installed. were 7.99USD free shipping anywhere in the world. Try the Aceracer web site. The quality of your bearings should be fine at the price you paid. Keep us informed Fran.
DTUT. The ceramics I bought come oiled with a very light weight synthetic lube. I'll try them before cleaning, just to see how well they work. Earlier on I did try lubing with 5 wgt Nano-oil, the ultimate clock oil. after lubing and running them in a bit, I blew them out with the air hose so only the thinest possible film of nanoparticles would remain. Performance was not as good as the clean, dry bearing. Doug, do you use the ceramics with the as shipped lube, or did you flush them out.
Rgds to all,
BillG
Last edited:
Thanks Bill,
The spray is an evaporating type of teflon spray - but I'll go back now and flush it out again and see how it goes. It goes dry to the touch almost immediately, but does leave a film. Its used for the sliding ways of lathes etc., where dry lubrication is needed.
I haven't added any tonearm wires yet, so that's not an issue. I have some very fine copper for that - same as what I used on my air bearing arm where they cause no trouble. Thinner than hair, a PITA to work, but excellent for this purpose.
Is the 46g weight for the carriage OK do you think? Only thing thats left after that is the bearings/slide....
The spray is an evaporating type of teflon spray - but I'll go back now and flush it out again and see how it goes. It goes dry to the touch almost immediately, but does leave a film. Its used for the sliding ways of lathes etc., where dry lubrication is needed.
I haven't added any tonearm wires yet, so that's not an issue. I have some very fine copper for that - same as what I used on my air bearing arm where they cause no trouble. Thinner than hair, a PITA to work, but excellent for this purpose.
Is the 46g weight for the carriage OK do you think? Only thing thats left after that is the bearings/slide....
Fran: Bill is right, clean dry bearings zero lubricant. Your PTFE lubricant may be a bitch to remove, I have no idea what solvent will wash that off 100%, you might ask the maker how to get it off your bearing or just replace them if you cannot get them to roll for you.. Maximizing the hardness of the track is so important as in glass, tungsten or ceramic anything as hard or harder than glass. Think along the lines as a railroad car steel wheels on a steel track, low friction. Best regards Moray James.
Last edited:
I'm gonna try remove it anyway.... I reckon some acetone or dicholoromethane will shift it OK. Don't think of this stuff as an oil though - I wouldn't have used oil! To explain exactly what I did... I soaked the bearings in acetone, then blew them out with the compressor, mounted them on a bolt and spun them with air. Then squirted in a little of the PTFE (its an aerosol can), then blew that out again with the compressor and spun them for another 30 secs-minute. They look and feel 100% dry - eg you put them on tissue paper and the paper is dry, no oil spots etc.
But hey, I'll wash them out again, that'll only take a few mins and try again. If that works I'll be happy man...... but then I'll have to make a decision about the schroder arm!!!
Fran
But hey, I'll wash them out again, that'll only take a few mins and try again. If that works I'll be happy man...... but then I'll have to make a decision about the schroder arm!!!
Fran
I just got back from selling some surplus audio stuff, so now I'll be able to get a compressor. Anybody know if one from HF is worth messing with.
I've found that completely clean and dry is best for bearings. Somethings, like Ronsenol lighter fluid or kerosene, seem to sort of work, but just not as well as really clean.
BillG -The ceramics didn't have any visible lube I could see, which surprised me, but I gave them a thorough acetone wash anyway. I hope they work well for you.
Another thing I've found is that cherry picking may be necessary. Sometimes just a pair will be fine right away. Other times, I have to go through a tube of ten to get three or four acceptable bearings. The ceramics I got all spin beautifully and all work mounted in the arm, but two of the four spin quieter and smoother.
Fran - It's great you've gone ahead with your LT project. 46 gr. should be plenty light so I don't think the problem's there. What's the bearing spacing distance and the effective arm length? Probably no problem, just curious. Beautiful job on your Schroeder, by the way. Congratulations.
I'd like some feedback on a thought I just had. We're dealing with the inertia of the entire arm, of course, but I wonder if the bearings may have a separate inertia of their own and, if they do, is the possible relative inertial difference between larger and smaller bearings an important consideration?
I've found that completely clean and dry is best for bearings. Somethings, like Ronsenol lighter fluid or kerosene, seem to sort of work, but just not as well as really clean.
BillG -The ceramics didn't have any visible lube I could see, which surprised me, but I gave them a thorough acetone wash anyway. I hope they work well for you.
Another thing I've found is that cherry picking may be necessary. Sometimes just a pair will be fine right away. Other times, I have to go through a tube of ten to get three or four acceptable bearings. The ceramics I got all spin beautifully and all work mounted in the arm, but two of the four spin quieter and smoother.
Fran - It's great you've gone ahead with your LT project. 46 gr. should be plenty light so I don't think the problem's there. What's the bearing spacing distance and the effective arm length? Probably no problem, just curious. Beautiful job on your Schroeder, by the way. Congratulations.
I'd like some feedback on a thought I just had. We're dealing with the inertia of the entire arm, of course, but I wonder if the bearings may have a separate inertia of their own and, if they do, is the possible relative inertial difference between larger and smaller bearings an important consideration?
You echo my thoughts exactly.
Hi Doug, I've been having problems with my laptop when trying to reply to forum posts. Thought it could be my wireless mouse, but am now on USB mouse and still problems. Got to try something else. Sorry, back later.
BillG
Hi Doug, I've been having problems with my laptop when trying to reply to forum posts. Thought it could be my wireless mouse, but am now on USB mouse and still problems. Got to try something else. Sorry, back later.
BillG
Last edited:
some thoughts
Hi Doug,
I have been having a lot of trouble trying to type answers to postings on DIY Audio. The cursor keeps moving around and shifting the positiion of words or partial words elsewhere on the page. I find my entries getting lost or deleted and other strange stuff. Thought it could be the wireless mouse sending spurious signals, so I tried a USB mouse to no avail. Right now I'm on word pad and having no trouble at all. Will copy and paste this to the forum if that works.
Your comments on the LT arm being ready for polishing up to something more than looking like a "little thing" hit home with what has been my thinking from the day one. In fact the "little thing" put me off building a LT for a long time. I'm about ready to build a more or less final model. My TT is made of grey Corian with a white Corian platter. I intend to use the same materials for the LT arm and scale the parts where possible to give an integrated appearance. The base will be like an arm board, curved to follow the platter and into a corner and side edge of the plinth. Wish me luck. In a reply to Fran I mentioned to you that I had just ordered ceramic bearings. I was able to get 4x10x4 mm bearings which are the same size as I am using in SS abec 7 bearings. So I will be able to make a direct comparison. I note that Acer-racer delivers these bearings lubricated with a low viscocity synthetic oil. Did you use yours as delivered or did you flush them out? I'm really looking forward to trying ceramics. When we feel that we have a matured and reproducible LT, maybe we should distill the process into a LT CookBook like the loudspeaker design cookbook, so future builders needn't dig through all our postings and efforts to reproduce one. But there is much fun and much to be learned by digging deeply into the forum and this thread. I tried to give Fran some help with his hunting problem. My hunting seems to be corrected, but I'm not really sure just what fixed it. Anything you can suggest or comment on would help him and possibly shed some light for all of us.
Rgds,
BillG
Hi Doug,
I have been having a lot of trouble trying to type answers to postings on DIY Audio. The cursor keeps moving around and shifting the positiion of words or partial words elsewhere on the page. I find my entries getting lost or deleted and other strange stuff. Thought it could be the wireless mouse sending spurious signals, so I tried a USB mouse to no avail. Right now I'm on word pad and having no trouble at all. Will copy and paste this to the forum if that works.
Your comments on the LT arm being ready for polishing up to something more than looking like a "little thing" hit home with what has been my thinking from the day one. In fact the "little thing" put me off building a LT for a long time. I'm about ready to build a more or less final model. My TT is made of grey Corian with a white Corian platter. I intend to use the same materials for the LT arm and scale the parts where possible to give an integrated appearance. The base will be like an arm board, curved to follow the platter and into a corner and side edge of the plinth. Wish me luck. In a reply to Fran I mentioned to you that I had just ordered ceramic bearings. I was able to get 4x10x4 mm bearings which are the same size as I am using in SS abec 7 bearings. So I will be able to make a direct comparison. I note that Acer-racer delivers these bearings lubricated with a low viscocity synthetic oil. Did you use yours as delivered or did you flush them out? I'm really looking forward to trying ceramics. When we feel that we have a matured and reproducible LT, maybe we should distill the process into a LT CookBook like the loudspeaker design cookbook, so future builders needn't dig through all our postings and efforts to reproduce one. But there is much fun and much to be learned by digging deeply into the forum and this thread. I tried to give Fran some help with his hunting problem. My hunting seems to be corrected, but I'm not really sure just what fixed it. Anything you can suggest or comment on would help him and possibly shed some light for all of us.
Rgds,
BillG
I wonder if the cylindrical tube of the Opus 3 allows for a fudge of torque analogous to the "crabbing" of servo assisted LTs. 90 degree reactions are intrinsic to Newtonian structures, and attempts to achieve 100% rigidity are doomed. I'm thinking of the Millennium bridge in London which had to have dampers installed after the grand opening resulted in serious oscillation. The original is sometimes the best.
Fran, Couldn't tell whose pics you were looking at. DTUT's or mine. Mine measure 46.5mm spacing and 107mm apex of track to stylus. These numbers taken with hand held caliper held close to but not precisely against the arm. So yes you are in the ball park considering the pics are small and all taken at oblique angles. Sorry to hear your bearing blew up. Cut down the air pressure next time. Really, that spacer shouldn't have fallen apart. Get a refund or a replacement.
BillG
BillG
ceramics here and working
Hi Fran, Doug and others,
My 4x10x4 ceramics came today. Installed them tonight and spent the rest of the evening listening to records. Brilliant! First I flushed them out by spinning them slowly by hand in an acetone bath. then blew them out with compressed air and repeated the wash. There was a surprising amount of stuff that flushed out so the second rinse was in clean fluid. Acerracer says the bearings are lubed with thin silicone(check this) oil not grease so I didn't remove the seals. Then mounted them in place of the abec7's, aligned the arm again and the rest is listening to it. It tracks perfectly. The sound is no different than with the old bearings. It seems to be tracking at a lower stylus pressure, have to measure that. Like you Doug, I won't be going back to all steel bearings. I didn't want to buy a tube of 10, so I settled on 2 pcs. Perhaps cherry picking could have found even better ones. Will have to ask what the ABEC rating is. I think there may be a bit more radial play, and that may be to our advantage. Did a lot of watching the cart to check for hunting. There is none visible but I'll check more carefully. Now to make a pretty arm. I'm a happy guy tonight.
BillG
Hi Fran, Doug and others,
My 4x10x4 ceramics came today. Installed them tonight and spent the rest of the evening listening to records. Brilliant! First I flushed them out by spinning them slowly by hand in an acetone bath. then blew them out with compressed air and repeated the wash. There was a surprising amount of stuff that flushed out so the second rinse was in clean fluid. Acerracer says the bearings are lubed with thin silicone(check this) oil not grease so I didn't remove the seals. Then mounted them in place of the abec7's, aligned the arm again and the rest is listening to it. It tracks perfectly. The sound is no different than with the old bearings. It seems to be tracking at a lower stylus pressure, have to measure that. Like you Doug, I won't be going back to all steel bearings. I didn't want to buy a tube of 10, so I settled on 2 pcs. Perhaps cherry picking could have found even better ones. Will have to ask what the ABEC rating is. I think there may be a bit more radial play, and that may be to our advantage. Did a lot of watching the cart to check for hunting. There is none visible but I'll check more carefully. Now to make a pretty arm. I'm a happy guy tonight.
BillG
New bearings arrived today - and yes they are a massive improvement! I flushed them out as normal and I did remove the seals - they ran much freer without those. I quickly mounted them up and tried them out..... and it works!!
Now, its not perfect yet, I think a bit more tweaking is needed, I need to polish the outside of the bearings, plus refine the mounting for the slide, plus I think I can shave a few grams off the mass too. I made a short vid and loaded it to youtube. Quality ain't brilliant, but you can get the idea. I shot some of the cart running in the lead out groove to show both the deflection on the stylus, and then again to show the carriage movement. The deck is just a junker with a warped platter, plus the record is not great either, so its a test!
Link:
VIDEO0095.3gp - YouTube
Fran
Now, its not perfect yet, I think a bit more tweaking is needed, I need to polish the outside of the bearings, plus refine the mounting for the slide, plus I think I can shave a few grams off the mass too. I made a short vid and loaded it to youtube. Quality ain't brilliant, but you can get the idea. I shot some of the cart running in the lead out groove to show both the deflection on the stylus, and then again to show the carriage movement. The deck is just a junker with a warped platter, plus the record is not great either, so its a test!
Link:
VIDEO0095.3gp - YouTube
Fran
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.