After fighting with this problem for almost a month I finally got it.
I had been formatting the drive in an MDD (because the earlier machines would not see drives over 128 MB. I had OSX 10.5 installed and used Disk Utility to format it. It tried all the different Mac formats. The Mac OS Extended format could be seen on the 10.2.8 system profiler on the G3, but only as a 128 and would not mount it. I finally booted the MDD with 10.3 and used Disk Utilities to format Mac OS Extended (HFS+), a precursor to the current Mac OS Extended. This format was unavailable on the 10.5 system disk.
It now works great on the Beige G3.