Most of you are aware of this.. but thought I share this link.

http://www.theonlinedarkroom.com/2014/09/making-ground-glass.html#more

Thanks for the posting. Sounds like a lot of work. I'm wondering whether you could use some wet-dry "sandpaper," say 400 grit, mounted on a sanding block. Guess there's one way to find out! If I ever do this, I'll post my results here. Meanwhile, I stocked up on glass for my Century some years ago, from that guy who used to post on this site but now no longer offers the service. His glass is really good, and I figure I'm set for life.

Henry wrote:

Sounds like a lot of work. I'm wondering whether you could use some wet-dry "sandpaper," say 400 grit, mounted on a sanding block

Last night I read about making your own ground-glass and tried exactly that. I used 320 grit wet-and-dry with mineral oil and spent around 20 minutes sanding the (4x5) pane of glass using, then moved up to 600-grit, spent 5 minutes with that, then 800, another 5 minutes.

Result appeared to be fantastic, a good bit brighter than my old (1939-made) ground glass that came in my Speed Graphic. Alas I tripped on a stone on the way back in from the shed and the freshly-ground glass fell and smashed. Still, at least I learnt that it works

The OEM ground glass may have been a coarser grind but you may want to wash
the ground glass that came with your pre-anniversary graphic,
years of dust grime can dull a GG, take the GG out and use dish washing liquid
or Windex work equally well, just don't trip carrying the GG to the sink

Well thank you, 3X8P, for actually doing the work and telling us how it's done! One question: how did you fasten down the glass while (oops, pardon me, "whilst") working on it?