I've been a drum man for years. I bought a Hummel 8 inch belt machine two years ago...and I'm at my wits end.
It seems this thing needs parts all the time.
We've recently seen the floors getting chattered alot, mostly softer woods...red oak..american cherry..ect. It seems to be cutting more aggressively as well, lots of dishing out. Am I loosing my mind and missing a step here? We've replaced the belts, fan system, tention pully, tention roller, drum and wheels. It feels very unstable when cutting. I never had this much trouble with my Clarke, and I'm hoping it's just that I'm not familiar with adjusting this big green German monster. ANY suggestions from people familiar with the Hummel would be greatly appreciated. Thanks !!

Did you buy it new? Used? Hummels are tempermental if banged around and can get knocked out of adjustment. It is possible that you are not operating the machine by the manufacturer's recommendations. Do you have Lagler's Operator's Manual? The parts you mention will get worn out in time with any belt style floor sander. Furthermore, any replacement parts should always be Lagler parts. I have tried after market parts from other sources. There is no comparison. Do you live/work by an authorized repair center? You can always contact Palo Duro in Denver. They are the importers of Lagler sanders and know them pretty well. They can make service recommendations plus supply you with manuals and parts, if needed.

Palo Duro Companies
12655 east 42nd Avenue
Suite 60
Denver, Colorado 80239
Fon: 800.8HUMMEL (800.848.6635)
http://www.laglersanders.com

There are many unique factors to operating a Hummel:

1) Rough/course cuts are ideally done at 7 to 15 degree angle to the direction of the floor.
2) The sander should be run left to right.
3) The belt should track dead center
4) Drum pressure is 69 PSI. This needs to be verified and checked.
5) Drum head should not be dressed
6) machine should run smooth and vibration free

Common errors:

1) walking too fast or too slow
2) using a coarser grit than necessary
3) sanding right to left
4) uneven belt tracking
5) out of round wheels
6) poor quality drive belts
7) drum head pressure incorrect
8. grit and debris in wheels, drum head and upper roller
9) failure the clean machine ( blow out ) often.
10) knocking wheel adjustment out of adjustment

Yes..it was bought used.
There is a slight vibration to it, but when I sent it out to my local distributors repair center, they said it felt fine. I've experimented with the grits, I try to stay away from the reall heavy grits unless I need to use them. The drum I bought was a Lagler drum...and I do believe my partner dressed it about three months after we put it on. It wasn't an aggressive dress, but no the less...it my need to be replaced.
Thank you for the advice...I will try Palo Duro..the more I can learn the better.

Thanks again !

i bought my2nd hummell less than a year ago and its been to the shop twice for chatter they say its fine. Ive had to re-sand 2 jobs. thanks hummell

Same here. My old boss says it has to be something simple, because Hummells don't chatter...but the repair shop said it was running fine..and it still left patterns. I'm about to drop new drum bearings in..we'll see. I'm also borrowing a brand new Hummell to sand my next one to see if mines running rough...could be a motor bearing.

Lagler Hummels are not the only sanders to have problems. I've heard similar stories about every brand; Clarkes, Pro-Sands, Galaxy's, K&T's, etc. It sucks when the machine you've spent thousands on is not operating correctly and the repair center says it's working fine. I believe most repair centers think that if the machine turns on and actually sands wood, then it's fine. The operational nuances of a well-tuned floor sander evade most service techs unfortunately.