Surface grinder chatter?

Drew Riley · Mar 1, 2015

I just recently converted my Reid 618 surface grinder over to 1x72 belts, and I'm getting a chatter pattern. I was getting a slight grind pattern with stone wheels, but I was hoping that the belts would wash it out a little more...

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

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

If I put a dial indicator on my spindle while it's running, I get absolutely no movement of the needle. If I push down hard on the spindle, I'm only getting about .001 to .0015 of deflection.

I do feel the very slightest of vibrations on the back of the spindle motor, which I'm told there should be none at all, but I'm not sure where what to really look at.

Any ideas for further troubleshooting?

Don Hanson III · Mar 1, 2015

You need to scrape the grit off the belt where the splice is.

Joel Chamblin · Mar 1, 2015

It's the joint in the belt that's doing that not your machine. I've gotten better results using a trizact belt for the finish work.

ggoose · Mar 1, 2015

If you use a diamond pad (like this, for example) you can knock the belt joint down, as mentioned, to the same thickness as the rest of the belt and eliminate the chatter. I have found it only to be a problem with the thinner, higher grit belts above, say, 100 grit. Above that I have to smooth the joint.

javand · Mar 1, 2015

You may also need to grind in your wheel by gluing some abrasive to your chuck, and then engaging it.

Is your wheel running smoothly? Any new vibration? Balance issues can cause this also.

I personally think belts are great for hogging, but never produce near the finish quality of appropriate and properly dressed stones.

If you were getting this kind of finish with stones, something was not right. Either junk stones, or something. I recently was showing a friend how to use his surface grinder and noticed a lot of vibration from it, I assumed it was from not having been leveled. Only stones he had were some fine grit stones and he had a box of them, I asked if I could have one. Tried it on my SG and got the same vibration. Made in Mexico, obviously very out of balance. Switched back to a quality stone and problem solved.

Don Hanson III · Mar 1, 2015

I'd put a stone wheel back on it. I get a 180-220 grit finish with a 46 grit stone.

Cliff Parker · Mar 1, 2015

Don Hanson III said:
You need to scrape the grit off the belt where the splice is.

That's the truth. The bump is for sure the splice. I use a 400 trizact belt for final clean up and the bump went away when I started scraping grit off splice.
Try it you'll like.

Cliff

Don Hanson III · Mar 1, 2015

Cliff Parker said:
That's the truth. The bump is for sure the splice. I use a 400 trizact belt for final clean up and the bump went away when I started scraping grit off splice.
Try it you'll like.

Cliff

Cliff, you are the one who told me about this.

Drew Riley · Mar 2, 2015

Thanks for the responses guys. I'm gonna order some diamond pads and hope that that's the issue!

Drew Riley · Mar 6, 2015

Well, I got my diamond pad and dressed the splice. I also chucked a file up on my magnetic chuck and trued my wheel.

The difference is night and day! I almost couldn't believe it was that simple.
I'm finally able to get the finish I've been looking for. Thanks for the help everybody.

Here's a pic of the finish:

http://flic.kr/p/rb8aEzh.