Anyone else losing drive shafts on their NWGS?

Drew Riley

Drew Riley

Well-Known Member
:sad:
I think I'm going on about my fourth drive shaft... the first couple I thought were due to the set screws loosening up on the pillow bearings, causing the shaft to groove and start spinning out of center. This time, however, it appeared to develop some wobble and only get worse from there.

I've always been leary of the amount of overhang on the drive wheel side of the pillow blocks when building to drawing spec, so this time, I'm going to widen the pillow block bearings so that that is only an inch or so of overhang on the shaft, for both sheave side AND drive wheel side.

I know I've seen similiar mods to other makers' NWGSs, and I think they were on to something.

Stay tuned.....
 
When I first built my NWG, I had issues with bad wobble. I think most of it was in the shaft I was using (home fab'd), but I went ahead and welded a 2"x4" rect tube extension outwards to mount the second pillow block. It seemed much sturdier.

Since then, I have bought two shafts from Beaumont for replacements and have gone through a couple sets of pillow blocks. I just replaced one (shaft) a couple months ago. I started getting vibration, then it got a little worse, then the drive wheel suddenly went flying across the shop! My NWG isn't the smoothest in the world, not too bad, but maybe just constant minor vibration makes them go???
 
This is going to be my 2nd or 3rd beaumont shaft. I put a slightly heavier spring on my NWGS tracking arm then the plans call for, and kind of built everything else up accordingly, EXCEPT where the drive shaft is concerned. It can probably handle a couple thousandths or so worth of flex, but after a while, things tend to compound. Come to think of it, I've snapped a few belts recently, and gotten a piece or two wedged in between the belt and rest, and I'm sure that sudden stop/jerk puts a lot of extra force against an already over extended shaft. My plan to widen the pillow block stance should help tremendously in that regard.
 
We had one snap today. It's the first time I've seen this happen. I'll widen the pillow blocks myself on this one and keep an eye on it to know how it works.
 
Sounds like you all need to convert your grinders to direct drive and with a VFD. You will be amazed at how much smoother and quieter the grinder runs and that you have more torque. You do have to get a new motor along with the VFD but in the long run may be saving money, reduce frustration and down time as well as having a better machine with more control.

Let me know if I can help you.
 
The narrow stance was something I changed when I built my grinder. I mounted them on a 10 inch long plate to widen them out for more stability. Never had a problem with the shaft.
 
Wayne Coe said:
Sounds like you all need to convert your grinders to direct drive and with a VFD. You will be amazed at how much smoother and quieter the grinder runs and that you have more torque. You do have to get a new motor along with the VFD but in the long run may be saving money, reduce frustration and down time as well as having a better machine with more control.

Let me know if I can help you.
Click to expand...

That would be fantastic, but unfortunately that this time, very cost prohibitive. I'm thinking that widening my pillow blocks will solve the problem for the time being, and take a lot less of a dent in the pocket book.
The suggestion is appreciated though.
 
Well, I spent some some time re-vamping the drive train last night...


Untitled by AR Custom Knives (Andrew Riley), on Flickr

Untitled by AR Custom Knives (Andrew Riley), on Flickr

Untitled by AR Custom Knives (Andrew Riley), on Flickr

Untitled by AR Custom Knives (Andrew Riley), on Flickr

It's about as simple as it gets. I had about a 15" piece of 1.5"x1/8 angle, as well as a scrap cut off of 2"x1/8 angle. I gut the 1.5" angle in half, and and transferred the existing holes (per drawing specs) to each piece of angle. The inside pillow block is in the same position as before, and the holes for the outside pillow block were used as additional mounting holes for the angle. I then mounted the drive wheel side bearing to the end of the angle, and using the same holes, added a piece of angle underneath for rigidity. I did have to put a slight chamfer on bottom corners of the pillow blocks to fit the inside radius of the channel. I could have drilled the holes in the channel a little farther forward instead, but I wanted as much rigidity from the channel as possible. I felt this was the better compromise.

Now, instead of having 4" or 5" of shaft hanging past the bearing, there's only about an inch or so between the bearing and the inside of the drive wheel. This should make for a much more stable machine, and MUCH longer drive shaft life.
 
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