- Joined
- Feb 17, 2013
- Messages
- 4,415
Actually, more like shop-UNmade tooling ... but this is my best guess for where to post it ...
I've often used various odd parts of old office chairs (which I get at Goodwill for a very few bucks). For instance, the base "spiders" make dandy Lazy Susan "bearings." I've also kept a few of the lift cylinders, hoping I could find a way to "harvest" the nicely polished rods, etc. But I've been paranoid about cutting into them, given the pressures involved!:nono:
Today I figured out how to do it safely! The breakthrough came when I thought about how well polished the rod has to be, in order to maintain the pressure seal against the internal gaskets.
I started by grinding a tiny groove in the rod with a Dremel disk. It doesn't need to be deep, and probably doesn't need to be as long as I made mine (~1/4"). The groove is visible in the photo, just outside the cylinder.
Next, I put couple of washers around the release button at the other end. Normal air springs don't have this, so the washers aren't needed. I just needed to end up with a flat surface when the button was depressed, as it doesn't retract completely.
Finally, I put the air spring into a suitable (ie, long enough) gluing clamp. Before tightening the clamp and compressing the air spring, I made sure that the groove was facing down toward the table. I also placed a rag atop the air spring, so that any oil or whatever wouldn't fly around. I then slowly tightened the clamp. The first 1/8" or so compressed the release button. Then after about an inch, I started to hear a slight hiss.
I left the assembly alone until the hissing stopped, then closed the clamp a bit further to be sure of the last of the pressure.
Once that was done, I took the deflated air spring to the lathe, sliced the ends off the cylinder, and completed the deconstruction. The "harvest" was not just a nice piece of very straight, hard, and highly polished shafting, but also some heavy walled tubing (the outer cylinder) and a piece of thinner tubing that was inside the assembly.
I've often used various odd parts of old office chairs (which I get at Goodwill for a very few bucks). For instance, the base "spiders" make dandy Lazy Susan "bearings." I've also kept a few of the lift cylinders, hoping I could find a way to "harvest" the nicely polished rods, etc. But I've been paranoid about cutting into them, given the pressures involved!:nono:
Today I figured out how to do it safely! The breakthrough came when I thought about how well polished the rod has to be, in order to maintain the pressure seal against the internal gaskets.
I started by grinding a tiny groove in the rod with a Dremel disk. It doesn't need to be deep, and probably doesn't need to be as long as I made mine (~1/4"). The groove is visible in the photo, just outside the cylinder.
Next, I put couple of washers around the release button at the other end. Normal air springs don't have this, so the washers aren't needed. I just needed to end up with a flat surface when the button was depressed, as it doesn't retract completely.
Finally, I put the air spring into a suitable (ie, long enough) gluing clamp. Before tightening the clamp and compressing the air spring, I made sure that the groove was facing down toward the table. I also placed a rag atop the air spring, so that any oil or whatever wouldn't fly around. I then slowly tightened the clamp. The first 1/8" or so compressed the release button. Then after about an inch, I started to hear a slight hiss.
I left the assembly alone until the hissing stopped, then closed the clamp a bit further to be sure of the last of the pressure.
Once that was done, I took the deflated air spring to the lathe, sliced the ends off the cylinder, and completed the deconstruction. The "harvest" was not just a nice piece of very straight, hard, and highly polished shafting, but also some heavy walled tubing (the outer cylinder) and a piece of thinner tubing that was inside the assembly.
