drilling out spring plates

I bought the black diamond 3 inch lift for my 57 cj5. The ubolts included did not line up with the original holes in the spring plates as the new ubolts are thicker and wider. I had them drilled out to fit the new ubolts. How much metal is safe from the hole to the edge the ubolt goes through (how much is needed to be considered safe)? I did not want to buy new spring plates.
Thanks
Paul NC

 

id say 3/16 inch is safe but you do want as much meat as possible there beacuse the plates usually bend that way putting more stress out there

 

I had the same problem with the black diamond 3" lift on my 59. I had different U bolts made at a local spring shop. It was right around $50 to get all of them made. I contacted where I bought the kit from (turner4wd) and they were going to inform Black Diamond of the problem. Glad to hear that I'm not crazy and the only one that had this problem though. I didn't want to drill out my spring plates because mine didn't have much excess metal. The width of the U-bolts was also a little off, so I figured I was better off with ones that fit more like the factory set up.