Viel Sander Pulleys - To Crown or Go Flat?

[Ken C]

In general, I found the sander to be fairly nicely built and finished.  There is something that I am wondering about, however.  The ODs of the pulleys.  They show the rough finish of the sand casting mold they were poured into, including the parting lines. 

So, here are my questions. 
1) Should the parting lines be smoothed out and blended with what appear to be the straight inclined surfaces on either side of center?
2) Should the pulley crown be "crowned"?  Or should the surface on which the belts ride be smooth and flat, like my woodworking sander? 

I've owned/used a Viel S-5 now for just over five years.  Initially, I wasn't that impressed with the design and construction but as the years passed and as my experience increased I marvel at the simple engineered design and performance.  I too was concerned about the pulley finish--especially the sand cast parting line.  So, I carefully, while it was running, filed it smooth finishing with 120 grit paper.  End of concern.  I occasionally have a belt tracking situation (with certain belts) that gives me grief and in my mind I'm going to add the two additional adjust screws.  Then I change belts and problem goes away.  So, I haven't done that modification as yet.

Now, your question about pulley crown:  The purpose of a crowned pulley (or tapered pulley) is to assist with belt tracking.  In most operating conditions, a belt will follow the path of highest tension.  So, it makes sense to have the diameter of the pulley larger in the center than at the edges.

I use my Viel almost exclusively as a scissor sharpener using the Wolf scissor clamp (pictures and description elsewhere on this forum).  So far I have not decided to incorporate the variable speed motor conversion since I'm going to replace the drive pulley with the smaller diameter one available from Steve B.  That'll slow down belt speed enough for me.

Good luck with your Viel--I'm thinking you'll soon really enjoy it's performance.

Ken C