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Turntable Leveling, Again

I may have asked this here before, but...I'm in the proces of moving my music room and am having a HUGE amount of trouble getting my Technics SL-1800 level. I have it on a homemade wall shelf constructed of pine and metal braces. The shelf is as level as I can get it. The strange thing is, using a cheap see-it-both-planes level from Lowe's, at the center of the platter I'm way out, but if I move the level to the edges I'm in. This would mean to me that my platter's not flat...is that the case with the SL-1800, or do I have a big problem? I have another turntable sitting beside it I use for 78s, and it leveled up in about a minute, so I'm not sure what part of this is throwing me off. I have a circular level as well; would I be happier (and less frustrated) with a metal torpedo level, do you think?

Much appreciated,

John Sellards
vanmeter
dogeatpuppy
96 posts
 
Two levels are alot easier to use for a four point set-up. Front/back,left/right. "Starrett" machinist levels(4")are very accurate & can be had cheap used.
aceto
273 posts
 
Just seconding the wise above and even my own that levels are accurate only to their rating.
fatparrot
1,314 posts
 
Aceto, a bulls-eye balance looks like a clear circle with a bubble at the top, and a small marked circle at the top, in which the bubble should be positioned for true level. Makes leveling much easier and more accurate, than having to continually move a linear level! They are very small, too; mine has a base with a 1-1/2 inch diameter, which makes it handy for fitting into tight spaces as well. Just remember, that the bubble move toward the high position
shasta
155 posts
 
IMHO -- Stabila brand is the level to beat, 'tho they have some econo models as well. The #81S 9.5" torpedo I use is good to 0.5mm/meter in the upside position, which is really hairsplitting. OT, but the other tool I'd pay anything for and never give up, is the Armstrong Tools #64-005 torquing screwdriver for setting receptacle and breaker terminals to correct torque.

I'd check the platter for bearing wobble (run-out). If you can't borrow a dial indicator (I think it's called; ask a machinist or auto engine builder), I'd build my own. Use a RS soldering aid -- the weighted base thingie with multiple arms with aligator clips on the end. Clamp something hard with a smooth finish in one of the clamps, and place it so it just barely touches the platter surface. I'm thinking a toothpick for starters...Slowly rotate the platter by hand and see if the object touches the platter evenly around it's edge, middle, and inside. You might need some other jig to check the inside. You could also build a jig out of scrap in no time...

(What do the black lines on a bubble level indicate? Some kind of tolerance based on the level accuracy, I'd guess...)
fatparrot
1,314 posts
 
Shasta, why is torquing receptacle and breaker terminals so important? Isn't just "tightening the snot out of it" O.K.? (Sort of like Marisa Torme's "balls on" technical calibration standard for the dripping faucet in MY COUSIN VINNY!
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