Pardon the stupid question in advance. Almost-lone (and non-engineering) mentor trying to help kids figure stuff out, here…
We have some Vex versaplanetary gearboxes attached to a couple of bag motors to drive two mechanisms. They have 1/2" hex shaft outputs, and we wanted to connect them to a longer shaft that stretches across the body of the robot.
However, hex shaft couplers are totally out of stock at Vex (as is everything else). Is there some other way to connect the shafts, or someplace else to order a shaft coupler?
That’s exactly what we’re doing, now (plus a layer of duct tape), and we’re afraid it won’t hold, but maybe it will. How much of a load could it take? This is for a pivot arm that doesn’t have too much of a load on it.
Thanks for your kind offer! I recall that we have a couple of the AndyMark hubs that Chris Fultz suggests, so I will have someone check that first thing tomorrow. If we don’t have anything that works, you’ll be hearing from me.
I appreciate all the feedback. I was just thinking that we were probably missing something obvious.
As part of our climber mechanism, we just cut the adapter off of a 1/2" hex deep wall socket. It seems to work fine. I’m sure you could find one at any hardware or automotive store.
Other option is to use the 1/2 round output on the Versaplanatary, turn~ half an inch of the Hex shaft to .500 round on a lathe, and use standard and common round coupler.
If you or someone you know has access to a 1/2" hex broach, you could make your own out of a piece of 3/4 or 1" aluminum bar and a couple of setscrews. You could also make one without the hex by drilling and boring (for concentricity) a piece of 3/4 bar. Setscrews could lock it in place and transfer torque.
Last year my team extended the versaplanetary output shafts by threading another piece of thunderhex shaft onto the end and using a hex collar over the seam to keep it all together. Worked great and held up the whole season on both sides of our elevator.
How big was this hex collar? If it is the size I’m thinking of (the ones from Vex), I am very surprised that worked. I definitely don’t think it would last this season with robot-on-robot defense and banging over defenses. I suppose if you had a longer shaft collar it might work, but at a certain point you blur the line between collar and coupler.
