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How many rotations are correct, VPI HW19 MkIV?

After all is said and done, you've found the right belt (stock, silk , dental floss, etc...), you've positioned your SAMA at what you think is the best possible distance so the platter can do most of the work, you've made the correct adjustments on your SDS, you've cleaned and oiled the bearing, cleaned and talcom powdered your belt (if using a VPI belt), you've set everything level,etc... Is it just me or... do you pay attention to how many rotations the platter makes after you cut power until it stops? This is of coarse after all the above is optimal? My finding is almost exactly 2 rotations. I'm VERY interested in others, if you've noticed.
128x128slaw
grinnell
1,099 posts
 
i got just over 2 (2.2) on my mkiv with tnt platter (lead/cork) standard motor no sds
slaw's avatar
slaw OP
21,541 posts
 
I know this must seem inconsequential to everyone, but somehow it must make some sense. If everything is setup perfect, then there should be more free rotation on the platter, right? I've paid attention to this for a long time, ( I know, I need a life) and just as a small reminder, after a fresh washing of your VPI belt and then a smothering of talcom, after a while you'll notice that you'll have less rotations after motor cutoff, as time goes by. I truly am obsessed!
thegage
7 posts
 
I never let my platter free rotate to a stop. I stop it with my hand. I'm obsessed with unneeded belt wear.
markd51
763 posts
 
Are you folks taking into account, the effect the Motor itself has on the Platter? If you've ever rotated just the Motor Pulley on these AC Synchonous Motors, you will feel cogging, an effect from the magnets on the stator of the motor (I think I have this right!?)

This probably acts like a brake after the Motor is then shut off. To get a better idea how freely your Platter spins, remove the Belt, then spin the Platter by hand.

I'm certainly no Harry Weisfield of VPI, or Thom Mackris of Galibier design to debate Platter design, and theory, but I am of the impression-belief that using lighter oils-lubes, just so one can see their Platter spin for 10 minutes straight may not be the best for the Bearing itself, nor for optimum turntable performance.

Thom would probably say, to use the "right" lubricant per given application, which is often dictated by the tolerances-design of a Bearing-Bearing type.

That some "slight" lubricant drag may actually enhance speed stability. And that too light of a lubricant will lessen speed stability, as well as increase Bearing rock-cant. Mark
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