Elevator Linear slide help

Hello, once again I am building a new elevator lift. I believe I’ve got everything all up to standards to what should work. However, I’m having issues with the new linear slides. I’m not too great at explaining so here are some pictures:
(Please tell me if the link doesn’t work. This is my first time using imgur)

Ok, some info to go with it all. First, there are only two stages on the lift because i am not satisfied with what i have so far so i havent continued.

My question is how why aren’t my linear slides sliding smoothly? I have tried loosening them and repositioning them multiple times with no success. The only way i have been able to make it even slightly smooth is by leaving the plastic linear slide pieces loose (Which is not ok with me). What can i do to try to fix this? I’m not sure if even the linear slides being lubricated would make it perfect.

Please Help! Thank you!

I’m not exactly sure what you mean by it not working “smoothly” - do you mean it sticks and slips? or moves only so far and then stops? or what?

I don’t have any experience with linear lifts but I know when my kids were experimenting with a 12" section of two parallel linear slides, they ran into a problem of the linear steel pieces becoming non-parallel and therefore the moving “carriage” that traveled atop those slides jammed all the time. The non-parallel nature of the steel rails (or whatever they’re called) caused their carriage to “wedge” itself between the rails. Is that the kind of problem you’re having? Might that explain why loosening the linear slide pieces allows it to work better?

Just thinking out loud.

It’s like they’re tight and take too much force to slide them. Also, i know for sure that my rails are 100% parallel because that what i thought it might be initially too, but now they are completely lined up with the holes (no overlapping or anything between the holes of the linear slide rails and the c channel it’s attached to.)

Could it be possible there are some manufacturing tolerances causing problems despite your best efforts? One way I helped my kids deal with their “wedging” problem is I had them tighten their green sliders and their steel rails a little, then run them back and forth, allowing the green sliders and rails to self-align themselves in relation to each other. Then they tightened them a little more, and ran them back and forth again. They did this several times until the sliders and rails found their own “sweet spot” where the friction was the least.

When one set of parts (for example the steel rails) is locked down, it might be too much for the plastic sliders by themselves to accommodate any errors in being parallel, etc. By letting both sets give and take a little, perhaps it can reduce the friction.

Maybe the trunks/tracks are tilted from a top-down orientation. I’ve had c-channels that weren’t perfectly straight in that position, and having the trunks separated by screws and spacers could make it worse.

Whoa, your linear slide trucks are completely out of line! Make sure they line up with each other perfectly, and that should solve the problem almost completely.

Edit: Just to clarify, the trucks are the green plastic slider pieces.

heres a picture of my current linear slide lift before i chained it

the slides are sideways to reduce friction, this helps because there is less room for the metal slide to rotate
i also slightly loosen the metal slide slightly and keep it loose with a locknut reducing even more friction

3 of my sections fall easily under their own gravity

ok. Well yes maybe it could be from manufacturing issues that cause this issue, but i think that itrelies more on the trucks being incorrect. I’m going to spend a few minutes moving the stages to try to make the trucks realign like was mentioned. Secondly, I would rather not go to the design with the trucks on the side. I just got done with an elevator lift with that design and it didnt work like we’d like.

Try to loosen the screws, move them so they visually line up, tighten but not completely so they still have a bit of movement, test that they move through the rails really well, then tighten it all up again.

I have tried that countless times. I’m starting to think the rails might be messed up since they 're looser at the top and bottom but tighter in the middle, or vice versa.

Take one of the slide trucks out completely, so there is just one, and see if that slides. If it’s still binding, then there is an issue with alignment.

Is your lift applying force to the the trucks straight up and down, or bending/twisting them out of line? This cause them to bind as well.

We have the trucks in pairs so there is a left set of 2 and a right set of 2. If we drop a lone linear slide truck in the rails it slides out smoothly without problems. At this point we have 4/5 stages moving smoothly, but it is all a bit wobblier than I’d like due to having screws loose. We are going to continue to tinker. We are also planning to add lubricant to the linear slides this Sunday.

Does anyone know the name of the thread that stated the best lubricants to use the linear slides for? Or if you just know what kind for us to get that is legal?

Are you talking about this?
https://vexforum.com/t/lubricating-grease-for-linear-slides-motors-axles-etc/27422/1

No, it was a much older thread, but that thread answers my question too. white lithium grease non-aerosol. Thank you

Like everybody else already said, loosen up the slides and just keep sliding and tightening little by little until it works. Our team had to do that, but after about 10 minutes for all of our stages it went a lot smoother. Another suggestion would be to use shoulder screws or bearing flats to line up the slides. Our lift is built in a way so that neither option is possible for us, but it could potentially help your robot out by making the slides more aligned.

Another really important thing is lube. Our slides weren’t that great, even though they were aligned, so we sprayed on some WD-40 Lithium Grease, which made it a ton smoother. Standard WD-40 only works for a little while before the slides get sticky again, but the Lithium Grease is great! I also know of a few other lubrication tricks, so you might want to look into things like that.

Isn’t this an illegal aerosol lubricant? Or is spray on lithium grease not aerosol

An idea to try is using a bearing block to the metal and using the bearing to center the screw. it might help it might not

Oops, my bad! We actually use this lithium grease. Sorry, I’m used to saying the spray-on kind because that’s the one I use at home :stuck_out_tongue: but we use the other kind on the robot. The standard WD-40 is technically illegal, but we were desperate and only had that. After it didn’t work, we bought the new lithium grease and replaced the old WD-40.