How to calculate drive wheel size?
 

Pete Macke wrote:
If a shaft is turning at about 800rpm and you want to use a drive wheel to
friction spin a 12" disk at 30rpm what size should the drive wheel be?

Have you seen the carnage when such questions were asked previously? Are
you /mad/?

Ok, assuming the drive wheel was at the very perimiter of the 12" wheel,
the size would be 12*(30/800) or about 0.45", ballpark 1/2" category
unless it is rocket science, in which case I recommend other means...

PK

Sue lol.. glad someone knows how to do this.

-- Log

"Paul Kierstead" wrote in message
...
Pete Macke wrote:
If a shaft is turning at about 800rpm and you want to use a drive wheel
to
friction spin a 12" disk at 30rpm what size should the drive wheel be?

Have you seen the carnage when such questions were asked previously? Are
you /mad/?

Ok, assuming the drive wheel was at the very perimiter of the 12" wheel,
the size would be 12*(30/800) or about 0.45", ballpark 1/2" category
unless it is rocket science, in which case I recommend other means...

PK

Pete Macke wrote:
On Sat, 22 Jan 2005 15:46:44 -0500, Paul Kierstead wrote:


Pete Macke wrote:

If a shaft is turning at about 800rpm and you want to use a drive wheel to
friction spin a 12" disk at 30rpm what size should the drive wheel be?

Ok, assuming the drive wheel was at the very perimiter of the 12" wheel,
the size would be 12*(30/800) or about 0.45", ballpark 1/2" category
unless it is rocket science, in which case I recommend other means...


The problem then is finding a 'rack', maybe plastic that can be attached around
the edge of the disk.
Finding a small drive gear should be doable. I could probably fashion one out of
round bar myself.

By rack I assume you mean the toothed thingy that make up the connecting
part of a gear. If you application is not high torque, consider plain
friction drive. You can also certainly consider belt drive; often much
easier to do in a custom situation. The drive end in this case, being
only 1/2", will be troublesome; you would need to use a leather belt I
think. Perhaps a two-step process - an intermediate idler wheel such as
found on many drill presses.

PK

That's absolutely correct, which leads to the next step of deciding how to
actually accomplish this "friction spin" process, and how to start & stop
the contraption since the mass (wieght) of the 12" disk is a consideration,
as well as just what sort of load you're planning to put on this disc (since
that's going to cause slippage, etc.) A good starting place would be to put
some sort of rubber rim on your 12" disc, and just lay the shaft against it.
If this works for your application, great, but don't be surprised if it
doesn't. In all probablilty, you're probably going to have to use a v-belt
arrangement and a jackshaft (idler pulley arangement) to get the necessary
torque transmittal in conjunction with the rather substantial speed
reduction you need (dropping 800 rpm to 30 rpm).

BJT


"Paul Kierstead" wrote in message
...
Pete Macke wrote:
If a shaft is turning at about 800rpm and you want to use a drive wheel
to
friction spin a 12" disk at 30rpm what size should the drive wheel be?

Have you seen the carnage when such questions were asked previously? Are
you /mad/?

Ok, assuming the drive wheel was at the very perimiter of the 12" wheel,
the size would be 12*(30/800) or about 0.45", ballpark 1/2" category
unless it is rocket science, in which case I recommend other means...

PK