issues with compression rings when securing undercut items

[mike bacanin]

hello

can anyone direct me as to where this was discussed on this site?

sure i read a discussion on how the undercut on barrels can be a problem

thanks

mike

[GordonCopestake]

I also find that some eyepieces get cought on brass compression rings, it's a pain but better than my eyepieces hitting the floor

[Macavity]

The "catching" phenomena is indeed something with which I am now aquinted (LOL) But I do agree, it's much the lesser of evils and avoid those little "dinks" in the eyepeice nosepieces. Part of the problem seems to be a lack of (any) standard. More by luck than judgement and may not fit ALL your eyepieces? Also the tendancy to find (retaining) knurled knobs (ooooer) that "get in the way" somehow...

For more critical uses - Holding in whole diagonals etc, I prefer "threaded things", OR have resorted to drilling and tapping ONE of the retaining screw-holes to M4! Probably none too kosher, but allows me to "swing" on a hex-key bolt and be sure that the whole thing ain't gonna fall out at some stage!

[mike bacanin]

my problem is solved with the william optics 2 inch dielectric diagonal. after trying one out, it locks perfectly using compression ring due to the fact that it doesn't use an undercut on the nosepiece, but rather a taper on the bit that the compression ring locks on to.

[AndyH]

I dislike the undercut barrels. All my diagonals have compression rings in one form or another(Takahashi, W.O. and clones). I like the idea of tapered barrels on eyepieces. As mike says, the compression ring holds them nicely.

Undercut barrels are the only thing i dislike about the Burgess/TMB Planetaries.

My two bobs worth.

Andy.

[GordonCopestake]

I for one would buy eyepieces with a tapered barel rather than an undercut barel

[mike bacanin]

maybe the eyepiece manufacturers will see that a taper is the way to go with the use of compression rings now so popular. this is why binoviewers with self centring collets are so nice to use.