(click photo to enlarge)

This is my shop built 22 inch tilting table drum sander.

In preparing to build my version of the drum sander (sometimes called a thickness sander), I looked at commercial versions and several shop-built versions on the Internet. Most shop built models used variations of the basic plans published in "Power Tools and Accessories", a good, solid machine, but I had several requirements that I wanted to incorporate that made this option unacceptable, so I went at it on my own.

First, I found that most of the shop-built sanders used a single screw mechanism to raise and lower the table, i.e. a threaded rod or bolt located at the front of the table that, when turned, raised the table at a single point. This (to me) seemed to be a bit unstable unless you used some sort of locking mechanism on the sides to hold them tight. Without side locks, no matter how well the table is secured at the far end, you still had the potential for wobble or misalignment on the sides. I wanted a single solution to lift the table securely across its entire width, without the need for any sort of stabilization. I came up with a hinged sled mechanism that fills the bill nicely, and is ultra stable.

I also did not like the vertical stand...all of my shop tools have canted legs, titled at around 15 to 17 degrees, which makes them very stable and less prone to tipping. So, I wanted a stand that had these canted legs.

I did not particularly like the pillow block bearing sitting up on top of the stand of many of the shop built units I saw. Again, (yes, I am a stability freak!) it just looked like it would/could weaken over time and allow wobble or misalignment to creep in. So, I used three bolt flange bearings I found at an Internet surplus center (all of my sources are included below). These bearings bolt right to the sides so there is lots of stability.

Finally, I have never liked the "hanging motor" type of tensioner. I like everything nice and tight. So I bolted my motor flat to the stand and used a v-belt that was the correct size for the pulleys. Tightening the motor to the table pulled the belt exactly tight enough without putting much stress on the bearings.

Other features I found on shop-built sanders were difficult to improve on so I incorporated them as I went along.

Here is my construction as it progressed. As of this time, I have yet to complete the sawdust collection; my sawdust collection system consists of a 6hp shop vac, so I don't have a ton of suction...I need to be conscious of how I direct the suction to maximize its effectiveness. I am still thinking of what to do there.

Here is how it went! Let me know if you want me to expand on anything! Note: click on any picture to enlarge it in a new window.

Here are the major hardware parts. You can see the 3/4" keyed shaft I used for the drum. There are the two flange bearings. Two pulleys, and key way keys. Best of all was this massive piano hinge. Turns out is was military surplus and really thick aluminum. No holes either, so I got to drill my own only where I needed them. Here is the parts list with stock numbers and source:

Part Number Description Price
1-2982-75-3 3/4" X 36" KEYED SHAFT $22.75
1-1974 2.25" DIA 5/8" BORE PULLEY $1.99
1-BK57-C 5.45 O. D. 3/4" BORE PULLEY $9.00 
1-2870 3/4" 3 BOLT FLANGE BEARING (2) $7.90
1-2994 2 X 1 SWIVEL PLATE CASTERS (2) $3.78
1-2283 3" x 50" ALUMINUM PIANO HINGE $4.99

Source: http://www.surpluscenter.com

Note: click on any picture to enlarge it in a new window.

 

These are pictures of the basic stand construction. The legs are canted at about 15 degrees. Note that the top cross braces are made of two pieces of 3/4" plywood laminated together, cross grain, for rigidity. The dados in the horizontal table support are for the elevating sled. These will be the sled tracks. Note the 1-1/4 inch hole in one of the laminated cross braces for the drum shaft to protrude through. It needs to be oversized to allow the shaft enough room to be dropped in at an angle (see below). The 1/4 inch vertical dados in the top cross braces will be for the dust hood to slip into. All joints are dado or half lap, then glued and screwed, for stability. Though not really visible here, the shelf supports at the bottom are beveled 15 degrees to make them parallel to the floor so that the motor shelf will lay flat across.

Frame made of 2x4 construction. I scrounged the lumber from old election signs that were left standing after the elections were over. Some of them needed to be run through the planer to scrape off the weathering.

Note: click on any picture to enlarge it in a new window.

Drum construction is pretty much like all of the other shop-built sanders. I used MDF, cut 4 inches in diameter. The MDF was from some cabinet doors I had laying around from a neighbor who replaced his kitchen cabinets. I rough-cut the 32 disks with a jig saw then I used a circle-cutting jig on my router table with a straight cutting bit to shape the disks. Here they are glued together using Gorilla Glue. You can't see the shaft behind the pipe clamp.


 

Here are the preparations for mounting the table. The table is made of two pieces 3/4 inch ply with a layer of 3/8 inch ply in between. I oriented the plywood so that each layer was cross-grain to the one below it (for stability). You can see that I have the motor mounting shelf installed and the motor positioned for the mounting holes to be drilled. Note the monster hinge! This hinge is really huge compared to the ones I saw at Lowes and Home Depot. I used 3M weatherstripping adhesive (the worlds toughest glue) and screws to mount the hinge to the stand. The table is only temporarily fastened at this point.

The motor mounting shelf was made of cabinet grade mahogany plywood that my brother-in-law scrounged from a boat building shop. The plywood for the table I got from a construction dumpster at a home being built nearby.


 

Mounting the drum to the stand. I inserted the shaft through the hole in the frame, then clamped the other end to the support and maneuvered it around until it was square to the table and the shaft 90 degrees to the stand. Then I marked the mounting holes for the bearings, removed the drum and drilled the holes. You can also see the little mounting plates I made instead of using washers to take some of the stress off of the plywood. I made them out of some aluminum I found along the road (formerly a Speed Limit sign that had been hit by a roadside mower and cut up pretty badly...this is some sort of special aluminum alloy, very rigid!).


 

Sled construction. First, I cut a piece of that cabinet grade plywood to fit in the sled tracks in the frame. It is not cut to size yet, since the size will be determined by how far the sled needs to travel back and forward. Next, I raised the table to within 1/8 inch of hitting the drum (first picture), then with the table held at that position, I measured the distance from the top of the sled to the bottom of the table. This will dictate the height of the riser, or the piece of wood that does the lifting. With this dimension, I cut the riser (seen in the third photo). I mounted the hinges (left over from that massive piano hinge) onto the riser, then mounted them onto the sled. To determine where the hinges would be positioned on the sled, I placed the riser on the sled and moved it around until the riser was short of being 90 degrees. In other words, when the table has been lifted all the way up, the riser will not quite be straight up, it will be maybe 60 degrees to the table.


 

Photo 1 is a simple side view of how the sled elevation works. Photo 2 shows how I marked the mounting holes for attaching the sled to the table. Once I got the positioning right, there was no easy way to get a pencil in to mark the holes, so I drilled a 1/4" hole in a piece of slender scrap and then cut the head off of a pencil and inserted it in the hole. This gave me the 90 degree marker I used in photo 2. I only needed to mark a couple of holes. Next, I removed the table and positioned the riser hinges over the holes I marked and marked the remaining holes, then I pre-drilled all the holes for screws. After the sled riser was mounted to the table, I flipped it over and slid the sled into the tracks (photo 4 above). Now I am ready to cut the ends of the sled to the right length for bottom and top elevation control.


 

Table elevation will occur as the sled travels forward and backward in the tracks. To control where the table stops in the all-up and all-down positions, the sled ends are cut so that they bump into the table supports in the front and back of the sled. In other words, when the sled goes back as far as it can go, the table should be just reaching its full-down position. And, when the sled travels forward as far as it can go, the table should be within 1/8 inch of the sanding drum. In photo 1, I have blocked up the sled hinge so I could take the picture. You see that the front of the sled has been trimmed so that it now will butt up flat against the front table support (which will be rabbeted 3/4 inch in). Now, I needed to build the height adjustment mechanism. The sled will travel back and forward by means of a threaded rod running through the front table support to the middle table support (the space occupied by the sled). The sled will have two nuts fastened to it so that when you turn the threaded rod, the nuts will move along the rod taking the sled with them. I thought about this arrangement for a long time, specifically, how can I attach the nuts securely to the sled. Remember, these nuts will bear the force of the downward pressure as you are working on the table, so they need to be really securely mounted! I decided to use steel flat stock I had left over from another project. The flat stock was something like 1 1/2 inch by 1/8 inch stock, standard stuff you can get at any hardware or home improvement store. I cut off a piece about 5 inches long (photo 2). Using the vice and a big hammer, I created the little "nut holder" bracket in photo 3 and 4. As you can see in photo 4, the nut is already installed in this photo. Since I didn't have any welding skills, I went to a friend of mine who has one of those wire welders and he spot welded the bottom of the nut onto the bracket. To do this, I slipped the nuts into the brackets I made and then I ran the brackets and nuts onto the threaded rod. This guaranteed that when they were welded, the would be properly aligned.


 

Continuing on with the bracket installation, I positioned the brackets on the threaded rod so that they would be installed at the front and rear of the sled. Then I squared the rod to the sled and marked the mounting holes, then removed the threaded rod and installed the rod brackets to the sled. Next, I needed to mark where the threaded rod holes would be located in the table supports, so I put the threaded rod back into the brackets and reinstalled the table and sled on the stand. Then I bumped the threaded rod against the table support (photo 4) so it would mark where the hole needed to be. After I drilled the hole in the middle support, I did the same thing for the front support and drilled that hole.


To prevent the threaded rod from wallowing out the hole in the front table support, I made a bushing from a 1/4 inch iron pipe nipple, available at any hardware store. The threaded rod fits very nicely into this pipe nipple with very little slop. First, I cut a little slot in it for my screw driver to fit into, then I screwed the pipe nipple into the front support. The middle support needs something different...as you turn the threaded rod to elevate the table, the pressure of the table will be pushing the threaded rod back against the middle table support, so I need some sort of thrust washer arrangement. Here's what I decided to do... I had some old roller skate ball bearings laying around. These are available pretty cheaply at at most sporting goods stores. However, the inside diameter of the bearing is a little less than 1/4 inch (must be metric), too small for the 7/16 threaded rod. So to bring down the size of the rod, I installed the threaded rod in my drill press and clamped on a board with a 7/16 inch hole to keep the rod from wobbling. Then I spun the rod at a fairly slow speed and used a metal file, held against the rod, to whittle away at it. Once the size was right, I removed the rod from the drill press and cut off the excess, leaving the small piece on the end of the rod. In photo 5, see how the rod now fits perfectly into the bearing.


 

Now I needed to make the bearing holder in the middle support. I decided that the pine would be too soft to offer good bearing support, so I cut a piece of Maple into a block about 1 1/2 inches by 1 1/2 inches by 1/2 inch thick and drilled a hole just deep enough for the bearing to fit flush. Then with a wood chisel, I cut out a square hole in the middle table support for the bearing block and glued it in. Photo 1 above shows the bearing block installed and the threaded rod fitting nice and snug. This should give a really secure surface for the rod to push against, as well as making turning the rod very smooth! Even though the critical thrust is always to the rear, I didn't want the threaded rod sliding forward either, so I drilled a small hole at the point where the rod just met the front table support. Here, I will install a big flat washer and a cotter pin to keep the threaded rod from sliding forward. I drilled another hole up toward the front of the threaded rod to hold the hand crank. I picked up the crank at our local overstock store. They carry a bunch of stuff all the time from stores that have closed, had fires, etc. The crank looks like it came from some sort of small ice cream maker. The crank had a tiny hole on it for a shaft or something, but I took a 7/16 inch nut and put it on my electric stove burner for a few minutes until it was hot enough to melt through the plastic, then I pressed the nut into the crank, letting the nut melt itself into the plastic. Next I drilled a hole in the side of the hand crank, through the nut, that aligns with the hole in the threaded rod, then I screwed the crank onto the rod and inserted a cotter pin to keep if from spinning off.


 

I don't have any pictures of attaching the surface to my table, but that is pretty standard stuff. I found some 4' by 8' fiberglass sheets at my local salvage construction supply yard. It looks like it was for shower stalls or something. It is really thin, like maybe 1/32 inch thick. Since it was only $5.00 per sheet, I brought it home! I cut out a chunk the size of my table and laminated it to the table with contact cement. It makes a really nice, shiny, surface, and appears to be really tough and the wood slides easily over it. You will see it in some of the following pictures. Anyway, next it was time to true the drum, which again, I did just like the other shop-build drum sander builders did. I hooked up the motor to the pulleys (Photo 1), then I used an old belt sander belt glued to a flat piece of plywood. I just slid the plywood in and out under the drum as it spun until it was perfectly round and true to the table. Next (again copying the other builders) I wrapped a string around the drum and marked the string for the diameter of the drum. Then, I used this string to cut the sand paper belt I bought on eBay. As you can see, the string gives you the exact dimension to cut your belt so when it is wrapped around the drum, it doesn't hang over.


To attach the sandpaper to the drum, I cut a slit in the end of the drum with my Dremmel tool, just wide enough to tuck the end of the sand paper into, and about 3/8 inch deep. Then I screwed a 3/4 inch long hex head screw into a predrilled hole in the middle of the slit. The screw threads press tightly against the sand paper as they thread into the drum and do a good job holding the sanding belt tightly on the drum. Next came the dust hood. I had already cut the 1/4 inch dados in the side supports before I assembled the stand. The sides and top are just 1/4 inch luan plywood. To join the sides and top, I made a little corner piece out of 1 inch by 1 inch stock. As you can see in photo 2 above I first cut the 1/4 inch dados on my router table, then I knocked off the corners on the table saw.When installed, the sides extend beyond the corner about 1/4 inch so they can slide into the dados on the side of the stand. The top extends over about 1/2 inch on each side to catch the top of the stand so the dust hood doesn't slip down onto the drum.


 

The guard covers the pulleys and belt to keep my shirt on my body and not wrapped up in the mechanism! I found some sheet metal, like the kind a heating and air conditioning duct would be made from, at the local overstock store. It was 70% off which made it about $3.00! I don't have a metal working brake, so I just shaped the guard using a 1 x 4 which I laid on the line and then held with my knees as I bent the sheet metal upward. Then while I was still holding it down, I gently tapped the edge with a hammer until the bend was tight. It isn't real pretty, but it sure works well! It screws onto the side of stand. The wheels are just 3 inch casters I picked up at Harbor Freight. I glued a block on the inside of the back legs and the wheels simply screw into the legs there. I did have to modify the wheel mounting bracket by cutting off part of the mounting flange (see photo 4 above). This part was hanging over the wheel so this configuration wouldn't work if it was there. The flat part I cut off goes right against the floor. I also drilled a hole in the middle of the flange since I lost the other two mounting holes.


That's about it! I leave you with some pictures of the finished product. Let me know if you have any questions or comments. Also, I'd like to know your thoughts on the dust collector...as you can tell, it still doesn't have a connection to the vacuum system. I use a 6 hp shop-vac for dust collection, so my suction is limited and it needs to be directed to be effective (versus just a simple connector stuck up on top of the dust hood). Since all of the sawdust will be generated immediately in front of the sanding drum, I am thinking about a flat funnel shaped thing that I could mount on the front of the dust hood that would have maybe a 1/4 inch slit opening that would be positioned so the slit would be right at the bottom of the dust hood so it would be sucking the dust up at the point where it was being generated. When I finally have something built, I will post it here! Your thoughts and ideas are welcomed! Contact me.


***UPDATE***
Okay, I finished adding the suction device to the dust hood...it works really great!

I took that really wide floor cleaning attachment that comes with the shopvac and I modified it to fit on my dust hood. When you realize that most of the dust comes right off of the front of the sander as you push the wood through, I figured rather than just stick a connection on top the dust hood like some folks do, I wanted to catch the dust as it is generated! This is what I have done...I made a narrow chute that has about a 3/8" opening (more or less) and runs the width of the drum. This chute gets wider toward the top so that it can fit around the vac attachment. I placed a small spacer rib in the center of the chute to keep the thin luan plywood from bending in or out at this point...you can kind of see the end of that rib in the center of the chute in photo 2 above. I am thinking about adding one of those little sweeper-seals to the front of the chute to REALLY concentrate the vacuum toward the work piece. I just haven't found such a thing yet.

When the sander is operating, I have the shop vac hooked to the attachment, the hose running straight up and over to the vac, totally out of the way. As you would expect, the suction is amazing since all of it is totally concentrated to that single little slit in front of the sanding drum. I am really happy with the way it turned out.

Many, many thanks to the other drum sander builders who have taken the time to post their projects to the Web. You guys got me motivated!
     Home-made Thickness Sander
     Shop Made Drum/Thickness Sander
     Homemade Drum Sander
     A Shop-Built Drum Sander by Ray Lanham
     Sturdee’s drum sander

Also to the guys on the shop-built tools forum for their inspiration.