heavy gauge spring for Kurokumo vibramute?

[jjj333]

Hi there- I am looking for a heavier gauge spring for a kurokumo vibramute. I ordered a heavy gauge spring built to original mosrite specs from ebay, and unfortunately, the inner diameter of the spring does not fit over the conical nut that holds the trem arm to the rocker piece. The spring's inner diameter is too narrow. Any ideas what may work? Thanks in advance!