Bridge looseness

[tcube]

I recently removed the strings on my Distillate (changing strings, oiling neck) and noticed that without the tension of the strings pressing down, the bridge is loose. Of course, if I screw the bridge all the way down, it's firm, but once I raise it, it rocks back and forth.  Is that normal?  The sustain block is firmly screwed in.

[terryc]

Some free play is the norm, how much looseness is there, can you measure it? obviously the higher the bridge the greater the lever movement.
The reason must be if the threads were snug tight then once the strings were up to tune with max tension in would gall the threads(gall - make the thread helix wider) especially if your were changing the bridge height whilst in tune.
As long as it doesn't move once you are in tune I wouldn't worry about it.

[tcube]

Thanks, terryc,
 
There's no movement once the strings are in place and tuned up.  There seems to be no effect on the sound, so, I guess I won't worry about it.
 
I suppose that the galling (new vocabulary!) will increase with age.

[terryc]

The only reason 'galling' will occur and this applies to any fixing, screw or bolt is that if it is overtightened or even worse, cross threaded.
Mechanics(as I once was) always use copper grease on bolts which may be exposed to weather conditions to prevent seizure but also to protect the threads after any corrosion is removed.
Being the finicky type I am I applied a very small smear on the threads of the bridge before I locate it in the brass sustain block(overkill I know!!!)

[tcube]

Thank you for your advice.  I may try the same thing, but given that the bass is > 30 years old, it'll be to prevent further damage.

[JimmyJ]

Terry T, if you're talking about the bridge mounting screws having play in the block then what Terry C says is right.  Brass isn't the hardest material so I think it wears a bit and the tolerance of the threaded hole can change.  But when under tension it shouldn't matter.
 
If you mean the bridge appears to teeter on the bolts then you could snug down the nut that the bridge actually rests on (right arrow in pic).  It's only supposed to be loose enough so that it will turn.  Once I decided on bridge height I slipped a thin wrench in there, held the nut and tightened the screw down.
 
As long as nothing rattles once it's strung up all is good!
Jimmy J

[terryc]

tcube no problem, glad to help and thanks for reinforcing advice jimmyj.
Any pics of your 30 year Distillate for all of us to drool over???

[tcube]

Thank you jimmyj, I'll check that nut.  
 
And terryc, the Distillate can be drooled on here:
http://club.alembic.com/Images/411/93579.html?1295463835

[terryc]

Oh very nice bass indeed....good looking top wood