Gas strut force calculation

[Fazerruss]

Afternoon all, question to see if my methodology is correct.
The gas stru has failed on my tool chest. Unfortunately there isn't a force rating on it. So using the other good one I pressed it against the bathroom scales and it displays 6.7 kg.
Now am I correct in thinking this would be around 66 newtons (6.7×9.81) According to an online calculator 1 kg is 9.81 Newtons.
Or is the formula more complex to factor in distance too?
This is the strut


I ordered a pair off Ebay rated at 100N but they are way too strong. I put them on the scales and they displayed 18.7 KG
So is my crude measurement technique wrong by mile or are the new struts out of spec. They were only 14 quid for a pair delivered and 100N was the lowest rating available so I took a chance.
If.my calculations are correct then these new struts are actually over 180N

Old strut on scales

New strut on scales




Thoughts please...

 

[Newlands]

My thought is that putting that point load on the glass scales is very brave

 

[p0689109]

The old strut could be considered worn and so is low on its original pressure, maybe?

 

[hotponyshoes]

You can get them with a little valve, they are supplied over pressure and you let little blasts of gas out until they work properly

 

[Fazerruss]

My thought is that putting that point load on the glass scales is very brave

I like to live dangerously

 

[mike os]

Put them on, if it works does it matter?

 

[Fazerruss]

The old strut could be considered worn and so is low on its original pressure, maybe?

The old one I tested is alright. The other old one is definitely fubared as it doesn't expand at all.
Problem is the new ones are way too powerful so I want to check if they are what they say they are on the tin and if the old ones should be rated at 60N ish

 

[Burdekin]

Try looking for 15lb gas strut and see if you have any luck.

 

[Fazerruss]

Put them on, if it works does it matter?

That s the problem. Because they are too strong the lid doesn't stay shut under it's own weight.

 

[Fazerruss]

Try looking for 15lb gas strut and see if you have any luck.

I've since found a supplier of lower pressure struts but I need to know if my calculations are correct befor ordering

 

[Burdekin]

I've since found a supplier of lower pressure struts but I need to know if my calculations are correct befor ordering

Yeah how you did it would be correct. N is just kg X 9.8

 

[Fazerruss]

Yeah how you did it would be correct. N is just kg X 9.8

So these I bought off ebay are not as described. They should be 100N but show 18.7 kg on the scales which equates to 183.47 N nearly double the rating.

 

[Burdekin]

So these I bought off ebay are not as described. They should be 100N but show 18.7 kg on the scales which equates to 183.47 N nearly double the rating.

Looks that way. N = Pres X area so probably just pumped up higher maybe when being made.

 

[Newlands]

The actual force needed also depends on the angle - triangle of forces and all that. It could be that the ones you bought are rated at 100n assuming an angle of, say 60° down to zero when the lid is closed, and also assumes that the mounting points at each end are (almost) horizontal when closed - in which case the force pushing the lid open is nearly nothing until you raise the lid and the strut is able to start pushing it upwards.
Need a photo of the lid showing the mounting points I guess.

 

[colnerov]

Hi, It maybe like the Chinese diesel heaters, they offer three different heat outputs but in reality they are all the same. Also any new one is going to be better than the knackered one coming off so is going to be a perceived improvement.

Colin

 

[zzr1200]

Gas Struts

www.sgs-engineering.com

 

[MoreWellie]

My thought is that putting that point load on the glass scales is very brave

That would be just like the idiot who was curious about the actual nose weight on a trailer and tried using metal bathroom scales to measure it

on the plus side, I am a lot lighter now than I used to be

SGS do a lot of struts https://www.sgs-engineering.com/gas-struts

edit: beaten to the useful bit of info

 

[Newlands]

Have a play with this calculator and see what it comes up with:
https://www.gasspringsshop.co.uk/gas-spring-calculator/

 

[julianthegypsy]

I have visions of unlocking the chest and firing a coffee across the workshop...

 

[johnik]

I have visions of unlocking the chest and firing a coffee across the workshop...

like the "open all hours" till ?