Hi everyone,
For years, I have been reading the various DIY turntable threads on this website, hoping to get some ideas for a design of my own. It seems that everything imaginable has been tried, and the only variations from turntable to turntable are visual rather than technical. The one area of interest to me is the design of the turntable main bearing.
No matter how precise the shaft and the sleeve bearings are made, there has to be even the smallest clearance and that clearance causes the shaft and platter assembly to wobble in a counter-clockwise direction. I have learned that quite recently. So, I set out to design my own “Zero clearance” main bearing.
My bearing design is based on a principle that was discovered hundreds of years ago, but to my knowledge, has never been used in the design of a turntable main bearing.
I am not ready to disclose how the bearing is going to function, for fear that I’ll fall flat on my face if it doesn’t.
Because of that uncertainty, and because I don’t have the money to build “iffy” turntables, I am going to build a no-cost test model, just to test the bearing principle.
So, I looked around my shed and discovered a discarded disk brake rotor, left over from a brake job I did on my pick-up truck some time ago. The rotor weighs 24 LBS. and is about 12” in diameter. I machined a spindle for it from aluminum pieces lying around my shop, and I made a base from ¾” hardwood plywood also lying around my shop. And then my CAD computer crashed. That was in December 2021.
I used to do all of my design work on a drawing board many years ago, and around 1994 I switched to CAD, and there is no going back! Luckily, I paid off my mortgage in January of 2022 and I was able to build a new computer. Three weeks ago I finally got it set up and running.
So, in this first post I’ll show you the beginning of my test model, and in subsequent posts I’ll show you the proposed design of my turntable that I will build, if my initial tests work out.
The build might take the rest of 2022 because I have yet to establish sources for the various components of my turntable.
Sincerely,
Ralf
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For years, I have been reading the various DIY turntable threads on this website, hoping to get some ideas for a design of my own. It seems that everything imaginable has been tried, and the only variations from turntable to turntable are visual rather than technical. The one area of interest to me is the design of the turntable main bearing.
No matter how precise the shaft and the sleeve bearings are made, there has to be even the smallest clearance and that clearance causes the shaft and platter assembly to wobble in a counter-clockwise direction. I have learned that quite recently. So, I set out to design my own “Zero clearance” main bearing.
My bearing design is based on a principle that was discovered hundreds of years ago, but to my knowledge, has never been used in the design of a turntable main bearing.
I am not ready to disclose how the bearing is going to function, for fear that I’ll fall flat on my face if it doesn’t.
Because of that uncertainty, and because I don’t have the money to build “iffy” turntables, I am going to build a no-cost test model, just to test the bearing principle.
So, I looked around my shed and discovered a discarded disk brake rotor, left over from a brake job I did on my pick-up truck some time ago. The rotor weighs 24 LBS. and is about 12” in diameter. I machined a spindle for it from aluminum pieces lying around my shop, and I made a base from ¾” hardwood plywood also lying around my shop. And then my CAD computer crashed. That was in December 2021.
I used to do all of my design work on a drawing board many years ago, and around 1994 I switched to CAD, and there is no going back! Luckily, I paid off my mortgage in January of 2022 and I was able to build a new computer. Three weeks ago I finally got it set up and running.
So, in this first post I’ll show you the beginning of my test model, and in subsequent posts I’ll show you the proposed design of my turntable that I will build, if my initial tests work out.
The build might take the rest of 2022 because I have yet to establish sources for the various components of my turntable.
Sincerely,
Ralf
�-��m�
Yes, where's the bearing?
And I don't know if it is a good idea to support the LP at just six points. I know that Transrotor did something similar with their Transcriptor TT, but I always had my doubts on that.
Best regards!
And I don't know if it is a good idea to support the LP at just six points. I know that Transrotor did something similar with their Transcriptor TT, but I always had my doubts on that.
Best regards!
You learned that wrong.Some of the cheapest turntables are able to have zero clearance.You just need to study a bit of fluids physics.
If it is just a proof of concet then sorry, but how do you remove the thing in the middle, to make the platter flat?
I remember seeing a DIY turntable in the 80s using a brake disk in a Meitner style platterless setup
Every car part can make a turntable if you're brave enough 🙂
http://www.altmann.haan.de/turntable/
Edit: okay, it's a motorbike part
http://www.altmann.haan.de/turntable/
Edit: okay, it's a motorbike part
Didn't seem to make a lot of difference TBH, I have a Transcriptors hydraulic reference and it sounds pretty good to me. But then I don't have 'golden ears'. Also, have a Google for "Transcriptors round table". I had one. It also sounded remarkably good, microphony aside. Eventually I built the platter into a proper plinth.
Actually that's a really professional way to do the bearing.Just a bit of dense blue molibdenum (or titanium) disulphide grease at the bottom and mineral oil for sawing machines on the sides and not a single high end manufacturer can beat your performance.
Sure, you need a good bearing, but I think people get overly fixated on it. A bearing with proper clearance for the speed and oil viscosity won't have any slop or play in use. The larger problem is how to generate the necessary perfect geometry. Lathe isn't good enough. You need a grinder and/or hone. It can be done by hand if you have more time than money.
You can use a car engine flywheel too.
Some cars use metal to metal bushings in various ares, those are cylindrical ground.
Much more accurate than lathe. May be useful here.
How to precisely center the whole thing is also an issue.
Some cars use metal to metal bushings in various ares, those are cylindrical ground.
Much more accurate than lathe. May be useful here.
How to precisely center the whole thing is also an issue.
Hi Icsaszar,
I have prepared six CAD drawings for this thread. I did not want to post them all at once so that the thread would last a bit longer.
There will be an information gap between posting the drawings and actually producing turntable parts because I am still trying to find sources for the various parts.
sincerely,
Ralf
Hi Kay,
I apologize for not making it clear that, the test "turntable" is not meant to play records!
Being on a fixed income, (I am retired) I have to be very careful as to how much money I spend, hence the "no-cost" mock up described in my first post.
As to the bearing details, please refer to my first post for the explanation why I don't want to disclose any details for the time being.
Sincerely,
Ralf
Hi planet IX,
There are many ways to achieve zero clearance in bearing design. If my idea works it will be superior to W. Firebough's design.
sincerely,
Ralf
Hi NareshBrd,
Turntable platters always rotate clock-wise. I don't understand the question.
Sincerely,
Ralf
Hi Pano,
Please refer to my first post as to why I won't disclose details of my bearing design.
The bearing is not from "hundreds of years' ago. The principle is that old.
Sincerely,
Ralf