I have a new Woodmaster 38" Drumsander. It produces consistent ripples, or rotation marks, perfectly spaced, across every board I sand. There is also evidence of snipe, once you apply finish to the sanded stock and check low angle reflection. I have done all the checking listed in the manual, lubed every spot suggested, tightened down the tie bars, and etc. I have talked with Woodmaster three times, resulting in new Velcro (not a fun job), and advice to tighten the tie bars down on the screw jack posts. None of these has done anything to reduce the problem.
I found this link, and wondered if it might relate to my problem:
I am really frustrated that having spent much money on a machine, I am spending more time troubleshooting than woodworking, not to mention all the hand sanding needed to get the ripples out of lots of beech shelving. Any thoughts, ideas, or experiences out there?
(Solid Wood Machining Forum)
From contributor Z:
It sounds to me like you may have a balance problem. Can you feel any vibration? Snipe comes from misalignment or lack of support at the infeed or out end.
How fine do you sand to now? I would try progressively sanding to 180 or 220g and random orbit sanding back with 150 or 180g. RO sanding is a given with a drum sander. The money you spent on a drum sander is not a lot. Compare it to the price of a widebelt and you will see you got what you paid for. I had a nice 24" Woodmaster for a number of years. It easily met all my expectations for a drum sander. However, I never expected it to leave a surface ready for stain. Even now with my doublehead Timesaver widebelt with a platten we RO sand if we want a really good finish. Shortcuts don't work. From my experience I do not think there is anything wrong with your sander. You are just expecting too much out of a $3,000 machine.
The snipe is caused from heavy work pieces with no support as they enter and exit the drum. They need to be well supported until the area under both hold down rollers, and as they exit they need to be supported after the infeed hold down drops off. Woodmaster sells an extension roller kit that I installed that helped some. The cost was around $100 if I remember correctly. It was probably worth it.
Comment from contributor C:
It looks like a lot was covered concerning the drum and the abrasive, but it's also worth mentioning the conveyor feed mechanism. If there's a gearbox and a "flat spot" associated with it internally, the result will be a jerk on the conveyor at regular intervals. To troubleshoot this, run the conveyor at minimum and maximum speeds and measure the distance between chatter marks. If they stretch out during the "fast" cycle, the chatter is originating in the head assembly (drum, pulley, drive belt, bearings, and motor.) If the chatter mark spacing doesn't change, it's in the feed mechanism.