Are you sure it is a 1/2" and not a 12mm boring bar?
NO it won't reach Just make a new sleeve.
That's about the best thing you could do with these.This is how I modify the cheap boring bar holders. One is a Phase II 250-304 and the other is a Shars 250-341. The stainless screws are the modification.
View attachment 485416
ETA: These things are heat treated so they weren't super easy to drill and tap. Lol!
Tomorrow I'm going to make a few sleeves for my smaller boring bars. I can make a 1" sleeve with a 1/2" bore and another with a 3/8" bore. Easy peezy. Small flat on top. Set screws to hold the bar in the sleeve.I put my 1/2" bar in a standard BXA tool holder, seems to work fine.