[Halld-tracking-hw] CDC Drawings

[Curtis A. Meyer]

Hi Tim -
 
      can we set up a meeting tomorrow morning at 11:00am to go
over all the drawings. We have a few questions that I will type in
below, and then a number of questions on what certain holes are
for that we can discuss.

FeedThru/Donut:

   1)  The groove for the glue has been slightly modified. This looks to
         be a good design as it avoids the chance of breaking a drill 
bit. We
         are however worried that the sharp edge will catch on 
insertion. Can
         we put a champfer on the sharp edge on the grooves on the donuts
         and the inserts?

    2)  The vent hole on the donuts and inserts was increased in size to 
0.035.
          We originally had it smaller to aid in construction so that it 
is obvious
           which hole the syringe goes into. They are a too close in 
size now to
            be able to do that. If it was increased for a manufacturing 
reason, then
            perhaps we should just make both holes the same size. 
Otherwise, we
            should shrink the vent back down.


End Plates:

     1) One endplate is still labeled as 6mm carbon fiber. This needs to 
be fixed.

     2) There are several places where 12/24 screws are used. This is a 
very odd
          size and difficult to get parts for. This should be changed to 
a standard
          size.

     3) The grooves that are used to hold the shells have widths of 
0.050 and 0.100
         inches. Do you have a suggestion for what we should use in 
these. Basically,
         we want to discuss the size of these.

     4) The upstream endplate has 1 mil tolerances on the survey ball 
holes and the
          support rods. The down stream has 2mil tolerances. Why the 
difference?

     5) The holes to attach the bearing blocks seemed to us to be very 
odd sizes. Perhaps
          the match a known unit, but seeing them as drawn, they seemed  
odd. One is
          15-thou over a 1/4 and the other is 0.188 inch.

     6) It does not appear to us that there are marks on the endplates 
to indicate the
          first hole in each layer. There is a call-out to the 
manufacturer as to which they
          are, but it is not obvious that they are marked on the plates.

     7)  There is probably a good reason for this, but we noted that the 
holes for support
           standoffs and gas at the outer diameter are placed at four 
different radii. The
           numerical values for these seem to be random numbers. The 
question is can these
           be at round "english" numbers.

     8)   We are not sure what a number of the holes are, but the 
twelve  5/16" threaded holes
            at 23.15" radius confused us. What are they?

  Cheers -- Curtis,

-- 
Prof. Curtis A. Meyer		Department of Physics
Phone:	(412) 268-2745		Carnegie Mellon University
Fax:	(412) 681-0648		Pittsburgh PA 15213-3890 
cmeyer at ernest.phys.cmu.edu		http://www.curtismeyer.com/