After seeing how quickly the hex-heads were getting stripped, resulting in removing collars from shafts becoming extremely difficult, I found
VEX Clamping Shaft Collar (10-Pack)
I’m trying to figure out if it’s worth switching over or not. Noting the mass of the screw and nut, they’re probably about the same weight as the typical collar, but I know nothing of their performance. Does anyone work with these? Do they hold as well as the typical collar? Are they the same thickness as the typical collar? Are they too grippy if a side touches a rail or bearing?
They can’t fit in a tight space as easily, and I’ve had trouble with the side that formed to hold the nylock nut just letting the nut spin before it gets tight enough to do its job. Because of the form, you can’t get a wrench on the nut to finish tightening. We use them to keep an axle in place, but not for continuous rotation axles.
Thanks. And that bit about the wrench and sliding really wasn’t clearly an issue from the diagram, so I hadn’t even asked. Sounds like we should stick with the standard collars. Hopefully one day soon VEX will port their VEX Pro clamping collars over to VEX EDR.
You might try periodically replacing the set screws of the metal shaft collars so they don’t strip so often. You can usually get a bag of 100 or so for a few dollars. My observation is that the black plastic clamping collars don’t hold so well but they can be acceptable for things like horizontal axles that need to resist very little side loads. I would not recommend using them on vertical shafts that need to hold any vertical force.
The L-shaped Allen wrenches can be purchased fairly inexpensively from McMaster or other places, but if you want to recycle your old ones because of their tips rounding off, you can snip off their ends with bolt cutters and then de-burr them (so long as you maintain the flat part and don’t round it off when de-burring). Just be sure you use safety glasses when you use the bolt cutters as the steel of the Allen wrenches tends to be hard and the cut portion will fly off with a lot of energy. Do not try to use tin snips to cut Allen wrenches: the steel is too hard and your attempt will either mangle the wrench or damage the tin snips.
Do you know where we could find T8 star drive set screws. Apparently the links I mentioned were motor screws, not set screws. It’s been a while since I found those links but I haven’t ordered them yet, so I got mixed up. Sorry
Place these brand new set screws in the rubbish bin
Buy new set screws
Our observation is that the set screws supplied with metal shaft collars are total crap. Even just replacing them with VEX sourced set screws is fine. I suppose it’s just a supplier quality thing but it’s always the small things which let down an otherwise good product line.
The problems you are having can also be helped by a bit of training. I encourage students to look for the flat side of the shaft before tightening and not to over-tighten. You frequently hear the screws click when too much pressure is applied. This is the screw stripping which damages both the screw and the tool. Shaft collars tend to come loose more often when the screw is not seated parallel to the shaft.
Best practice is to grind the tool tips flat to keep the shape and replace the screws when they are damaged. It helps to loosen then tighten the screw a few times to make sure it is properly seated on the shaft.
One other thing is if you have enough space you can use a standard 8-32 screw instead of the set screw. It provides a little more torque to tighten the screw and it wont break as easily.
That exact part is sold on the EDR page also, they are 100% legal. We use them for prototyping usually then change them out to normal shaft collars when building the final. If it’s not got any lateral force on the shaft, they are good as long as you inspect them between matches.
When I was running a team, we replaced the standard VEX setscrews in the lock collars with these from McMaster-Carr. They cost only $5 for 100 and they last a lot longer.
Any setscrew with a cup on the end will eventually wear out. If you are installing a previously-used lock collar, pull the setscrew and replace any in which the cup is squashed flat. The cups are necessary for the lock collar to work at its best.