[TheForge] OT: Deep hole spot facing

[Bob Ehrenberger]

Andy,

Your ascii art doesn't really tell the story.  I have a 1/4" blind side 
deburring tool for my drill press. You run it through the hole slide the 
collar down and then lift up to clean the blind side of a hole.  You 
then lift the collar which retracts the cutter and you remove the tool 
from the hole.

If this is what you are looking for I can look to see who made it and 
get a part number. I can also measure how deep it will go, I think at 
least 2".

I had a project a couple years ago that needed to have flush rivets on 
the inside of scrolls. I forged a countersink tool that you would push 
through the hole and then chuck into the drill to make the countersink.  
It was kind of a slow process because you had to re-chuck the tool for 
every hole.  This tool was complicated because my apprentice sharpened 
the wrong edge of the cutter and we had to run the drill in reverse when 
in use.

-- 
Bob Ehrenberger
Shelbyville, MO

----original Message: 1 --------
Date: Fri, 05 Dec 2014 12:53:05 -0500
From: Andrew Vida<osan at netlabs.net>
Subject: [TheForge] OT: Deep hole spot facing

I need to produce a reasonably accurate spot face at the bottom of a
deep (~ 2.5") 1/4" diameter hole.  Furthermore, I would very much like
to relieve the corner in order that a precision ground facing shim (or
washer) will seat solidly and precisely normal to the axis of the bore.
To wit:


________________________________________________________________
| |
|       __________________________________________________________|
|     C_ <--Relief
|_____|<.
|            \
|_____     \
|      _|<-Spot-faced surface
|    C___________________________________________________________
| |
|_______________________________________________________________|

The only spot-facing tools of which I am aware are for shallow holes and
often have pilots.  What I would ideally like is a .250" reamer, face
cutting, with the relief provision ground into the face. Single
operation to ream, face, and relieve.

Anyone know who might make such cutters?  I know I can make a boring bar
to do this, but for some reason I seem to welded myself to the idea of
this approach.

Thanks.

      -Andy