using a horizontal grinder --

Burchtree

Burchtree

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I've got one of Frink's horizontal grinder that is run off a 1725 Leeson motor. It seems that when I'm trying to contour the inside of handles with it, it leaves bumps and waves instead of a smooth finish. Is this crappy belt problems, or do I need to slow the grinder down? Anyone else have this problem with finishing the curves on your blades?
 
I also found this problem with the hor grinder. I think that the vibrations from the motor creep thru the base plate and find their way to your work. I tried insulating the motor with rubber ..no go. I slowed the motor down with a motor controller and things are much better.
 
I wondered if that was the problem. I was hoping it was belt splices from crappy belts. :(
 
Hi,
I have a horizontlal grinder that the Bader folks built for me.
Find that slower speeds are much more manageable and that using as large a wheel for the job as possible also smoothes out the condition you mention.
And/or go to a flat platten if it will do a particular job as well as a wheel...the more contact you make with the belt, the smoother the grind...
 
It seems that when I'm trying to contour the inside of handles with it, it leaves bumps and waves instead of a smooth finish. Is this crappy belt problems
Click to expand...

hmmmm.... this is the first that I've heard about this. My initial thought is that the belt type is the culprit. Are you using J- weight..or J-flex backings? These belts have a very flexible fabric type backing.

I have limited experience actually using the machine...but what I noticed right off the bat was that small wheels...say 1/2" are very aggressive and require a "craftman's touch" for a nice finish when comapared to larger wheels like a 1". The little wheels will "dig in" faster than you can blink your eye.

I'll be watching this thread....as I'm very interested!

Rob
 
You definitely gotta be light-handed with the smaller wheels and I've tried going light, but it isn't working on the higher grits. I think I'll first try using some different belts and see how that goes. I'd hate to have to rig up another motor w/variable speed as I had just put on a new leeson when I got the grinder. I'd get an extension for it to run the 72-inchers, but I'd run out of table. :( ;)
 
are you sure they're not divits left because of the small diameter wheel?

If so......I've run into this problem on my small-wheel setup. I've managed to solve it by "swiping" the contoured part in one motion, with a good amount of pressure. Hard to explain...but if there is any variance in speed or pressure, you'll get a divit. At the finer grits, there are still small "waves" but they go away quickly by gently moving the piece to-n-fro against the wheel softly and then going over it with a scotchbrite belt.

I encounter this a lot because, frankly, my stuff is very contoured. That's the best I've come up with so far. Still learning...
 
Daniel Koster said:
are you sure they're not divits left because of the small diameter wheel?
Click to expand...

You see the same phenomenon using a small wheel fork with 1/2", 5/8" wheels on a BII, so it's not the grinder per se.

Daniel's got the workable technique, there: decent pressure, one smooth swipe. I never thought much about it until this thread, but that's exactly the "fix" I came up with.

Don't use a smaller wheel than you absolutely have to.
 
swipe the knife with the belt...... small wheels are tough but can be done. I go 60, 220, 400 grit.....you'll get it :)
 
Daniel's technique is right on. I was having the same problem with my KMG horizontal. Finally turned the speed downand made the pass all in one smooth sweep and got acceptable results.
One thing I learned quickly was that when putting small parts on the small wheels or platen this grinder will throw them clear across the shop if you are not careful. Again stop and think about your technique, especially on rounded surfaces, and when possible use a stop block in the other hand to brace the work against.
Rob, I still haven't gotten around to installing my extension for 72" belts (still got a couple of 48's to use up first). How is the small wheel attachment tied down to the primary base? With screws, roll pins or??
 
Bill,

The fork has a single bolt and 2 rolled pins. The pins are for alignment. Take out the bolt...then gently tap the pins from the bottom of the main base plate to push them out. This keeps you from prying the fork up and putting burrs and scratches on everything ( which is an alternative method). Then move the fork over to the extension plate and set it in place with a soft mallet....then bolt it down.

Any probs or questions...don't hesitate to drop me a line.
 
I had a problem like this using Rob's small contact wheels on a machine I built. Being very careful helps but to stop it I made a new contact wheel from an old copy machine roller. The rubber covering on the roller is much softer than Rob's. Now I use the harder contact wheels to removes most material and the softer wheel to final finish.
 
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