Drum Sanders have been the stuff of professional shops for years, but only recently have tool manufacturers started to build a

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Tool Review:
The Delta 31-252 Limited Edition Drum Sander

Drum Sanders have been the stuff of professional shops for years, but only recently have tool manufacturers started to build affordable models that fit the average woodworker's budget. Delta was one of the first to come out with a drum sander that is reasonably priced yet constructed to be at home even in a production environment. The Delta 31-250 Wide Drum Sander was their first 18" model, then someone got the great idea of adding to it an extra long extension shaft, and a 4" pneumatic drum to make the sander much more versatile. Thus the birth of the Delta 31-252 Limited Edition 18" Drum Sander, which we will be reviewing in this article. Of course if you already own the 31-250, you can buy the components individually to turn your sander into the 31-252.

We'll begin the review with the unpacking of the sander and all the parts, then assemble it, set it up, and then use it to sand some boards! We'll provide you will all the stats on the 31-252, talk about all its good features and mention anything that doesn't seem right. I think by the time we're finished you’ll at least be interested in taking a closer look at the new Delta Drum Sander!!

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Since the base drum sander is actually the 31-250, the components that make up the 31-252 Limited Edition 18" Drum Sander come in separate boxes. Here's what you get in the four (4) boxes shown here:

31-250 - 18" Drum Sander
31-281 - Extra Long Extension Shaft
31-269 - 4" Pneumatic Drum
31-279 - Dust Tray

Be sure to have someone help you the day the truck arrives because the big box weighs in at over 190 pounds!

The manual instructs you to set the box on the floor with plenty of room on each side so you can peel the sides of the box away from its contents. You don't want to try to lift this heavy thing out of the box! When the box was still intact, the legs were laying atop the drum sander with foam wrap to protect the painted surfaces. The drumhead rests on top of some large pieces of Styrofoam to protect it from any type of impact shock while in transit.

The feed table is tucked neatly along side the drumhead to make for a pretty compact shipping container considering the tool's dimensions when it is fully assembled. Also inside the box were the manual and other documentation, a bag full of parts, and a few nice tools you'll need for set up and tuning.

Delta tells you to take a couple of 6" tall blocks of wood (I didn't have any blocks this large so I sandwiched a length of 4" x 4" between a couple of lengths of 2" x 4") and carefully tilt the head assembly back onto them so the legs could be mounted. Since the legs provide a much larger footprint than the 10 ¼" x 26 ¼" drum sander chassis, you need plenty of clearance for them while the unit is on its side.

The picture to the right shows the drum cylinder and pressure rollers facing the feed table support plate, with the feed table elevation screws in the fully down position. Notice that the bearings for the drum roller are mounted on the outside of the chassis. This is nice if you ever need to replace them but I can't see the bearings of this tool ever wearing out under normal conditions.

The 1 ½ HP, Single Phase, 115V motor is mounted beneath the unit with the belt running up to the drum cylinder pulley, and you have the option of two drum speeds, depending on what type of sanding you are performing. More on changing the speed later.

Take note also of the belt that runs around the inside of the chassis. You can see one of the table elevating screws in the bottom right corner next to the motor and how the belt passes along timing gears at all four corners and their respective elevating screws. A hand wheel attaches to the shaft extending from the front and a set of miter gears enables the table assembly to be easily raised and lowered. More on this later too.

This is a fairly large piece of machinery. Its overall size is 28 ½" wide x 24 ½" long x 46" high and it weighs in at 190 lbs. Not quite heavyweight but close! It also has a large capacity, handling stock up to 4" thick.

The picture to the right shows the motor arbor and dual pulley. As you can see, there are two different diameters on the pulley for changing the speed of the drum sander to 2210 sfpm (standard/surface feet per minute) and 3300 sfpm. The drum pulley has the same type of dual pulley, and changing speeds is a pretty simple task. There are a couple of knockout disks on the end of the unit that you have to remove, then using a 5/8" socket on an extension through the access holes you simply loosen the two motor-locking hex bolts to release the tension on the poly-v drive belt. Then move the belt to the appropriate pulleys for the speed you want (inner pulley is 3300 sfpm and outer pulley is 2210 sfpm), apply downward pressure to the motor until you have the proper belt tension (about 3/16" deflection midway between the pulleys) and retighten the two hex bolts. Put the knockouts back in place and you're done!

The abrasive belt for the feed table is attached to the table and the conveyor motor provides feed rates of between 0 and 15 sfpm. The tracking and tensioning of the feed belt has been set at the factory but the manual includes excellent instructions for testing and adjusting the tracking if the belt starts to wander towards one side or the other. The belt also needs adjustment if it slips on the feed drive roller during sanding operations. Delta states in the manual that the feed belt may need to be adjusted frequently for the first few hours of operation but I didn’t see evidence of any misaligned tracking or slippage until after a few hours of use.

The legs consist of two identical components which bolt to the base of the unit creating a very stable stand on which the sander is supported. As with all the metal chassis parts these are painted with a heavy enamel paint that should prevent rusting or corrosion and make cleaning as easy as wiping with a damp cloth or vacuuming with a brush attachment on your shop vac.

One minor difficulty I experienced when mounting the legs called for the use of a clamp to draw in the legs in order to align the boltholes. The legs were sprung outward a bit on the open side but after installing the bolts at each inside corner I pulled the outside edges in with a clamp until everything lined up. I was concerned at first thinking something was really wrong here but the solution is quite easy to perform.

After the two leg pieces are bolted firmly in place it’s time to stand this baby up. Be sure to have someone assist you here because the unit is definitely top-heavy and you may find yourself sliding it all over the floor without getting it in a vertical position. Once it is up though it is very solid with the wide footprint provided by the legs. Having had a set of four, lockable casters laying around unused in my shop for some time, I made some little adapter brackets to mount them to the four legs (not shown here) so I can wheel the sander around in my shop as needed. I would suggest that anyone do this unless you have the space to dedicate to it and bolt it to the floor, or better yet, buy a nice mobile tool base that will fit the base dimensions.

Once the unit is standing tall it’s time to install the feed table assembly. It’s bolted to the feed table support plate in four places with ¼"-20 socket-head screws, lock washers, and nuts. The feed table is extremely heavy with a solid cast-iron slab inside the belt so it might be wise to have a helper assist in the installation and alignment.

The feed table’s side rails have thru-holes that allow access to the elevation screw locking bolts. We’ll go into the table height adjustment in a little bit. Notice in the image above that the feed table rollers use brass bushings instead of bearings. Since the fastest speed is 15 feet per second it’s doubtful the bushings will ever show much wear.

In the image to the left you can see the lower portion of two of the elevation screws, the height adjustment belt and one of the two timing gears. A gear attached to the end of the shaft running from the height adjustment hand wheel mates with the unseen timing gear. When the wheel crank is turned the four elevation screws all move equally to raise or lower the table.

It is important that the feed table is parallel to the drum assembly. The manual states that this is already set at the factory but I found mine to be just a bit out of alignment. However, Delta provides clear and precise instructions on how to level the feed table and the operation is not that difficult.

You will use a 3" or 4" block of wood to determine the correct spacing between each side of the feed table and the drum. The elevation screws (one at each corner) are adjusted individually by loosening the locking screw then using a ½" wrench to adjust the elevation screws up or down as needed using the block of wood as a guide. The manual states that when sanding boards wider than 18" you’ll want the outboard end of the table to be set a few thousandths of an inch lower than the inboard side.

One very important thing you’ll want to know before you start using the drum sander is that this machine produces an enormous amount of sawdust! It is absolutely imperative that you connect either a dust collector or shop-vac to the dust collection port at the top of the unit before you begin using the sander. Since the port is a 4" diameter and my dust collector has 2 ½" fittings I had to fabricate a reducing coupler from some cardboard and duct tape. I have a single stage, 1 ½ HP dust collector that was adequate to draw most of the sawdust away during use. Without a means to remove the sawdust I can see it collecting enough to create problems with the idle rollers on either side of the sanding drum.

The Delta 31-252 Limited Edition Drum Sander comes with 120 grit aluminum oxide sand paper installed on the drum. Replacement is easy as the belt is made of 2" wide material and it is wound around the drum and secured with spring clips built into the ends of the drum cylinder (see image below). The drum cylinder is 5" in diameter and there are about eight rotations of sanding material, which makes the strip roughly 40" in length. Rolls of 2" wide sand paper is fairly inexpensive - not nearly what you’d pay if the unit used pre-made sanding drums! In the image to the left above I scored several deep gouges into a 1" x 12" pine board, then using the stock 120 grit sanding belt I made a single pass through the sander removing just enough material to take out the gouges. As you can see in the area between the knots on the image to the right the board is perfectly clean of the scratches. Not only that, but the surface comes out extremely smooth even with the rough grade of sand paper. With 280 or 400 grit paper you could expect to see smoothness comparable to what you’d get from a planer!

Sand paper replacement (From the Delta 31-252 manual).

Another great thing about the drum sander is that it will remove cupping from a board. In the left image above you can see about 1/16^th” bow in the middle of this red oak board. After a single pass through the sander the board is perfectly flat (image at right). I was worried that the tension of the infeed idle roller might compress the board such that the bow is flattened just before the sanding drum makes contact, much as you would experience with many planers, so I was pleasantly surprised with these results.

But the best thing of all when comparing the drum sander to a planer is that there is absolutely NO SNIPING on the ends! This means you can sand after you cut your board to length!! Most tabletop planers dig out a groove upon entry and exit whereby you have to whack a couple of inches of material off the ends of every board you plane. This produces quite a bit of waste over time and is especially troublesome when your raw stock is no longer than what you’ll actually need for your project.

The Delta 31-252 Limited Edition Drum Sander turns out to be extremely durable and heavy duty. The slab of wood you see at the right here is 1 ¾" thick maple 27" wide by 40" long, weighing in at over 70 pounds, but the sander took it without any difficulties whatsoever. I was able to bog the sander down to where the belt began to squeal by taking too big a cut but I found after some trials that a quarter turn of the hand wheel removes about 1/32" or so without problems.

Take notice of the controls on the left side of the machine: the red safety switch at the bottom controls the power of the drum sander and the potentiometer above it controls the on/off and speed of the feed table. If you need to shut the sander down in a hurry just slap the red button but to turn off the feed table you have to crank the knob all the way counterclockwise.

As mentioned before, the feed table speed can be adjusted from 0 to 15 surface feet per minute and anything between. I find that when taking off material to dimension my lumber a faster feed rate helps reduce the time spent sanding but when I go for the final clean-up pass I slow the feed rate all the way down to 1 or 2 sfpm to get the smoothest finish – even with the rougher 120 grit sanding belt.

The Limited Edition unit comes with an additional 4” diameter pneumatic drum sander that mounts to the outside of the unit for freehand sanding of edges, profiles and such. An extension shaft mounts to the end of the long arbor on the drum sander and is secured with a couple of hex head set screws using a special T-wrench that comes with the package.

The long extension shaft needs to be centered through the hole in the chassis but as you can see in the image to the left the shaft on my sander was off considerably to the right. The only way to solve this problem and center the shaft is to loosen and adjust the end plate of the sander chassis.

This exercise was not difficult at all as there are only eight bolts to loosen and plenty of slop in the holes to move the plate enough to center the shaft.

The second image of the extension shaft shows that it is now centered through the side plate of the sander. Visible also is one of the two set screws used to secure the shaft to the main hub.

The pneumatic drum sander has a standard air fitting on the end of the inflatable cylinder, which allows you to set the firmness of the drum for different sanding applications, profiles, and materials. The installation instructions for the pneumatic drum stress that after the abrasive sleeve is in place only a hand pump should be used to inflate the cylinder to a maximum of 8 psi. Unlike the main drum of the 31-252 which uses 2” wide sanding belt material, the pneumatic drum requires pre-made sleeves. The sleeves can be ordered in the following grits:

§ 80 grit (Medium)

§ 120 grit (Medium)

§ 120 grit (Fine)

The unit comes with the 80 grit sleeve which is suitable for most sanding applications except for really fine finishing. In tests I made with the pneumatic drum I found it to be quite aggressive at removing material if strong pressure is applied but is capable of a fairly smooth finish as well when using a lighter touch. When using the additional sanding drum, always remember to position yourself on the power switch side of the 31-252, which pulls the work piece away from you.

As a part of the 31-252 package a dust chute or dust collection tray is included for the pneumatic drum sander. It features a quick clamping assembly that allows easy removal of the tray should a larger area of the drum’s circumference be needed. When in place and connected to a dust collector or shop-vac, the dust tray does a great job of pulling the dust away. With the dust collector off a cloud of dust builds around the drum pretty quickly, so it is a very useful item to have for your health and safety!

Having seen the results on boards passed through a huge Performax drum sander at a local wood supplier some years ago I knew then that this was a tool I would love to own. Of course at the time that particular machine cost thousands of dollars and was the size of a Buick! But times have changed and the industry has, over the past few years, realized the huge potential in the casual woodworker and small shop owner. The result of this is the infusion into the market all the affordable bench planers, jointers, power miter saws, etc.. that we have gladly purchased for our garages and shops. Delta is certainly one of the leaders in recognizing these trends and supplying us with a wide variety of affordable woodworking tools.

The Delta 31-252 Limited Edition Drum Sander, at just over $800, is easily an affordable tool for even the smallest of woodworking shops of professionals and hobbyists alike. The quality is what you would expect of Delta – top-notch – and the features you get for the price, such as the 36” width capacity and an excellent variable speed conveyor system, make this a tremendous investment for your shop.

I have run a couple hundred board feet of lumber through my 31-252 in many widths, thicknesses, and species, and so far I have no major complaints about this machine. It’s relatively easy to assemble (with some muscular assistance!) and set up, and tune-ups are simple to perform when required. I’ve even ‘benched’ my bench planer lately in favor of using my bandsaw to resaw boards then finish the dimensioning with the drum sander. I save quite a bit of material this way and the timesavings are enormous. You know what the piles of sawdust and shavings looks like beneath your table saw and planer after dimensioning lumber for even the smallest of projects!

Also, I no longer worry so much about individual board thicknesses when gluing up tabletops and such because I know I can run it through the wide sander and come out with a perfectly flat, smooth surface. You can’t do that with your 12” planer! And then there’s the snipe issue that you don’t have to contend with when using the drum sander; a nice change from what I’ve put up with from my planer all these years. I suppose I could get by without this tool but now that I’ve owned and used one I wouldn’t want to have to do without!

In closing, I’d like to pay special thanks to Woodworker’s Supply for working with me on this project. These great folks have a wonderful selection of tools at great prices and can ship to you anywhere in the country. They carry an extensive selection of fine Delta machines, including the 31-252 Limited Edition Drum Sander and its accessories, and would be delighted to help you with any tool needs you may have. Check out their web site at www.woodworker.com today and order their free catalog!