PRO Arm canister combinations

[Brian Freesh]

Matt, if you are talking about having a blue and a black canister in one arms section and adjusting one of them, then the question is answered. that was the previous discussion, so that was what I assumed you meant.

 

If you are talking about having only a blue or a black in one arm section, or two blues or two blacks, then I believe you answered your own question. I would assume a 360 on a black would adjust more than a 360 on a blue based on the adjustment range being nearly the same, but the number of turns to go through that range being different. If you find out for sure from George, I'd love to know!

 

I've really enjoyed this thread, I've learned a lot, and still learning!

[Eric Fletcher S.O.C.]

Okay, thanks guys, this makes sense.

 

But I don't see how it answers my original question:

 

If I insert a t-handle allen into a black spring canister in my arm, and I rotate it 360 degrees clockwise, does that action change the lift of the arm exactly the same, more, or less then if I rotate a t-handle in a blue canister 360 degrees clockwise in the same arm?

 

 

I answered this in my post. It doesn't matter if you adjust the blue or the black it will have the same adjustment. One turn will always have the same effect no matter what.

 

You are changing the total length of a single spring since springs in series are treated as a single spring

[Jerry Franck]

wow, this has blown out of proportion (in a good way!) from my original question... :)

 

so, from what Eric said a few posts ago, the blacks are stiffer...so that tells me that they should feel a bit different than the blues.

Ok, that's all I wanted to know...

 

Again, this arm is amazing, and yes it performs perfectly on blues, blacks or combination of both!

 

thx for the great discussion here...

if someone finds out something else, please post...

 

Jerry

[Eric Fletcher S.O.C.]

wow, this has blown out of proportion (in a good way!) from my original question... :)

 

so, from what Eric said a few posts ago, the blacks are stiffer...so that tells me that they should feel a bit different than the blues.

Ok, that's all I wanted to know...

 

Again, this arm is amazing, and yes it performs perfectly on blues, blacks or combination of both!

 

thx for the great discussion here...

if someone finds out something else, please post...

 

Jerry

 

 

What you are noticing is the higher natural frequency of the stiffer (black) springs

[Matt Petrosky]

Matt, if you are talking about having a blue and a black canister in one arms section and adjusting one of them, then the question is answered. that was the previous discussion, so that was what I assumed you meant.

 

If you are talking about having only a blue or a black in one arm section, or two blues or two blacks, then I believe you answered your own question. I would assume a 360 on a black would adjust more than a 360 on a blue based on the adjustment range being nearly the same, but the number of turns to go through that range being different. If you find out for sure from George, I'd love to know!

 

I've really enjoyed this thread, I've learned a lot, and still learning!

 

 

I answered this in my post. It doesn't matter if you adjust the blue or the black it will have the same adjustment. One turn will always have the same effect no matter what.

 

You are changing the total length of a single spring since springs in series are treated as a single spring

 

 

Apologies if my original question was misunderstood. I realize that adjusting any one canister will have the same overall effect no matter which of the four positions it is located in. My question was more about the difference in adjusting a blue or a black canister.

 

Here is George Paddock's Reply, reprinted here with his permission:

Hi Matt.

The answer to your question is simple. One turn on a Blue spring has less effect than one turn on a Black spring.

 

The lead screw mechanisms are the same for both springs (i.e they have the same thread pitch), but the springs themselves are different. The light (Blue) spring has a "rate" of 48lbs/inch, while the heavy (Black) spring has a "rate" of 60lbs/inch. Thus, changing the length of a Blue spring by 1 inch results in a change of spring force of 48 pounds, while a 1 inch change in the length of a Black spring results in a change of 60 pounds. Keep in mind that while the "spring forces" affect the weight the arm will carry, the numbers referenced above are not a direct indicator of that weight.

 

Let me know if I can shed any more light on the subject.

George

[Eric Fletcher S.O.C.]

Matt, if you are talking about having a blue and a black canister in one arms section and adjusting one of them, then the question is answered. that was the previous discussion, so that was what I assumed you meant.

 

If you are talking about having only a blue or a black in one arm section, or two blues or two blacks, then I believe you answered your own question. I would assume a 360 on a black would adjust more than a 360 on a blue based on the adjustment range being nearly the same, but the number of turns to go through that range being different. If you find out for sure from George, I'd love to know!

 

I've really enjoyed this thread, I've learned a lot, and still learning!

 

 

I answered this in my post. It doesn't matter if you adjust the blue or the black it will have the same adjustment. One turn will always have the same effect no matter what.

 

You are changing the total length of a single spring since springs in series are treated as a single spring

 

 

Apologies if my original question was misunderstood. I realize that adjusting any one canister will have the same overall effect no matter which of the four positions it is located in. My question was more about the difference in adjusting a blue or a black canister.

 

Here is George Paddock's Reply, reprinted here with his permission:

Hi Matt.

The answer to your question is simple. One turn on a Blue spring has less effect than one turn on a Black spring.

 

The lead screw mechanisms are the same for both springs (i.e they have the same thread pitch), but the springs themselves are different. The light (Blue) spring has a "rate" of 48lbs/inch, while the heavy (Black) spring has a "rate" of 60lbs/inch. Thus, changing the length of a Blue spring by 1 inch results in a change of spring force of 48 pounds, while a 1 inch change in the length of a Black spring results in a change of 60 pounds. Keep in mind that while the "spring forces" affect the weight the arm will carry, the numbers referenced above are not a direct indicator of that weight.

 

Let me know if I can shed any more light on the subject.

George

 

and if you put a blue and black in series its a 108lbs/spring (vs 96 for 2 blues and 120 for 2 blacks) and it doesn't matter which end you adjust 1" of adjustment travel will be a 108lbs adjustment

[Kevin Andrews SOC]

Ok, with all this PRO arm talk, I'm going to have to get one now. Can't wait to try it out for the first time at the stabilizer expo.

[Eric Fletcher S.O.C.]

Ok, with all this PRO arm talk, I'm going to have to get one now. Can't wait to try it out for the first time at the stabilizer expo.

 

 

Quite simply it's the best are available.

[Robert Starling SOC]

Ok, with all this PRO arm talk, I'm going to have to get one now. Can't wait to try it out for the first time at the stabilizer expo.

 

Don't bother Kevin unless you have the money to buy one; it'll only make you want one as it did me, it became my standard of comparison. Having my own now for roughly two months has been awesome; no regrets at all!

 

Robert

[Brian Freesh]

Wusses, gotta buy a $20k arm when you could just hold the sled up yourself!

[Kevin Andrews SOC]

I don't think I'll be able to resist trying it out even though it will open a can of worms for me. Plus I do believe they have it selling for 17,400 now.

 

blue canisters, black canisters, green clovers and purple horse shoes. It's all too enticing.

[Robert Starling SOC]

...Plus I do believe they have it selling for 17,400 now.

 

For all eight canisters? If so, jump on it, if not jump on it; the last arm you'll ever need to buy until you're ready to build a second rig.

 

Robert

[Brian Freesh]

Plus I do believe they have it selling for 17,400 now.

 

You're thinking of the G-70.

 

The Pro arm is $17,100 with 4 canisters, $18,000 with 6 and $19,800 with 8

[Kevin Andrews SOC]

Oh, I was just referring to the 4 canister one which seems to fly most cameras. But back up canisters are always a good thing or the ability to use four blacks if you need to lift your car for an oil change.

 

 

But first I'm going to pick up my new G-21. Robert knows what I mean. ;)

[Robert Starling SOC]

...But first I'm going to pick up my new G-21. Robert knows what I mean. ;)

 

You'll need extra "canisters" for that too! Also, you can always borrow or rent some black canisters as needed.

 

Robert