Well, I messed up using the hammer.
Did I understand the drilling correctly?
"Drill the guide out to within about 1/8" of the outside diameter, then use an air hammer to drive the remaining sleeve out. "
The OD of the guide is about 9/16 - so 1/8 less would be a 7/16 bit to drill out the guide
This leaves the remaining sleeve wall about 1/16 thick
Or did you mean leave the remaining sleeve wall about 1/8 thick

Sorry for the stupid question, but I'm trying to understand this

Thanks for your patience
Jim