Originally Posted by
JIMinPHX
If all you want to do is make a few sizing dies, then why don't you just bore them on a lathe, open up smaller ones a little with a hone, or lap them out to size? Grinding a reamer for a 1-off on a simple part like that seems like more work than it's worth. If you were going to make 10 or 20 sizer, that might be a different story.
When I've sharpened reamers in the past, I've usually found that by the time I take a few thousandths off the cutting surface, I need to cut a clearance angle behind the cutting edge.
Most of the ones that I have sharpened have been cut using a finger rest on the preceding flute to line things up. In the event, that I had one that I could not index that way, I would first locate on the back side & grind a finger groove under the cutting surface, like you do before resharpening a roughing mill for the first time.
The little ones are a real pain in the backside if you don't have a micro tiny little air bar to work with & even then, I'd need to work wearing a 10x triplet loupe to see what I was doing. If a new reamer is less than $20 to replace, I don't regrind them.