RE: ATM Al tubes: end rolling and wall thickness; was: Irrigation Tube Irregularities?

[Richard Ozer <rozer@ois-online.com>]

The problem with getting the ends rolled is that it assumes you know exactly
what length the tube should be.  I cut the tube once before construction and
trimmed it at the end of the process to shorten it by an additional 2
inches.  The scope is solid without the rolled ends and I can use automotive
weather stripping to soften the edges if I want.  So far it's fine the way
it is.  Your diameters seem right....  I got the .064 wall thickness for my
10" and I'm glad I did.  It's heavy enough without the extra weight of a
.094 wall.

-----Original Message-----
From: Matt Tarlach [mailto:matttarlach@jps.net]
Sent: Tuesday, December 14, 1999 9:52 AM
To: ATM mailing list
Subject: ATM Al tubes: end rolling and wall thickness; was: Irrigation
Tube Irregularities?



>Once the spider and mirror mount
were put in, they added some extra structural strength to the
tube (especially at the ends).....

Parallax and Hastings both offer end rolling...this would seem to be an
alternative to the door edge strips that's also supposed to add strength.
On the downside, rolling also reduces the effective id at the ends,
according to Hastings by as much as 1/2".  Anybody have their tube
rolled?...does it help, and how much is the id reduced?

Also, what wall thickness would y'all recommend for two scopes my friend and
I are working on:

6" f8, which will have an 8" od tube unless you can convince me that 7" will
not have problems with tube currents; choices are .050", .064", .074"

 and 10" f6, which will be in a 12" od tube, with either .064" or .094"
wall.

Thanks!

-----
Matt Tarlach
Carmichael, CA
matttarlach@jps.net