Grinder Belt Flapping?

T

The Mighty Ginsu

Joined
Aug 11, 2016
Messages
258
The other day I pushed the tool arm into my grinder to save space. Later I pulled it out, tightened everything, and turned the grinder on. The belt flapped while it ran. This was new.

Before I moved the tool arm, I had adjusted the tool rest so it was about 3/32" from the moving belt. After I moved the tool arm, the belt flapped against the platen and tool rest enough to make it hit the rest and give off occasional sparks.

I'm wondering if this happens to everyone, and if there is a well-known cause. I adjusted the tightness of the belt, and it didn't seem to make any difference.

The belt is pretty old. I haven't put a new one on because I've been putting the finishing touches on the machine itself.
 
It sounds like the belt is loose, but you say you tighten it? Perhaps a photo would help us see what you're talking about?
 
It would really have to be a video, since you can't see it in a still photo. The belt is just moving up and down off the platen. When I say "up and down," I mean toward the user and away, since the platen is vertical.
 
if it is moving toward and away from the user, that means you are getting space between the platen and the back of the belt?
 
Did you leave it under tension for a long time while not running? Sounds like a kink of sorts from the tension pulley of it was left under tension.
 
Thanks for the replies. The problem went away. Go figure.

I've noticed that strange black blobs form on the pulleys. They're very thin, and they appear to be a combination of dust and something else. Maybe oil. I scraped a couple off of the platen pulleys. Am I the only one who gets these things?

I checked the inside of the belt to see if there was gunk stuck to it. You know how shops are. Mysterious substances show up and do strange things.
 
It is just gunk and water and who knows what. I, carefully, hit it with scotchbrite while its running to clean them off.
 
I've noticed I get those black blobs more from some belts than others. Norton blaze belts being on of the worst for me and the 3M 984 cubitrons the best

Sent from my SM-N915V using Tapatalk
 
This is embarrassing, but I figured I should be honest and post it here, because I am not the only belt grinder noob who will make the same mistake.

I forgot to compress the gas strut (which tensions the tracking wheel) before running the grinder. I was tightening it by pulling the tool arm out and setting it. Naturally, there was too little tension on the belt, so it flapped. I should have pushed the tracking arm down, pulled the arm out, tightened the arm in place, and THEN turned on the grinder.
 
The Mighty Ginsu said:
This is embarrassing, but I figured I should be honest and post it here, because I am not the only belt grinder noob who will make the same mistake.

I forgot to compress the gas strut (which tensions the tracking wheel) before running the grinder. I was tightening it by pulling the tool arm out and setting it. Naturally, there was too little tension on the belt, so it flapped. I should have pushed the tracking arm down, pulled the arm out, tightened the arm in place, and THEN turned on the grinder.
Click to expand...

I thought that may be the case, but was too lazy to type out.

Glad you figured it out, you won't do that again.
 
The Mighty Ginsu said:
This is embarrassing, but I figured I should be honest and post it here, because I am not the only belt grinder noob who will make the same mistake.

I forgot to compress the gas strut (which tensions the tracking wheel) before running the grinder. I was tightening it by pulling the tool arm out and setting it. Naturally, there was too little tension on the belt, so it flapped. I should have pushed the tracking arm down, pulled the arm out, tightened the arm in place, and THEN turned on the grinder.
Click to expand...

Depending on how strong your gas spring is, this is actually how I tension my felt belts. My 60 lb gas spring will just stretch them to the limit of it's travel if I try to tension them like I would a normal canvas belt.
 
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