I did notice it looked slightly off when was adjusting the screw earlier but didn’t realise it could be centered
I am interested to see if a 309 might suit my Shelter better than the AN Arm 1 on my Gyro. We shall see when I get around to fitting it.
Oooh, nice, I dream of having one of those on my disco deck 
Which is quite a lot on such a small shaft
Thinking back to when the Lencos were made I would be surprised if they were working to much less than a thou.
There’s an Actress and Bishop joke just crying out from that post 
What’s the shaft diameter ? If it was 0.5" the error would be 1 part in 500 and that would map directly onto the speed variation of the platter. Wiki says the ear’s frequency resolution is 3.6Hz in the octave 1000-2000Hz ‘in a clinical setting’. So (to make the numbers easy) let’s take a frequency of 1800Hz which makes the ear’s resolution also 1 part in 500. So the error on your shaft is right at the limit of what we can hear. Maybe Goldring knew that and didn’t bother to machine it any more accurately.
If the hole in the middle of a 12" record is 12thou off centre then at the outer edge of the disc it’ll be alternately one part in a thousand too far out then one part in a thousand too far in, giving a full range (max to min) of 1 part in 500. Are holes that well centred in discs ?
VB
No. 0.05" was the RIAA spec.
Handy spread sheet I made earlier off center speed change - Google Sheets
I learn something new every day.
VB
http://www.aardvarkmastering.com/riaa.htm
To be honest, Id be surprised if most pressings, especially recent ones get close to those standards. When I made my turntable I put a lot of effort into getting the top of the platter true. Waste of time, Vinyl is wibbly wobbly rubbish.
Have you tried your speed testing software on the SP10 yet Ed?
No not yet, I will eventually. I’m still in the oooo that’s so pretty stage.
It’s about gap around the motor (the green cylindrical part) being equal in the chassis all the way around. What I mean is the chassis could be out of alignment and need adjusting so the 2 bearings at the front and back of the spindle are perfectly inline. You use the paper shims to help achieve this as the chassis is loosened to allow some movement of the 2 parts.
Something has to be up to cause the vibration you’re hearing. These motors are so basic there’s nothing to break or fail, it should just be a matter of setup after 40+ years. Some do make a little more noise than others but all the ones I had (10+) once set were quiet enough not to be audible, or only slightly audible with my ear up very close to the platter.
Of course I’ve wandered away from the point. One thou error on the motor shaft might not make a significant difference to audio frequency flutter, compared to the disc hole error. But Stu’s problem is vibration/noise which is another thing entirely … as just pointed out.
VB
Matt has found a motor,so will give it a try at some point
We have some standard shims at work so will try it out
Can’t you just hit it with a hammer and swear a lot?