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Eyepiece undercut.


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They are the work of the Devil!  

I'm in the loathe camp!        😡

If that is true then what price the concept of "meeting customer needs / preferences"? - a concept that drove the marketing strategy of all of the major companies I worked for in my sales & market

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An undercut is a royal pain in my opinion, but sadly something I live with as I like TeleVue kit.

The images from John do explain visually rather well.
Supposedly the undercut ensures the item does not slip from the telescope.

I disagree as the undercut catches when taking items on off the scope and move the scope position. 
The only time something fell from my scope was an undercut that caught as I removed an EP.
But each to our own favours of course, some love them, many loathe them. 

Edited by Alan White
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I think undercuts may have had a purpose in the days before compression rings when screws were used to lock the eyepiece in place but now are just an anoying anachronism. 🙁

Edited by johninderby
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14 minutes ago, johninderby said:

I think undercuts may have had a purpose in the days before compression rings when screws were used to lock the eyepiece in place but now are just an anoying anachronism. 🙁

Exactly in this day and age they are not needed and actually problematic as allot of the time it can just end up tilting adaptors etc as the compression ring closes on the cut. 

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I don't have a problem with bevelled undercuts, to be honest.  They seem like a very reasonable compromise.  I've even machined them into various bits and pieces I've made myself.

James

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1 minute ago, johninderby said:

Or Vegemite.  😁

I couldn't say, to be honest.  Having smelled Marmite once and nearly lost a perfectly good breakfast, I now make it policy not to eat anything with a name that ends "...mite".

James

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 Vegemite is the equivelent of Marmite in the land down under.

Still I suppose it’s one use for the sludge scraped out of old engine oil pans, or at least that’s what it smells like. 🤮

Edited by johninderby
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Oooh, now, this is way off-topic, but John's post just tickled a memory that I've had hidden away for far more years than I care to consider.

Who else remembers home oil changes with the old engine oil being drained out into a metal oil can with one side cut out of it?  Has to be a metal can, mind.  Bonus points if the sump plug was accidentally dropped into the can and you had to fish around in the filthy (and probably quite warm) engine oil with your hand to find it again.

James

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While working in Canada, I took some Vegemite with me....why not!

Showing it to friends....looked at it....looked at me....looked at it and said " Do you really take that stuff internally????"

 

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4 hours ago, Alan White said:

An undercut is a royal pain in my opinion, but sadly something I live with as I live TeleVue kit.

The images from John do explain visually rather well.
Supposedly the undercut ensures the item does doe slip from the telescope.

I disagree as the undercut catches when taking items on off the scope and move the scope position and
the only time something fell from my scope was an undercut that caught as I removed an EP.
But each to our own favours of course, some love them, many loathe them. 

I'm in the loathe camp!        😡

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I seem to recall that the undercuts could be filled using metal tape ?

They don't bother me personally but I know quite a few people really don't like them.

 

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has to be remembered too that not all of us are using more modern compression ring fitted gear so I guess the undercuts could be around for a while yet.

as for hammer and screwdriver to the oil filter, yeah I tried that one time on a stubborn one, wouldn't shift. so chain filter wrench and the old-style torque wrench and... at an off the scale 140+ lbs/ft the filter moved... just as the chain broke! Never let an ovlov garage service an alfa is all I can say (by the PO not me).

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I have a “collection” of four old eyepieces - no undercut. On the diagonal there are two screws (bolts) with v. fine threads. New OTA and a new EP with an undercut. At first I thought this would be a problem but I realised that it takes 9 half turns to fully undo the screws but 2 half turns to retract the screws so that the screw is retracted into the mount and the EP slips out. So I settled on 3 half turns is all that’s needed to retract the screws.. So two screws and an undercut looks to be a simple solution but also a more reliable one.

I haven’t handled a twist to lock or compression style fixing but the size of these doesn’t seem to be standardised. Since some of them push a ring sideways the EP isn’t held as securely as the two screw method. I can see this style being difficult to release because the mechanism eventualy sticks/twists.

So the old method of two screws doesn’t seem to be bettered? It doesn’t look sophisticated but it doesn’t seems to cause problems either?

Simon

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