lastlight's 225 - Page 19

mseepman · #**181** 07-15-2009, 04:36 PM

This is very cool, in spite of the fact that you're an apple guy

How did you calculate how long the blue wire needed to be compared to the red? Can you take a couple of other pictures of how the actuator is attached to your maple base?

Thanks

lastlight · #**182** 07-15-2009, 06:43 PM

The prototype proved the fact that the lengths don't seemingly matter. I think maybe because the bearings are the same size and they don't do any funky doubling up. From what I saw my pvc test rig went up evenly. Even if my light ends up going at a slight angle (or angel), It won't be a big deal assuming it's very slight.

lastlight · #**183** 07-16-2009, 05:48 AM

So tonight was a bit frustrating. The good news is I got the lift mounted on my ceiling. I don't trust the 5/8" enough to stand on it so this was a really tough task leaning out over the tank. In the end a step-stool, box of pampers and a bunch of children's books came to the rescue to hold the assembly in place! Props to Sfiligoi for making one hell of a sturdy light. I'm sure I could stand on the thing. It has ZERO flex.

Now for the bad news. The bracket on the end of the screw/shaft still seems to do what it wants especially under load where the forces are quite high. The fixture I'm guessing is 60lbs or so with the glass shields so I'll have to adjust my guide for the bracket to allow it to orient like it does under weight and that's it. I need to ensure the bracket always does exactly the same thing in both directions. If it doesn't and something catches after my cover is installed it will rip the entire thing to shreds. 150 lbs of force it's capable of.

The bigger letdown was the fact that the angle brackets I have the bearings mounted to bent under load. The bearing on the far left is mounted closer to the wood and it bent far less. One of the bearings for the other wire bent a lot. I was foolishly thinking these brackets were ok because the forces are downward only and they felt solid in that respect. Of course the forces on them are horizontal as well! So I need to swap these with wide brackets that allow zero movement in the horizontal axis.

Slightly bent:

Really bent.

On a positive note these issues can be easily fixed. The side with the slightly bent bracket lifted up about 4 inches before I chickened out. It was an incredibly smooth motion! The other end didn't lift at all though.

I'll update with a video tomorrow night when I have new brackets installed...

lastlight · #**184** 07-17-2009, 08:04 AM

Success!

Movie 1:

http://www.fishbrains.net/images/build/lift_up.html

Movie 2:

http://www.fishbrains.net/images/build/lift_down.html

Here is a shot of the piece of aluminum i bent with great difficulty. It keeps the bracket on the actuator from spining and is also nice and rounded so it doesn't tear into my wood. There is a long piece of aluminum on top of the wooden guide base to allow even smoother sliding. I need to tweak the bends in the 'shoe' however because it's a touch too bulky and the actuator is maybe a few millimeters from fully retracting. This means the built-in limit switch currently doesn't work and the thing grinds to a halt. The limit switch on the fully extended side won't ever be used. Turns out my ceiling clearance is JUST shy of 24" so i'll have to stop the lift myself when it's high enough.

Here are the beefier mounts for the bearings. ZERO sag/bend after I drilled additional screw holes right where the bracket bends 90 degrees. Wasn't fun since all i had was a nail to pound and a standard wood drill bit lol.

I'm letting the lift hang suspended 1 inch above the 2x4s to ensure nothing sags over the next day. Will also run it plenty with the guts exposed. When I'm satisifed I'll attach the decorative bottom.

fishytime · #**185** 07-17-2009, 12:31 PM

Wow Brett, that is soooo cool....great job. So when do you start marketing your lifts? ...I could use one

Dez · #**186** 07-17-2009, 12:34 PM

Brett,

That is pretty neat. Props to you. Just wondering why it's so much louder going up, then coming down. Or is it just the placement of the video camera that makes it appear this way?

lastlight · #**187** 07-17-2009, 02:05 PM

The actuator works it's metal butt off going up. Going down you have the 60+ lbs of the light helping you out. Woke up today and it's still hanging lol.

The metal shoe was seriously my last-ditch effort. All other options somehow stuck and risked tearing my ceiling apart. This is the LAST one I'm building haha!

mseepman · #**188** 07-17-2009, 03:30 PM

Wow, this looks and works great. Your build really leaves nothing out!!

lastlight · #**189** 07-17-2009, 03:32 PM

Mark I forgot more detailed pics for you but that second last one shows how I just used a pair of brackets to pin the actuator in. Long bolts with some wooden spacers make it super tight. There is a bracket with a bolt that fits into the back of the actuator to keep it from sliding under force...

Stones · #**190** 07-17-2009, 03:54 PM

That light fixture lift you built is awesome. Sure answers the question of the third hand needed to raise or lower a fixture suspended by cables. Top shelf job as always.