Making a blind hole lap

[fcs]

I heard once that you could make a blind hole lap just turn a soft brass rod down to .007-.008 under the diameter. Does this sound right?

 

[Nutfarmer]

You would have to have some way to expand the lap to make it work. It's common to build in a way to expand a lap , like slitting the lap and using a tapered screw to expand it.