final dimensioning with drum sander

[mark mcfarlane]

I just picked up and assembled a Supermax 19-38 and ran a few test boards (pine and maple) through it. This sander comes with 80 grit installed, which, as expected, leaves some pretty deep scratches in both wood types.

I picked up some 120 grit also.

I plan to use the sander for final dimensioning on some soft maple stiles and rails for flat-panel shaker style doors. I'm thinking multiple passes with the 120 grit is the way to go. I don't have very much material to remove, just remove a few marks and small ridges from jointing/planing. I probably should have picked up some 100 grit, I didn't expect the 80 grit to be quite so scratchy, it is very different from a ROS.

Also, do people run stiles/rails through 'on-edge' to thickness the width of the boards (i.e. the ~2" width)? I'm thinking I should pass a half dozen boards at a time, side-by-side, together, grouping ones of a similar length in each pass. Is this a common practice?

I also planned to use 120 grit for the final sanding of the front of the panels, just to even out the joints between rails/stiles.

Anything else to watch out for?

I know I'll learn more about which grits to use in which scenarios as I use this machine, but I thought maybe y'all could help me jump start the process before I start sanding tomorrow.

Cheers,

[Nick Decker]

You'll have ridges even with 220, just smaller, of course. I've been drum sanding to 220, then backing up to 150 or 180 to finish with the ROS to remove the ridges.

[Bill Adamsen]

Mark ... not sure I have much to add that you haven't already learned.

I frequently use the SM 22/44 pro drum both on individual components and also on completed pieces like door frames. It requires pretty close attention and a slow moving platen for any wider material (more than 6 inches). It is exceptionally useful for frames. But requires patience and the willingness to do passes removing very little material at a slow pace. I typically test the thickness first with scrap wood and a digital caliper. The digital caliper is always in my hand when running the drum sander. For items like assembled frames it will create crossgrain scratches. But even with the grain the scratches can be very hard to remove. Using 80 grit – depending on the hardness of the wood – does require significant sanding afterwards with an ROS or as sanding block. But it is a heck of a lot easier getting a flat frame than the sanding block alone. Your recommendation for dimensioning individual pieces seems reasonable.

For my next big roll I may test your idea of 100 grit.

[Bob Michaels1]

Mark, your jointer and planer are your friends for dimensioning. Changing grits gets pretty old quick on my 16/32, as it would on your 19/38. I just leave one grit (120) on my 16/32 and use it for its intended purpose...sanding. Regards, Bob.

[mark mcfarlane]

Mark, your jointer and planer are your friends for dimensioning. Changing grits gets pretty old quick on my 16/32, as it would on your 19/38. I just leave one grit (120) on my 16/32 and use it for its intended purpose...sanding. Regards, Bob.

Thanks Nick, Bill, and Bob.

FWIW, it only took me about 2-3 minutes to change the paper on the 19-38 the first time not knowing how it works. I bet I can do it in around 1 minute the next time. It's a pretty simple operation with pre-cut paper: clip, wind, clip.

Edit: Also, some planers like mine have steel serrated infeed rollers that leave marks unless you remove a fair amount of stock, so if you only have to remove 1/32 or so of wood you can't do it on the planer.

[Mike Cutler]

My dual drum sander has 80/120 grit on it normally. I do occasionally have 150 on it, but not often.
Drum dander to 120. ROS's at 150/220/320 and 400.

[Nick Decker]

I fall into the camp that doesn't mind changing paper. It's easy enough, and once you get past initial stock removal with 80 or 100 grit you're just doing a couple of VERY light passes to remove the grooves left by the previous grit.

My thoughts on running multiple pieces, side by side: I generally don't do it. These open end sanders don't flex much, but they do flex. As they flex, the outboard end of the drum gets farther away from the bed than the inboard end, so the outboard piece of stock gets sanded a little less. Whether that difference is a problem is your call, of course.

[glenn bradley]

Thanks Nick, Bill, and Bob.

FWIW, it only took me about 2-3 minutes to change the paper on the 19-38 the first time not knowing how it works. I bet I can do it in around 1 minute the next time. It's a pretty simple operation with pre-cut paper: clip, wind, clip.

Edit: Also, some planers like mine have steel serrated infeed rollers that leave marks unless you remove a fair amount of stock, so if you only have to remove 1/32 or so of wood you can't do it on the planer.

I use my 19-38 for thicknessing on thin or delicate material. Also to get a jump on any material too wide for my planer. I do run things through on edge; they have to be substantial enough to stand up under the pressure rollers of course. The finish is nothing like a ROS as there is no oscillation of any kind, just a linear abrasion path.

My planer also has the serrated outfeed that can leave marks on light passes or softer materials. I did back the pressure of this roller off nearly three times lighter than the factory setting. The ridges occur rarely now and the outfeed still has a grip like an alligator.

I am a one man shop doing custom work and am able to take the time for some more involved use of my machines. A lot of folks put 80 grit on their drum sander and leave it and that's fine for what they are doing. I actually have paper for my drum sander all the way to 400 grit and use it.

Like you, I enjoy how quick and easy the paper change is on the 19-38. I never hesitate to change grits to get the result I am after. I do not apply thick film finishes so I never go straight from a machine to the finishing process. Its almost 'George Jetson' woodworking but, not quite .

[Nick Decker]

Mark, if/when you use the "fast lever" function for sanding wide stock, this might be of help. I adjusted the tension on mine (16-32) per the manual, but it was still pretty hard on my hands. A short piece of hose pushed over the bare metal lever helps a lot.

[Warren Lake]

final dimension on a planer. I dont get how you guys use a drum sander, clean knives, clean finish, sand other ways. I have a small wide belt drum. I only tried it once as a sander and it wasnt as good as other ways. one comment up above about slow and patient and so it takes longer and doesnt leave as good of a finish as other ways thats what I hear. Maybe I dont get it I can see doing a guitar top or something like that but not for furniture or doors I dont see why you need it

[John TenEyck]

Well I'm in the camp that likes and uses a drum sander for most every board that comes out of the planer. It's just easier for me to bring the board to final dimensions, remove the planer marks, and end up with dead flat wood than any other way I've tried. And when I'm working with wood that tends to tear out I stop well short of final thickness and use the drum sander to work it down to perfection. I have 80 grit on the front drum and 120 on the rear of my sander. When I had a single drum sander I settled on 120 as the best compromise. 400 grit on a drum sander? I tried 220 once and it would burn just looking at the wood. Even 150 grit tends to burn unless I'm very careful, especially on cherry and maple. Pine? Forget that stuff through a drum sander.

Scratches are nasty from a drum sander, to be sure. To deal with them I usually start with 100 grit on my ROS, but have even had to back up to 80 grit to get rid of them. Better to use a coarse grit and remove them quickly than to struggle with a finer grit and risk rounding over edges or creating a non flat surface. Once the linear scratches are gone you're home free and can proceed on to finer grits very quickly.

John

[David Kumm]

I use a widebelt now but I'm in John's camp. For years I ran a Performax dual head and it did pretty well. It is slow so the second head helps a lot. 80-120 and sometimes 60 on first or 150 on second but anything finer was a waster of time. I really like the sander when dealing with glue ups as the grain can be going in opposite directions. I put a Wixey on mine to control the DOC and you can hear and feel when the machine tends to bog down so running it within capacity is fairly easy. Keeping the belt wrapped tightly solves problems and a quick run with the ROS makes for a nice product. If you have the amperage, a used WB is a step up. A used Performax 25x2 is in the 1000-2000 range and a used 25" WB runs in the 3-5000 range. Dave

[mark mcfarlane]

Thanks everyone for the help. The wood is milled, rough sanded, and I'm setting up the shaper this morning. The sander did a great job removing a small amount of snipe and some ripples due to uneven feed speed on the jointer. As my joint/plane technique improves I'm sure this will be less of an issue.

I did have one good learning mistake using the sander. I ran a group of 5 short boards at an angle through the sander but I did this with the rails/stiles 'on edge'. I didn't hold the boards well and they vertically rotated a little and were gouged. Obvious problem, since the angle of entry put a force on the boards which would make them want to tip sideways.

I fed the remaining on-edge boards straight into the sander without an issue.

[Warren Lake]

one more reason why I dont or would never do this process. You never machine material after you sand it because pieces of grit get left in the wood and it dulls your knives. I got crap for that in the first few weeks.

[Robert Engel]

I generally don't use a drum sander for thicknessing stock like you're talking about, only on very thin stock.

I do run rails/stiles/panels through the drum sander, but only to remove machine marks. I use 80 grit I don't see a lot of scratches, maybe you're taking to heave a pass?

Lighter colored wood tends to burn with finer grit paper.

and oh, I don't sand the edges because I leave rails/stiles wide until I've got the routing done.