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.

John Doe wrote:

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.

Use the shaft full diameter and pop on a 'shaft coupler' to
compensate for misalignment.

--Winston

John Doe writes:

How would you do that?

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.

On Oct 1, 6:43 pm, Richard J Kinch wrote:
John Doe writes:
How would you do that?

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.



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

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.

How about a piece of reinforced rubber hose ...

Won't work.

See my list of the universe of flexible coupling principles:

http://groups.google.com/group/rec.c...f26dc704d6d31c

On Wed, 1 Oct 2008 17:53:59 -0700 (PDT), wrote:

On Oct 1, 6:43 pm, Richard J Kinch wrote:
John Doe writes:
How would you do that?

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.



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


Been there, done that, worked pretty well

On Oct 2, 5:18*am, Gunner wrote:
On Wed, 1 Oct 2008 17:53:59 -0700 (PDT), wrote:
On Oct 1, 6:43 pm, Richard J Kinch wrote:
John Doe writes:
How would you do that?

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.

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

Been there, done that, worked pretty well.

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.

On Oct 2, 3:42 pm, Richard J Kinch wrote:
How about a piece of reinforced rubber hose ...

Won't work.

See my list of the universe of flexible coupling principles:

http://groups.google.com/group/rec.c...msg/56f26dc704...

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.

On Oct 2, 7:13 am, wrote:
On Oct 2, 3:42 pm, Richard J Kinch wrote:

How about a piece of reinforced rubber hose ...

Won't work.

See my list of the universe of flexible coupling principles:

http://groups.google.com/group/rec.c...msg/56f26dc704...

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.


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

On Oct 2, 1:42*am, Richard J Kinch wrote:
How about a piece of reinforced rubber hose ...

Won't work.

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.

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
www.kwagmire.com/metal_proj.html


"John Doe" wrote in message
...

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.

"Wild_Bill" wrote:

Just about anything less would very likely result in a unsafe
and/or unreliable connection.

Safety might be an issue in some other application, Bill, but not in
this one.

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.

When I cut something that's spinning very fast, Bill, it usually
ends up very well rounded.

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.

Yes, Bill, depending on RPM.

You haven't described a method of constraining the tubing or shaft
extension,

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.

and the separation of spinning parts can be very dangerous for
anyone nearby.

That's not going to be a problem here, Bill.

You might be better off saving the drill motor for another
project,

Too late, Bill, I just bought another 36 V cordless drill for this
specific purpose.

and finding a more suitable motor/power source for your current
project.

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.



--
The first big front wheel rollerblades.
http://www.flickr.com/photos/27532210@N04/2565924423/