LumberJocks Woodworking Forum banner

Any engineers out there? Gas spring question

3K views 17 replies 11 participants last post by  joeyinsouthaustin 
#1 · (Edited by Moderator)
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.
 
#4 ·
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.
 
#7 ·
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.
 
#13 ·
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.
 
#14 ·
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.

 
#16 ·
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.
 
#17 ·
The Maxi solution I proposed operates on a cam, and actually varies the force applied to the lid at different stages of operation. they are sweet. They can be set to "touch to open" or oppose each other for a "zero gravity" effect. I have used them on panels up to 120 lbs. And they "soft close" as well. And they are not that expensive.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top