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Question about max pay loads regarding boom arms?


imran qureshi
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So I am thinking of buying an avenger d650 junior boom.

Its chrome steel silver and extends 300cm long.

The max pay load at minimum extension is 40kg. The max pay load at maximum extension is 10kg. I am wondering if this max pay load refers to everything on the boom (light and counterweight on the other end of the boom) or just the light?

 

I am hoping to boom an aputure 300dmk2 with a lantern, roughly its just under 5kg. If i was to mount this on a boom arm fully extended I would estimate that it would take around 25kg of counterweight to make that balanced and stay horizontal. (This doesn’t take into account the clamping force on the pivot or other variables so it would probs be a bit less than 25kg).

 

The boom itself already has a counterweight of 6.7kg already attached, I assume this doesnt count towards the max pay load. So that means to boom a 5kg light, i would roughly need to have a bit under 18.3kg of counterweight.

 

This means all together (both counterweight and light on either end of the boom) i would be putting 23.3kg on the boom arm and thats well over the max pay load at maximum extension. 
 

This maybe leads me to think that the max pay load only refers to what you’re booming on one end? Because the boom would be pretty useless if the 10kg max load referers to both counterweight and light.

Wondering if anybody can shed some light on this? Thanks!

 

 

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Hmm. I suspect you're right, but it instinctively feels like 40 kilos on the end of that arm is an awful lot (that's a sturdy child!). Your best answer will come from the manufacturer, or maybe the distributor. 

Send an email about it, I'd say. Or call a gaffer who has some.

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15 minutes ago, Phil Rhodes said:

Hmm. I suspect you're right, but it instinctively feels like 40 kilos on the end of that arm is an awful lot (that's a sturdy child!). Your best answer will come from the manufacturer, or maybe the distributor. 

Send an email about it, I'd say. Or call a gaffer who has some.

This is true, the minimum extension is 163cm and says max pay load is 40kg.

Ill have to ring manfrotto/avenger on Monday, thanks!

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It would be interesting to see how the manufacturer arrived at these capacities. I would think they would be based on most likely on the resistance of the hinge between the boom and tripod (that is tightened with a bolt) or possibly on the amount of "sway," in the boom that they would deem acceptable to most users. Lastly, I would think, would the capacity of the steel members before failure be  the determining factor.  

Since boom counterweights and sandbags on the tripod can be easily added, the amount of boom extension and the angle of the boom should be less of a factor in the capacity than as compared to a construction crane. 

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On 9/11/2021 at 3:36 AM, Phil Rhodes said:

Hmm. I suspect you're right, but it instinctively feels like 40 kilos on the end of that arm is an awful lot (that's a sturdy child!). Your best answer will come from the manufacturer, or maybe the distributor. 

Send an email about it, I'd say. Or call a gaffer who has some.

It's not at the full extension though. This is a Jr Boom not a Mini Boom; the tubing is bigger and can support a sturdy child when not extended.

 

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On 9/11/2021 at 11:30 AM, imran qureshi said:

So I am thinking of buying an avenger d650 junior boom.

Its chrome steel silver and extends 300cm long.

The max pay load at minimum extension is 40kg. The max pay load at maximum extension is 10kg. I am wondering if this max pay load refers to everything on the boom (light and counterweight on the other end of the boom) or just the light?

 

I am hoping to boom an aputure 300dmk2 with a lantern, roughly its just under 5kg. If i was to mount this on a boom arm fully extended I would estimate that it would take around 25kg of counterweight to make that balanced and stay horizontal. (This doesn’t take into account the clamping force on the pivot or other variables so it would probs be a bit less than 25kg).

 

The boom itself already has a counterweight of 6.7kg already attached, I assume this doesnt count towards the max pay load. So that means to boom a 5kg light, i would roughly need to have a bit under 18.3kg of counterweight.

 

This means all together (both counterweight and light on either end of the boom) i would be putting 23.3kg on the boom arm and thats well over the max pay load at maximum extension. 
 

This maybe leads me to think that the max pay load only refers to what you’re booming on one end? Because the boom would be pretty useless if the 10kg max load referers to both counterweight and light.

Wondering if anybody can shed some light on this? Thanks!

 

 

There you go, Imran - Ed's the guy to ask about this stuff. What were you proposing to do, exactly?

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On 9/14/2021 at 12:08 AM, Phil Rhodes said:

There you go, Imran - Ed's the guy to ask about this stuff. What were you proposing to do, exactly?

I want to boom a 5kg light on this boom arm at maximum extension but I would need to put around 15kg or so of additional counterweight on the other end (a guess) at maximum extension. 
 

as the max pay load is 10kg, I was wondering if this is safe. The people I have emailed at avenger seem to be giving mixed messaging, i think maybe the people doing the costumer service just aren't sure. 
 

I spoke to two different working grips and they said that the counterweight wouldn't count towards to max pay load as the counterweight would only help the pin strength. So I think I'm probably good to go but if anyone knows for sure that would be greatly appreciated! Thanks
 

 

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24 minutes ago, Ed Conley said:

We put about 5kg on the end of the Superbooms regularly and those are rated a little less in capacity.

You'll be fine with the 650 Jr. boom.

The counter weight that comes with the 650 boom will work good , no additional weight needed.
 

Thanks!! To confirm for future reference, if the counterweight that comes with the boom is not enough (lets just say just in case), is it okay to keep adding counterweight until proper balanced is achieved even if it goes over the 10kg payload or would you recommend to stay within 10kg near enough all together (counterweight and lights combined)? 

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Balance is not the issue:

The issue will be possibly bending the steel tubing if you go over the 10kg max weight at max extension. For a sliding boom like the 650 a bent extension will need to be replaced as it will not slide in to the other extension once it gets bent.

Same as a bent riser on a stand.

Menace arm set ups are great because there are no sliding extensions.
 

 

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1 hour ago, Ed Conley said:

Balance is not the issue:

The issue will be possibly bending the steel tubing if you go over the 10kg max weight at max extension. For a sliding boom like the 650 a bent extension will need to be replaced as it will not slide in to the other extension once it gets bent.

Same as a bent riser on a stand.

Menace arm set ups are great because there are no sliding extensions.
 

 

good point about the bending and not being able to slide back in.  Thanks!

I am planning on building a menace arm out of pipe like this in future, but the parts are sometimes hard to come by in the uk, not impossible though so ill just keep on the look out. Till then i’m going to be using the junior booms, hopefully it will be okay with balancing the 5kg lights. 
cheers!

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