Thorens TD150 project

[jdef]

Hi everyone,

I am new to this forum and have been working on a Thorens TD150 project for a while, off and on, and at last have a little progress to show. Here is the turntable.



I sandwiched two platters together to increase the inerta and speed stability and I like the look of fat platters anyway.



This was done on a lathe. I machined a step in the edge of each platter so they fit together and overlap by about 3/16 inch. They are a tight push fit and held together by loctite bearing seal as well. The outside edge was then turned to make it nice and smooth.



Because the new platter is almost twice as heavy as the original I decided to invert the main bearing. This puts the point of support above the centre of gravity so reduces the side thrust on bearing so it's easier to spin and quiter. This took me a while. Two years off and on. The bearing housing is mounted in the inner platter. The spindle is held in the sub chassis in a two piece housing that is also an oil bath and a new spindle is made to sit the record on which has a PTFE thrust plate under it which the point of the spindle sits on. The bearing components came from a TD125.



Here's a side on view. The deck starts about as quickly as a standard 150 although the belt is worn on this one so it should be a little better. The bearing has fine clock oil in it.

Next thing to do is make an arm although I have the motor and speed control from a 125 which I am thinking about putting in.

Yrs,

Jolyon

[kevinkr]

Looks like a pretty serious effort to me.. And welcome to the forum!

[jdef]

Hi,

Thanks for the welcome. I don't know if it'll sound any better than a standard 150, I just had a couple of platters spare and fancied the challenge.

J

[user510]

Very interesting work on the platter and bearing. It appears that you have "spliced" two inner and outer platters together by some rather fancy lathe work. You should have a platter weight of greater than 10 lbs but less than 14 lbs.

Bearing:
You have modified the original Thorens 10mm bearing into an inverted arrangement. It appears you have done some "splicing" there as well. Now the bearing housing is attached to the driven inner platter. what are you using for a thrust pad.
I don't see a bearing ball at the shaft tip. so I'd guess you are using something other than a Thorens part there.

Care to elaborate?...

Looks good.

Not sure how that little TD150 motor will work with almost double the platter mass, but I'd guess it should be able to hold speed once it finally reaches it.

Do you plan on making a different plinth for it?

-Steve

[jdef]

Hi Steve,

Thanks for your interest.

The bearing shaft comes from the remains of a TD125. It does not have a ball bearing pressed into it like the 150 but the end is formed into a cone with a polished rounded tip. The shaft is standard unmodified Thorens. I had to make a new sleeve to hold the bushes in the inner platter. It took a while to get it in, straight and true and secure. Once in place I machined the whole inner platter by holding sleeve in the lathe chuck so it's all true. I machined a ptfe disk to act as a thrust pad.

The whole lot spins very freely as the bearing's inverted so I am hoping the 150 motor will be up to it. But it may well not be...

Not sure about a new plinth yet. The deck has no arm so I'm thinking about that now.

Yrs.,

J

[jdef]

Here are a few more pictures of what I have done so far:

As the bearing is inverted I needed to make a thrust plate with a spindle on the top to take the LP. It's held on with three cap screws and made of Steel.



Under it is the ptfe thrust plate which goes between it and the tip of the spindle.



The old bearing housing was discarded and I made a new one with a flange on it which is bolted into the inner platter.



The spindle is held upside down in an oilbath which is bolted to the sub chassis via an Aluminium collar



The spindle is a push fit into a brass plug that's bolted to the bottom of the oilbath.





I need a new belt for the deck but it isn't too slow to start and is very quiet which is good.

More to do...

J.

[user510]

Really nice work on that bearing design. Inverted with oil bath.

Probably the ptfe thrust pad will wear out too soon, but alternate materials are readily available.

-Steve

[jdef]

Thank you, Steve.

Already the ptfe has a dent in it so I will be looking for something else. I have a block of Delrin somewhere which may be better. Any idea what Thorens used or do you have any suggestions ?

Also I have decided to put the remains of a TD125 motor and circuitry into the deck and may well make another plinth too !

Yrs,

J.

[user510]

Originally Posted by jdef

Thank you, Steve.

Already the ptfe has a dent in it so I will be looking for something else. I have a block of Delrin somewhere which may be better. Any idea what Thorens used or do you have any suggestions ?

Also I have decided to put the remains of a TD125 motor and circuitry into the deck and may well make another plinth too !

Yrs,

J.

Thorens used a product called "Nylatron" for their bearing thrusts. Those would go for several years before indicating a significant crater.

I've used Delrin in my TD124 bearings for a few years now. Softer than Nylatron but harder than ptfe. Plus the Delrin doesn't seem to have any negative affect on sound quality.

There is also teflon infused Delrin available for approximately the same price. It offers a tad better wear resistance than the regular Delrin and also doesn't seem to negatively affect sound.

Another plastic in use around the net:

Torlon ($$ expensive if bought in sheet form) Supposedly it outlasts any previously known thrust pad material. I intend to try it some time if I can get my hands on a remnant at a reasonable price.

-Steve