Oh man, this makes me wish I had photos from the electric skateboard I made when I was probably ~13 years old. It didn't use a drill but a motor I harvested from an actual electric scooter. (that scooter's charging circuit was defective and nearly burned down our house) All I did was mount it to an existing skateboard as a friction drive on one of the rear wheels, with a primitive switch on a wire as the control. It was not really practical, but I was kind of surprised just how well it worked for what it was. If I remember correctly, I had to adjust my center of gravity to keep it straight, but not by as much as one might expect. I later reused that motor to build a pretty badass Van Der Graaf generator.
I really admire the wiring job on this scooter! Goes way beyond what I did for the skateboard. And I imagine the scooter would have to navigate via only left turns. :D That is unless maybe a small third wheel were added to the end of it?
My first thought after reading this title: Oh cool, they've taken part in a drill and used the motor. I don't really know what that looks like inside a power drill. This will be an interesting post.
Immediately opened it and laughed out loud. Perfect execution, no notes.
You’d love how I’m starting my generator. Same drill. Hodgepodge of springs and string to manage the choke. ESP32 committing obscenities in the middle of all of it.
TFA has a link to the amazon page for the bearing used. It's a bearing plus freewheel clutch. Most commonly (and in this specific case) it means sprag clutch[1], but it may be e.g. a ratchet/pawl[2] (like most bikes have) or a roller freewheel[3].
Yup, I also have a sprag between the drill and the nut in the centre of the starter.
Honestly the hard bit was rigging something up to hold the drill in place - in the end, went with carpentry. Automating the choke just uses a strong spring, a Lego motor from the 90s, and, uh, Lego. And string. Latches with a solenoid when fully closed, and when coil power goes it releases it.
Like I said, obscenities, but it saves me a walk, in the rain, and allows me to keep the power on when I’m not here for months in winter and the sun is insufficient.
The first month was spent laughing at whatever had broken now, but it’s been two years now, and the only snag I had this year was that the string broke.
If I understand the question correctly then you're asking about a sprag clutch.
When used in-line on a shaft like this, a sprag clutch permits torque to be transmitted out of the drill motor but not into the drill motor.
Any operation as a support bearing for the spinny-bits is kind of a secondary function at very best (and may be ill-advised; a sprag clutch assembly may be shaped kind of like a roller bearing assembly, but that doesn't mean that it will live long in that kind of role). :)
That's a very good question. If I were a mechanical engineer then maybe I'd be able to provide a very good answer, but I'm not. So the best I can do is spitball:
I'd like to think that the sprag clutch would be happiest if it didn't see significant deviation or loading in any dimension other than axial rotation, which suggests that at least one bearing on each side is good. Maybe even two. The constraint needs to be sufficient.
But I also understand that shafts can be overconstrained, and that this can cause non-obvious problems because shafts are seldom ever perfectly straight or perfectly aligned, and the support structure for the shaft is seldom perfectly rigid.
Empirically, this is how we wind up with things like slip yokes, flex discs, and also U joints on the drive shaft for a front-engined RWD car -- even when the differential is bolted in place to subframe members. Those are all things that seek to soften constraint of the shaft. (Some of that stuff tends to remain necessary even on front-engine Corvettes, where the transmission and the differential are also connected with an ideally-rigid torque tube that surrounds the rotating drive shaft.)
It's also how people in the Cartesian 3D printing hackspace often find a reduction in print quality when they see the Z axis lead screws flop around a bit on travel and then endeavor to "fix" that by adding more support bearings, replace flexible motor couplings with rigid, and otherwise stiffen up the spinny-bits.
The combination of the imperfect leadscrews becoming overconstrained imparts stronger forces on the gantry in the X and Y axes than the previous state (doing ~nothing at all) did.
If they can get past the "WTF! More rigid parts must be better!" stage, take these extra parts out, and learn to embrace the slop, then print quality tends to go get better again. The Z screws go back to (mostly!) being just Z screws again instead of also being unintended movers-and-shakers for X and Y.
It's a really interesting topic, but it is also one that I've never taken the time to get my head all the way around so I can't explain it simply. Hopefully I've given you enough words and ideas to let you conduct some useful homework.
Years ago, some guy was selling a kit for some imported mini bikes that used a cordless drill and a right angle gearbox. Something about not being able to sell the gas engines that came with them, or something:
Hey all, author here. I had no idea this hit hackernews until my website traffic spiked. Happy to answer any questions. The scooter is still holding strong.
Does the scooter try to stop abruptly when you completely stop the throttle? Most drills today have this behavior, that I don't know the terminology for, where they eliminate their inertia immediately upon the trigger no longer being depressed.
Wonder how this would work with an impact? Also, since it already uses one-way bearings, could another drill/impact be fitted to the other side so that there are two “gears” available?
Not very well. It will work as long as the power demand is below the point it starts hitting, and then just stall with the tires absorbing all the impact hits once it reaches that point.
I do wonder how long the electronics, motor and little (plastic) gears in the drill would last with this. Especially since I'd suspect that it's designed for intermittent use, where it has time to cool down between each screw / hole drilling that you'd do normally. If you drive 2 miles in one go, that'll be a lot of heat that doesn't have time go anywhere.
Somehow I'd suspect that it won't last all that long...
I suspect there's very little power needed once you're up to speed and cruising, but constant stop-and-go and long uphill runs will certainly cause it to overheat.
It's brushless so brush wear isn't a problem, but these motors are air-cooled and will actually be cooler at high speed, low-demand. Lugging it up a hill would be a worst case.
Yes, but you could have made it out of PETG just the same. I have some PETG parts here that we have tried to break but couldn't, that stuff is ridiculously strong for its weight if you use the right infill and you take the layer direction into account when designing the part.
Missed the opportunity to add vacuums and blowers and go upside down plus lateral and rotational movement, with fancy dark themed site and buzz words all over :)
I really admire the wiring job on this scooter! Goes way beyond what I did for the skateboard. And I imagine the scooter would have to navigate via only left turns. :D That is unless maybe a small third wheel were added to the end of it?
Immediately opened it and laughed out loud. Perfect execution, no notes.
The contrast between the 3D scanning and bolting a power drill to the side was fun.
1: https://en.wikipedia.org/wiki/Sprag_clutch
2: https://en.wikipedia.org/wiki/Ratchet_(device)
3: Couldn't find a wikipedia page for this, so https://www.youtube.com/watch?v=AU4OguQmyMM
Honestly the hard bit was rigging something up to hold the drill in place - in the end, went with carpentry. Automating the choke just uses a strong spring, a Lego motor from the 90s, and, uh, Lego. And string. Latches with a solenoid when fully closed, and when coil power goes it releases it.
Like I said, obscenities, but it saves me a walk, in the rain, and allows me to keep the power on when I’m not here for months in winter and the sun is insufficient.
The first month was spent laughing at whatever had broken now, but it’s been two years now, and the only snag I had this year was that the string broke.
Engineered for… at least one 9 of reliability.
When used in-line on a shaft like this, a sprag clutch permits torque to be transmitted out of the drill motor but not into the drill motor.
Any operation as a support bearing for the spinny-bits is kind of a secondary function at very best (and may be ill-advised; a sprag clutch assembly may be shaped kind of like a roller bearing assembly, but that doesn't mean that it will live long in that kind of role). :)
Would it need a standard bearing on only one side of the sprag clutch, or should I double them up on both sides?
I'd like to think that the sprag clutch would be happiest if it didn't see significant deviation or loading in any dimension other than axial rotation, which suggests that at least one bearing on each side is good. Maybe even two. The constraint needs to be sufficient.
But I also understand that shafts can be overconstrained, and that this can cause non-obvious problems because shafts are seldom ever perfectly straight or perfectly aligned, and the support structure for the shaft is seldom perfectly rigid.
Empirically, this is how we wind up with things like slip yokes, flex discs, and also U joints on the drive shaft for a front-engined RWD car -- even when the differential is bolted in place to subframe members. Those are all things that seek to soften constraint of the shaft. (Some of that stuff tends to remain necessary even on front-engine Corvettes, where the transmission and the differential are also connected with an ideally-rigid torque tube that surrounds the rotating drive shaft.)
It's also how people in the Cartesian 3D printing hackspace often find a reduction in print quality when they see the Z axis lead screws flop around a bit on travel and then endeavor to "fix" that by adding more support bearings, replace flexible motor couplings with rigid, and otherwise stiffen up the spinny-bits.
The combination of the imperfect leadscrews becoming overconstrained imparts stronger forces on the gantry in the X and Y axes than the previous state (doing ~nothing at all) did.
If they can get past the "WTF! More rigid parts must be better!" stage, take these extra parts out, and learn to embrace the slop, then print quality tends to go get better again. The Z screws go back to (mostly!) being just Z screws again instead of also being unintended movers-and-shakers for X and Y.
It's a really interesting topic, but it is also one that I've never taken the time to get my head all the way around so I can't explain it simply. Hopefully I've given you enough words and ideas to let you conduct some useful homework.
https://www.youtube.com/watch?v=rBmnQN78aZU
https://www.youtube.com/watch?v=y8abvlYHK3Q
That one used a cable to pull on the drill's original trigger, so no rewiring needed.
https://www.youtube.com/watch?v=sv8Q4bDl6lo
Not very well. It will work as long as the power demand is below the point it starts hitting, and then just stall with the tires absorbing all the impact hits once it reaches that point.
The real deal would be putting another drill on the back wheel, so that you have All-Wheel-Drive!
Somehow I'd suspect that it won't last all that long...
It's brushless so brush wear isn't a problem, but these motors are air-cooled and will actually be cooler at high speed, low-demand. Lugging it up a hill would be a worst case.
But when the wipers in my car are set to intermittent, they are off most of time and ocassionally off.
(I wish there were a pattern to any of it, since it's often very difficult to fix things that are usually working fine.)
https://www.youtube.com/@RedGreenTV
https://en.wikipedia.org/wiki/Acrylonitrile_styrene_acrylate
Watch out for the gear change, may end up in hammer action.
He would see him leaning over and pulling the trigger get an electric assist on the uphill section of the commute.
it would have made more sense to just mount the motor and the planetary, but I think the planetary is important here.
I'm not sure where you are if you're seeing politicians turning left though.