Mr. FRAZIER. With reference to copper or other softer metals--it is a
steel. I could not say how hard it actually is.
Mr. EISENBERG. What will the effect of the metal used in the bolt face
be upon the tool which is used to finish it off, cut it and finish it
off?
Mr. FRAZIER. The tool will gradually wear out.
Mr. EISENBERG. Well, will the tool leave different marks on the end of
the bolt face from one bolt to the very next bolt face?
Mr. FRAZIER. Oh, yes; that very often happens. The tool is worn out or
the small cuttings get underneath the edge, between the tool, and nick
the edge of the tool, so that the tool will gradually change over a
period of time. The cutting edge--the amount of change depends upon the
amount of wear, the heat involved, and the hardness of the metal--the
relative hardness of the metal.
Mr. EISENBERG. Will that particular change be noticed invariably in two
consecutive bolt faces?
Mr. FRAZIER. No, sir.
Mr. EISENBERG. So what is the genesis of the difference in the two
consecutive bolt faces as they come from the manufacturer?
Mr. FRAZIER. The change, as I said, depends on the bolt you are using.
It does not always take place, because some bolts are made of a very
soft metal, and they will not necessarily change a machining tool to
that extent.
Mr. EISENBERG. But the markings, you said, would be different on two
consecutive bolt faces?
Mr. FRAZIER. Oh, yes.
Mr. EISENBERG. And if the tool is not changed, what is the origin of
the difference between the markings?
Mr. FRAZIER. There are other accidental markings placed there during
the machining operation.
Mr. EISENBERG. Could you describe that?
Mr. FRAZIER. For instance, as the blade of a milling machine travels
around a surface, it takes off actually a dust--it is not actually a
piece of metal--it scrapes a little steel off in the form of a dust--or
a very fine powder or chip--that tooth leaves a certain pattern of
marks--that edge. That milling cutter may have a dozen of these edges
on its surface, and each one takes a little more. Gradually you wear
the metal down, you tear it out actually until you are at the proper
depth. Those little pieces of metal, as they are traveling around, can
also scratch the face of the bolt--unless they are washed away. So that
you may have accidental marks from that source, just in the machining
operation.
Now, there are two types of marks produced in a cutting operation. One,
from the nicks along the cutting edge of the tool, which are produced
by a circular operating tool--which produce very fine scratches in
a circular pattern. Each time the tool goes around, it erases those
marks that were there before. And when the tool is finally lifted out,
you have a series of marks which go around the surface which has been
machined, and you will find that that pattern of marks, as this tool
goes around, will change. In one area, it will be one set of marks--and
as you visually examine the surface of the metal, these very fine
marks will extend for a short distance, then disappear, and a new mark
of a new type will begin and extend for a short distance. The entire
surface, then, will have a--be composed of a series of circles, but the
individual marks seen in the microscope will not be circular, will not
form complete circles around the face of the bolt.
Mr. EISENBERG. Have you had occasion to examine two consecutive bolt
faces from a factory?
Mr. FRAZIER. Oh, yes.
Mr. EISENBERG. And what did you find on that examination?
Mr. FRAZIER. There would be no similarity in the individual microscopic
characteristics between the two bolt faces.
Mr. EISENBERG. There actually was none?
Mr. FRAZIER. No, there was none.
Mr. EISENBERG. In the bolt face with which we are dealing, Exhibit 139,
can you say from inspection whether the markings on that bolt face
are predominantly the accidental markings introduced subsequent to
manufacture, or the markings of the manufacture?
Mr. FRAZIER. I would say that these were filing marks for the most part
which were made during manufacture, some of which have been obliterated
and changed through use--possibly corrosion.
Mr. EISENBERG. Mr. Frazier, taking Exhibit 543, did you prepare a
photograph of this exhibit----
Mr. FRAZIER. Yes, sir.
Mr. EISENBERG. Compared with the test cartridge case?
Mr. FRAZIER. Yes, sir; this is the photograph, showing the test
cartridge case from Exhibit 557 on the right and the cartridge case 543
on the left.
Mr. EISENBERG. This was prepared by you or under your supervision?
Mr. FRAZIER. Yes, sir.
Mr. EISENBERG. Mr. Chairman?
Representative BOGGS. It may be admitted.
(The item referred to was marked Commission Exhibit No. 559 and
received in evidence.)
Mr. EISENBERG. Now, that is marked on the left C-14, and on the right,
C-6.
Mr. FRAZIER. Yes, sir.
Mr. EISENBERG. And the left-hand photograph is a photograph of what?
Mr. FRAZIER. Of the cartridge case 543.
Mr. EISENBERG. That is the actual fired case?
Mr. FRAZIER. Yes, sir; it shows just a portion of the primer, and a
very small portion of the firing-pin impression.
Mr. EISENBERG. And the right-hand side of that photograph, marked C-6?
Mr. FRAZIER. It is a test cartridge case, fired in the rifle Exhibit
139.
Mr. EISENBERG. What is the magnification, Mr. Frazier?
Mr. FRAZIER. Approximately 100 diameters.
Mr. EISENBERG. And is that magnification equal on both sides of the
picture?
Mr. FRAZIER. Yes, sir.
Mr. EISENBERG. Did you make your identification of Exhibit 543, that is
the identification of that exhibit as having been fired in the rifle
139, on the basis of your examination under the microscope, or on the
basis of the photograph?
Mr. FRAZIER. Under the microscope. The photograph has no relationship
whatsoever to the examination.
Mr. EISENBERG. Can you explain that?
Mr. FRAZIER. The examination is made microscopically through the
use of your eyes, and your eyes will record depths and shapes to
a much greater extent than can be shown in a photograph. So that
the examination and comparison is made of these irregular surfaces
mentally, rather than mechanically by any means. The photograph is
taken primarily to illustrate the types of marks found and their
location, relatively, on the specimen.
Representative BOGGS. We will have to adjourn and come back at 2.
(Whereupon, at 12:15 p.m., the President's Commission recessed.)