Expandable Main Sled Post

[David L. Holmes]

Hello everyone,

In my DIY Challenge, I'm stuck with a new question. Seems easy enough, but I don’t want to have to buy more material later if I've made a mistake. To bad I can’t stretch aluminum if I do...

I have an expanding main post with two segments. How long should I make the main post that holds the adjustable Gimbal, and what would be a good length for the second sliding post?

I'd like to get a feel for what other people have for a minimum and maximum length on their main post.

Thanks for any feedback!

Dave

[Charles Papert]

David:

Are you active over at hbsboard.com? Would probably be a great place to ask this sort of question.

In any event, depending on what size of cameras you tend to fly, somewhere around 14" for the outer post. Inner post length depends many factors, including thickness of wall of the material you are using (and what material), tolerance between the two posts etc. You don't want it to get wobbly as you extend the post.

[David L. Holmes]

Hello Charles,

Yes I do post on hbsboard, lots of great insight from some well-respected people there. I like this board for the responses from people who have commercial rigs. Between both boards I should get a wide range of responses and the best information to make my decision.

For now I'm going to fly my Canon GL2, but I want to upgrade to an XL2 soon. The posts are 6061 aluminum .058 wall thickness. The inside pipe slides perfectly within the outside pipe so there is zero wobble when the clamp is tight. (By the way, I'm using a Manfrotto tripod clamp to hold the pipes)

With a 14" main post, then the secondary inner post would only have around 11" of adjustment. Would that be adequate? Also, what would be the advantage for having either a short, or long sled? I'm not sure I would ever be doing any "high" shots that would require the camera being pointed down onto someone's head. Plus my top stage will not be a tilting style.

Thanks for your feedback!

Dave

[Charles Papert]

The advantage of a short sled is that the three axes of pan, tilt and roll are made more similar in feel. In general, the shorter the sled, the better (to a point). A long sled will be much slower in the tilt axis , requiring more leverage to start and and stop tilts. However, you can get the lens higher and also lower in low mode. It also allows you to balance heavier cameras without adding more weight to the lower part of the sled.

I don't know what weight of cameras and/or sled combination you are looking to accomodate with your rig--14"-16" post length for cameras under say 10 lbs should be OK but if you plan to use heavier cameras, you will probably want a bit longer (also depends on the diameter of your post).