Sinar Pan/Tilt Head question

[Jeroen]

I can buy a Sinar Pan/Tilt Head with a crack in the side disk, see attachment. Is that disk used for tensioning the head or is just decorative? In other words, is it (un)wise to buy it?

194813

[mpirie]

I suggest putting your camera on the head and go through a series of movements to see if the crack opens?

If it does, then it's not decorative.

Mike

[William Whitaker]

There are plenty of clean examples on the market. I would suggest you pass.

[Bernice Loui]

That side disc is the primary structure that locks tilt. Never seen on that has cracked like this. A cracked disc like this would result in a no tilt lock.
Unless you're able to source a direct replacement disc, better pass on this one.


Bernice

[William Whitaker]

Yeah, like maybe a gorilla tightened it. Then threw it down on the concrete for good measure!...

[Jeroen]

That side disc is the primary structure that locks tilt. Never seen on that has cracked like this. A cracked disc like this would result in a no tilt lock.
Unless you're able to source a direct replacement disc, better pass on this one.


Bernice

I've never laid hands on a Sinar Pan/Tilt Head -hence my question- but that's exactly what I suspected. I absolutely **will** pass on this one. Thanks everyone for your input!

[Jimi]

How a disc with six small screws can maintain the lock of the tilt when set up with a heavy camera is beyond my mechanical understanding. Looking at my own example, I was actually thinking it was a "beauty ring" and the real stuff holding it together (like a large nut) was inside. Live and learn something new every day ...

[Bernice Loui]

Those six holes are not for screws, they are for an anti-rotation 2mm pin that sets the lock handle position. The tilt works by clamping the top and bottom casting together with a M10x1.00 screw and long handle between polymer friction disc. Combination of long handle and fine threads can produce a LOT of clamp force. This combined with the friction generated by the polymer disc between the center tube and castings absolutely LOCKs the two sections together when clamped.
194854

194855

I've yet to encounter another tripod head design with this degree of stability and solidity once locked. It is an excellent item of mechanical engineering and lightweight for what it can offer.


Bernice




How a disc with six small screws can maintain the lock of the tilt when set up with a heavy camera is beyond my mechanical understanding. Looking at my own example, I was actually thinking it was a "beauty ring" and the real stuff holding it together (like a large nut) was inside. Live and learn something new every day ...

[steyr1973]

I checked on mine and these "holes" are not screws. Could be for a big spanner with six little poles to unscrew the whole aluminium chunk. Plus there are no efforts on this axis. The whole weigth is supported through the black rings on the vertical axis. So I m not sure there is a lack of thinking there.

[Bernice Loui]

Presumption that holes have screws.. example of Cognitive Bias.


Bernice

[steyr1973]

Those six holes are not for screws, they are for an anti-rotation 2mm pin that sets the lock handle position.
Saw your reply after posting mine. I was wrong assuming the use of spanner. I had seen the one pin through one hole but I wasn't sure whether it was the material behind or, indeed, a pin. Thanks for the photos, crystal clear !

[Jimi]

As I said - I learn something new every day here - thanks for the description and the photos! It makes the pan/tilt head even more impressive, knowing what is going on in there.

[Jeroen]

Those six holes are not for screws, they are for an anti-rotation 2mm pin that sets the lock handle position. The tilt works by clamping the top and bottom casting together with a M10x1.00 screw and long handle between polymer friction disc. Combination of long handle and fine threads can produce a LOT of clamp force. This combined with the friction generated by the polymer disc between the center tube and castings absolutely LOCKs the two sections together when clamped.

Thank you for the pictures of the disassembled head, Bernice! They tell the whole story.

[Jimi]

Resurrecting this thread again - I am having a bit of a worry. I used my pan/tilt head the other day and happened to see that the outer disc on mine (the one that is cracked in the OP) was moving and possible to pull out a bit. I was able to put the outer disc into what I think is the correct position again. I can see there is a guiding pin in one of the holes.

I don't think it should be able to be moved around like that, or? What would be a good place to send it for a check-up (preferably in Europe)?

The three screws on the bottom seems to have been tampered with - what sort of dimensions are these, if they would have to be changed out?