Viel Sander Pulleys - To Crown or Go Flat?

[Rick Kr]

I recently received a Viel S5 belt sander from Steve B. and through a separate order, the PSI variable speed motor.  I've run into some glitches, with the adapter plate, that I posted a question on the Viel Conversion thread.  I also asked some other questions as I'm not finding the "build" nearly as straightforward as I thought. 

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. 


I thought this strange at first, but didn't think much about it.  In fiddling with the unit and trying to sort out the motor mounting vagaries, my brain kept coming back to those parting lines and that rough surface.  Did Viel intend for the pulleys to be so rough?  Did they intend for the belts to rid over those parting lines?  I haven't taken my 1x30" apart to examine the pulleys on it, but my memory tells me they are crowned but are a smooth, uniform arc across from one side to the other.  My 4x36" woodworking sander, I know the pulleys are smooth and FLAT.  Both have obvious means of adjusting tracking.  Tracking adjustment on the Viel is not very evident, but evidently the two little funky screws on the vertical 1"x1" square tube are the tracking adjustment.  I am not impressed, but since I don't have it up and running, I cannot judge whether they are funky just in appearance. I did read a post where a guy added two more screws down lower and uses all four in concert to obtain superior tracking.  And I think he also added nuts in place of the springs so things stay put once the right tracking is found.  This makes sense to me, as it seems two screws pushing on surfaces that can spring away aren't going to be particularly effective or stable.  

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 have other questions, but let this be enough for now. 

Thanks,

Rick

[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

[Ken S]

Rick,
One of my Viel conversions uses the pulleys as is. The other conversion uses a smooth, flat drive pulley, a gift from Rupert. Both work.

Ken,
I really like the combination of the Viel with the Twice as Sharp clamp. (Mine is the ezy grip version with the standard width.) I did the set up before I realized that Viel had redesigned their scissors clamp. There may be less difference with the redesigned clamp.
I wish you well with your pulley conversion. I am puzzled. Due to its smaller diameter, the smaller pulley must sit closer to the bottom of the frame. Unless you have access to a reasonably priced fixed speed motor, you might look more closely at the PSI variable speed motor. Yes, the smaller pulley will reduce the speed by one third, however, a smaller pulley vombined with the variable dpeed motor is a dynamite combination.

Ken

[Rick Kr]

Ken(s),

Thanks.  I'll probably start by only smoothing out the parting line and giving the crowns a smooth radius.  The Viel will get used for sharpening but also woodworking and general metal working.  One use I anticipate is sanding the inside of radii of metal and wooden parts where I want that edge to be flat.  I am inclined to think a flat belt/pulley would do that better, but perhaps a slight crown would work also - even maybe better. 

I can also see trying out the 2-screw tracking adjustment to see how it works and what is really needed.  The notion of 4-screws appeals to me but I have quite a few projects waiting in the wings, so I don't need more to do. 

I do plan on putting some time and effort into a good motor mount.  I'll try a mount first that does not have any tracking adjustment, but I've been thinking of a way to make it adjustable.  Simple shims would be simplest, but what fun is that....   ?

And I'm sure you are right, I'll be using it very soon and forgetting all about any of these issues. 

Rick

[Ken S]

Rick,
When I became interested in converting my Viel (inspired by Max the Knife), I did not realize that it would be in pieces during so many modifications. I called the process "Gen I, Gen Ii, and Gen III". With all the changes, "Gen III.06, etc" might be more accurate. While I certainly understand the desire to complete the project, the simplicity of the Viel makes it easy to make later modifications if desired.

I found the fit of the modified Viel drive pulley on the PSI shaft to be more of a force fit than I wanted. With the motor mounted on the frame, I ran the motor with a file against the shaft until I liked the fit.
After I liked the fit, I pit a clamp on the shaft to prevent rotation and filed a flat for the pulley locking screw.
Adding the second pair of alignment screws is easily done. I am still considering it, but have not felt the need. I did switch to thumb aligning screws on the unit I gave to my nephew, however, I am content with the original screws on mine. If I decide to switch later, it is easily done.

I use my Viel more often for general shop projects than sharpening. It is a versatile tool.

Ken