Radio-Television-Film - Equipment Tip Sheets

Standard Porta-Jib Assembly Instructions
1. The tie down assembly (1) consists of a 3/8-16 threaded rod (1a), a 3" washer (1b), and a threaded knob (1c). Thread the 3/8-16 rod (1a) into the base of the Main Center Assembly (2). No tools required; finger tight is enough. *(An additional knob reference guide is located at the end of this packet.)

parts more parts

Note: some confusion occurs with customers who are used to seeing the tie-down assembly of a fluid head as a fixed assembly where the 3/8-16 threaded rod is pinned to the knob. They are accustomed to mounting the bolt into the bottom of their fluid head by turning the entire assembly of knob, washer, and threaded rod. Our system does not work this way. If the threaded rod is in our knob, turning the knob does not turn the rod. One may think he is securing the Main Center Assembly to the tripod or dolly, when in fact he may only engage a thread or two for his efforts.

To repeat: thread the independent 3/8-16 rod (1a) into the base of the Porta-Jib's Main Center Assembly (2).

2. Position the Main Center Assembly (2) onto the Mitchell plate (or 150mm bowl if you have a 150mm based Porta-Jib) of your tripod or dolly. (Note: the Boom Lock Arm (11) will be pivoting freely as you handle the Main center assembly. Avoid pinching fingers.) From below the Mitchell plate, connect with the 3" washer (1b) and tie down knob (1c).

3. Check the bubble level on the Main Center Assembly, and level accordingly. It is much easier to adjust it now, rather than later after the jib is built.

4. Locate the 3" diameter Main Tube (3), 1 Through-Pin (4), and 1 Main Tube Clamp (5).

clamp
Place the Clamp on one end of the Main Tube between the through-hole and the end of the tube. Slide the Main Tube onto the Main Center Assembly's pivoting 3" post, and secure with the Through-Pin. (Note: depress the button of the Through-Pin when inserting or removing to retract the ball ends.) Tighten Tube Clamp.

clamp
tightening the clamp

5. Locate the 1" diameter Secondary Arm (6), and the 2 Nylon-tipped Locking Knobs (7). (Notice that the Secondary Arm is two pieces threaded together. This allows you to change the overall length of the arm, which is used to level the front plate.)

Attach the 1" Diameter Secondary Arm to the 1" pivoting post of the Main Center Assembly and secure with a Nylon-tipped Locking Knob.

locking knob
secondary arm to pivoting post
6. Locate the Main Front Assembly (8), 1 Main Tube Clamp (5), and 1 Through-Pin (4). Slide the Tube Clamp onto the end of 3" Main Tube. Slide the pivoting 3" Post of Main Front Assembly into the 3" Main Tube, and secure with the Through-Pin. Tighten the Tube Clamp.

7. Connect the 1" diameter Secondary Arm (6) to the Main Front Assembly's pivoting 1" post and secure with a Nylon-tipped Locking Knob (7).

At this point you are temporarily finished with the front section of the Porta-Jib. You will adjust the length of the Secondary Arm after you have added your pan-tilt head and camera.

swing bar

8. Locate the 1.5" Steel Weight Bar (9) and Locking Knob (10) (which looks similar to the secondary arm's lock, but is longer and has no nylon tip. Also notice that one end of the weight shaft is threaded to receive the safety cap (16). This end will be the back end of the Jib.)

locking mechanism
9. Slide the non-threaded end of the 1.5" Steel Weight Bar (9) through the Boom Lock (11), and into the Main Center Assembly's 3" diameter pivoting post. Line up the 3/8-16 threaded hole on the Steel Weight Bar with the through hole on the pivoting post. Lock Weight Bar into place with its Locking Knob (10).

Notice that the Boom Lock has 2 locking knobs. Tighten the knob that clamps to the 1.5" Steel Weight Bar approximately 2-3" down the Bar. Make sure this is secure. The second locking knob functions as the Boom Lock. When it is unlocked the arm slides up and down its channel. Warning: If the first lock is not clamped tightly on the Steel Weight Bar, the following occurs: As you lock the second knob, which should act as the boom lock, the first lock incorrectly slides up and down the Steel Bar; and, therefore, you will have no lock. Be sure that you have firmly secured the clamp onto the steel weight bar.

turning weight
10. Slide the Tuning Weight (12) onto the 1.5" Steel Weight Bar (9) and lock it down (anywhere along the shaft is fine for the moment).

11. Attach Weight Shaft Coupler (13) to the end of 1.5" Steel Weight Bar (9) with the Vector Bar (14).

vector bar
shaft coupler

12. Thread the two Threaded Weight Shafts (15) into the Weight Shaft Coupler (13).

weight shaft coupler

13. Thread the Safety Cap (17) into the end of the 1.5" Steel Weight Bar.

This completes the basic assembly. You are now ready to add your pan-tilt head and camera to the front and the counterweights to the back, and to fine tune the set up.

14. If adding a lightweight camera and head, under 25 lbs., rotate the Porta-Jib so that the front arm is parallel to one of the tripod legs to minimize chance of tipping. For heavier cameras, bring the front of the Jib down onto a camera case or some object that will carry the weight of the camera and fluid head until you have added the appropriate amount of counter weight.

15. Mount your fluid head to Front Plate receptacle (100mm, 150mm, Mitchell).

Note: 100mm and 150mm and Mitchell inserts can be removed and reinstalled downward if desired for underslung heads with these bases. Helpful hint: a Weaver-Steadman head will not pan 360 degrees unless a Mitchell-to-Mitchell 6" riser is used to let it clear the front support of the Porta-Jib.

16. Add the appropriate amount of weight to the weight bars to balance the jib in a horizontal position. Add Weight Bar Locks (17) to secure weights. Use the Tuning Weight for fine tuning the balance.

17. After the jib has been balanced horizontally, remove some of the weight from the weight bars and transfer it to the Vector Bar. The amount needed is usually no more than 5 or 10 lbs. for a light weight camera, but may be as much as 1/3 of the overall weight for heavier cameras.

The Vector Bar gives the jib more stability in coming to a stop. Without it, the jib will want to seek its original balancing point, requiring the operator to apply force to overcome this inertia. With the Vector system, a small amount of weight is tilting forward or backwards when it is not horizontal, thereby countering the inertia. It works as if you were automatically moving the tuning weight. This is why it is important to begin your balancing in the horizontal position, before transferring weight to the Vector Bar.

18. Check the bubble level on the front plate. Apply the Boom Lock. Loosen the Locking Knob on the front of the Secondary Arm a quarter turn. Adjust the level as needed by threading in or out the Secondary Arm. (To relieve the pressure on the threads, have someone assist you by supporting the weight of the camera. If you also need a slight adjustment side-to-side, it means that the front is being affected by the way in which the through pins were positioned in the 3" Main Tube. The outer hole for the through pins is elongated to aid alignment, but this can sometimes cause the front plate to be slightly off-level. Simply loosen the two Main Tube Clamps, tweak the front plate until level, and then re-tighten Tube Clamps.)

19. Fine tune the amount of desired Boom Drag and Pan Drag. Do not over tighten the boom drag. The Pan Drag knob also functions as lock on both the newer Porta-Jibs, and earlier models that had Pan-Locks as an option. (Otherwise, earlier models only had Pan Drag; they did not have a Pan Lock. Earlier models also did not have a vector bar. The Coupler for the Counterweight Shafts was secured by a Lock Knob identical to the one that secures the main Weight Shaft to the Center Assembly.)

Extension Kit Note:

If you are building the jib with either the 17" or 36" extension kit, add the extension pieces to the center assembly (as described in Step 3) before adding the normal 3" tube and secondary arm. The secondary arms in the extension kit are a fixed length. You will want the adjustable secondary arm connecting to the front assembly so that you can see the front plate's bubble level as you rotate to obtain a level position.

*Knob Guide for your convenience:

knob guide