Drum sander problem

[Glen01 [OP]]

Hi I hope someone can help.

I purchased a used BB CX509 18/36 open end drum sander. There seems to be a problem with it making the boards flat. There is a are a couple of waves that are created through the length of the board so when I cross cut and try to glue up there are bumps that make a good joint impossible.

Anyone have an idea why this happens and how to fix it?

Thanks in advance
Glen

[gdtrfg]

Your sanding drum may be moving up and down while you are feeding your boards through. Check where it goes from vertical to horizontal, and if that is tight, it’s probably a bearing issue.

[MartyFromKingston]

Glen,

I'd second Paul's suggestions... but there are a few other possibilities what may be causing this problem.

1. ensure you're not trying to use the unit as though it's a thickness sander! These things are designed to take off only a few thou (.005" or so) at a pass. If you try to do more than that, the machine will usually deliver poor results similar to those you're getting, and blow a fuse.

2. check the conveyor table and the belt to make sure there's no sawdust clumped up beneath the belt.

3. it's certainly possible that the bearings on the drum may are shot.

[Saw_Dust25]

it could be the rising and falling of the board going through if you aren't using support rollers that are perfectly level with the feed table. This is a common issue people have when using a drum sander the the table moves up and down as opposed to the sanding head on the CX509. This could possibly be the issue. Is it possible that the work piece isn't properly supported?

[Glen01 [OP]]

Thanks for all the suggestions. It turns out that the conveyor table was out of adjustment.

I have found another issue. It seems that the conveyor table creeps lower while in operation. Anyone have this issue? That and an on going problem with the sanding belt in those spring clips

[longspur]

unfortunately these open end drum sanders seem to be plagued with set up issues - I had to get rid of my King industrial 22-44 drum sander as it was not possible to set up to the kind of accuracy i demanded of it.

It was close but not close enough - for general sanding work when accuracy was not critical it would do - other than that it was not good

[Sawdust]

I have a pro open end. It works fairly well for what it is. Ive seen it referred to as a calibrating machine which I will accept better than a sander. They dont sand very well, not if you have used better.

I ran the machine, its a wide belt rather than a drum. I ran it down to the conveyor and into the conveyor so that both are true. That worked well. first i trued the drum running it on a sanding block block to make sure the drum was true. Both those things increased its accuracy and it was pretty parallel and accurate.