Dear Jack,

We have some questions about the SAE J444 and AMS 2430. The SAE Staff
Representative (Gjysta Kqiraj) requested us to direct any questions
about the J444 to you.


Last year we bought a new Ro-tap sieving machine (DuraTap). However,
when running our yearly calibration we found that the machine did not
completely comply with the J444 and AMS 2430 requirements. An short
investigation led to the conclusion that this is due to differences
between the American 60 Hz AC system and the European 50 Hz AC system.
We got the impression that machines operating at 60 Hz AC do comply, but
on the European 50 Hz AC are non-compliant.
However when we compared several manufactorer specifications with the
standards, the problem got even worse. In the attached Excel sheet
you'll find the specifications of our current DuraTap machine and of an
alternative model of Haver-Boecker (which is actualy the original
Ro-Tap(r) Test Sieve from WS Tyler). As you can see, when the tolerances
specified by the manufactorers are included, neither model does comply
with the SAE J444 and/or AMS 2430 requirements. At the moment we have
not found manufacturers that do comply to SAE J444 and/or AMS 2430.

Because of this situation we have the following questions:
1) On what basis were the requirements for shaking speed and taps per
minute determined (in both the SAE J444 and the AMS 2430)?
2) Why would the characteristics of the machines from Duratap and
Haver-Boecker not give a good sieving result?
3) Is it possible to use less stringent tolerances for rotation and
tapping speed?
4) Can you help us in finding a manufacturer that does comply to SAE
J444 and/or AMS 2430?
5) SAE J444 and AMS 2430 do not specify characteristics like amplitude
or tapping force. We feel that such kinds of characteristics can be
relevant too for the sieving result. Is the committee planning to
implement additional requirements for sieving machines?

We would appreciate a response to these questions as we are in a
situation that we have to purchase a new sieving machine compliant to
J444 and/or AMS 2430. In addition you will understand that we want to
prevent that in the (near) future, due to revised criteria of SAE J444,
this new machine will become non-compliant as well.

We look forward to your response.

Best regards,
(Name witheld)