How many grams weight for mm cartridge?

@ gongli3,
You should use what the cartridge manufacturer recommends.I have never seen a cartridge as low as .5 grams. Back in the old days high compliance cartridges and low mass arms were the rage. If you track too light it will cause more damage than going a little heavier!

What cartridge do you have? Most carts will have a "range" of tracking force. I have always tracked most carts towards the higher end of that range.

I have setup hundreds and hundreds and hundreds of turntables and have never seen a cart that tracks at .5 grams.  I agree you can do a lot of damage tracking too low.

@mofimadness 

I have setup hundreds and hundreds and hundreds of turntables and have never seen a cart that tracks at .5 grams.

You may never seen Grace F9 cartridges (F-9F, F-9L, F-9U, F-9D) tracking force range is 0.5 - 2g. I agree that 0.5 is too low, i would say 1g minimum. 

You may never seen Grace F9 cartridges (F-9F, F-9L, F-9U, F-9D) tracking force range is 0.5 - 2g. I agree that 0.5 is too low, i would say 1g minimum.

I was a Grace dealer for many years and have owned several of the Grace cartridges, (actually I currently have a couple of F9E carts).  I have also setup MANY Grace carts through the years.

According to the F9 series manual which I just looked at, Grace doesn't give a range of tracking force, they recommend 1.2 grams.  So the .5 grams is not with a Grace F9 series cart...sorry.