Lokerola’s Pioneer PL-41 restoration

I just pulled my bearing to check wear to the thrust plate after about ten months of use and found that it had a small dimple. No big deal but it should probably either be replaced or resurfaced after a few years use. The tolerances of the spindle and sleeve are very tight and the smallest speck of lint or debris will prevent it from going together. That’s a good thing.
 
Blackdog61 said:
It fit for fifty odd years so you’re missing something. Either there is debris in there or you have scratched something.
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Blackdog61 said:
I just pulled my bearing to check wear to the thrust plate after about ten months of use and found that it had a small dimple. No big deal but it should probably either be replaced or resurfaced after a few years use. The tolerances of the spindle and sleeve are very tight and the smallest speck of lint or debris will prevent it from going together. That’s a good thing.
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Yes, I'm sure that I've missed something or gotten a bit of grit in there. It's not the fault of the spindle/bearing. I'm going back in with a clear head this weekend to re-clean and re-check everything.
 
On my Pl-41D the bronze bearings were honed to size and the clearance was very small, much less than 0.001 so you might not even see the debris that causing it to hang up.

BillWojo
 
T68 said:
Crazy idea: put the pin in the freezer to make it shrink and the bearing in the oven to make it wider and then see if you can fit it?
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My PL-41 bearing fits with no kind of trouble or such need.

Something must be wrong there, perhaps the spindle is bent or there is something else.
 
BillWojo said:
On my Pl-41D the bronze bearings were honed to size and the clearance was very small, much less than 0.001 so you might not even see the debris that causing it to hang up.

BillWojo
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Blackdog61 said:
Mine hung up last night and it was possibly a piece of lint. Very tight bearing.
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Blackdog61 said:
Mine hung up last night and it was possibly a piece of lint. Very tight bearing.
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flavio81 said:
My PL-41 bearing fits with no kind of trouble or such need.

Something must be wrong there, perhaps the spindle is bent or there is something else.
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Guess who's back in business!

After stepping away for a few days, I got the bearing up under a bright light and used a toothpick to probe the inner brass sleeve. Sure enough, there was one extremely small nick in the brass. Small enough I could barely see it, and I couldn't feel it with a q-tip. At first I couldn't believe this small of a nick could stop the spindle dead in it's tracks.

I picked up a few small jewelers files and VERY carefully filed down the nick. After light polish I applied a few drops of sewing machine oil.

It fits! And it spins smoothly!

Now - the question is - is the bearing assembly compromised in any way by my filing job? It doesn't feel like it when I spin it by hand. But on the turntable, it might be a different story.

I'm tired, so I'm stepping away again to get a good nights sleep and I'll mount it up tomorrow and see how the table spins.

Thanks everyone for your encouraging words and suggestions! :beerchug:

backinbus.jpg
 
lokerola said:
Now - the question is - is the bearing assembly compromised in any way by my filing job? It doesn't feel like it when I spin it by hand. But on the turntable, it might be a different story.
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In practice the spindle is slightly tilted in operation so the spindle does not contact evenly the whole surface of the bearing. Instead, the top and bottom part of the bearings are contacted with greater force.

In other words... if it spins smoothly (i.e. a spindown time of 2 minutes or more) then call it a day.
 
flavio81 said:
In practice the spindle is slightly tilted in operation so the spindle does not contact evenly the whole surface of the bearing. Instead, the top and bottom part of the bearings are contacted with greater force.

In other words... if it spins smoothly (i.e. a spindown time of 2 minutes or more) then call it a day.
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That's what I'm hoping. I couldn't resist mounting it up and giving the platter a spin. There's still a very light scraping sound when spinning, so I assume I need another milk-bottle shim under the delrin, but I'll work on that tomorrow. Without the belt hooked up, scraping a bit, with a medium spin of the platter it took a little over 3 minutes to spin down. It still spins very smoothly! I think we've got a good bearing assembly.

platter1 - Copy.jpgtimer - Copy.png
 
lokerola said:
That's what I'm hoping. I couldn't resist mounting it up and giving the platter a spin. There's still a very light scraping sound when spinning, so I assume I need another milk-bottle shim under the delrin, but I'll work on that tomorrow. Without the belt hooked up, scraping a bit, with a medium spin of the platter it took a little over 3 minutes to spin down. It still spins very smoothly! I think we've got a good bearing assembly.
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There are two possibilities, or three, or more:

1. Delrin hrust plate is too tall, thus, the spindle (which has a conical section on top) is rubbing the bushing. Solution: unscrew the bearing cap a little or remove shims under thrust plate.

2. Delrin thrust plate is moving, moving also the shims underneath and generating noise. -- fix it

3. Not enough lubricant / viscosity too low -- use higher viscosity

4. Bearing is scratched. Might be fixed by (3) or by ingenious tricks like putting Nivea cream on the bushings (haven't tried this but somebody mentioned this trick.)
 
I suspect the thrust plate is spinning in there. If you assemble it without the spindle in place you can possibly see how secure it is with a flashlight.
 
flavio81 said:
There are two possibilities, or three, or more:

1. Delrin hrust plate is too tall, thus, the spindle (which has a conical section on top) is rubbing the bushing. Solution: unscrew the bearing cap a little or remove shims under thrust plate.

2. Delrin thrust plate is moving, moving also the shims underneath and generating noise. -- fix it

3. Not enough lubricant / viscosity too low -- use higher viscosity

4. Bearing is scratched. Might be fixed by (3) or by ingenious tricks like putting Nivea cream on the bushings (haven't tried this but somebody mentioned this trick.)
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I don't think the scraping is coming from the bearing assembly. I'm almost positive the platter is riding just a hair low and it's gently scraping the base plate.

But your suggestions are all valid and if my theory doesn't work out, I'll be sure to test these. Thanks!!
 
OK, so here's what I've learned today:

1. It's not scraping against the motor mount screws
- I dropped the motor below the plinth - sound still there.

2. I's not the delrin/round bearings rotating in the cup.
- I made some shims and ever so slightly oversized them so nothing could rotate. - sound still there .

3 It's not riding too low, and it actually has nothing to do with the plinth or base.
- I could see it wasn't contacting anything on the plinth, so I removed the bearing assembly altogether, put the platter on it, spun it in my hand, and Aa ha! It makes the noise!

So what could it be? Here are my theories:
1. Maybe these aren't 100% dead silent and I'm being OCD?
Does anyone else's PL-41 make a slight rotational sound? Is your PL-41 dead silent with the platter spinning?

2. Maybe it's the small "O" ring bearing at the bottom of the spindle?
- Although I oiled it, I didn't remove and I'm not sure how I could without damaging it.

3. Maybe there are scratches in it from my filing and polishing?
- It's dead silent when the platter isn't installed and I spin the spindle by hand. Hmmmm.

EDIT:
4. As @flavio81 noted, maybe this is a lubrication issue? Although everything was cleaned with iso and lubed with sewing machine oil, maybe I need a higher viscosity oil. I do have some full synthetic 5w-30 sitting around. I could try it?
EDIT2: Now I read that people don't like synthetics because of added detergents. I guess I could get some old fashion dino oil.

The plot thickens.......................


Making slight sound
sound1.jpg

O-ring is the root cause?
sound6.png
 
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I put 5/30 synthetic in mine Thursday and it runs quietly; certainly the motor won’t be stressed. The platter is probably amplifying the bearing noise, but mine is inaudible to my 62 year old ears. Take that for what it’s worth.
 
Well, I think the noise reduction is a lost cause. I cleaned the o-ring with carb cleaner, blew it out with compressed air, cleaned it with iso, re-lubed it, and no change.

Next up I removed the bottom cap altogether and held the bearing on top of a plastic up and spun the platter. Still noise.

Either time or me have somehow scratched this bearing assembly. It spins forever, and with a record playing I probably wouldn't hear it. But it's a bummer.

And I retested the speed and it's back up to 33.7, LOL. My old, dirty bearing was slowing things down.

Sigh.
 
That clip at the bottom of the spindle isn’t a problem. Just a thought; put the top of the spindle in your drill and run it in the bearing sleeve with some oil with the cap off. Just spin it. Might just mimic a few weeks of use. I suspect there is a rough spot in that sleeve. From everything I‘ve read, these things always run fast so don’t stress too much. Again, I got the bearing together and then wrapped electrical tape around the platter to get it down to 33.4. Consistency is more important than 33.3 or 33.4 or whatever.
 
Problem solved. Any guess as to what it was?????? :)




As I sat there dejected, the turntable running and the platter making it's annoying sound, I was poking at parts of the table, thinking about how it would fit in my firepit.

When the noise stopped!!!!

I had pressed down pretty hard on the outside motor mounting bolt. Holy crap. I let off the bolt. Noise. Push down on the bolt, no noise. Must be a rotted motor mount, causing the motor to tilt up and scrape again something!

I jammed some handy stuff between the motor and the plinth and fired it up. Perfectly quiet. DAMN BEARING!!!!!! I swear to God that sound was coming from the bearing. Well, there was some sound from the bearing, so all my cleaning, polishing, recleaning, repolishing did pay off.

Welp, I'm off to have dinner and have nightmare's about PL-41 bearings. Motor mount fix next, I guess. Geez.

shim2.png
 
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The big rotational noise I had to sort out with my 41 ( same problem with my PL50 as the platter speed selector works the same way) was the belt rubbing against the speed selector device. You either have to bend it or push both speed buttons to position the C shaped metal bracket so the belt runs through the middle and won't touch the top or bottom of the C. Its fussy, but I got it done.
 
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