I am measuring simple diameters of the 14" to 22" range
both inside and out. The artifact is located in the X-Y
Plane and has some distortion, which can be as high
as .020". I take 25 to 30 points, using a 2mm ruby
ball x 50mm long probe. My questions are, I would like
to use a 35mm disc styli to measure additional features
and save handling time. The qualifying ring gage,feature
measured, alignment of the part, and the disc itself are
all in the same plane. All seams right with the world !
But I look at that precision red ruby, then I look at
the disc then I ask what are the unknowns?Do I lose
accuracy? Will it wear ? Are there static considerations
(metal to metal)? Is there vector/cosine issues?
Will dynamics come into play? How parallel must the
disc be to the plane,or concentric to its' shank?,
and many more questions.

Will any of you share some of your knowledge and
experience about the use of a disc.


Thank you,

Bill Ferri

Ferriwh@navair.navy.mil
Power Plants Division
Naval Air Depot
Jacksonville, FL