I'd hoped that someone had quick answers but it seems not.
So, I spent some time researching my questions. I found little using web searches but went to the re.crafts.metalworking site and found this:
Jens (p...@islandnet.com) asked what areas on a camlock spindle
nose/camlock
faceplate or chuck are the seating surfaces. Subsequently Jens asked in
effect how the short taper on the spindle nose could provide central
location
if it's able to enter the tapered hole on the faceplate or chuck far
enough
to allow the flat surface on the spindle nose and the flat surface on the
faceplate to be in contact with each other. This question occurred to me a
few years ago, so I bought ANSI B5.9 "Spindle Noses for Tool Room Lathes,
Engine Lathes, Turret Lathes, and Automatic Lathes" from American National
Standards Institute. It's all you ever wanted to know and more on the
subject.
As I understand it, the standard allows a maximum clearance of .002"
between
the face of the master plug gage and the face of the backplate or
faceplate
(i.e. the face) for nominal spindle nose sizes of 3"-11". The minimum
clearance can be zero as long as the plug gage fits the taper hole
"without
shake". Similarly the spindle nose is checked with a master ring gage.
Here
for nominal sizes 5"-11" the maximum clearance allowed between the flat
back
of the ring gage and the flat front of the spindle nose is .002", the
minimum
is .0008". Maximum clearance for the 4" spindle nose is also .002", it is
.001" for the 3" spindle nose. Both these sizes are allowed a minimum of
.000", presumably only if the spindle nose taper fits the ring gage taper
hole "without shake". This publication also fully describes the master
gages.
The mounting is between tapered faces only, and therefore poses no particularly difficult machining.
The question of the strange angle is not answered.
Ozzie
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