• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Pioneer PL-41 DIY thrust bearing

HTHMAN

HTHMAN

Super Member
I have begun work of the PL-41 that was gifted me. After many years in a storage shed, it need some TLC. The thrust bearing, it it really was a bearing, is shot. The reason I say tat is that it does not appear that it was a nylon or plastic bearing as it is soft. It appears more like an engine gasket that has been soaked in oil and dried out. Anyhow, being cheap and trying to figure out a way around spending $20 to have a Derlin disk sent to me, I would make something. Looking around, I saw the lids on my wife's Tupperware and thought that would work but she did not see it that way. Then I found some old prescription vials with snap caps that are about the same material. So I cut about a 1 inch circle out of one and use my 1" belt sander to whittle id down to size. It is not quite as thick as the stuff I pulled out, but the platter was not rubbing anyhow with the spindle all the way through it. I really think the purpose was to avoid metal to metal contact anyhow.

Any reason this should not work? Oil should not harm it.

A bit of dirt and corrosion to deal with


What is left of the bearing-you have seen this before



This does not appear to have been nylon or plastic but more like gasket material


Here is the disk I cut out


And placed in the cap
 
Register to hide this ad
I can't see a reason why not to do what you did. In fact I made something similar for some table or other.
 
I've done similar things as well. I don't have the knowledge to know if oil will degrade the plastic you are using, or if the plastic has friction characteristics similar to Delrin, or what the longevity of your solution will be.

For those reasons, and in the interest of assuring that you don't damage the spindle itself, my only advice would be to check it on a regular basis and see how it's doing. Heck, you may find that you've created a better solution, and get rich selling them on ebay!
 
I put the Delrin thrust bearing in my PL 50. To me it was worth it not to have to worry about it again.
 
There have been threads on this before, and many DIY ideas have been floated about including plastic milk carton caps etc.
The service manual for PL41 calls the item a rubber mat if I recall correctly.
The delrin material is sometimes conjectured to have been used in some PL41 and similar designs as I do believe the material was available back in those days. Delrin does seem to be a good material to serve as a replacement for whatever the original was made of. I went with the delrin on my PL41.

The PL41 is a real nice table.... lube her up and enjoy!
 
The remains in the bearing cap were indeed once plastic. That's what 50 years will do.

Whatever you end up using to make a thrust pad, it will need to be about 1/8" thick to keep the platter from grounding on the plinth. I don't think the Tupperware will be thick enough.

Honestly, I don't think it'll be hard enough either. I once made a thrust pad out of a plastic glue scraper I just cut a 7/8"(?) disc out of the blade up near the handle where the material was of an appropriate and uniform thickness. (It begins to taper as you get closer to the business end.)

John
 
boreas said:
Whatever you end up using to make a thrust pad, it will need to be about 1/8" thick to keep the platter from grounding on the plinth. I don't think the Tupperware will be thick enough.

Honestly, I don't think it'll be hard enough either

John
Click to expand...

I think I will make another one and use two of them. It appears that no harm will come if the platter is very slightly higher and will allow for compression and/or wear. I thought about the hardness too, but with that rounded spindle and an oil bath, I doubt that it will be a problem. Better that it wear rather than the spindle. It will probably outlast me.

Edit update
Made another disk, oiled the spindle, added oil to the reservoir and it spins like a top. Cleaned it up a bit and used a little Howards restorer on the base and it is looking promising. Dust cover need a lot of polishing. Belt should be here in a day or two. When I see how the speed holds, I will decide on the cartridge. Part of me wants to keep it original and get a stylus for the PL-C6 but the rest of me wants a better cartridge.

Edit Damn!!
My belt came in today. Speed seems to run slightly fast with no record. Plugged the TT in and HUMMMMMM. Narrowed it to one channel. The ground shearth on one of the RCA's seems to be pulled loose. Got to solder on a new pair. Time for dinner. It will have to wait.
 
Last edited:
It's alive!!!

After soldering on some new RCA jacks, everything works fine. I need some dampening fluid for the cueing device as it drops too fast. I hooked it up to the Sansui 2000 that I was recently gifted and had on the bench. Plugged in an old pair of Koss headphones to listen and put on an old beater record. My biggest surprise was that the PL-C6 cartridge actually sounded good. Even more surprising because the stylus was bent and I straightened it. I guess conical styli are not as critical to alignment as elliptical.

Two small criticisms of the turntable. First, the speed runs just very slightly fast even while playing a record and there is no speed adjustment. Second, the counterweight indicator is not accurate through its range. It is right on at 1 gm and just slightly under at 3 gm, but at 2 gm is nearly 0.3 gm light. The scale does not seem to be very linear. Other than that, a very nice turntable that is very simple to service with little to go wrong. It will soon be pretty to look at too.
 
So when do we get to see the final product? I got my PL-41 around the same time as you yours, and solved the speed problem with the correct belt. Btw, get a digital scale because you're right the counterweight force is always off on all these arms.
 
Delrin is an OK bearing material, though it does wear slowly. There's an AF grade (anti-friction) that has some Teflon content, though I've never been convinced it's really better. They're both quite a bit harder than bottle cap material. For the adventurous, if you can cut a small disk of hardwood like maple or cherry, and saturate it with oil, it will beat most plastics for friction, life and not marring the spindle. Don't sand it, only cut and scrape! Otherwise you'll embed grit in it. It doesn't have to be finely finished- the spindle will take care of that. A piece of genuine old Lignum Vitae is even better, but it's hard to find. Do polish the spindle tip to a mirror finish with suitable stuff- 3-9 um polishing film or leather and rouge.
 
Hi everyone, I’m restoring a PL-41. Ive removed the thrust bearing (it was shot) had to use a pair of vice grips to remove the cap it was so glued up. I order a new one on eBay and installed it. I was getting a scrapping sound when the table was rotating and was wondering if it was a result of needing to add lube to the pin or new bearing. Also any recommendation websites to order a new belt would greatly appreciated. Thx all
 
Yes, you need to lubricate the bearing well. I used 10w40 motor oil based on recommendations here.
As far as the belt goes search this site for a fairly recent thread. I've ordered a few for mine and have only received one that was the correct thickness (from LP Gear) but recently read that they no longer have right belt. The belt needs to be thin or the turntable will run fast.

Edited: Link to recent belt thickness thread
 
You must log in or register to reply here.
Back
Top Bottom