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Post Clamp issue on a Zephyr

Zephry Post Clamp

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#1 Steve Rausch

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Posted 15 July 2013 - 11:00 PM

I have had my Zephyr for 8 months now. Doing well, learning lots and having some fun and success. Recently got to fly an Alexa EV on a short and the week after it was an Alexa XT with Cooke 5/i.  To date I have one one concern...

 

My concern with the sled are the clamps. They are awefully stiff and hard to open and close. I am familiar with the "quick release" design from riding bikes for 20 years but these are definately not Shimano parts.  The lower post clamp is managable but the gimble clamp  is a bugger. When having the weight of the Alexa XT and a Cooke lens  (23.7 lbs verified by a shipping scale) I opted to get it closed but then use an allen wrench to make it secure. --meaning when I could close the clamp it was not secure and the gimble could slide. After shortening the screw length and therefore the throw of the lever, I could not hand tighten it. I honestly thought the plastic parts would snap. 

 

After that shoot I took the sled to my shop and tried ot diagnose the issue. When applying force on the clamp lever it appears almost as if the screw inside was starting to bend or flex under the stress. I tried to find a replacement bolt in hopes of finding a sturdier one but the hardwre shop near by didn't have an exact match. I did toss a washer in help close the gap but this is a bandaid as best.

 

Any suggestions what is going on here? Could I have a clamp assembly that needs attention or am I expecting too much out of the hardware for a secure fit on the post?


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#2 Robert Starling SOC

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Posted 15 July 2013 - 11:26 PM

You should not have to use extreme force on any of the gear we use.  I don't know the Zephyr's clamps specifically but if a bolt or clamp feels like it's about to break it probably is. Snap a screw off in a clamp and you have a big problem.

 

Something just to check is that we all have a lot of sweat and body oils on our hands.  That stuff builds up on the posts and other parts and may mean you're not getting a good normal clamp friction. Clean the post with denatured alcohol or something similar.

 

Meanwhile I'm sure some of the Zephyr owners will likely chime in.

 

Good luck!

 

Robert


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#3 Alan Rencher

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Posted 15 July 2013 - 11:42 PM

Yeah, that was a mistake. Before Tiffen upgraded the clamp, it was possible for the clamp to over tighten by itself. This happened to me, and the bolt bent when I clamped it down. Tiffen replaced the bolt and gave me a clamp upgrade free of charge. I did learn one thing from the experience: when tightening the clamp bolt, don't tighten it so much that it's difficult to clamp the post down. You can test if you've tightened the bolt down enough by just clamping the gimbal down, hanging the rig on the dock, grabbing the gimbal grip, and applying some of your body weight. If it doesn't slip, you're golden.
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#4 Victor Lazaro

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Posted 16 July 2013 - 08:17 AM

I contacted Derek at Tiffen and he sent a replacement for both clamps. Also make sure to apply some loctite 222 (the purple not the blue one, low strength) on the screw and make sure the handle of the clamp doesn't turn when you unlock it.
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#5 Chris Van Campen

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Posted 16 July 2013 - 08:53 AM

In a similar boat here - there seems to be a small "sweet spot" where you have enough clamping force versus having the throw lever not too stiff. I've been using both the clamp and the allen to make it stiff enough not to slip (mostly the gimbal clamp in my case).

 

Was actually pondering whether changing those levers out to a kipp handle might be a good move...


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#6 Steve Rausch

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Posted 16 July 2013 - 10:55 AM

..when tightening the clamp bolt, don't tighten it so much that it's difficult to clamp the post down. You can test if you've tightened the bolt down enough by just clamping the gimbal down, hanging the rig on the dock, grabbing the gimbal grip, and applying some of your body weight. If it doesn't slip, you're golden.

 

Thats the main issue. On the Gimbal clamp, I can clamp it closed, but it is not tight enought to hold position--i.e. it slides. 

If I tighten the bolt, it very quickly becomes to difficult to close the clamp.

 

Time to call Tiffen. Thanks guys.


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#7 Victor Lazaro

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Posted 16 July 2013 - 11:02 AM

Loctite really is the key. When you get the new clamps and install them, adjust the screw to the right tension and let the loctite 222 dry in that position. Don't turn the screw after after that or you will break the loctite bond and have the same problems over again. If you need to readjust the screw apply some loctite before resetting the screw.
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#8 Victor Lazaro

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Posted 16 July 2013 - 11:22 AM

[double post]
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#9 Chris Van Campen

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Posted 15 November 2013 - 02:01 PM

Old thread, but I finally got sick of having to torque my gimbal handle clamp down with an allen wrench to get enough grip to keep the handle where it should be.

 
If your clamping force seems weak even when it takes a lot of torque to close the clamp you might have the same thing going on.
 
I took the clamp apart and set aside the delrin washer and spring. Found that the rotating captive nut portion of the clamp handle could barely turn using the bolt.
 
I applied a few drops of teflon lube (fresh outta lisigav), then worked it in. 
 
Now it works amazingly well, just like it's supposed to. Tons of clamping action and easy to open and close.

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#10 Victor Lazaro

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Posted 15 November 2013 - 06:39 PM

Or you could contact Tiffen to get a pair of new clamps. Use some loctite to prevent the bolt from tightening itself and bragging the clamp.
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