The Best Way To Attach

What is the strongest way to attach an intake tray to the end of a 4-Bar or 6-Bar? Are there any parts that we can use to make it really strong? If we hang this year, having a flimsy connection will not work. It needs to be solid.


Gorilla Glue.

Arctic Silver 7

Arc weld it.

Explosion welding.

Align the quantum spin of all the photons and electrons of the two parts such that they are all entangled. While they would not be “attached” as we know it, science can in fact prove that they are (somehow) attached at the most basic level.

Duct-tape a piece of toast with one buttered side facing up to a cat and throw it out the window. It probably has a chance of attaching the two pieces, among it’s other equally-unlikely possibilities.

Or you could try, oh… bar locks on a shaft, the vex hinge, a shoulder bolt … … … sigh … the turn table, a gear that acts a lot like a turn table, lexan with holes where you need them. Andrew could probably add to this list, he always finds a way to bend / break the conventional ways of doing things.

It’s a round peg in a hole, it’s really not that hard.

If you want a serious answer, go with a beam that connects the two ends of the four-bar (the top and bottom on both sides) and bridge it with either shafting and bearings, or shoudler bolts.

I’m just already sick of these “please design my robot for me posts.” We talked about this before, design is a process. Go experiment, make a few drawings, CAD it up and then go build it. Then if you want, go iterate on it and make it better over and over again until it’s all pretty and stuff.


We have tested multiple configurations, but wanted the community’s opinion on the strongest way to attach the intake tray to a 6-Bar/4-Bar. I was in no way asking for someone to design a robot for us. I was merely asking for opinions.

I understand whole heartily that robot design is a process. That is what we do. Ideas > Drawings > CAD > Ask opinions on CAD/drawings > Prototype > Build > Test > Iterate > Don’t stop iterating >Your robot will never be 100% complete. That is what we do.

I’m sorry if my first post had a slight sign of “please design my robot for me”. That would take all the fun out of robotics.

Nylocks, rubber bands, tied rope and as many points of attachment as possible.

Combining every option would logically be the strongest way to attach something.

Then you gotta tell us. Post results, add to the conversation in a meaningful way. Post some pictures, explain your thought process, tell a story.

To be honest I’ve been watching this forum for way too long. It needs an overhaul, if I was tasked with recreating the community experience (IFI take note here) I would divide the community into a StackExchange for questions regarding VEX (including the Q&A), I would extend RobotEvents into a more team social experience and I would kill the forum in favor of a more Reddit-like upvote-based community, but that’s another story.

Anyway, do better at communicating your progress when asking general questions like this. Really narrow specific questions are fine, there’s an (singular) answer out there and you just need it, everyone understands that - but when it comes to designing a lift, or even attaching something - there is no “best” way. There are many options all with design trade-offs and the story about how and why you chose method X would/will be neat to hear.


There are few that have added more to the conversation over the past year than Jesse. An Inspire Award does not go to a wallflower. And Jesse my thought on a hanger is a custom cut polycarbonate piece–no need to count Sq inches this year and nylocked flush to fourbar it should be indestructible.

It’s fine, and for what it’s worth I like Jesse. This forum is a bi-directional place, things should generally be a give and take and this format of “Best way to do X” is all take. I’m mostly guffing at the format, not the OP.

Good luck with the lift :slight_smile:

What is wrong with the design shown in your CAD pictures?
Maybe you could attach the hanging hook to a more secure part of the robot?

We have that currently, but (as Cody suggested) I will mess around with making it stronger. Do you have any tips for connecting an intake ramp to a lift?

Sometimes, the c-channel is facing out when you want it facing in. One way to get by that is to attach two c-channels together facing apart from each other. (Picture attached; feel free to duplicate it. :p)

This allows the lift connection point to be closer to the manipulator/basket connection point, giving a more secure connection. If there are bearing blocks on the insides of the c-channels then a screw can be put through.

Attach another bar at a 90 degree angle to the bar at the end of the lift?
Look up vex videos on YouTube for inspiration?
double c-channel.jpg

Um, you take a screw and use a locking nut? Is there something wrong with that? Use the white nylon between the two parts for spacing?

As cody was saying, try to be more specific about what you’ve tried and what the problem is. We can’t really help otherwise.

Not sure if you’re still thinking, but I found it. We have what I think may be the best way to mount a table for hanging. We hoisted our robot up by the table earlier today without a problem.

A few years ago, there was a part available that is since discontinued. It’s a piece of metal called a “Square Shaft Bar Lock.” I think the reason they were discontinued is that the holes you’re meant to put axles through are SLIGHTLY too small. You have to beat them in with a hammer, and it took me 40 minutes to pull ONE off today after I found out we made a mistake.

But that’s ideal for what you’re talking about. Put the table on using these, attach it to your n-bar arm, and that thing is never going to twist, turn, or pull apart. Literally, it can’t move. We put four on, one on each side of the arm, and two on the C-Channel, or whatever you’re using in the middle for your basket. Beat the axle all the way through, and you’ve got essentially a solid piece.

If the image tag works, it’s the item on the right side of the middle row here.

Either way, even though VEX is no longer selling them (at least as far as I could find), you can buy them at either of these.

I didn’t know those were discontinued. We use those all of the time and find them very useful. I guess when we need more we will have to buy them from a third party.

I found them today, just sitting in a box. I was looking for something to mount my table with after two days of aimless tweaking, found those, and just went “Oh. Yeah. That would work.”

I thought I would try my idea out before I said anything, and other than being a royal pain to put on and take off, they’re great. Seriously, to anyone looking for a way to mount anything, at any angle, these are the answer.