Flat platen problem.

Tod Lowe

Tod Lowe

Well-Known Member
I just finished my flat platen for my nwg. I thought I worked all the bugs out but when I lean into it the belt takes off to the side.
I can put light pressure on it without any problems. Is this normal?

The only thing I can think is wrong is possibly the platen is not square to the belt..?? The tracking seems to be ok.

Any ideas?
 
Thanks for the replies guys.
Tension is one of the 1st things I checked since I had some problems with it when I first started hollow grinding with the grinder.Amazing what not enough tension can cause.

I will check again to be sure though .
 
i found that if you realy keep those belts tight they run real straight. unless you had a bad belt like i did.
 
tension is a good place to start. But if that does not help one other problem depending on your grinder, i have not seen the nwg yet, is also your drive or guide wheel. It should have a slight crown to it 1-2 deg. this will really help your tracking. I had bought a cheap delta 1 x 42 a while back and it was an ok (small) sander but when i got it the wheels where plastic....we can't have that i thought so i fired up the lathe and made some new wheels (it had 3) out of 6061 Aluminum. Though it was better than the original when ever i put a heavy load on the belt it would shoot over to one side or the other and if i took the pressure off it would go back to center. well after some trial and error i found that if i put a slight crown 1-2 deg. on the guide wheel (also the wheel that changed the tracking) the problem whent away so much so that i could actually put pressure on the side of the belt and it would actually fight back. Worth looking at.

Travis
 
+1 on crowning the tracking wheel.

My grinder came to me third hand, and it still has a crown put on the tracking wheel by the second owner. He said Gil helped him set up the wheels and wrapped the idler wheel with good quality electrical tape. :rolleyes:

That tape hasn't shifted, melted, or slung adhesive goo everywhere yet. :D

So you don't have to do anything expensive to try adjusting the crown. ;)

Mike
 
Travis,

You described my problem better then I did. When I lay on it the belt moves over and when I let off it goes back to center.

I got my wheels off Tracy and they have a pretty good crown on them.Maybe im just leaning on this thing to hard.unsure I can lay into the 8 inch contact wheel pretty good though.
Maybe I just wont flat grind.:D
 
Shankmaker said:
Maybe I just wont flat grind.:D
Click to expand...

That's not a good solution! :D

But considering that you've pretty much done everything you can to keep your belt straight, it seems you might have a square issue. Are you confident that the glass face on your platen is flush to the platen? It might be worth taking it off and re-gluing. (It'll drop off if you carefully heat the back of the platen with your propane torch.) I have the same issue with my Bader platen. I've found that the only way I can keep it tracking is to be very careful about applying even pressure across the face of the platen. That's not a good solution either, obviously.

I recently got a new platen from Rob Frink, and so far it does not suffer from this issue. But I haven't faced it with pyroceram yet either...
 
Dave, you may have something. NOT flat grinding just can't be. It's simply an issue that needs to be found and fixed. It probably won't be a big deal.
Not being square is a possibility. If the the top and bottom wheels *are* square and then the platen isn't. That would explain it's behavior also. The angle iron holding the platen may not be 90degrees square.
 
I havent put the glass on the platen yet. I wanted to get it all lined out before I put the glass on.
Could that be the issue?
Just to be sure on tension im buying another spring today.:bud:
I will check squareness of the platen also.

Thanks again.
 
Guys this is alot of good info. I have had some problems with tracking and it was that the platen was off a little. Boy I am glad this forum is hear. You can learn alot and get so much help.
 
Hey guys.
I went ahead and put another spring on for tension and snugged up the botton wheel on the attachment. It seemed to be flexing a little under the tension. I had drilled my hole for the bolt a little too big so there was too much slop in there causing the flex. It seems to running good now....I layed into pretty good with some scrap and it didnt move.
Thanks!
 
good to hear. no one should put up with belt wobble. it can be 'tuned' out.
 
Excellent. It's always good to know how to troubleshoot stuff and everyone's experience adds to that. Thanks!
 
Im having the same problem with a nwg It was perfect at first but now the belt wobbleswith the flat platen only, my 8" 6" and small wheel track straight I think the spring has lost some tension gonna get me a new one today and tryit out
 
Keep working with it. I have not had this problem on any of the grinders I have built, except when I didn't have enough tension. If increasing the tension doesn't help look closely at alignment. On my grinders for the patten I use a piece of 2" X 3" angle iron. Look at the pictures on my brochure. If you can't see it well enough contact me and we will discuss it. The way I build it there isn't much way for it to be out of alignment. Good luck. Really just keep working on it. It will be worth it to have the grinder working correctly. Even if you arn't flat grinding you will find lots of uses for the flat patten.
 
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