Questions about drum sander feed angle.

[Ben325e]

I'm going to be picking up a drum sander from frazierk's classified ad this week (performax 16 32) and have been reading up on them. It seems that other than material removal speed the drawback is that the sander leaves lines on the workpiece that need to be cleaned up. I've read that you can angle the piece one way then the other to help minimize this to an extent, but because the feed belt travels in line with the drums rotation, it won't ever be perfect.

I know that if the feed belt on a belt sander travels at a slight angle to the direction of the abrasive travel, small belt defects will be minimized, but I'm not sure that this same benefit will translate to drum sanders because of the thin line of contact the drum has with the wood.

Basically, my query is this: although it might not be perfect, does anyone see a benefit of turning the direction of the drum or the feed belt slightly to minimize the linear marking of the drum. Here's a video that illustrates my idea, except with a wide belt sander:

[video=youtube;TZObeIRx1tE]http://www.youtube.com/watch?v=TZObeIRx1tE[/video]


I assume that this would be very effective on an oscillating drum sander as well as a belt sander, just not sure about a non-oscillating drum sander.

 

[Mike Wilkins]

Simple answer to the question about lines on the work after it comes out of the sander; these lines will be there due to the nature of sanding in a straight line. If this is an oscillating sander, the lines will be erased by this method. With my dual drum sander the final grit is 120. After that I have to go over the material with an orbital sander starting with 120 to get rid of the lines. Hope this helps. Even running the wood through at an angle, the lines will still be there, just at an angle.

 

[Tarhead]

If you keep your abrasive clean and tight you will reduce the grooves. The X weight abrasive (ie: the kind that comes with it w/hard backing) can be soaked in a strong Simple Green or 409 or any similar detergent solution and scrubbed with a stiff brush when you start seeing burnt resin building up on it. Put duct tape on the back of the abrasive at the ends to prevent wear and keep the tensioning mechanism clean and lubed. It will glom up in a few heavy uses.

I've owned two drum sanders and as far as I know the drum has been at 90 degrees to the belt travel direction. If the belt is tracking straight scribe the location of each corner position before you make any adjustments on it. You'll save yourself an hour of aggravation.

 

[Bill Clemmons]

I have a dual drum, 37" sander w/ 80 grit on the front drum, and 120 on the back drum. I always try to angle my work as I run it through, reversing the angle w/ each pass. This does nothing to reduce the scratches left by the sanding. In my opinion, the main reason for doing this is to even out the wear-and-tear on the abrasive belts. If you constantly run narrow pieces through in a straight line, and in the same location, your paper will wear out quickly in one spot, but still be fresh in another area.

By going through at an angle, you spread the wear over a wider section of the belts, and also reduce the heat build-up along the drums. As someone else mentioned, when I have my boards to the final thickness I want, I still clean them up w/ a ROS and 100 or 120 paper.

Bill

 

[tryingtokeepmyfingers]

I'm going to be picking up a drum sander from frazierk's classified ad this week (performax 16 32) and have been reading up on them. It seems that other than material removal speed the drawback is that the sander leaves lines on the workpiece that need to be cleaned up. I've read that you can angle the piece one way then the other to help minimize this to an extent, but because the feed belt travels in line with the drums rotation, it won't ever be perfect.

I know that if the feed belt on a belt sander travels at a slight angle to the direction of the abrasive travel, small belt defects will be minimized, but I'm not sure that this same benefit will translate to drum sanders because of the thin line of contact the drum has with the wood.

Basically, my query is this: although it might not be perfect, does anyone see a benefit of turning the direction of the drum or the feed belt slightly to minimize the linear marking of the drum. Here's a video that illustrates my idea, except with a wide belt sander:

[video=youtube;TZObeIRx1tE]http://www.youtube.com/watch?v=TZObeIRx1tE[/video]


I assume that this would be very effective on an oscillating drum sander as well as a belt sander, just not sure about a non-oscillating drum sander.

was it the new or older designed sander that you are getting from him ?

 

[red]

I've had the woodmaster drum sander in the past and like everyone has said, you still need to hit it with the R/O sander to clean up the lines. It's the nature of the beast. They do a wonderful job of making your work piece flat but there is still a little clean up afterwards.

Red

 

[Ben325e]

Just to be clear, my question is not about merely skewing the workpiece, but actually changing the direction of the feed belt travel. If the drum axis of rotation is east-west, then the direction of the feed belt and the sanding media would be north-south. if the feed belt were to go Northnorthwest-southsoutheast and the sanding media remains north south, much like if you had one tire that was badly out of alignment on your car. Just rotating the direction of the feed belt travel, not merely turning the workpiece so that more even wear on the drum/sandpaper happens.

 

[Tarhead]

I can see why you would want this skewed belt in an industrial sander going through thousands of lin. feet of stock per day. The abrasive on a 16-32 sander can be taken off and replaced with a cleaned strip in less than a minute and is cheap (<$5 if you buy the 80 meter rolls at Klingspor and cut your own) in comparison to the big industrial belts. It's never been an issue for me and I'm thickness sanding very soft, thin Spruce which will dent if you breathe hard on it and oily Cocobolo which oozes goo when it's sanded.

 

[Ben325e]

Your right, the sanding belts are cheap. The purpose is for surface finish, not abrasive life, like in the video I posted.

 

[FredP]

Just to be clear, my question is not about merely skewing the workpiece, but actually changing the direction of the feed belt travel. If the drum axis of rotation is east-west, then the direction of the feed belt and the sanding media would be north-south. if the feed belt were to go Northnorthwest-southsoutheast and the sanding media remains north south, much like if you had one tire that was badly out of alignment on your car. Just rotating the direction of the feed belt travel, not merely turning the workpiece so that more even wear on the drum/sandpaper happens.

what you are saying would prolly get a better finished surface but you may run into tracking issues. with the drums pushing to the side you would most likely run the feed belt off track to the same direction.:dontknow:

 

[Tarhead]

Your right, the sanding belts are cheap. The purpose is for surface finish, not abrasive life, like in the video I posted.

I don't see any problem with surface finish on mine as long as I have clean stock and clean abrasive. It leaves uniform scratches the depth of the grit. If I put 150g on it I can go directly to grain fill. I normally use Abranet on a 5" or 6" ROS or a half sheet sander on big flat surfaces to go higher in the grits between the sealing coats. IMO having the drum skewed on a home sander is a solution looking for a problem. Having the belt skewed on an industrial machine is a solution to a problem. Like Apples and Pineapples...similar but very different.

 

[DWSmith]

When I had the 22-44 Performax, I found that if I ran the pieces through the sander straight, if there was a bit of glue left at a joint or if the joint was slightly higher, I would see and feel the bump that was left which required another pass to smooth it out. Now with the double drum sander I have, I run the pieces slightly angled which has done away with any bumps and kept the surface smoother. Also, as another poster stated, running the pieces through the sander at an angle helps to prolong the life of the sanding belts as well as keep the drum and belts cooler.

Just my observations.