Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Brass Compression rings eat your heart out

  • Please log in to reply
16 replies to this topic

#1 MartinPond

MartinPond

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 5052
  • Joined: 16 Sep 2014

Posted 08 November 2019 - 02:49 PM

I often need a 1.25" extension, what with the stubby EPs I get

  and the indoor testing.  This scheme works great:

 

DSC_0116.JPG

 

That is a piece of "lavatory" (bathroom sink) hardware in HDPE plastic

 with a compression ring of LPDE that presses in evenly around the whole

 circumference.  Less pesky than the brass rings, and holds well.

Fits just right in 1.25", since the OD of plumbing needs to have tight tolerance.

 

For suppressing  stray light, winding in a bit of black drywall

  sanding screen works awesome...best low-angle blackness ever!.

  You put it in tight then push it out, It locks against itself and stays put.

  Note the tapers....this keeps the stuff from 'springing in' at the ends.


Edited by MartinPond, 08 November 2019 - 02:51 PM.

  • Astrojensen and Joe1950 like this

#2 TOMDEY

TOMDEY

    Aurora

  • *****
  • Posts: 4969
  • Joined: 10 Feb 2014
  • Loc: Springwater, NY

Posted 08 November 2019 - 03:41 PM

Best apply for a patent ASAP else the Premium eyep. manufacturers catch wind of this!    Tom


  • Thomas Marshall and Joe1950 like this

#3 MartinPond

MartinPond

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 5052
  • Joined: 16 Sep 2014

Posted 08 November 2019 - 03:48 PM

Heh...

I think I just filed an "anti-patent"..

Tada...it's "prior art" now.


  • stargazer193857 and Joe1950 like this

#4 Dynan

Dynan

    Gemini

  • *****
  • Posts: 3138
  • Joined: 11 Mar 2018
  • Loc: NOLA

Posted 08 November 2019 - 04:28 PM

In the Army, it was called 'Field Expedience'...get 'er done! waytogo.gif


  • Joe1950 likes this

#5 MartinPond

MartinPond

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 5052
  • Joined: 16 Sep 2014

Posted 08 November 2019 - 04:35 PM

In the Army, it was called 'Field Expedience'...get 'er done! waytogo.gif

That's it.

It did take many years prowling  and a little risk taking

  ($6 worth) to see the obvious, though. 

  Well, experiments too...that taper is key.

    Strange how the answers  hide in the great mass of stuff.


  • Joe1950 likes this

#6 Joe1950

Joe1950

    Cosmos

  • *****
  • Posts: 9911
  • Joined: 22 Aug 2015

Posted 08 November 2019 - 04:47 PM

Said it before... The plumbing industry will never know of the prodigious contributions it has made to amateur astronomy.


  • ATM57, kevint1, airbleeder and 2 others like this

#7 MartinPond

MartinPond

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 5052
  • Joined: 16 Sep 2014

Posted 08 November 2019 - 04:52 PM

Indeed! And other things too..

 

I was a microwave engineer way back,

and the 'waveguides' for radar/comms  and

 thus the frequency bands were all driven by common

  hollow rail dimensions.  

  The first rule of inventing is:

     try to use already mass manufactured things first.

   (unless you're going to do something really 'out there'.)


  • Joe1950 likes this

#8 stargazer193857

stargazer193857

    Cosmos

  • *****
  • Posts: 7804
  • Joined: 01 Dec 2013
  • Loc: Southern Idaho

Posted 08 November 2019 - 06:22 PM

Heh...
I think I just filed an "anti-patent"..
Tada...it's "prior art" now.


That won't stop the big boys from patenting it anyway. I've seen it happen. USPTO only looks in the PTO. Courts will look more places if you submit it then. You then have to wait to be sued to challenge the patent, not knowing if your anti-patent will disappear off the web. When they sue, they can go 6 years retroactive for damages. You can challenge preemptively, but it costs $3000.

#9 Stargazer

Stargazer

    Vostok 1

  • *****
  • Posts: 136
  • Joined: 30 Jun 2006
  • Loc: NewBrunswick, Canada

Posted 08 November 2019 - 09:51 PM

Best apply for a patent ASAP else the Premium eyep. manufacturers catch wind of this!    Tom

seems to me I posted years ago about my Ronchi eyepiece tester I used on my 10", now I see folks selling them. Who Knew...  lol.
 



#10 MartinPond

MartinPond

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 5052
  • Joined: 16 Sep 2014

Posted 08 November 2019 - 10:09 PM

In some cases (like mine), the real competition

for the big guys is people just making their own

 (takes a mitre saw and xacto).

 

If someone made a use patent for a fancier eyepiece holder that

used the LDPE ring in it, that would be nice.

The copper ring as a split in it, go it doesn't work

   (so you have to rotate the ring manually.)

 when the gap is centered on the pin, and it can bend

in if the screw goes too deep right next to the gap.

Thus the complaints about "I can't get the eyepiece in anymore".



#11 Ken Watts

Ken Watts

    Mariner 2

  • -----
  • Posts: 275
  • Joined: 19 Sep 2016
  • Loc: Sun City, Az

Posted 09 November 2019 - 03:49 PM

The sanding screen is genius!  I sprayed the inside of my PVC "extender."

 

Clear and steady skies,

 

Ken W


  • Joe1950 likes this

#12 Joe1950

Joe1950

    Cosmos

  • *****
  • Posts: 9911
  • Joined: 22 Aug 2015

Posted 09 November 2019 - 04:03 PM

One of the big problems for inexpensive binoviewers is the relative alignment of the two eyepieces causing problems merging images. The even grab of the LPDE compression ring as opposed to the brass ring, may be a solution. Just thinking out loud.


  • stargazer193857 likes this

#13 MartinPond

MartinPond

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 5052
  • Joined: 16 Sep 2014

Posted 09 November 2019 - 08:17 PM

One of the big problems for inexpensive binoviewers is the relative alignment of the two eyepieces causing problems merging images. The even grab of the LPDE compression ring as opposed to the brass ring, may be a solution. Just thinking out loud.

 

If there is a small looseness, it's true: the way the brass ring acts

   can be quite assymetric.  You could shim up the EP, but

  then it snags on the ring.   Seems like the LDPE ring could 

  lock a misalignment in place, though...but not if the EP

   is 'shelved' where the diameter goes up. 

   Now....using an LDPE squeeze with a bit larger (like 1.253 ID)

     tube would allow you to steer the EP a bit..   


  • Joe1950 likes this

#14 don clement

don clement

    Vendor (Clement Focuser)

  • -----
  • Vendors
  • Posts: 1690
  • Joined: 02 Feb 2011
  • Loc: Running Springs, California

Posted 09 November 2019 - 09:31 PM

A collet would fix looseness issue and keep eypieces centered. 

 

Don


  • brave_ulysses and Joe1950 like this

#15 BGRE

BGRE

    Mercury-Atlas

  • *****
  • Posts: 2518
  • Joined: 21 Mar 2016
  • Loc: New Zealand

Posted 09 November 2019 - 11:02 PM

An ER style collet (flexes at both ends) would accommodate small variations in eyepiece diameter better than the alternative (flexes at one end only).


  • brave_ulysses, don clement and Joe1950 like this

#16 don clement

don clement

    Vendor (Clement Focuser)

  • -----
  • Vendors
  • Posts: 1690
  • Joined: 02 Feb 2011
  • Loc: Running Springs, California

Posted 10 November 2019 - 12:35 AM

An ER style collet (flexes at both ends) would accommodate small variations in eyepiece diameter better than the alternative (flexes at one end only).

I agree. I have both ER collets and 5C single ended  collets.  One thing about single ended collet is that the fixed length of the chucked part (eyepiece) varies with the diameter of the part (eyepiece). 

 

Don


  • brave_ulysses and Joe1950 like this

#17 don clement

don clement

    Vendor (Clement Focuser)

  • -----
  • Vendors
  • Posts: 1690
  • Joined: 02 Feb 2011
  • Loc: Running Springs, California

Posted 12 November 2019 - 11:12 AM

I think that printing the double ended part for a collet that  firmly holds an eyepiece or camera  and keeps them centered  would best be done by 3D printing in plastic. https://www.youtube....h?v=eMtLdE5Zq-8  The rest of the "collet" could be made from easily machined aluminum on a manual lathe.

 

Don


  • Joe1950 likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics