Tonight’s technical question. I want to order a replacement gas strut for a cupboard. It’s american so is listed as 40psi 12″ Ext x 8″.

Found a UK supplier with a similar sized unit but it asks for the force in N. Any clever types tell me how to convert 40psi to N for this?

TIA

Kev

psi is a measure of pressure.

N is a measure of force.

Pressure = force/area so you’d want to make the conversion to N per square metre.

(I think; this is from a hazy recollection of school physics over 20 years ago…)

Try here:

http://www.onlineconversion.com/pressure.htm

IF you can calculate the area of the piston within the strut then you can convert the psi value into a Newton value.

You can estimate the piston diameter as a bit smaller than the outside diameter of the strut body – not the pushrod. Say 1/8″ smaller.

Once you’ve calculated the area as pi x r^2 then you multiply the area by the pressure to give an answer in lbf (pounds-force).

Then multiply this value by 4.448 to give you Newtons 8)

For info’: pi = 3.1415926 and r^2 means radius squared (ie radius x radius)

40 pound/square inch = 275 790.291 2 newton/square meter

from stuartie c site..

Oh yeah, you should measure the strut body diameter in Inches.

That’s because PSI = Pounds per Square Inch

Thanks for replies. Have a feeling i might end up with a decimal in the wrong place trying to do this. Anyone please 😉

Sizes are

Cylinder Dia. Ø 18mm
Stroke 100mm
Cylinder Length 140mm
Force 50-700N

of course – give me a few minutes 😆

Is that info’ about the existing strut?

I need the body diameter and the strut diameter (preferably in Inches) of the strut you want to replace.

Length etc…. doesn’t matter

I’ll assume 40 psi unless you say otherwise

Thanks JAG, need to take it off to measure properly. Will post tmrw thx.

email me if it’s easier. Address is in my profile 😀

It’s 0.4 square inches, which at a pressure of 40 psi will generate a force of 16 pounds (presumably fully compressed).

40 pounds (treated as a force) is approximately 175 Newtons. Could of course be completely wrong!

Too many beers, ignore my last post! Please can a moderator delete it or correct it for me? Correct version:

It’s 0.4 square inches, which at a pressure of 40 psi will generate a force of 16 pounds (presumably fully compressed).

16 pounds (treated as a force) is approximately 70 Newtons.

Remember reading that post and thinking that 17kg of lifting force was quite high but too lazy to double check the working. 🙂

strut is 8mm
body is 19mm

thx

(sorry don’t know inches equivalent)

Assuming the cylinder wall thickness is around 2mm, i.e. the piston diameter will be 15mm, that would give you a force of close on 50N.

weigh the cupboard door in kg, multiply by 9.8, that’s how many newtons of force the strut has hold in equilibrium, multiply by 1.2 for safety and any strut with a force over that will be fine,

Ffs, just ring the supplier and ask!!! They’ll tell you right away

Then send then a link to this thread so they can have a good laugh