RD4B Joints?

What type of joints should I use for my RD4B? I have seen teams use screws and lock nuts, shafts and shaft collars, and also standoffs with Teflon washers. But I don’t know the advantages and disadvantages of the different joints and I could use some help from some more experienced people. Thank You in Advance for the help.

The best joints would have to be screws and nylocks. Advantages of using this joint would be that they have the least slop in the joints when tuned correctly. Disadvantages are that you’re gonna have to play around with the tightness of the joints for each side so they have the same amount of “tension”? (IDK what to call it)

I would avoid using shafts and collars on the joints other than the places where the gears of the 2, 4 bars meet at the mid section. Advantages of this would be that no tuning would be required for the joint, assuming that all joints are smooth and have new bearings. disadvantages would be that you joints have to be quite bulky since the shaft must be supported on each side, and it also has alot of slop.

You can also use shoulder screws from vex with a nylon washer in the middle for very compact joints and also has little slop due to the screws fitting snug inside the square holes of channels.

I hope this helped. PM me if you need more help. Ill be more than happy to help you out.

Skip to the end of the video if you just want to see the best one to use.


Not meaning to be rude, but you can get your answers much faster if you do a simple Google Search of your question. For the most part, these posts all reccomend screw joints

Well I planning to build a RD4B for our next competition but I saw this pic on google and I’m thinking how would I attach the lower bar and the top bar it. Would you just use a big screw and spacers. And would they have a better way like maybe shaft for example.

I find screws with nylocks, and a washer in between the metal works well.

@To_Bi_As That would work for low weight/movement applications but if you don’t use a bearing the screw will eat through the bar metal.

Agree with the screw joints everyone seems to be advocating. Additionally, two bearings can help with stability on important joints (mostly bottom 4 bar)

@Vyx Ya this is not my bot saw this on google images. Just wanted to know best linkage for bottom bar and I believe this bot is for Skyrise and the X drive thing was not my idea team idea to get that clear. If you want to go in detail I prefer 4 motor drive base with chains. And Thanks for people who suggested good ideas I will be trying the screw joint when our team gets new metal.

@Aponthis Yah Maybe this is enough lol all for good laughs

Screws and nylocks no questions asked