I'm putting together my first 2x72 belt grinder build.  Using the simplistic stacked tubing design with vertical compression belt adjuster.  

I sourced a 1.75hp DC motor from a treadmill as drive power for the time being.  Can't really afford an AC motor with VFD at this moment.  The DC motor works fine and the MC35 speed controller also works great.  

My problem is that after taking the flywheel off and measuring the arbor I found it to be 17mm (.669") instead of the standard 5/8" arbor.   My intension was to purchase a machined aluminum wheel package to complete my build.  Unfortunately it seems that 90% of all the drive wheels available are for 5/8".  The other 10% is 3/4" drive.   My thought was that maybe I would luck out and find a supplier that makes 17mm drive wheels.  Or else maybe find a sleeve/shim that would allow me to use a 3/4" drive wheel on the 17mm arbor.

Any ideas?  I do not have the machining equipment to take off the required 44 thousandths to get the arbor down to 5/8".

Guess I could go the risky route and use a file to decrease the arbor down during operation.  But that's a stretch.

Any ideas?  Thanks.

Contact a local Tool and Die place and ask them what they would charge to reduce it, assuming they have such places in what ever country you are in

I used a file and sandpaper wrapped on a bar to take down a metric motor shaft under power as you indicated to imperial dimensions.  Worked for me. Go slow and check often. Keep flat.  Turned out to be easier than I thought it would be. 

Of course the real problem you have is the motor from the treadmill isn't sealed and the metal dust you create once your sander is complete will kill it eventually unless you figure a filter system to keep it safe.

I'm in US.  I have a few emails out to some suppliers in regards to 17mm drove wheels.  There are some machinists around and I'll give them a shout and see what they can do.  Otherwise I will get the file out and see what I can do.

Yes the metal dust will be a problem.  But I'll see what I can come up in terms of a filter system.  I've seen a lot of people placing magnets all over their grinder in an attempt to intercept the metal particles.  I could add those as well.

What did you end up doing? I'm having the same issue.