How tight do you tighten a record clamp

Depends on design of the record clamp, not sure what do you mean, but i have only one Disc Stabilizer with chuck (lock) around the spindle. It's rare japanese Orsonic DS-250 It's impossible to damage anything with this stabilizer, also i think this stabilizer can be used on aty type of turntable from belt-drive to direct drive, self weight is only 250g, but with this chuck (lock) it's pretty easy to make any record absolutely flat on the platter without too much force. Also no harm for the bearing or not too much weight for the lightweight platter of the belt-drives. Beautifully designed unit by reputable Orsonic engineers. 

The other stabilizers i use are much higher weight and without chuck/lock for the spindle, but my turntables are Direct Drives. 

Don't use these:

https://en.wikipedia.org/wiki/Locking_pliers

just finger tight is fine.

My analog is a vpi  scout with grado sonata wellbourne tube phono

I tap lightly on the record with the back of my fingernails as I tighten the screw-down record clamp. The record will give off a hollow sound until the clamp hits the right level of pressure. Then it will sound solid as the record mates tightly against the platter.

When the record is properly mated to the platter, the soundstage and imaging come into focus and the upper midrange and treble is smoothed out, bass is solid.

I don’t know if your scout has a threaded spindle to fit a VPI record clamp rather than a weight.  I'm using an Aries Extended with a platter / spindle that is set up for a VPI screw-down clamp.

@g11657 Great question - I've always wondered.

I have an MMF-5 with felt mat and was always thinking I'd might pull the center down too much and make the disc concave. FWIW, I always just go finger tight to make it snub, not finger tight till I can't turn it anymore.

 I just bought a Herbies mat, but haven't received it yet. I'm thinking the platter mat will make a difference depending on how flexible it is.

On my VPI I tighten the clamp until the platter turns and then hit the start button.  It works.

I barely ever use the clamp on my VPI. When I do use it I make sure not to make it too tight!

Put a rubber washer about 1/8" thick down over the spindle, then put on record then clamp. That takes out most warps as it dishes down against platter slightly. 

8.7 Newton.meters of torque.  No more; no less.

Lew, … I have a VPI steel clamp.  I am a bit OCD about the torque like you.  I use a piezoelectric laser torque gauge when I tighten the clamp down.  But I only tighten to 7.4 Newton.meters of torque. Should I put more torque on the clamp? Now you have me concerned.  lol

Dear @g11657 : Which is the use of a clamp?, some could say to tighthen the LP against the platter but in reality this just can't happens exactly in that way due that LP are a ductile build material and suffers " deformations " under some little pressure .
 
A very good  clamp/mat is the AT vaccum hold down LP that's the best way to really tigth and flattens the LP against the TT platters.

For clamps alone the reflex type as the Sota Reflex or the Basis one are really fine and don't puts so many weigth/mass down there.

At the end what we want with a clamp is try to put at minimum the distortions/resonances between and a ligth weigth clamp can do it just changing the frequency response resonance I'm talking about.

It's not easy to determine in specific the torque or weigth of the clamp because not only depends on the clamp design but on each LP too because does not exist two LPs with the same surface deformations and that's why the the AT I reffered is really good about.
I used this AT and tested with and with out additional clamp and sounds different either way.


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

@rauliruegas It's all about mating the record to the platter surface.  That's why testing the record for that flat contact is the key.  Being concise is nice.  After all, we are not dealing with intermediate public key infrastructure management techniques.  

Dear @bpoletti : What's your point?, I just can't undersnd it.

R.

@rauliruegas Concise is nice.  

Adjusting the clamp (over the rubber washer) to each record drove me nuts.  Different record weights and different kinds of warps each call for a unique deformation of the disk.

Got rid of the clamp and replaced it with a peripheral weight and inexpensive center weight.  Much easier to manage; just throw them on and play.  No thinking involved.  Better SQ too!

Sold my VPI SS clamp making the ring weight cost a bit easier to bear.

Finger tight.

bpoletti's instructions are correct. Indeed, Oracle use to teach this method to it's dealers.

Best is to tighten the clamp until it cracks, then back off a bit.