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Old 2nd December 2006, 04:20 PM   #141
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Casey- my main problem is the macining- the tools at my disposal are a power drill and a router.

Andy,
The at-110e has an elliptical stylus, but for £25 it is well regarded. I was thinking of making my own arm.

James

p.s. To avoid thread-jacking, I will open a new thread.
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Old 2nd December 2006, 05:55 PM   #142
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JesseG-

I was in a hurry in my last reply, and see I didn't answer your question about the pulley..oops.
The short answer is no. My new motor is 600 rpm, as opposed to the 300 rpm the pulley was cut for. Since , in theory, I won't have the shaft vibration to tame with my new design, I wont need this style of pulley (fingers crossed).

Going back to the PVC tubing for a moment, I forgot to mention that the length is about an inch, which is why I'm not to concerned with it twistng up. I can see if the tube was ran the height of the pictured mount twisting would be a concern.

Nordic-

Quote:
Something that keeps nagging at me with these belt driven type TTs is the unbalanced force on the shaft of the rotating motor.
Yep, it's a problem. Every design is a compilation of compromises. In my case, the inverted splindle bearing and (now) double stack pulley bearings were chosen to minimize the effects of the belt pull.

jrevillug & NjoyTHEMUSIC-

Quote:
Casey- my main problem is the macining- the tools at my disposal are a power drill and a router.
In my opinion, access to tools is the problem to DIY. The trick is to work your design around what you have. The biggie with a TT project is the spindle bearing. If you can't make one (and it's not likely you can with a drill & router), then look at what others have done. My favorite that I have seen (sorry I can't remember the guys name or link, maybe someone here can point to it) is the bearing using an engine valve, valve guide, and ball bearing. Mount the valve upside-down on the plynth, bore (drill) your platter to fit the guide, put ball in guide, and slide your platter-guide-ball assy. onto the valve stem..a very clever solution. As for the platter, using your router with a circle cutting attachment can get you a reasonably round disc that can be trued up with a sanding drum on your drill motor attached to a cheap drill press attachement ( or you can make a stand for it.

If it were me, I would look in the phone book for any cabinet shops that do Corion counter work. Case the place out to find were the actual work is done (Corion is worked in the shop, not the field), and ask about there cut-outs. I'm sure they will either give you a couple, or at least sell them to you cheap.

The biggest thing to remember..HAVE FUN.

-Casey
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Old 2nd December 2006, 06:07 PM   #143
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jrevillug & NjoyTHEMUSIC-

Found it..

http://www.altmann.haan.de/turntable/

...very clever idea. I would stay away from the stepper motor though..the ones I tried were very noisy ran as synchronous motors.

-Casey
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Old 3rd December 2006, 03:55 PM   #144
JesseG is offline JesseG  Canada
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Quote:
Going back to the PVC tubing for a moment, I forgot to mention that the length is about an inch, which is why I'm not to concerned with it twistng up. I can see if the tube was ran the height of the pictured mount twisting would be a concern.
Hi Casey (and All)...

I agree that if your coupling tube is short, and the two shaft ends are close to each other, the tubing will not collapse. However keep in mind that the closer the two shaft ends are, the less vibration damping effect of the PVC tubing. The surface coupling between the shaft surface and the inside surface of the PVC will stiffen the PVC. I think you will need some space (say, 1/2in) between the 2 shaft ends for the PVC to do its intended job. Fill this space with silicon grease and your coupling will have two vibration modes to help cancel the nasties.

I took a lesson from your experience with the iron powder in a previous motor mount where the intended vbibration damping effect was killed by the damping material packing to near solid by the vibration it was intended to cancel.

I just finished a quite ambitious hifi rack. The shelves are hollow and filled with sand. From reading your post I changed from using the fine concrete sand to playround sand (much coarser) and did not fill the shelves all the way full. Instead, they are 7/8 full so the fill has a chance to shift around a bit. I hope that will give it a better chance of continuing to do it's job.

When are we going to see some more pictures, Casey?

Jess
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Old 4th December 2006, 01:04 AM   #145
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Jess-

Quote:
I think you will need some space (say, 1/2in) between the 2 shaft ends for the PVC to do its intended job. Fill this space with silicon grease and your coupling will have two vibration modes to help cancel the nasties.
As it turns out, the length of the PVC coupling is exactly ½”. I have decided to give it a go hollow for now. The inside space needs to be compressible to some extent, otherwise it becomes to rigid (think of a high pressure water hose). It seems to hold fine..for now, If it twists up I'll fill it.

Quote:
When are we going to see some more pictures, Casey?
Umm…now

First, I give you reason 462 why, when you are tired, it is time to walk away. I tend to give myself a schedule for the work so that I can squeeze as much as I can in a weekend. This can get me in trouble. I was intent on getting the components I needed to build the coupler done Fri. night. It takes a fair amount of finesse to run a 6-32 tap through a ¼” of steel, a finesse I apparently don’t possess after being up 20 hrs. I was just about done with the first hole, when..*tink*…

Click the image to open in full size.

I now had half of my tap using my collar as its permanent resting-place. Time (past time) for bed.

Sat. morning after coffee and an hour of waking up and another hour to get to the store and buy a new tap, I examined my dilemma, and decided there was no way to remove the dead tap without scrapping the piece. Instead I used a 1/8 oxide stone on the Dremel, and carefully ground the tap flush on both sides. I then re-drilled the piece, and tapped my holes. These are the pieces of the coupling…

Click the image to open in full size.

I had decided to include one Sorbothane barrier in the coupler after all. I carefully marked out the round disc so that the balance would be reasonably close with the blocks, and made a jig that was cut to fit the OD of the two pieces that were to be glued together…

Click the image to open in full size.

…in the picture the top piece is already seated in the jig. This is what the “drive shaft” looked like assembled…

Click the image to open in full size.

I eagerly cobbled it to the motor to see how well it would work. Not well. It turns out that the Sorbothane is formed in a mold, and the thickness varies around .02”. I cut all my blocks for the suspension and coupler in one go, so they came from one end of the sheet to the other, as such they are not consistent. Neddless to say, the back disc wasn’t square, and once it started to spin, it would try to level itself, throwing the whole shebang out of balance..WAY out of balance.

Seeing that getting a balanced shaft using this approach would be another huge bunny trail, I abandoned it, and JB Weld’ed the two pieces together..good thing I made the jig…

Click the image to open in full size.

A made another alignment tool to center the suspension on the top plate. The OD on the fat end is the same as the OD of the bearings (5/8”) and fits snuggly in the plate, while the other end is drilled and reamed to to fit the motor shaft…

Click the image to open in full size.

I slid the pin in the top plate…

Click the image to open in full size.

…and after shimming the top blocks of the suspension so that it would seat square, and fastening the motor solid to the bottom ring, I glued the assembly to the top plate…

Click the image to open in full size.

…after the glue dried, I removed the pin and motor, and assembled the components…

Click the image to open in full size.

…the motor is running in this picture.

I bought my bearings from the only place in town that stocked them, and was concerned when I discovered that I could feel play in them. A bearing this small shouldn’t have discernable play, I was further alarmed when I spun them with just the spindle and top half of the coupler mounted …I could hear them. Well, they are junk. I should have got a clue with the $7 retail price tag..real quality here. The good news is that I “kilt dead” my motor noise, the not so good news is that my bearing noise at this point is beyond bad. If I loosen the set screw on the motor, so it can spin free, there is nothing but eerie silence. The bearing noise is too great to tell how effective the PVC is from isolating the buzz from the spindle ,though I imagine it is, but I can’t tell for now.

So it seems my journey to the “perfect” motor will be a little longer, but I feel all but assured of success. I will order some good German bearings first, and if it’s still too noisy (I doubt it), I have a couple other ideas to try. Bottom line, a quite bearing is a heck of a lot easier than a quite motor…which I now have.

Well, That’s it for now.

-Casey
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Old 4th December 2006, 02:12 AM   #146
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Default Valvitube, the turntable maker you refer to is Altman

Here is a link to his motorcycle valve for platter bearing.
ALTMAN TT
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Old 4th December 2006, 02:15 AM   #147
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I forgot to ask...any suggestions on a top drawer bearing Mfg.? The brand I won't be getting again is "General Bearing".

Thanx
-Casey
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Old 4th December 2006, 02:18 AM   #148
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Hi Phileas,

Ya musta missed it..I posted the link a few post up.

-Casey
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Old 4th December 2006, 02:54 AM   #149
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Yes I did, just after I posted I saw that you found the ALTMAN link.

His DIY tonearm began my quest to do a DIY tonearm for my DIY table.

I just finished the arm the other day, only little tweaks in set up are being done now.
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Old 6th December 2006, 01:52 PM   #150
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Hello All,

After contemplating my bearing noise problem, I have decided to try a different approach. Intsed of "hunt and pecking" for the quietest cage bearing, I decided to go with Oilite sintered bronze ( I ordered them locally, but thy're similiar to these). I rejected these originally because of there loose tolerance, but it occured to me that I could simply turn my spindle to fit ( it also gives me an excuse to make a spindle a little taller than the original I made..that one was a little short). Of course that means I might have to make another one if I had to replace the bushing, but since these things are known for there very long life in conditions far more severe than this one, I have decided to take a chance.
I will modify it slightly by cutting a 60 deg. bevel in the top (and a matching bevel on the spindle) to ensure the shaft/pulley runs true center.

Thoughts ?

-Casey
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