The thinking process of preparing to build a full system takes a lot of planning and preparation. If you have not read the introduction then please do it now:
Click Here. This article should be used as a guide-line in building a stabilizer with the notion that fewer mistakes will be made along the way then finding out a minute too late. People have different ways on going about building a rig but as long as the end results is the same then you should be Okay. So here we go:
First thing that any good planner will have on hand is an idea of how he/she intends the object to look. In other words how simple or elaborate you want your rig to be. If you haven't got a plan then you do not have a rig - point blank. Its like having a car with no gasoline. The car is useless. one of the easiest way to start is by looking at other stabilizer designs and see how they look...
N.B. Now I just want to mention that it is illegal to copy any patented designs for sale. It's a NO! NO! HBS is not about implementing any illegal copy right designs other then for complete personal knowledge or use. In other words - Do not copy the designs of the Steadicam and pass them off as your own and try to sell them. Very important! Continuing on...So if you have access to a CAD program then by all means, use it. Here is a collection of programs other members have used, including myself:
Click Here. Read through them and see which one would best fit your taste. The idea is to have a workable plan on how everything will work together. This is also a good way to see if the design will work or not. Believe me it will save you lots of time during the building process.
Arm building tips1. One of the foremost decisions you’ll have to make is to a have purpose of building a full rig stabilizer. No point in going through with a project of this size if there are no criteria. For example:
• What will you be achieving?
• Is it a must that you built a stabilizer?
• Will it be used often, seldom or once in a blue moon? In case of the latter it would rather be better to rent one then to purchase a unit.
• Is it worth it?
• How much are you willing to spend? Or simply put, what is your budget?
• Do you have the time?
The latter question is one of importance because it dictates whether or not your decision is, to make an Okay system or an outstanding system. Nothing is ever easy is it?
2. What will be the purposed weight-bearing capacity of the arm in question?
3. What will be the ratio (3:1) or size of the configuration of the arm structural framework? A good example of a 3:1 arm ratio, roughly that is; is a section of my arm bone or shell which measures 26cm long, 50cm wide and 10cm high. Some arms are slightly shorter but 26cm was an ideal length to start with in terms of the type of construction I had in mind. So for you, this might be shorter than my specs.
4. There are different configurations to choose from depending on the complexity of the arm.
For a spring arm to be frictionless two methods are used; Bushings and Bearings.
• I prefer bearings because they give a much smoother axle motion than bronze bushings. One good reason to use bushings would be to keep the cost down as we all know bearings cost. As if getting bearings for a single arm is not expensive enough, let alone getting double the amount for a dual arm. So make sure you have your priorities set and decide on how you are going to plan for the materials needed for your project.
6. High grade composite material is expensive. T6 aluminum is the next best thing. There is also aluminum 7075 and 6061 but any good grade aluminum should do the trick. Just make sure they are durable. Remember a sturdy arm must be able to withstand the maximum weight of the pre-determine load.
Composite materials can get away with very thick materials due to the light molecule structure of its components. Aluminum on the other hand, although light is still heavier than high composite materials. So, one must compromise to get an even balance between strength and thickness size.
7. Some things to know about springs:
• If the spring coil has a smaller diameter, then the spring will be stronger.
• The more coils that are active, the less load you can apply to get it to stretch a particular length.
• The thicker the spring wire, the stronger the spring will be.
• There are two types of springs used commonly in stabilizers. Extension springs and Compression springs. Both do the same job but in a different way.
Extension springs do exactly what the name entails; the coils are extended out wards to provide the needed force to support the load. One disadvantage of extension spring is that they are more prone to failure over an extensive period of time. Don’t worry it takes a lot or a critical fracture to make them fail but it’s good to keep that in mind. Just as long as you stay within the limits of it’s capacity.
Compression springs on the other hand does the opposite of what extension spring does. They compress, which means they move in wards. Unlike their sister counter parts; they are less likely to fail over an extended period of time.
8. The Choice of springs. There are two types to choose from. Titanium and Steel springs are the ones available. The latter is the more common of the two. As always there are advantages and disadvantages with both.
• Titanium springs are stronger and has a longer life span than their counter-parts. They are able to withstand larger stress endurance which makes them ideal for carry larger loads, like flying 35mm panavision film cameras. This is why most of the high-end arms use them. Could you imagine a fully loaded 35mm camera plus extra equipment failing on you, bringing your arm crashing down? Yikes! God forbid. The only downside is, they are expensive and are not as common as steel springs. Of course there are steel compression springs but like their sister steel extension springs, they are slightly heavier; which equals to added weight. This of course increases the weight of the arm.
• Steel springs are less tolerant to stress than titanium springs and their life span is a little shorter than their siblings. A good thing with them is they are cheap and very common items. You can find them, pretty much off the shelf. For us homebuilders, this is the one of choice.
Whichever you decide to use, will still get the job done regardless of the type you choose. Again, your budget and criteria will determine the outcome. This, of course, is our plight.
9. Another thing to remember is the type of arm you will intend to use. There are two basic types. The single action arm and the dual action arm. Again, if your goal is to keep the cost down than a single arm it is; but like all cheaper methods there are always limits. Not much though. It is more a matter of what one can live with and live without.
A single arm:
• Limits the boom in the vertical range. It decides how high or low the arm can be boomed.
• Slightly more prone to outside influences in forms of vibrations getting through. With extra practice this can be avoided but it takes time.
• Less parts that can go wrong
• Weight is lessened but this is not such a big deal, if not really nothing to get worked up about. For some (very few) this might have a hand at making the final decision.
• Cost. As mentioned, if you are on a budget than this design might suit your wallet. Less parts to buy and machined the less time it takes to build a unit.
A Dual arm:
• Increases the boom range of the arm
• Less prone to vibrations getting through but still one must practice to avoid such influences.
• More parts that can go wrong
• Weight increase. Again, this is not such a big issue so it should not be the overall final decision breaker.
• And finally cost. You basically have to double up on everything. What you do for one arm section, you will have to do to the second one. So everything is done in pairs. More parts more money and more time it takes to build the unit.
My preference of course is the dual arm. It may be a little more work involved but to me it gives a smoother ride and better stability than a single arm but in the end it’s what you are comfortable with that makes the difference. Your decision to go with a particular type of design will be based on what you will be flying. So take some time to think it over before venturing out into the machine room.
One thing to remember when building either dual or single arm, is that the elbow, that connects both arms in a dual arm or connects the arm to the vest bracket in both single and dual, is strong or thick enough to support both arm arms under load. Otherwise the arm will torque or twist under load. Something best avoided. See next page for the elbow I use to connect both arms in my dual design.
Another design, which has been my personal choice, is the GPI ® pro. This design excludes the pulley/wire configuration which is no way ISO-elastic but instead as a smooth vertical movement throughout the entire boom range.
One particular feature with this design is the ability to exchange different set of springs or individual springs to suit different setups by simply just detaching the canisters that contain the springs. This is a real optional feature found on no other arm. This means you could fly the rig with one spring instead of two in each arm to compensate for the change-over to very light weight cameras.
The option to use lighter with heavy springs together or 2 sets of lighter springs or 2 sets heavy springs makes this arm an absolute exception over all other arms. See pic on next page for my version of the Pro GPI®.
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Vest Building TipsIn keeping with the same profile we attack the vest with the same methods we use on the arm - Solidity and stability.
1. The vest has to be strong; yet light to fit the body like a piece of clothing and at the same time provide comfort to the operator.
2. The vest has to sit tightly; yet comfortably on the body while carrying the rig.
3. The purpose of the vest is to distribute the weight.
4. The rig has to remain steadfast at a fixed point on the arm bracket at the vest area while the operator is carrying the rig.
5. To provide the comfort needed to the operator, the combination of padding and light metal materials should be weighed so that both provide enough comfort and stability to succeed in doing its job. Remember comfort to the operator is essential has this will help prevent some of the quick fatigue associated with badly constructed vest when operating a rig for longer period of time.
6. Another thing to remember is that on the real Steadicam® vest there is an arm adjustment mechanism that determines the balance of the arm or the pitch. This is one of the most important features on the vest. This mechanism helps immensely in providing the stability for the arm when fully loaded.
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Sled Building TipsAah yes. The sled. The last of the three components. Personally I think the sled is the least difficult of the three. I say this because you can practically use any type of sled (post) as long as the gimbal handle is adaptable to the arm pin, you should not have any problems flying a rig. This part is not so complicated and involves no special treatment but there are still a few tips to help you on your way. So here are a few short pointers to help you out:
Things to consider for your sled:
• The two most important things you should have on your sled are: a monitor (simply a must), and a battery (something to power the monitor, camera or both).
• Keeping things light weight is always the main theme when building a rig and the sled is no exception. Composite materials are the top choice with major stabilizer manufacturers. For us mere mortals, aluminum based alloys are the material of choice. This is usually because it is cheaper and more common. Again. This is a budget issue and should be your decision to make.
• Having a movable mechanical stage enables you to minute adjustments or in other words, makes trimming fore/aft easy. Though these take some machining to get right its still worth it. Another alternative would be to use two Manfrotto® plates, one placed on top of the other for fore/aft and side-to-side adjustments. See pic 1a on the following pages.
• While we are on the subject of camera adjustment stage options here’s another product you can use instead of the mundane adjustment of the .357 Manfrotto® plates. Micro positioning plate / Cat. No: 454 => Bogen code (USA only): 3419 .You can find these at any decent camera equipment store. The advantage of this is the built-in micro adjustment. Unlike the .357 plates, these can be adjusted in minute stages more accurate compared to the other suggested alternative. Remember though that the max weight for this particular mechanism is around 8kg. Regardless of the choice you will make there is always something that can be adapted to your liking. You must know your needs and work within those parameters to achieve them.
• Another thing to remember is to make the sled as flexible as possible. Example. The ability to adjust the monitor and battery for dynamic balance. Probably not such a big deal for homebuilt stabilizer builders but this feature does come in very handy, regardless.
• Now, one of the most important or should I say The most important part on the sled is the gimbal. This part must be very well machined to be able to fly properly without any friction what-so-ever. Finding a good machine shop that will do the job for you is always a challenge in itself. Knowing what weight you will be flying helps in knowing what tolerance the gimbal should be machined to.
The material also plays a part in the tolerance of your gimbal. So whether composite or aluminum base materials the decision you make before hand affects the deciding factor of how your gimbal will behave and feel.
There are many designs that can be achieved. As always the type of design will effect the amount of work needed to get the job done.
Another thing to remember is the alignment of the two tilt bearings embedded on the sides of the main bearing or the tilt bearing as it is called. If the cross axis is off a couple of millimeters than the gimbal will go out of balance and will be difficult to balance. This is noticeable when you do a spin balance or dynamic balance. The result is a rig that spins off balance. Not a characteristic that you will want in a certain operating situation.
So, be careful and make sure you play it accurate.
• As I mentioned before, simplicity is always best. Don't add something to the rig if it hasn't a part to play. It will just add extra weight unnecessarily. Why make the sled heavier than it already is. Even if it looks good, try to avoid it.
• Post rigidity plays an important part in the construction of a sled. The pros use a post diameter of 1, 5 or a 2 inch. One big advantage for having a wide post is solidity. This prevents any instability in the form of vibration when flying the rig. This is not so important for those flying very light rigs. If your project is less than 7kg than you should not concern yourself over this issue. Even if you decide to go this route than you can at least know that it is future prove.
• When you make your post you have the choice to include a telescopic option over the one-post design. This is a big advantage as this will give the operator the ability to adjust the length of the sled. A very important, functional and at times a required feature fro any operator. A length of 50 to 100 cm works fine.
So, there you have it, a few simple tips to guide you in reaching your goal. Always remember that testing before hand will lessen the chance of you wasting materials thereby making the final delivery less expensive. Especially, if you are on a budget, this will make your pockets deeper than shallow.
Will update when time permits.
Hope this little article helps in getting you started but please remember that the need for building a full rig is not a MUST. It is certainly less time consuming than building. So think about your priorities and need before jumping in with both hands. 
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