[Test-Equipment] How to get a capacitor standard calibrated/validated/verified?

[Barry]

I have a General Radio 1409-X (0.5uF) capacitor standard for which I would like to know how close to 0.5uF it really is.  How would one go about getting this done?  It's not exactly a "calibration" procedure as much as it just a "check" but I assume a cal lab would do that.  Anyone know where I could get this done and approximately how much it would cost?

Note that this is for personal/hobby use and does not have to be NIST traced, etc.  I'm trying to repair my GR1617A whose standard capacitor failed.  I have a temporary "standard" I made that's close but I'm wanting to make something a bit better.  I'm wanting to use my 1409-X as a comparison cap to trim the new standard capacitor but don't know just how close my "standard" is to 0.5uF.

Thanks,
Barry - N4BUQ