We have typically used the vex pro collar clamps, but they tend to have a habit of coming lose and letting the part wander. What should we be using, particularly for parts like drive wheels which have a lateral load on them at times? Retaining ring / e ring style? Would we have to cut a groove in the axle for that?
My favorite way for retaining something like a drive shaft is to just tap the ends for a 1/4-20 bolt, and then pop a 1/4-20 and washer onto the end of either side of the shaft. Add some loctite for added durability and it works great.
Use a quality shaft collar and it will be fine. The Rudland ones available from AndyMark are quality units designed and manufactured by a company that specializes in shaft collars and they work exactly as intended when properly tightened. The Vex collars are good spacers however.
We ran into many of the same issues with the clamp style collars. grooving the shaft and popping an e clip in there proved to hold all season without any replacements. definitely recommend this instead of the shaft collars.
That’s really good to know. Do you use the ones with the two screws (on on each side)? They look more expensive but yeah, probably better quality.
Thanks for the recommendation.
Do you have any recommendations on what clips you use? Thanks!
do you need a lathe to groove the shaft for an e-clip?
For a half inch hex shaft, we typically use the 1/2” clips from harbor freight. they have a nice assorted set if you’re not sure about sizing.
It really helps. I have had some success carefully making a groove with a hacksaw before we got our lathe.
We use the single bolt versions that have been available in through FIRST Choice in recent years, which have been available in different colors. AndyMark keeps the clear anodized units in stock though. http://www.andymark.com/product-p/am-1238.htm
That’s typically how we do it, yes.
I’ve done a few techniques:
Bolt and washer on a Churro shaft in low-load applications.
The AndyMark collar clamps are nice, too. The am-1238 linked above is totally fine, though I like how the am-2871 lets you add and remove it in the middle of the shaft without disassembly.
I’ve also used E-clips from McMaster when lathe access was easy. They worked fine, and in 2016 I recall we used them on drive.
We use Thunderhex almost exclusively now. We use our low-quality 7x10 lathe to just tap the ends to 1/4"-20, and stick a nylon-path-locking buttonhead 1/4"-20 on the end with a washer. Very easy, very quick, and effective. You can also tap by hand or with a power drill as long as you torque-limit and are very careful.
They can come loose, but it’s rare. Next year we’ll have a better lathe to make grooves for circlips with, and may use both methods at once on shaft ends for added security.
We did have to use a couple shaft collars on the robot, but we buy only the 2-piece “heavy duty” shaft collars from Vex when we need to. They don’t suffer from slippage nearly as much as the thin single-screw types.
Loctite the screws and put a little retaining compound between the face of the shaft collar and the hex shaft. Help them take lateral loads.
+1 for this method over collar clamps when possible
We had 1/4-20 bolts and washers on the lower shafts for our elevator/climber last year and they worked flawlessly, but the collar clamps on our upper shaft failed a few times.
We pretty much exclusively use grooves cut into the shaft and snap rings. It has yet to fail us in any way. We do however use shaft collars on something that we want to be adjusted a lot. In that case we try to use 2-piece shaft collars as they don’t require removal of the shaft to get it off.
Are e-clips and snap rings different in any way?
E-clips are nice. Easy to install, and very secure. But they do require a little more clearance, compared with c-clips or plier-type snap rings. See linked examples. Note that each of the three examples linked requires a different groove depth.
Starting in 2017, we have pretty much exclusively been using snap rings for the ends of shafts. We did learn when using with hex shaft that it’s not as simple as just making a groove so far in, it makes things a lot easier turning the section down between the groove and the end to .5" or else you stretch the snap rings too far. We have used e-clips before but primarily in locations where it’s impossible to get a snap ring without destroying it, e.g. the center of a hex shaft to locate a sprocket.
EDIT: I can not remember but I almost want to say we went up a size of e-clip for the inside of the shafts to give us a larger diameter groove.
Since I’m seeing a lot of people recommend snap rings and E-clips and no one else has mentioned it, I guess I will. Cutting a groove in a shaft creates a stress riser, which significantly reduces that amount of torque the shaft can transfer at that point. You shouldn’t use snap rings or E-clips between loads on any shaft carrying a decent amount of torque, only at the ends of shafts for retention.
Good to know. Are shaft collars or PVC spacers still the best for retaining in the middle of the axle?