The frame is a ~1990s shogun team issue, tange prestige. A bit of surface rust here and there but otherwise rest of bike is in good shape
Trying to replace the BB with a cartidge BB. Got the left locknut off with no problems and found the spindle had deep grooves and lots of pitting at both ends.
Right side is stuck fast. After half a can of wd40, and several attempts with a bench vise I still cant get the locknut off. I cleaned out the BB as best I could with rag and screwdriver and this is what I could see. It looks like more than a little surface rust to me. I'm afraid removing the locknut might damage the frame beyond repair


detailed photos of my bike can be found here