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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

Showing 2 responses by shasta

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...)
shasta
155 posts
 
Fat P.-

My comment and your inquiry are a bit OT. Sorry to everyone. Having said that, buy a new panelboard, receptacle, or circuit breaker. Look at the instruction sheet and you will see torque specs for all electrical connections. These must be followed per NEC 110-3(b).

Overtightening or guesing at fastener tightness doesn't work. Ask any auto engine builder. On an electrical connection, it screws up the metal due to thermal expansion/contraction cycles, and you end up with a looser connection over time. That's why infrared thermograpy was developed, it's part of industrial PM, and everything is re-torqued on a scheduled basis.
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