Introduction: Exploded View Bench
The idea behind this was to make a bench that looks like it is in the "exploded" view as in how it might look in a CAD rendering; where you are looking at how the components fit together and said components are hovering slightly away from one another. I made this using 2 inch x 8 inch x 8 foot construction lumber, 1/2 inch rebar, 4 inch "L" brackets, screws and construction adhesive.
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This is a fairly simple build that doesn't require a lot of tools or precision. The first thing I did was clamp the lumber to my workbench. Using my circular saw, tilted at 45 degrees, I cut an angle the length of one side, only one side the other side does not get cut. Then I repeated this step for the other 2x8x8.
I wanted the top to be 4 and 1/2 feet in length so I measured from the middle of the board out 27 inches to the left and right of my center mark. You want the bench top to come from the middle section of the boards. Here again using my circular saw tilted at 45 degrees I made the cut. I clamped a straight edge to the board to help guide my saw. Pay attention to the direction of the angle; you want the top to be a trapezoid and not a rhombus. Cut both 2x8x8s to the 4 and 1/2 foot length.
Earlier I said this doesn't have to be super precise this is what I mean. Here you can see the cut drifts and is not straight. That is actually okay because since my miters don't have to actually touch they can be less than perfect. Small variations like this will not be noticeable once the pieces are assembled.
Now its time to cut the 45 degree angle for the legs. Its the same process as the top you just have to make sure the angle you make matches the bench top. I will talk about the measurement in the next step. Also here you can see I got a little better at making the angled cuts.
Here I am trimming the legs down to size using my cross cut sled this could have been done with my circular saw as well but I chose to use the table saw. I wanted the bench to be 18 inches tall but screwed up and ended up making these about 16 inches tall, it still works its just a little lower than I wanted.
The second picture shows the mitered cuts on the leg this should be what you end up with once you are done cutting.
Here is a quick mock up of one half of the bench. The center, the part laying on the cement are all flat. The sides facing up all have a 45 degree angle cut or a large bevel.
Now the not so fun part, the sanding. I used an angle grinder with a flap disc to get rid of the major saw marks. It makes quick work of rounding over the edges too. Then it was time to palm sand all the wood. This took quite a while. I sanded up to 220 grit.
* Limited tool disclaimer - (I know I stated you don't need a lot of tools for this project. I did use my angle grinder for this but it can be done with a palm sander or even by hand. I paid less than $20 for this angle grinder and I can say it is one of the best purchases I have ever made it has more than paid for itself.)
The rebar is going to serve as the connection points. I used my angle grinder to cut eight 4 inch pieces and eleven 5 inch pieces but I only ended up using nine 5 inch pieces. I ended up cutting more than I needed I changed my mind on the design after I did a quick mock up.
* Limited tool disclaimer - (You don't have an angle grinder you can use a hacksaw for this, it will just take a lot longer)
Using my angle grinder again with the flap disc I smoothed out the tips of the rebar. 1/2 inch rebar is slightly bigger than 1/2 inch. And the holes I would be making are 1/2 inch so I needed to remove some material for a good fit.
* Limited tool disclaimer - (don't have an angle grinder, you can use a file for this it will just take longer)
I divided that bench top in to 5 equal sections and marked where my holes would go. I used my dowel jig to drill the 1/2 holes. The blue tape is my depth stop. The rebar dowels are 5 inches long and I want 1 inch to be exposed so I make sure to drill a hole that is 2 inches deep. I check the fit with one of the rebar dowels.
* Limited tool disclaimer - (I realize I am using a specialty tool for this part of the process but this could also be done with a piece of scrap and a couple of clamps. You could probably even just free hand drill this.)
I repeat the process for the legs making sure to line up the marking with the mating piece. Then again using my doweling jig I drill the holes to the same depth.
The dowels were still a little to large in diameter even after grinding so I chucked up one of the rebar dowels in my drill and then reamed out all the holes. This worked nicely to enlarge the holes just enough for the rebar dowels.
First I assemble the legs. I used construction adhesive since I was joining the two different materials. Plus the construction adhesive is rather thick and helps fill any voids/gaps due to the imperfect nature of the rebar. Some of the rebar had a tight fit so I used a hammer to persuade it in to the hole.
I squeezed the two sides together. The clamps are not really tight they are just there to maintain the 1 inch gap. I thought the construction adhesive might expand and push the pieces apart so I added the clamps. Not sure this is necessary but better safe than sorry. Also make sure to cleanup any of the construction adhesive as you assemble the pieces.
Now I repeated the process for the bench top. I set this aside and let it dry overnight. I didn't use clamps on the bench top because the fit was pretty tight.
I propped up the pieces next to one another as they would be assembled and used a small diameter drill bit to make eight reference holes. Two in each board of the bench top. These reference holes will let me see where I need to drill holes for the rebar dowels in both the bench top and the legs. This will probably make more sense after the next few steps.
Using one of the cut offs I made a jig that would help my drill straight holes in the mitered section of the bench top. I clamp the jig to the bench top and drilled 1/2 holes at my reference marks, the ones I drilled in the previous step with the small diameter drill bit. These holes do not go all the way through the bench top they stop just short. Then I test fit the 4 inch rebar dowels.
* Limited tool disclaimer - (This is the kind of jig you can make with scraps fairly easily.)
For the legs I was able to use my dowel jig for the holes on the legs. If you look closely you can see "x" marks, those are my reference holes that I drilled with the small diameter drill bit earlier. As long as I drill in those spots my rebar dowels should line up.
Assembly time again. More construction adhesive in all the holes, then I gently tap the dowels in to place. Then I fit the legs to the bench top. One thing to note is that when I made all my miter cuts I tried to keep the grain direction the same and from the same board. In doing so the grain flows from one side of the bench to the other giving it a continuous look.
I lightly clamped the legs to the benchtop to maintain a 90 degree angle on both legs. I let this dry over night.
I applied five coats of dark walnut Danish Tung Oil to the bench per the instructions on the can. I really like this finish because its easy to apply and dries relatively fast. I don't add a protective finish, like a polyurethane top coat, because I enjoy the feel of the wood that the Tung oil gives the piece. But that is a personal choice. I don't expect this to get a lot of wear and tear and if it does I will just reapply the Tung oil.
The connection between the legs and bench top is very weak so I added some steel brackets to the bottom. These are just 4 inch "L" brackets that I painted black. I made sure to predrill for the screws. Then I added some 1-1/4 inch screws which helped stiffen the piece quite a bit.
The first picture is a shot of where the bench top meets the legs. The spacing between the bench top and legs is about an inch, I eyeballed it for the most part. I added a few other pictures of the different angles.
I really like this project because it had quite a bit of trouble shooting and problem solving which required me to change my design. This all resulted in much more interesting final piece. I hope you enjoyed reading this as much as I enjoyed writing it. Thanks.
Link to build video.