Problems with Tensioning KMG Grinder

[Pittknife]

Hi Guys,

I've had my KMG for about a year now, it has a vfd is is 2hp on 220. On the flat platen when I use x weight belts I can't tension the belts as tight as I used to when I first got it. I Have to have very minimal tension for the grinder to start up or the motor and vfd stalls. I've tried moving around the motor mount to adjust tension on the drive belt and that doesn't seem to do anything. If I tighten the grinding belts down I sometimes can get it to run if I start it at almost 70% speed.

Anyone run into this issue?

 

[Josh Rider]

I haven't encountered that with mine Mike. But I'm not using the motor or vfd that Rob sells. I assume you're using the kbac vfd and leeson motor?

 

[john april]

i had that problem when my pulley belt started to get loose. but using a vfd i assume you have direct drive with no belts? i thought my motor was stalling/quitting. i put a big black dot on the motor pulley with a magic marker so i can easily tell its spinning.

 

[Pittknife]

I haven't encountered that with mine Mike. But I'm not using the motor or vfd that Rob sells. I assume you're using the kbac vfd and leeson motor?

"i had that problem when my pulley belt started to get loose. but using a vfd i assume you have direct drive with no belts? i thought my motor was stalling/quitting. i put a big black dot on the motor pulley with a magic marker so i can easily tell its spinning."

Yup I have the kbac vfd, it's very weird that this started happening just about a month ago. I checked the pulley belt and even moved the motor mount to have more tension on it, and also tried it a bit looser. My kmg is not direct drive. Thanks for responding guys

 

[Drew Riley]

How freely do your wheels turn? Are they bound up, or are the bearing going out? Could just be a little too much friction for start up. You may try replacing the bearings in your wheels and see if that helps. You should also look at your pillow block bearings. Try pumping a little grease in them, and see if there's any improvement there.

 

[logem]

How freely do your wheels turn? Are they bound up, or are the bearing going out? Could just be a little too much friction for start up. You may try replacing the bearings in your wheels and see if that helps. You should also look at your pillow block bearings. Try pumping a little grease in them, and see if there's any improvement there.

Otherwise, you may be having an issue with the drive. Perhaps one of the POTS vibrated to another position, etc? There is absolutely no way that you should be able to stall a 2 Hp motor with just belt tension, whether its the drive belt or grinding belt.

Good luck,

Mike L.

 

[12345678910]

How freely do your wheels turn? Are they bound up, or are the bearing going out? Could just be a little too much friction for start up. You may try replacing the bearings in your wheels and see if that helps. You should also look at your pillow block bearings. Try pumping a little grease in them, and see if there's any improvement there.

The bearings in a KMG are sealed and those grease zerks don't go anywhere

They come in the pillow blocks standard.
He's just too lazy to remove them

 

[Drew Riley]

The bearings in a KMG are sealed and those grease zerks don't go anywhere

They come in the pillow blocks standard.
He's just too lazy to remove them

I don't know what brand he uses, but some of them do have a couple of small holes in he periphery of the outer race. Often there will be a small groove for the grease to travel in if not exactly lined up with the zirc, as well. You have to make sure the bearings are oriented to the correct side though, and it'd probably be better to use a syringe to directly lube the hole anyway.
I've successfully greased this type in the past to get some more life, though any more I just replace them when they start dragging or making excessive noise.

 

[Frank Niro]

Is it a brush type motor VFD? If it is could be poor brush contact on the armature usually caused by brush wear. 2HP? That will mountains.
Frank

 

[Jesenius]

Hi Guys,

I've had my KMG for about a year now, it has a vfd is is 2hp on 220. On the flat platen when I use x weight belts I can't tension the belts as tight as I used to when I first got it. I Have to have very minimal tension for the grinder to start up or the motor and vfd stalls. I've tried moving around the motor mount to adjust tension on the drive belt and that doesn't seem to do anything. If I tighten the grinding belts down I sometimes can get it to run if I start it at almost 70% speed.

Anyone run into this issue?

At first check if grinder is in warranty. If it is, call to seller to solve problem.
If it is not You can identify problems this way: Start grinder and let it run for about 5 min. Stop grinder, remove grinding belt and check wheels if they generates heat. If they do, problem is in bearings. If wheels are cold start grinder (still without grinding belt) at about 60Hz, wait for motor to get nominal rpm. Take some stick from middle hard material like G10 or micarta and push to powered wheel from side. Be careful, it can harm You. If wheel can't stop or slow down too much then motor and VFD are in good condition. If it slow down easily problem is in VFD or motor. I hope it can help You.

 

[Matthew Gregory]

Hey Drew, Rob has specifically stated in the past NOT to grease them:

Here's a crazy tip.....if you don't grease them, they will run forever.

If you shoot a few squirts in the zerks...they'll run hot and cause nothing but troubles.

 

[Pittknife]

The bearings in a KMG are sealed and those grease zerks don't go anywhere

They come in the pillow blocks standard.
He's just too lazy to remove them

I'm trying to understand what you mean by "too lazy to remove them"? I've taken this whole thing apart trying to fix this, thanks for the insinuation.

EDIT
*Sorry man, thought you were talking about me... I have been working on fixing this thing for a couple weeks taking it apart and trying to get the wobble, then the tension fixed, just really frustrated. The tension is fixed but now the wobble is back to where it was on some belts..

Again sorry, I thought you were talking about me, my bad.

 

[Pittknife]

Hi All,

Thanks for the help guys, I finally figured it out yesterday based on a couple of the suggestions. I over tightened the bearings and the idler wheels where not freely spinning. I had tightened them to try and get the belt wobbling to stop.

After loosening them I could tighten the belts down like before. Again thank you so much for helping out guys, really appreciate it.

 

[Elgin]

I'm trying to understand what you mean by "too lazy to remove them"? I've taken this whole thing apart trying to fix this, thanks for the insinuation.

I believe he was referring to Rob at KMG, and not you.

I did the same thing on my grinder the other day (over tightened the idler wheels). Glad you got it figured out.

 

[Pittknife]

I believe he was referring to Rob at KMG, and not you.

I did the same thing on my grinder the other day (over tightened the idler wheels). Glad you got it figured out.

Thanks for clearing that up, I added an edit to my post with an apology.

I'm just very frustrated with not being able to fix this grinder to where it needs to be. I fix one thing and another thing gets out of whack.

 

[Drew Riley]

Hey Drew, Rob has specifically stated in the past NOT to grease them:

Normally they don't need to be greased, I agree. In my case, a believe a seal had been compromised, or the bearing had developed some kind of issue (probably from me greasing them in the first place... hahah) and I had some high speed, low viscosity grease on hand, so I cleaned them up and pumped a squirt or two, and it seemed to help until I could replace them. Like I say, anymore I just buy a new set for $15 or $20 and swap them out, and adding any grease is usually a last resort.

 

[Drew Riley]

Hi All,

Thanks for the help guys, I finally figured it out yesterday based on a couple of the suggestions. I over tightened the bearings and the idler wheels where not freely spinning. I had tightened them to try and get the belt wobbling to stop.

After loosening them I could tighten the belts down like before. Again thank you so much for helping out guys, really appreciate it.

Glad you figured out the problem, but I thought Rob's wheels had spacers to prevent over tightening? Maybe I'm remembering wrong.

For what it's worth, I just bought a set of wheels from vwjackstraw on eBay, and at first glance, they seem to be as well made as anything I've seen out there (I have Beaumont wheels on my NWGS). They for sure have a spacer, and I was able to tighten the snot out of them with not binding whatsoever. Might be an option to consider if you're unable to get the Beaumont wheels to where they need to be. The price is about half of the Beaumonts too.

 

[Pittknife]

Glad you figured out the problem, but I thought Rob's wheels had spacers to prevent over tightening? Maybe I'm remembering wrong.

For what it's worth, I just bought a set of wheels from vwjackstraw on eBay, and at first glance, they seem to be as well made as anything I've seen out there (I have Beaumont wheels on my NWGS). They for sure have a spacer, and I was able to tighten the snot out of them with not binding whatsoever. Might be an option to consider if you're unable to get the Beaumont wheels to where they need to be. The price is about half of the Beaumonts too.

They use a nut as a spacer on the spindle. When I originally tightened them they were pretty loose and you could feel the wheels move back and forth. I would up setting the nut/spacer so the wheel was free, then tightened the bolt/spindle to get them in better alignment top and bottom. I didn't think to check it again but because I was tightening the bolt down the nut/spacer tighten too. The wheels still spun but it took some force to do it.

The way I fixed it last night was to set the wheels so they were spinning freely and then tighten the nut/spacer to secure the bolt location, not the bolt itself.

 

[Drew Riley]

They use a nut as a spacer on the spindle. When I originally tightened them they were pretty loose and you could feel the wheels move back and forth. I would up setting the nut/spacer so the wheel was free, then tightened the bolt/spindle to get them in better alignment top and bottom. I didn't think to check it again but because I was tightening the bolt down the nut/spacer tighten too. The wheels still spun but it took some force to do it.

The way I fixed it last night was to set the wheels so they were spinning freely and then tighten the nut/spacer to secure the bolt location, not the bolt itself.

What I mean is inside the wheel, I think there is a spacer that bears against the inside if the inner bearing races to keep them from tightening against the inner bore of the wheel. On the outside, you may need some machine bushings so that your not tightening anything against the bearing seals and causing binding there.

 

[Matthew Gregory]

I'm just very frustrated with not being able to fix this grinder to where it needs to be. I fix one thing and another thing gets out of whack.

This statement summarizes my experiences with my KMG, as well. I've had to bust my ass to make it a real grinder. Works pretty well, now, but not without a LOT of fixing. Next machine will be a Wilmont or a Weurtz.