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Functionality of Dovetail L-bracket

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#1 va1erian

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Posted 14 January 2020 - 08:02 PM

There is a dovetail L-bracket, e.g. here, https://www.amazon.c.../dp/B001DGR54O/

It is used to fix a small scope in the Alt-Az mount, or a DSLR in a star tracker. The bracket has a slotted plate to which the telescope/camera is bolted with a threaded post. However, the threaded post has some kind of washer with a lever. The lever is circled with red in the attached picture. What is the purpose of it ?  I could think only of putting a triggering cable of DSLR through it.

 

 

 



#2 Mike Lynch

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Posted 14 January 2020 - 08:15 PM

Looks like a locking lever to me !

 

Mike


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#3 Agatha

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Posted 14 January 2020 - 08:31 PM

The lever will allow you to slide the telescope or dovetail bar simply by moving it, instead of turning the knob.  Put a dovetail on there by turning the knob but not all the way tight.  Do this with the lever positioned on the left, as in your picture.  Then move the lever to the right to lock in place.  Play with it a little and you will see how it works.  

 

But you need to screw something on there to see it work.  


Edited by Agatha, 14 January 2020 - 08:34 PM.

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#4 outofsight

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Posted 14 January 2020 - 08:32 PM

Locking lever is what I'd call it, too. I sometimes use a bracket like that for binoculars and an 80mm telescope, the lever gives you the ability to quickly loosen and reorient whatever you have attached, and the quickly retighten. So I guess I'd call it a quick release locking lever. It also might help you if your screw is bottoming out with whatever you're attaching it to. 


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#5 va1erian

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Posted 14 January 2020 - 09:21 PM

The lever will allow you to slide the telescope or dovetail bar simply by moving it, instead of turning the knob.  Put a dovetail on there by turning the knob but not all the way tight.  Do this with the lever positioned on the left, as in your picture.  Then move the lever to the right to lock in place. 

 

Mmm... the others said it was a "locking lever", and you elaborated that it could be used to slide easier the optical instrument along the slotted plate. You said that one could turn the lever by maybe 10 degrees, and this would tighten/untighten the knob allowing the sliding. Is this correct ?

 

Well, I have the device. It does not work that way. I would need to turn the knob at least by half-turn (180 degrees), in order to be able to shift the camera along the slotted plate.

 

The "locking lever" is not connected to the "knob" (post). This is why I called it a "washer with lever". When I slightly untighten the knob (post), the lever can rotate freely, independently of the knob. It makes no sense to me to use the lever to tighten the knob only by few degrees. I can easily turn the knob itself.

 

Also, the tip of the lever has a hole in it. All of this made me thinking that the "lever" could be used for something else, hence I asked the public on the forum. maybe it is used as some kind of stop to prevent the camera from moving further or falling out ?


Edited by va1erian, 14 January 2020 - 09:24 PM.


#6 Agatha

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Posted 14 January 2020 - 10:16 PM

outofsight used the term, "quick release".    That is correct.  It is the same as a quick release on a bicycle wheel, if you are familiar.  

 

I have two of the devices in question.  It works exactly as described by me and others. The tension on the lever is determined by how much the main screw (via the knob) is tightened.  If you can't make it function as designed, you can remove it, but keep in mind the added length of the knob screw after the cam lever is gone.  The purpose of the lever is to make things quicker and more convenient.      Good luck.  smile.png



#7 va1erian

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Posted 15 January 2020 - 01:15 AM

outofsight used the term, "quick release".    That is correct.  

Yes, the contrivance would work as the quick release, in my (tactile) experience.




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