VEX EDR Hardware Questions

Topic: VEX EDR Hardware Questions

Dear All,

I am a newbie on this forum so please excuse any harmless misunderstandings. I hope I have posted this on the right channel. I have 8 questions, please try and answer as many as you can.

  1. Is this an axle, motor coupler post, shaft coupler, or what. Are they all the different names for the same thing?

  2. Are these both spacers, what is the difference between these two in FUNCTION? (other than physical size)

  3. What are the different functions of these two screws? Is the right one a button head and the left a lock on screw (that why it got that patch)?

  4. Is this a Clutch? Does it function similarly to a motor coupler as it is always displayed with motor coupler posts (or axles)? If not, what is it’s function then?

  5. Are these two wheels both Traction wheels? Is the one on the right a High traction wheel and on the left is just a traction wheel?

  6. So both show these motor coupler posts… The right one shows a motor coupler and the posts and the left one is a clutch and motor coupler posts, are they the same things with the same functions just different versions?

  7. I only have one motor coupler that came with my kit but I got three motors, I definitely need more than one?!? Also the motor coupler post only goes halfway through this motor coupler is that supposed to happen?

  8. Do you suggest any good VEX EDR Guides? I need beginner and intermediate material as not only am I learning, but I will be creating my own VEX EDR Course at my School and my own VEX EDR Robotics Club. Any guides, learning material, tips please feel free to tell me; I really need them!

  1. Yes, same stuff. It’s so short, though, that you can only use it in limited ways, as opposed to longer shafts which have room to lock them down.

  2. The function is their different size. It makes spacing things out easier to have different sizes. I would note that if you want narrower spacing you could use washers.

  3. I can’t see clearly, so I’m not sure if the black one is the same size or is larger.

  4. Yes, those are clutches. It gives way when there is too much torque so as to avoid damaging the motor/servo. However, they’re not needed for the newer motors, though they still ship with servos. Also, you can rip them apart to get a hold of springs that are legal for competition.

  5. Yes, they’re both traction, and there are even larger traction wheels. The main difference is radius/diameter/circumference, which makes a speed/torque difference. I haven’t tested the coefficients of static friction to be sure how relatively grippy either one is aside from knowing they have different tread patterns.

  6. No, they’re not the same things. The clutch will give way if there is too much torque. The coupler on the right won’t give way at all until you’re at the point of stripping it.

  7. No, you don’t really need any of these, but they can be handy. Yes, they’re only supposed to go halfway through. You slide the ends of two different shafts into it, and now the shafts are connected as one longer shaft.

  8. The VEX site has a lot of instructional material. I think a wiki of some sort is being created by members of this forum. I’m in the middle of creating and posting about 60 videos split between VEX IQ and VEX EDR, though neither set uses RobotC for coding. I’ll post something here when I’ve got them going.

  1. That is used for the shaft coupler, which is used to make replacing motors easy. You can use it as an axle, but it won’t really be as useful as longer ones.

  2. Yep, those are spacers. They differ from the white nylon ones because the nylon ones have their sizes in increments of .125”, while the black ones only come in 4.6 mm and 8 mm. They both serve the same purpose.

  3. The black screw has 8-32 threading, so it is used with the Keps nuts or the Nylocks to connect metal together. The gold one has 6-32 threading, and is used to screw the motor onto the metal. The thread locker is just to keep the screw in the motor.

  4. Yes, that is a clutch. It can be used as a motor coupler, which makes replacing the 393 motors easy. The main function of the clutch is to help the motor under high stress. If you install a motor with a clutch and put it under high amounts of stretch, you will hear the clutch making popping sounds, which helps the motor.

  5. Both of the wheels have traction, but VEX sells Traction Wheels, and the smaller wheel in the picture is one of them. VEX Traction wheels also come in different sizes. The bigger wheel is a standard 4” VEX wheel, but it has decent traction.

  6. The ones on the right are normal motor couplers, and the ones on the left are clutches. (See #4)

  7. Motor couplers usually come with the motors, so I’m not sure where the other 2 went. You can still use a motor properly without a coupler, though. It will just be harder to replace if you ever need to. The small shaft is supposed to only go halfway. You are supposed to put a normal size shaft (2”, 3”, etc) on the other end that actually outputs the turning of the motor.

  8. is a good place to start. There are also explanations of VEX parts on the bottom of the product pages for most of them.

Careful. There are also black 6-32’s. Not sure if they still ship or if the ones I got are left over from before, but I’ve got some. That’s why I said I couldn’t see the picture clearly enough. I’m pretty sure you two are right, but with them photographed at different orientations I’m really not positive.

So far I think that @callen @The Pioneers and @Coffee have answered questions 1-7 to their full extent.

  1. Here are some fun and useful threads that are on the forum.

If you ever want to look up previous threads on the forum or have a specific question, use google and not the forum’s search feature. Many people along with myself have found that using a search engine yields better results.

Good Luck and keep us on the forum updated with your progress! :slight_smile:

@The Pioneers you said in #1: “which is used to make replacing motors easy”… what do you mean by that, why would I need to replace the motor, does it damage it?

@callen For #2: How could such thin washers be of any use? And plastic vs metal ones, what makes a plastic one better in some situations than a metal one?

It just makes it easier to replace it if the motor needs to be replaced, like if it gets burnt out or is really old or something. It doesn’t damage the motor. You use it with a shaft coupler.

@The Pioneers Does a shorter length of the motor coupler post make it easier to replace? Or is that a motor coupler + motor coupler post is good for quick removal?

As a rule, I would never use motor couplers or clutches or anything, those were for back when there were motors with weak internal gears that needed those to protect them from harm. So don’t worry about those.

@Mark185A So I just stick a shaft in it? I have the VEX Classroom kit… do those corresponding motors have strong internal gears? I am making a robotics club in my school, should everyone follow this piece of advice or is it like a 50/50 chance it’ll break?

The new internal gears with the 393 motors are plenty strong. They might break after lots of use in high torque applications, but putting the shaft directly in the motor is fine.

@Bryan R How do I know if I have the new 393 motor (or is that the only one out that there called that)

All of the motors that come with the clawbot kits are 393 motors. There are two other types, called 269s and servos, but both are noticeably smaller. It should say on the top or side of the motor casing.

There is only one type of motor coupler, but it isn’t really required. The motors that come with the classroomklit should be 393s.