Rollers that move individually make it easy to pull heavy sheets of plywood and MDF in and out without disturbing the other sheets.  I was inspired to make this by a tip from from American Woodworker magazine, and made it for my small storage space at Techshop San Francisco.

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The design of the whole system was purpose-built for my space, but the same basic concept could be used for storing sheets in any shop. For me, in addition to helping me corral my plywood, this will also serve as a nice high shelf and will become a place where I will mount an assembly table (as shown in my Sketchup model).

I tried to make the directions and pictures as clear as I could, but it was a little difficult because I was figuring out this whole project as I went along, making little changes along the way. If anything is unclear, I've also included the entire Sketchup model of the project so you can see how things were put together.

Tools used

• Chop saw
• Table saw
• Wood lathe w/ roughing gouge
• Drill bits:
  • 1/2 inch bit - for allowing 1/2 inch bolts
  • 27/64 bit - just under 1/2 inch, for threading 1/2 inch bolts into wood
  • 9/16 inch bit (or anything just over 1/2 inch) - for rollers to easily roll on 1/2 inch bolts
  • 1.5 inch forstner bit - optional
• Drill press
• Hand drill

Materials used

• Kiln dried fir 2X4 studs
• 2 inch thick maple
• 3/4 MDF / plywood
• (4) 1/2 inch hex-head bolts - 12 inches long 
• (4) nuts for 1/2 inch bolts
• (68) washers for 1/2 inch bolts
• Wood screws
• Wood glue

I used a wood lathe to make my rollers, but any method that can create neat circles should work. You could use a circle jig for the bandsaw, use a hole saw or fly cutter, or just cut up a round dowel or curtain rod

Pictured first is a photo and model of the finished rollers. The rollers are made of stacked 1/2 inch maple discs separated by washers to help them spin freely. Instead of making individual discs, I started with long rods on the wood lathe, which I later sliced into individual rollers.

Making rollers

1. Cut the rod into a square profile
2. Find the centers on each end of the square rod, and use those centers to chuck it into the lathe with a live center.
3. Use the roughing going to round out the entire rod
4. Check the rod for consistency with a pair of calipers. Mine all came out to around 1.65 - 1.68. If the rods need further rounding, continue with the roughing gouge or switch to a skew chisel to smooth out the surface.
5. Next I had to shorten the rods for drilling holes into the centers. I cut each rod in half, making it slightly shorter than the length of my 9/16 inch drill bit
6. Use a 4-jaw chuck to mount one side of the shorter rod into the lathe. When mounting, use the tip of the drill bit or a lathe-center on the other side to make sure the rod is centered in the jaws.
7. Slowly drill into the end of the rod. I started with a 5/16 bit to make my pilot hole, then stepped up to a 9/16 bit. I had to make each hole with several plunges, because the swarf from drilling would clog up the hole and start smoking.
8. After I had all the rods drilled out, I switched to the bandsaw to cut them into individual rollers. I used a cradle sled that I made for cutting wood-rounds from logs. Be careful even with this setup - the bandsaw will try to make the rods roll in your hand. To measure each disc, I just marked a line 1/2 inch from the blade and 
9. After I had all the rods drilled out, I switched to the bandsaw to cut them all into individual 1/2 inch rollers. I used a cradle sled I made for cutting wood-rounds from logs. To measure each disc, I just drew a line 1/2 inch from the blade and measured each cut to the line.
   • Be careful when using this bandsaw setup - the motion of the blade will try to make the rods roll in your hand. The V-shaped cradle helps control this, but you have to keep a firm grip just to be safe.

Fixing mistakes

To be honest, I made a mistake when I first started drilling my rollers. Instead of using the 9/16 bit from the start, I first used a 1/2 inch bit to match my 1/2 inch bolts. Unfortunately, 1/2 inch holes will not roll around a 1/2 inch bolt - there is too much friction. I only thought about this part way through my work and forgot to fix a couple of my rods before turning in the lathe tools. To fix these holes I had to mount pieces in the drill press and finish the job.

This worked pretty well, and actually went faster than drilling with the lathe. If I had a reliable way to center the rods I might use the drill press for such work in the future.

Next I made the base of the stand where I could mount my rollers. I used two 2X4 studs, and made sure to check them carefully for warping - at least one side of each needs to sit very flat on the ground.

Drilling the base

1. I cut each 2X4 slightly short to 7 feet, so that the sheet goods would have a little overhang outside of the storage case, to allow for easy sorting through pieces.
2. I clamped the 2X4s together so that I could drill holes through both at the same time to ensure a perfectly matching layout. Again, make sure that the floor-side edges are both flat and flush together when clamping.
3. Next I laid out the pattern for my rollers. I used a measuring tape to space out the holes, and then used a combination square to make a cross-hair down the center of the board at each mark. 
4. I spaced the first two holes close together, allowing me to store short pieces in the front supported by at least two rollers. I put the last roller further back, making sure that long pieces were fully supported.
5. I gripped the clamped boards in a vise to hold them steady while I drilled them on the drill press.
6. First I drilled a 27/64 inch hole into each marked spot.
7. Next I used a 1.5 inch forstner bit to make a 3/4 inch deep stopped holes on the OUTSIDE faces of each board. This is to allow a socket wrench to tighten the nuts and bolts beneath the surface of the wood. This step is optional - I just wanted my hardware to be buried.
8. Finally, I separated the boards, and widened the 27/64 hole to a full 1/2 inch hole. This will allow me to push my bolts through one board and still screw the bolt threads into the other.

Assembling the base

1. I laid out the boards side-by-side, and pushed the bolts through the board with larger, 1/2 inch holes. I had a lot of resistance, but that was good - since I want both sides of the bolts to be held tightly. I had to hammer each bolt in to get it started.
2. Then I put rollers and washers over each bolt, leaving enough space for the bolt threads to go into the second board
3. Next I pressed the threaded ends of the bolts into the holes, and one-by-one started tightening the bolts until they all sunk into the board. This step wasn't easy, and is something that could probably be improved upon if making another one of these.

My problem with the last step is that while it's easy to thread one bolt into wood, it's difficult to thread 4 bolts in at the same time evenly. At first, I tried tightening one bolt, then moving on down the line, but tightening each bolt put stress on the other ones, and while I was busy tightening one, the others were busy popping out of their holes again.

In the end, I had to cycle back and forth, tightening each bolt just 1-2 turns at a time, then the next one, and the next one, etc... This worked, and I'm happy with the rollers in the finished product, but they still didn't all end up even in the end.

To make sure the boards stored on the rollers didn't spill out into the rest of my cage, I made a frame around the roller assembly - which will also eventually become part of a shelf system and a place to mount an assembly table.

The parts for the cage include: 8 vertical posts, 4 horizontal braces, a set of stilt-feet for the whole system, and some pieces of scrap 3/4 inch plywood for making a shelf on top of the system.

I assembled the whole unit while sitting up on several stacked 2X4s. This was because I have to work around the awkward base of a pillar that rises up through the back of my cage - the whole unit has to be lifted 3 inches high.

Assembling the frame

1. First, I screwed the vertical 2X4s directly to the roller base. Each vertical was 55 inches tall - giving a generous clearance for the 48 inch wide sheet goods. I placed the first vertical right at the front of the unit, and placed the other supports just behind each roller bar.
2. Next, I put a top brace between each vertical post. I used an F-clamp to hold the pieces together while I drilled pilot holes and screwed them together. I made sure to put each top brace just UNDER the top of the vertical posts - to make sure I had a nice, consistent surface for mounting my shelf next.
3. Finally, I screwed the plywood shelf pieces directly through the tops of the vertical posts. I didn't have a piece long enough to fit across the whole top when I made it, so I made it in 3 sections from scraps. I attached each piece to 2 different vertical posts, to make sure they worked as braces and pulled the whole structure together

I should note that I didn't have my parts ready from the start, I cut them in several stages. First, I cut the vertical bars - then after mounting those I measured the distance between opposite posts and cut the top braces, and finally I measured the distance between mid-points of each vertical post and cut the plywood shelf / braces. This took a little longer, but I'm happy with the result.

The rollers work great! I currently have a full sheet of MDF, some large pieces of particle board and various sized pieces of plywood. Even when stacked cloth together ,they all roll out individually when I pull on them. I can roll individual sheets directly out onto the floor or a waiting sheet utility cart. The top shelf is also pretty strong and steady - though it would be rock solid if I could secure some of the vertical studs to a wall (my current space doesn't allow for that).

Soon I'll be adding my assembly table, with a couple shelves underneath for storing small sheets.