Sponsored Links (Register now to hide all advertisements)
I agree with Bob. I'd also like to see dimensions, but from what I see in your picture, I'd hold a copper plate on the bottom side of the hole and weld the hole in to the correct size. Hold the copper in place with a bottle jack.
Years ago I worked on a frame that had NO hole for the spring bolt. I had to find exact center and drill a hole, then file the 4 corners.