Re: [ATM] too thin tube?

["Don Ware" <mimas@charter.net>]

> I got a 129mm duralumin (enhanced Al) tube, want to make screw
thread inside it and put 127mm lenses in. The question is, if 1mm
is too thin for a 127mm duralumin tube? Thanks for any
suggestions!
>
> Best Regards,
> Ukyo Chen

Another solution would be to make a pair of aluminum disks
approximately 3/4" diameter larger than the outside diameter of
your tube.  The first disk should have a hole machined so it fits
tightly over the tube and can be attached with machine screws
from the inside of the tube.

The second disk should have a hole machined in it to the outside
diameter of the threaded lens cell MINUS twice the thread depth.
You can then thread this disk to hold the lens.  The two disks
can be held together with three sets of push-pull screws that can
be used to collimate the telescope.

The disk attached to the tube can also be used to support a dew
shield.

Don Ware
http://webpages.charter.net/dware1/

_______________________________________________
ATM mailing list http://www.atmlist.net/