Proper drum sander usage

[brandon.nickel]

I need some advice from more experienced woodworkers than myself.  Here's my situation:

Last fall I decided to build every piece of cabinetry in my new house.  This project justified the purchase of quite a few tools to round out my collection.  I bought a jointer, but I couldn't justify both a planer and a drum sander (which I'd heard good things about).  I rationalized that if I had patience, a drum sander could do the work of a planer, just slower.  The drum sander also had two keys advantages:  no chipout on highly-figured woods and being open-ended opened up the possibility of thicknessing up to 36" panels.  I looked at the Performax models, but decided to cheap out and go for the Grizzly.  I also ordered a stack of sanding rolls from 80 - 220 grit.

Once the Grizzly arrived (My God this thing is heavy), and set up on it's stand, I then struggled to get the drum loaded with paper.  I admit I didn't completely read the instructions the first time.  Anyway, I started out with 120 grit sandpaper (and ruined several strips due to my reading problem).  I expected this thing to produce a very smooth finish.  However, the materials I ran through it came out looking like I'd taken a power-rake to them.  Think a fine-toothed steel comb with a car parked on it dragged across my wood.  I wasn't expecting deep scratches/grooves/channels in my wood.  So, I loaded up the 220 grit paper and sure enough, it looks almost the same.  The scratches aren't as deep, but they're not even CLOSE to the finish-ready surface I thought I was getting.  I called Grizzly to ask for advice and was told that's "normal" and that "all drum sanders do that".  I now use this sander exclusively from 80 grit rough thicknessing and finish all stock with the RO150, starting at 80 grit Rotex, then moving up through 180 or 320 RO (stain or clear finish).  I can only take off 0.015" per pass and it still looks bad.

So, my question is this:  Am I doing something wrong?  Could this drum sander really work better than this and I'm not using it correctly?  Does anyone have a Performax that could offer advice?  It kills me that this is the single most expensive tool in my shop (even the Domino by itself is cheaper) and it's the one I'm the least happy with.  I can deal with the cheap socket-head screws rusting and mediocre dust-collection port, but the performance is significantly lacking. 

Your thoughts/opinions are welcome.

 

[Eli]

The only thing I'd have to add of value is that I've never used a drum sander, only lunchbox size thicknessers, and I've always been happy. I've used the Makita 2012NB and the Dewalt DW744. Rarely need a final finishing sand, maybe a scrape. For cabinetry, I like to gang the face frame pieces through together for uniformity. I know that isn't helping much, sorry.

 

[Michael Kellough]

I have a Performax 18/32. I'm not too happy with it but my problem is with the open end design which allows open end of the drum to lift away from the work requiring multiple passes at the same setting to mill a board to an even thickness across the full width.

There is some truth in what the Grizzly guy said, the scratches cut by the drum will be in the form of parallel grooves compared to the pattern left by a random orbit sander using the same grit. There really isn't any fault of the machine itself that could account for the result being scratchier than you expected. I'm sorry to say, but the problem may simply be your expectations.

But, are the grooves randomly deeper than they should be? You could be using poor quality abrasives with too many oversized grit particles in the matrix. All the grooves should be the same size across the wood. If the excessive roughness is due to many deeper scratches than the grit should include then I'd try a roll of abrasive from another company like Klingspor.

A high abrasive particle will leave an abnormal line in the work just like a chip in a planer blade except the line will be a ditch instead of a ridge. I'd rather scrape or sand a ridge down than have to mill the whole board down to the depth of that ditch so it pays to get the better abrasives. When I install a fresh roll of abrasive I run a scrap board through first to check for high grit particles. Sometimes I run a wide oak board through sideways to try to knock the high ones down a bit. Tall grits that simply get dull rather than breaking loose will burnish a groove into the wood rather than carve a ditch. The embossed groove will sometimes swell up when a finish is applied so it's a good idea to raise the grain with water or steam prior to sanding with the RO.

The depth you can sand in one pass depends on the size of the abrasive grits. 80 grit will only allow about 1/64". 36 grit might allow a fat 1/32" but 220 will only cut a couple thousandths in a pass. Unlike with a planer, more HP doesn't get you more depth except in allowing you to use a courser abrasive without bogging down.

The best way to get more work out of this kind of machine is to learn to change grits quickly, assuming you have good quality abrasives. Then you can continue down to 120 or better and keep the stock flatter for longer before using the RO. If I need a lot of stuff to be really flat I go to 220 on the drum sander before switching to the RO. If it's just a one off I use the belt sander with frame. If it doesn't have to be quite so flat and the edges are going to be relieved anyway I just use the RO for the whole sanding job.

 

[Dave Rudy]

I have the Performax as well although I havent had the chance to use it a great deal.  I have not had the experience you describe.  In effect, the drum sander should, as Michael points out, leave a scratch pattern similar to a linear direct-drive sander vs a ROS.  In addition to abrasive quality and loading on machine, I would ask one more question -- are you trying to sand too much in a pass?  Try setting the sander to just barely contact the surface of the wood and push up the grit to, say, 180 or 220.
The drum sander is basically a pinch point mechanism.  When you say slower than a planer, you're right -- much, much slower.  Not a good way to prepare stock to size as opposed to final (machine) preparation for finishing, is how I would look at it.

HTH

Dave

 

[Les]

Brandon,

I also have a Performax. You are not going to get as good a finish as with a ROS. Try angling the work piece so the scratch pattern is not straight with the grain. I assume you have a variable feed rate, try a slower rate with a few thousands depth of cut. Watch out for heat build up in the work piece. This can cause problems with flatness and parallelism. Make sure you keep the belt clean.

Bottom line is I never expect a finished piece from the drum sander.

 

[brandon.nickel]

Thank you all for your input.  I guess my expectations were just unrealistic.  I think I probably would have been better off getting a planer instead.  I've heard that some of the lunchbox planers put out a finish-quality surface.  I wonder if that implies that the bigger ones don't.  I'd love to pick up that $1600 Powermatic 15" planer.  Does anyone have any insight into the surface quality of a drum sander vs a lunchbox planer vs a large planer?

 

[cflansbaum]

I've actually followed this thread closely, as I've been thinking of getting a drum sander (probably one of the open ended Performaxes) next year.  Then I thought well maybe I should wait and save up for a wide belt sander (Grizzly makes a nice one).  But following this thread as well as one on the Fine Woodworking website is getting me to re-evaluate my thinking.  I have a Dewalt DW735 13" planer and just last week I realized I hadn't switched the blades in awhile.  I did and I forgot just how nice the finish is coming out of it.  I have a digital gauge mounted to it which is also a nice feature.  I know that one of the complaints about this machine is that it does go through blades quickly, but maybe I'll just settle buying blades more often instead of spending the money for a drum or widebelt sander.

 

[Eli]

WoodGeek,
If those are the same/similar to the blades that came with the DW744, I think you might be able to sharpen, although they are disposable.
E

 

[cflansbaum]

I'm not sure if they're similar, and at first I thought this was an option as well.  However I now understand that sharpening them isn't an option as they reference into a specific spot on the cutterhead - therefore any deviation in the size of the blade (i.e. after sharpening) can't be accounted for by repositioning the blade and will throw off the result... 

Carl

 

[Les]

You can get a "good" finish with either type of planer. But you will still want to sand to remove minor tool marks. The big advantage is you'll be able to start with 120 or 150 grit and quickly work your way up with the ETS 150. Only way to avoid sanding is either to hand plane or scrape. I have a Delta DC 380 15". At the time I bought it, most of lunch box planers still suffered from snipe. From what others have said the good lunch boxes have all but eliminated this problem. Don't know if you'd really need the $1600 Powermatic unless you plan on planing thousands of feet of rough sawn. Spend your money on a quality 8" minimum jointer and a lunch box.

 

[Eli]

I'm not sure if they're similar, and at first I thought this was an option as well.  However I now understand that sharpening them isn't an option as they reference into a specific spot on the cutterhead - therefore any deviation in the size of the blade (i.e. after sharpening) can't be accounted for by repositioning the blade and will throw off the result... 

Carl

Well make sure you save them anyway, they could prove valuable someday .

Just kidding, toss 'em.

 

[pteubel]

I've heard that some of the lunchbox planers put out a finish-quality surface.  I wonder if that implies that the bigger ones don't.  I'd love to pick up that $1600 Powermatic 15" planer.  Does anyone have any insight into the surface quality of a drum sander vs a lunchbox planer vs a large planer?

I have a Powermatic PM15 and a couple DW733 "lunchbox" planers. The PM15 can hog a full width board with little change in RPM (5hp Baldor). But I use the DW733s far more because 1) the finish surface is better and 2) practically no snipe. The PM15 snipes no matter what....not much when I use the molding board extension, but it's always there. Even the manual says snipe can only be reduced...not eliminated. It's going to be a dedicated molder soon.