[sac-forum] Re: M48 thread load question

  • From: Greg Schwimer <schwim@xxxxxxxxxxx>
  • To: sac-forum@xxxxxxxxxxxxx
  • Date: Tue, 17 Nov 2015 16:45:56 -0700 (MST)

Best I can tell it is aluminum.

Good point about securing things. I can imagine a twisting load against the
threads at certain angles that could cause the load to shift, whether nosepiece
in the draw tube or even an "unscrewing" of the threads. Would this just be a
"make it all real tight and hope that's enough" or should I consider a more
positive means of locking things down, whatever that might look like.

- Greg

----- Original Message -----
From: "Michael Collins" <cal_donley@xxxxxxx>
To: sac-forum@xxxxxxxxxxxxx
Sent: Tuesday, November 17, 2015 4:11:23 PM
Subject: [sac-forum] Re: M48 thread load question

On 11/17/15 15:57, Greg Schwimer wrote:

I have a situation where I will need to have a field flattener w/ M48
thread at both ends support the weight of a camera/guiding system. The
FF is all metal and appears to be well made. In general, is it
acceptable/advisable to place such a load on M48 threaded connections?
My guess at the total weight will be 3-4 lbs.

Provided that the metal is brass or aluminum (most likely) and not
cast zinc or solder :-), there shouldn't be any issues related to
loading. You will want to be sure that the nosepiece is well secured in
the drawtube so that nothing shifts as the telescope tracks, of course.
Always good practice to test fit the equipment in your garage or living
room beforehand, then apply some pressure in all directions to ensure
that you won't get any surprises in the field. It may be a test for your
focuser, or it may be fine.

Anyone hanging a 31 mm Nagler off the back of an SCT with a focal
reducer is probably putting about as much of a load on similar threads,
not to mention engaging in an exercise in futility, or at least severe
vignetting combined with lots of edge distortion.
--
cal_donley@xxxxxxx


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