Shape an electric motor shaft/gear to drive a 5/16" rod?


After removing an electric motor from a cordless drill, I'm left
with a shaft/gear sticking out no more than 1/2" from the motor.
With that, I need to turn a 5/16" rod. I can buy tools, but
currently I don't have any high function metalworking tools. The
best metalworking I do is turning a rod with a cordless drill and
working that with another tool (like a rotary tool).
I need to turn that gear into something that will turn a 5/16" rod.
How would you do that? How would you do that if you didn't have some
really great tools?
My last method was to shave that gear and the rod underneath of it
all the way down into a small diameter rod, then cut a hole through
the center of the 5/16" rod, and then push the 5/16" rod onto the
now thin motor shaft. That took a lot of work to get the motor shaft
and the 5/16" rod to mate snugly.
Thanks.
Reply to
John Doe
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Use the shaft full diameter and pop on a 'shaft coupler' to compensate for misalignment.
--Winston
Reply to
Winston
Merely fastening them together is not enough. You need a more complex mechanism that transmits torque in the presence of imperfect alignment in multiple degrees of freedom.
Reply to
Richard J Kinch
How about a piece of reinforced rubber hose, such as hydraulic hose, as a compliant coupling. Use two hydraulic hose clamps to attach to pinion and shaft.
Wolfgang
Reply to
wfhabicher
I'll probably change my plans and use a 5/16" OD steel tube instead of a rod, then grind the motor shaft gear down to the inner diameter of the steel tube, and then roughen both surfaces and glue them together. At least that should work better than the last way I tried doing it.
Thanks to the replies.
Reply to
John Doe
Won't work.
See my list of the universe of flexible coupling principles:
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Reply to
Richard J Kinch
Been there, done that, worked pretty well
Reply to
Gunner
Try it, see what happens. Two hose clamps per side will help balance the shaft if it vibrates.
I think a lot of us with 'high function metalworking tools' started with hand tools and worked up slowly as our needs outgrew our capabilities. A drill press and a bench grinder will take you a long ways. You could make an aluminum shaft coupler with a hole for the shaft and a larger one that presses onto the gear with one. I try not to do something I can't undo, such as grinding the teeth off the gear.
Reply to
Jim Wilkins
Gosh, you must be good Richard - you managed to deduce WHAT the application was, sight unseen, and then suggest a remedy!
I am in awe of engineers, they have powers denied the rest of us.....
Andrew VK3BFA.
Reply to
vk3bfa
A Dremel tool uses a plastic sleeve to couple the motor shaft to the work spindle, albeit with internal splines on the sleeve.
i have used automotive heater hose as compliant couplings in my very early experimenters days without lathe.
Wolfgang
Reply to
wfhabicher
A piece of hose works pretty well as a flexible coupler in the chute rotating shaft on my snowblower, Not much speed but substantial torque, especially when it ices up.
Reply to
Jim Wilkins
I would be inclined to find or make a secure coupler/adapter that would fit both parts without reducing the geared motor shaft to a smaller round shaft. But then, I don't see what the gear looks like.
A coupler that fits the O.D. of a gear with a friction fit (and perhaps filled with epoxy during assembly), which also has a setscrew, might be adequate for some applications where the extension supports are stabilized/secured to the motor housing. Just about anything less would very likely result in a unsafe and/or unreliable connection.
The only coupler that I've encountered that was manufactured to adapt a geared shaft was inside the housing of an Oriental Motor gearhead motor housing. The OM application was for a geared motor shaft with an operating speed of about 1750 RPM, and the other parts were positioned in nearly perfect alignment, and had fully supported mounting/bearing supports within the case.
In your proposed modification, the gear on the end of the motor shaft is very likely to be round, and concentric to the shaft's centerline/axis. Grinding away the hardened gear teeth will likely result in a weak, out-of-round, eccentric stub that may be brittle from the hardening process.
Making a rigid connection of any part to a shaft that's not concentric to the shaft centerline will very likely break or shake loose in a short time.
You haven't described a method of constraining the tubing or shaft extension, and the separation of spinning parts can be very dangerous for anyone nearby.
You might be better off saving the drill motor for another project, and finding a more suitable motor/power source for your current project.
WB ......... metalworking projects
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Reply to
Wild_Bill
Safety might be an issue in some other application, Bill, but not in this one.
When I cut something that's spinning very fast, Bill, it usually ends up very well rounded.
Yes, Bill, depending on RPM.
I have already done that in a later post long before your replied here, Bill. I suspect you've noticed by now and are working on another troll.
That's not going to be a problem here, Bill.
Too late, Bill, I just bought another 36 V cordless drill for this specific purpose.
Much easier said than done, Bill. The methods I've employed have done reasonably well so far, and the current plan for attaching the motor shaft to the rod looks better than before.
Time will tell, Bill.
Reply to
John Doe

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