Any engineers out there? Gas spring question

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Forum topic by lateralus819 posted 11-15-2013 12:36 AM 2600 views 0 times favorited 17 replies Add to Favorites Watch
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2243 posts in 2671 days

11-15-2013 12:36 AM

Hopefully someone a lot smarter than i at this can help. I’m going to build a plane till, and instead of wasting space behind the trough for the planes, I’d like to make it hinged with extra shelves behind. The one’s I’ve seen you have to manually lift, which would be fine, but the way I’ve calculated it, would be around 80 lbs or so give or take.

I figured it’d be great to use some gas springs to assist with the lifting and to hold it in place while i get what i need.

What I’m interested in knowing is how much LBS of force per spring i’d need.

Since the planes will weigh roughly 60 lbs plus the panel they lay on another 10 or or 15.

The panel will be at a 25 degree angle. Length of panel is 26”, distance from pivot to center of gravity is roughly 10 inches.

17 replies so far

View MarkwithaK's profile


370 posts in 3959 days

#1 posted 11-15-2013 02:08 AM

By gas spring would you be referring to a hydraulic cylinder?

-- If at first you don't succeed then maybe skydiving isn't for you.

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10477 posts in 4429 days

#2 posted 11-15-2013 02:13 AM

My comment on gas springs is they lose strength over time. I
don’t know why, perhaps degraded seals. I’d get more
than you need but of course that will make it harder to
push closed.

View Dark_Lightning's profile


4111 posts in 3890 days

#3 posted 11-15-2013 02:26 AM

Go down to an auto parts store and look at their supply. I have a 2000 Chevy Astro Van that has about the right weight lift gate. Check out the lengths and mounting and see if they will work. The closed length is shorter than I think you need, but that’s OK, it just means you’ll have to shorten where the things mount.

Maybe you’ll want to keep with a woodworking motif and put counterbalance weights like a window sash instead of having high-tech pressurized gas cylinders on a wooden tool box. Plus, you could adjust the weight for a nice lid raising.

-- Steven.......Random Orbital Nailer

View Gman024's profile


2 posts in 3138 days

#4 posted 11-15-2013 02:38 AM

Check out the web site and search for gas struts. They provide information on sizing the struts for the load being lifted.

-- Glenn ~ Grafton, New Hampshire

View cutmantom's profile


407 posts in 3816 days

#5 posted 11-15-2013 02:38 AM

The counter weight sounds best to me, easy to fine tune and you don’t have to worry about a part that might be hard to find when it comes time to replace

View lateralus819's profile


2243 posts in 2671 days

#6 posted 11-15-2013 02:52 AM

Nothing high tech about it. I just saw they actually make them for furniture.

I’m not worried about them breaking down. I know they break down over time, but that’s years down the road. What is this “counter balance” you’re speaking of? Link to an explanation, I’m familiar with windows that use it, but how would i incorporate it into a plane till?
Thanks for the suggestions though i appreciate it.

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3263 posts in 3457 days

#7 posted 11-15-2013 02:58 AM

Show us a sketch of your plane till.

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2243 posts in 2671 days

#8 posted 11-15-2013 03:00 AM

I will in 1 second, just about finished.

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2243 posts in 2671 days

#9 posted 11-15-2013 03:12 AM

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2243 posts in 2671 days

#10 posted 11-15-2013 03:13 AM

Basically I’d like it to open about flat with the top, so the planes don’t fall off obviously.

View dawsonbob's profile


3716 posts in 2536 days

#11 posted 11-15-2013 04:08 AM

You might want to check out Rockler. I’m pretty certain they carry an assortment of gas struts for furniture.

-- Mistakes are what pave the road to perfection

View MrRon's profile


5914 posts in 4025 days

#12 posted 11-15-2013 10:07 PM

The gas strut must be great enough to keep the lid open, so if the lid + the planes weigh 80#, then the strut must be able to counter 80#. Too small, and the lid will not stay in the open position without some sort of latch. If the strut is too large, the lid will want to open by itself unless a latch is used to hold it in the closed position. At any rate, you will need a latch someware.

View joeyinsouthaustin's profile


1294 posts in 2854 days

#13 posted 11-15-2013 11:48 PM

We use these for that application. The one pictured isn’t the heavy duty, but the heavy duty can hold a lot. they can also be set to self open the lid. The tension is adjustable as well to set for multiple weights, and eliminates the sag that will happen over time with gas struts. You would need two. We get them at heafele.

-- Who is John Galt?

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1294 posts in 2854 days

#14 posted 11-15-2013 11:50 PM

Here is a pic of the heavy duty in operation. google maxi lid stay for heavy doors

-- Who is John Galt?

View patcollins's profile


1687 posts in 3646 days

#15 posted 11-15-2013 11:55 PM

The angle from the strut to the door is pretty shallow and thus alot of the force of your spring gets wasted. Im going to say the angle fully open is 15 degrees.

Lets also say the force your gas cylinder provides is 100 lbs, at an angle of 15 degrees the force holding the lid open is

force = 100 lbs * sine (15 degrees) or 25.8 lbs is all this cylinder can exert on the lid keeping it open. Now as the angle changes so does the force exerted on the lid.

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