# handle on a knob



## ship (Jun 20, 2007)

So, I have posted this fixture before, (just finally brought it home to get in line for a service call.) A question came up while looking at it - first of many I'm sure given the other similar Major fixture I just completed.

This fixture has a handle attached to the knob on the left side but not the right side. Why is this? Why not also the right side? Why is such a thing not found on say modern Lekos - what advancement in how it's done while not completely, normally makes this concept not necessary?


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## gafftapegreenia (Jun 20, 2007)

Well, I have a few guesses. 

The first is most fixtures now have the "friction discc" on the yolk. Two bolts are actually attached to the fixture, whereas tilt is controlled by a handle attached to the yolk that tightens down on the disk attached to the bolt on either one or both sides of a fixture.

The handle in this Major fixture would make locking the fixture in a position more reliable?

Or is it that clamps now have a "safety bolt" that allows for easy panning, whereas the old style clamps didn't? 

I think it might also be there for use as a followspot.


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## Chaos is Born (Jun 20, 2007)

Looks like a dampener to me... like from the old movies when they have the moris code from ship to ship by flashing the light... granted those were usually shutters on the outside... looks like a handle from that though...


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## ship (Jun 20, 2007)

Friction disc is one way amongst belleville washer and other systems I was thinking. This including the clutch plate. Yep, improvement.

It’s a Chicago Stage Lighting fixture not a Major fixture. Some difficulty in defining that brand’s history of even if it later became Major but while both were built in Chicago, they are very different fixture brands and styles by way of construction. (At the moment I have one of each sitting side by side with each other.)

Nope, or to some extent locking more reliable, but than wouldn’t if that’s the case both be done that way with a handle? Safety bolt, never heard of that type of part before, explain the concept even if I’m fairly certain not related. Do you mean a shoulder bolt?

Nope, not for use as a follow spot but it could be.

Why was this handle put on the left instead of right side of the fixture given the photo shown? The right side has the 3" knob this handle is rivited to alone without handle.


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## propmonkey (Jun 20, 2007)

what do you mean left side? looks to me as though thats the right side.

i am missing something?


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## Logos (Jun 20, 2007)

Yeah, I sort of thought that too.


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## avkid (Jun 20, 2007)

propmonkey said:


> what do you mean left side? looks to me as though thats the right side.
> i am missing something?


Perspective of the object.


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## gafftapegreenia (Jun 20, 2007)

By "safety bolt" I mean the little square headed bolt on a C-clamp. The one that allows you to pan withhouse loosening the bolt holding the clamp to the yolk. Is shoulder bolt the proper term?


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## ship (Jun 20, 2007)

That square bolt is a square head set screw or "[email protected]& you" bolt."
Nope, not related.

On the other hand, there are some lever/knobs in use on some especially audience blinder fixtures that use this concept of the push the button and the handle advances to the most useful position. You are correct in some modern fixtures using handles (often on this same side) but it as a handle attached directly to the knob - the same knob as on the right side of the fixture, does not slip. Just adds leverage = - why is extra leverage needed?

By the photo, it's the left side, also normally on a fixture you call it from the perspective of the lens.

The other side of the fixture will often have a socket head shoulder bolt and no knob - it just pivots in using one side to adjust with.

Again, how would it be different new or old were the lever installed on the reverse side of the fixture? What's the advantage to the left side and or disadvantage to doing it on the right side?

Perhaps also related to follow spots, they are also often left side operated as opposed to right side operated. Potentially by way of the handle in this photo, it could be related. What I'm searching for is some concept of why such a thing should be on the left side and not the right side? It's kind of a simple mechanical thing, perhaps so simple it's not realized.


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## gafftapegreenia (Jun 21, 2007)

Because most people are right handed?


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