Intro: Trestle Table With Floating Arched Stretcher
This is a dining room table that I just finished for our family in time for the holidays. It is made of walnut and maple, which are my favorite types of wood for furniture. The legs are walnut, the stretcher is maple, and table top is maple with a walnut inlay.
I modeled the table using Autocad and Inventor, mostly to check my proportions and to make sure it matches what my wife wanted in a dining table. The wood cost is more than I have ever spent for a single piece of furniture, so it also gave me piece of mind before buying the raw lumber.
For the tools used in this project: I have a garage workshop (that is usually limited to a single bay, but as you will see I wind up taking over the rest of the garage for a while due to the size of this project). I have a Ridgid hybrid table saw (with Incra fence) - this is my main power tool for most projects. I also have a router table wing on the saw that I used a lot for this project. For flattening faces and joints, I like to rely on handplanes where possible, especially for larger pieces of wood that are hard to move around by myself. I used the CNC at TechShop for large items like the stretcher and doing the inlay, as well as difficult to cut items like the stainless steel rod.
Step 1: Design and 3D Modeling
I don't 3D model most of my projects, as I find especially with rough lumber that I have to slightly change dimensions on the fly based on interesting grain patterns or defects that I have to work around. However, I wanted to make sure my proportions were correct before buying expensive lumber, and I also wanted to confirm the design with my wife. I started by sketching in a notebook, going over a few different leg and stretcher designs. After we decided on the highlighted ones, I then modeled in Autodesk Inventor, with the result render shown.
Although I modeled this from scratch, I certainly can't take credit for the general trestle table design or even many of the elements incorporated here, such as a curved stretcher or using pins instead of a wooden leg joint. Over the years I have received a lot of inspiration from projects on websites like Instructables, Lumberjocks, Wood Whisperer, and Sawmill Creek. I also have a friend with a large maple-top dining table that is very unique, and it has always been in my mind as to the style and type of quality that I would want in my own table.
Step 2: Legs Rough Layout and Cleanup
Let's start with the legs. Here you can see the 2 inch thick pieces of walnut that I bought for the table legs. I could not find single pieces wide enough for the vertical pieces, so I had to find 2 pieces for each of the 4 verticals that could be glued together and have fairly complimentary grain patterns.
After I marked all the pieces to work around large defects and reserve longer sections for the horizontal leg parts, I cut the full pieces down with my miter and table saw. I cut them all a little large because they still need to be flattened and cleaned up before shaping them.
After getting them to rough size, I stacked them up and put the bad edges on the outside that would become scrap from shaping the curves.
I cleaned up these boards using a jointer and thickness planer (this was way too much to do by hand). It still took the better part of a morning to get all these cleaned up and ready for glueup. The picture above shows the verticals and the bottom pieces ready for shaping. The verticals are glued up at this point, but I don't glue these pieces to each other until almost the end of the project, due to the way the stretcher is assembled.
Step 3: Leg Shaping
I mainly used the TechShop ShopBot CNC machine to shape the legs. Using the CNC was nice because the shapes turned out exactly as I modeled them. However, I had to screw the boards onto a plywood jig to get the wood piece to stay in place. This means filling the mount holes with putty/epoxy afterwards. They will probably be unoticeable, but the next time I do something like this I will probably use the CNC just to create a pattern out of tempered hardboard, and then use a bandsaw for the rough cutout followed by a router table pattern bit. The shape will be the same and there will be no mount holes to fill.
The other problem I had with the CNC is that I haven't yet mastered the feeds and speeds, selecting the best router bit, or tweaking the toolpaths options. Depending on these settings and the type of wood / grain patterns, there is a large risk of tearout or a finish that requires a lot of sanding. I still learned a lot on this step, but again I may choose not to use a CNC for this next time.
You can start to see the grain patterns above that I carefully selected from the rough walnut boards. I am also trying here to figure out which legs will be most attractive to see when walking into the dining room versus the ones to put in the back of the dining (that no one will see).
For the curves on the horizontal sections of the legs, I used a combination of my bandsaw and sander to sneak up on the lines measured from my sketches.
I used the router table wing on my table saw to round off all the curved edges of the vertical leg pieces, using a 1/2" radius bit. The straight / inside edges of the vertical leg pieces will probably just get eased off with some hand sanding instead of using the router table. The horizonal pieces also got all edges rounded over with the 1/2" bit. Since I was nervous from some tearout during the vertical pieces, I first did a pass with a 3/8" radius bit first, then worked up to the 1/2" when I was comfortable there was no crazy grain that would tearout.
Step 4: Loose Tenons for Leg Assembly
I recently invested in a Festool Domino and completed an outdoor bench and side table for our living room using it. Part of me wishes I got it sooner, but I also know I appreciate it so much more after having manually created so many mortise and tenons in other projects. It doesn't obsolete the need for every traditional mortise/tenon, or dowel, or pocket screw, or other type of joint, but it really is nice sometimes to focus on the shape of the furniture instead of the joint construction. Ok, enough Festool love - back to the project...
Each vertical leg piece got 3 loose tenons on top and 3 on bottom - for a total of 12 loose tenons (24 mortises) per leg assembly. Each tenon was 12mm x 50mm. I set the distance from the outside edge to place the mortises as close to the center as possible. I also made sure there was enough gap between the the vertical pieces to allow for the thickness of the stretcher (~1-3/4") and exposed steel pins (about 1/2" on each side of the stretcher).
In this picture you can also see where I have epoxied the holes from screws needed to hold the legs during CNC shaping. Once these are sanded and the walnut darkens during finishing, these will not be noticeable.
Step 5: Stretcher Prototype
This arched design element was stressing me out, so I used a piece of 2x10 construction lumber from Lowes to prototype the stretcher. For under $10, it allowed me to bring the arch and legs into our dining room and suspend it between the legs. I love 3D modeling, but I still wanted to see how these pieces looked together in their final location. What I found out was that the height of the stretcher ends and how far they stuck out past the legs looked fine. However, the arch obviously looked better tapered at the top compared to the ends. Also, I realized it would be hard to attach a curved arch to the bottom of the table - so I modified it to have a flat spot and notch. This would also allow to attach a cross support member in the middle, which seemed necessary for a table with ~6 ft span between legs. I changed my drawings and went to buy a huge chunk of 8/4 maple to make the actual stretcher.
Step 6: Create Stretcher Blank
I got an 8/4 (2 inch thick) piece of soft maple from Fine Lumber here in Austin. It was about 10 inches wide and just under 12 ft long. I chopped off a couple feet from each side so that the ends could be glued to create double width where the stretch curve comes down.
To flatten the edges where I glue the short pieces to the large piece, I use hand planes (mainly my #7 Craftsman that I restored from a garage sale heap). I use a small machinist square to check the result. I am going to do the facing with the cnc prior to cutting out the stretcher, so could only get this edge "pretty close" square to the roughed face.
Then I laid my prototype stretcher on top of the 3 unglued maple pieces and found a good position that didn't intersect any weird grain. I traced the prototype with a pencil to mark the final location.
To connect the maple pieces, I used 2 loose tenons on each side in addition to the glue - one tenon inside the stretcher outline and one outside (again with the Festool Domino) - this was mainly to help with alignment and keep the pieces from drifting during glueup, but I suppose some strength will be added to the final stretcher.
Now that the stretcher is glued up, it's ready for the CNC machine to cutout the shape, including the holes for the 3/4" stainless steel pins and the notch where the top of the stretcher ties into the bottom of the table top.
One note on all the waste material here - there are a number of other ways I considered assembling the stretcher that would have resulted in less waste. I could have used the above approach with smaller boards following the curve closer, or laminated long thin pieces together, or used short boards end jointed, or probably some other ways I can't imagine. In the end, this approach for me was a good balance between the look I wanted and simplest construction. As for the waste, you will see they come in handy later, and also I have no shortage of Christmas projects that will make good use of these thick maple cutoffs!
Step 7: Cutout Stretcher
I cutout the stretcher on the CNC at TechShop. First I used a surface planing bit to flatten one side, then flipped over the stretcher and surface planed again to final thickness of 1-3/4". Then drill the holes, pockets, and cutout the shape. In the pictures you can see a closeup of notch that will connect the top of the arch to the table top. Also shown is a closeup of the 3/4" pockets that will take the steel support pins. Notice that small holes go all the way through, but the larger 3/4" holes go less that halfway through. This is both to keep the stretcher from moving and to allow me to locate where to drill the other side's 3/4" pockets on a drill press after the cutout is completed.
Notice that the notch cutout has rounded inside corners - this is due to the radius of the router bit when it does the shape cutout. Because of this, I will have to manually round off the outside corners of the middle cross member where it interfaces with this notch.
I again used a 1/2 inch radius bit on my router table wing to round off all the edges. Because I wasn't sure if 1/2" inch would be too severe of a rounding for the look I wanted (and because I was worried about that pesky long grain tearout), I first did a 3/8" roundover, then decided to move up to the 1/2" inch, which looked perfect. I did not round the very top of the arch, where it flattens to connect to the table top.
Since my router table is a wing on my table saw, it was possible to use the router table for this step, but there were a few sections where an awkward amount of the piece hung off the table. For a similar piece in the future, I will bring a hand router to the piece instead of the large piece to the router table.
Step 8: Support for the Top of the Arch
I needed a way to attach the top of the arch into the bottom of the table. I was also worried about the span of the table top without support. Since the top of the arch was shaped with a flat part and a small notch, it gives me a place to attach a cross member.
I started by cutting a 3-1/2" wide piece of maple from one of my scrap pieces. One of the sides was already pretty flat, so I proceeded straight to my thickness planer and brought it down to ~1-5/8" thick (about the same as the leg tops). I only own a 3/8" dado blade, so I used it to nibble out middle sections so this piece could interface with the notch at the top of the arch. Because the stretcher was cutout on the CNC machine, the inside corners of the notch are rounded due to the radius of the router bit. Therefore I used a small file to round off the outside corners in this cross member's middle section.
I drew a curve on each end and rough cut them out on the band saw, then similar to earlier steps, I snuck up on the line with a belt sander. After the ends were smoothed out, I used the router table to round off the edges. I used a backer block to prevent end grain tearout.
I drilled a hole in the middle of this piece where it will attach to the stretcher (a backer block was used to prevent the hole from blowing out the bottom). I also drilled 4 holes across the piece where I can screw into the table top. Recesses for these 4 holes were created with a forstner bit to hide the screw heads.The 2 outside holes were oversized a lot to allow for table top wood movement.
You probably notice as I did that the 1/2" thick notch area seemed pretty thin compared to the rest of this piece. If I was doing it over I would have make the stretcher notch larger so the interface would be beefier. However, with Thankgiving approaching and still a lot of work to do, I decided this was a sturdy enough piece of maple for it's purpose.
Step 9: Drill Leg Holes for Stretcher Pins
Each vertical piece got 2 holes, and each side (of each end) of the stretcher got 2 holes. Both the legs and stretcher proved to be challenging to drill out.
I cut 8 pieces of stainless steel from a 3/4" diameter x 2 ft rod. Each piece is about 2-1/2" inches long and the ends were beveled on a disc sander to allow for easy insertion. I bought the steel rod from Mcmaster-carr.
Drill holes for Legs
I used a 3/4" forstner bit to drill holes on the inside edge of each leg at a depth of just under 1-1/4 inch. There will be ~1/2" gap between each leg and the stretcher (gives it the "floating" effect), and the rod sits 3/4" into the stretcher holes.
I decided to create a jig to drill the holes exactly the same for each leg. I measured the distance from the base of the leg to each hole from my Autocad sketch - I then created a jig on the CNC to make sure all 8 holes were drilled exactly the same distance from the top of the leg. It is basically a pocket that lays on the leg edge registering to the top of the leg, and has two 3/4" holes to guide my drill bit.
This did not work as well as planned when I first tried it - when I clamped my jig to the edge of the leg piece, I had a hard time keeping the bottom of the curved leg perfectly square to the drill press. I had to build a special fixture to hold the leg square and stable - I decided to sandwich one of the curved scrap pieces (from when I shaped the leg piece) between 2 pieces of plywood. It assured a perfect match to the edge of the leg piece. I then stacked the leg on this new jig, squared it to the drill press, and drilled the 2 holes in each of the 4 leg verticals.
Drill Holes for Stretcher
From the above step of cutting out the stretcher, you will see I have 1/4" locator holes that go all the way through the stretcher. I balanced and leveled the stretcher between a piece of wood in my bench vice and my drill press table, which allowed me to square the stretcher with the drill bit. I used a 1/4" drill bit to center on each existing through hole, clamped the stretched in place, and then swapped out the 1/4" drill bit for a 3/4" forstner bit. Then I drill to just under 3/4" depth - this leaves a middle section for the steel rod to sit against.
Another Stretcher Idea
One idea I decided not to pursue is the use of compression springs inside the legs holes. The idea here would be to put the springs in each (much deeper) leg hole, compress the rod into each hole, and then set the stretcher in place allowing the springs to hold the stretcher centered. This way if I ever need to disassember this large table, I can compressed the rods into the leg holes and take the table apart into 4 pieces (top, stretcher, and 2 legs). It would also make my leg glueup easier since I could do it without the stretcher in the way. I ultimately conceded that moving this large table in 2 pieces (table top + legs/stretcher) should be fine and there was no need to over-engineer this step. Also, I was worried if the steel pins were loose enough in the holes to compress, then the legs might be wobbly from the start - since flex and stretcher joint wear are already a problem with the trestle design, this was another reason not to do the springs.
Step 10: Table Top Rough Lumber
I planned on the table top being ~42" wide by ~9ft long and 1-3/4" thick. I needed to glue together 12 boards that were each 3-1/2" wide. Based on this, I purchased about 90 board feet of soft maple 8/4 (2" thick) rough lumber. This is more than what is needed to allow for waste. Most of my boards were about 8" wide, allowing me to get 2 of my 12 pieces out of each piece of rough lumber.
I started by cutting off about 6 inches from each board at the miter saw to get rid of edge splits and to bring each board to approximately 9-1/2 feet. I then used the jointer to get one flat face and square edge. I then used the table saw to cut each board to 3-1/2" wide. I removed any bad burn marks/dents in the cut edge with my #7 plane, to make sure they did not show in the glueup.
Once I had all 12 of my pieces, I laid them out next to each other. When I found any really bad knots or discolorations, I flipped over to be the bottom of the table. This soft maple had 3 main "tones" - yellowish, pinkish, and greyish. I tried to evenly distribute the colors. The oil/varnish I chose may mute some of the color differences, but I still wanted to do this selection process. Once I had the orientation finalized, I numbered the ends of pieces from 1-12 to help remind me during the glueup. Then I ran each piece through the thickness planer to bring them all down to about 1-3/4".
Step 11: Table Top Panel Glue-ups
The table top consists of 12 maple boards that are 3-1/2". To make the glueup easier and to allow me to move pieces around on my own, I did this in 3 panels, with each panel being 4 boards - so each panel is 14" wide x ~9ft long. I used a lot of Titebond #2 glue and mostly Bessey pipe clamps on 1/2" pipes.
After about an hour after glueing, I god rid of excess gluewith my Rockler scraper.
Step 12: Creating Table Top Inlay
I started to feel that the table top would be too plain given the rest of the design elements and some other pieces of furniture I am building for the dining room. So I decided to do an oval walnut inlay on this maple top with the CNC. I drew the shape in Autocad and cut the female section to a depth of 0.2" on the middle table top panel. The inlay is 1" wide.
For the male inlay, I chopped the oval shape into 4 pieces before cutting it out - this was to make glueing into the pocket easier, limit walnut waste material, and to make the grain at the corners look more interesting. I made the inlays about 0.007" thinner than the pocket on each side - this made for a snug fit but still room for glue.
I used piece of walnut just under 3/4" thick and resawed it in half on the band saw. After cleaning up the piece on the thickness planer, I was left with ~1/4" thick. This would leave the inlay proud after glueing it in place, and allow plenty of room for sanding and account for any minor variance in my inlay depth.
Step 13: Table Glueup
I used 6 loose tenons between each panels to help keep them lined up. I used every pipe clamp I owned, and some of them were actually coupled together to make them long enough. I probably could have used a couple more, but as you can see the glue squeeze out looked pretty good and even. Again I scraped off excess glue with my Rockler scraper after about an hour.
After I removed the clamps, I did notice a slight bow on one side. This is either due to 2 edges that were not perfectly square to the face, or because I applied too much clamp pressure (and only on the top side). No matter the reason, the bow was small enough that I hoped it would work itself out while smoothing the top. If not, attaching the top with screws should flatten out the rest.
Step 14: Inserting Inlay
I laid out the 4 male inlay pieces and lightly sanded the rough edges. I then used some detail sanding sticks to clean up the female inlay on the table top. After doing a loose fitting and finding an order where the grains lined up best, I brushed a generous amount of glue into the groove and pressed the 4 pieces into place. Normally you are supposed to tape, clamp, and place weight on top of your inlays to keep them in place. However, these fit very snugly and I had good glue squeezeout, so I just pressed on them every few minutes to make sure there was no movement or additional glue squeezeout. This seemed to work well, at least in this case
To address any very small gaps in the inlay, a trick that I saw on a Wood Whisperer video here is to use sandpaper to create a slurry with glue squeeze out and sawdust. You then press the slurry into all the edges and you sand it off later when everything is dry. It turned out perfect - there are no noticeable gaps anywhere on the inlay!
Step 15: Size and Shape Table Top
I evened up the end of the table with a circular saw. Since I am leaving the end grain exposed and not using breadboards, this brought the table top to a final length of 9ft. I did have to do 2 passes - the first pass squared off the end and brought it to approximate length, and the second pass was just the width of the saw blade, and was used to remove burn marks left fromt the first pass.
I rounded off the corners by drawing a 2" radius using a plastic guide. I drew the radius on both the top and bottom of the corners, placed a mirror under the table, and then used a belt sander to smooth up to the line evenly.
After a light pass on all edges with the belt sander, I rounded off all the edges with a hand router - since the table was little too big to carry to the router table...
Step 16: Flattening and Sanding Table Top
I used hand planes to smooth out the bottom of the table, followed by 80 grit on an orbital sander, and then 150 grit. I then flipped over the table (with some help!), repeated the same process for the top, and then hand sanded the edges.
When using the hand planes, I did a lot of 45 degree passes to get rid of the more noticeable CNC lines, then when I switched to a smoothing plane I did more passes with the long grain.
I found that even after the planes and orbital sander left the surface smooth and flat to the touch, if the light hit certain areas just right there was an obvious blemish that was going to stand out when my varnish oil is applied. To find and get rid of these hard to find areas, I turned down the lights in the garage and used a clamp light on a block of wood to inspect the entire top side. When I found an issue, I marked it with a pencil. Then I turned up the light and did another pass with the orbital sander to remove the pencil marks and the blemish. After 2 of these passes, my lighting approach could not find anything major enough to resand. The top was now ready to get finish coats.
Step 17: Sand Legs and Stretchers
The faces of the legs and stretchers were already in really good shape at this point. I mostly just went over these by hand with 180 sandpaper to prepare them for finishing.
The edges however were much harder, mostly because of end grain and curves. One of the ways I sanded these pieces was to use a small piece that was scrap during the shaping process - I sandwiched a piece of sandpaper between the scrap piece and curve, and the perfect fit made sanding go much quicker. Again you can see I am using the lighting approach to detect any small blemishes. You can also see that the epoxied holes from the CNC screw holes are becoming much less noticeable after final sanding.
The leg pieces are now ready for the finishing process.
Step 18: Applying Varnish Oil
I decided to use Tried and True Varnish Oil on this table. I recently used it for an end table, and the results were great. I know there are certainly more durable finishes out there, but I haven't found anything that matches 1) ease of application, 2) the way Tried and True brings out walnut and maple grain, and 3) the non-toxic/non-odor nature is also a big plus for me.
Before starting, I heat the varnish oil up for a few minutes up to about 150 F degrees. This seems to make the application go quicker. The application approach is to wipe on a very thin layer with a soft cloth (I used old tshirts). After about an hour, I wiped it down. Then after 24 hours, I did a quick hand buff with a fresh cloth and started a new coat.
I created a stand for the leg verticals using spare Dominos and a scrap piece of plywood - this helped keep the area as clean and organized as possible, since I had 8 leg pieces plus the stretcher and table top. Notice that a lot of area around the mortises does did not get any oil because this area will get some glue, but obviously I wandered into a few areas. As these in-between sections are not thought to be the strongest part of the joint, I wasn't too worried about it.
For the table top, the bottom of the table got 1 coat of varnish oil and the top got 4 coats. The legs and stretchers all got 3 coats.
Step 19: Glue-up Legs and Stretcher
I did a final dry fit of the legs and stretcher, including the stainless steel pins. Everything seems to line up well, so I laid out all the pieces got ready for the glueup. The stretcher was suspended between the leg verticals and loosely clamped together. Then all the tenons were glued into the legs bottoms and attached. Then the assembly was flipped and the process was repeated for the top. I had to raise the assembly up on blocks to allow my pipe clamps to fit.
The nice part about doing the varnish oil first is that any glue squeezing out here can be easily wiped off compared to bare wood where the glue penetrates quickly and can mess up the surface.
Step 20: Buttons to Attach the Table Top
I used the Domino to drill 3 mortises on the inside top of each table leg. The outer 2 on each side were drilled with a loose setting to allow for cross-grain table top movement.
To create the table mount buttons, I first used my #7 hand plane to flatten an edge on a piece of walnut. I used the miter saw to cut the piece to 12" in length. Then I cutoff to the approximate thickness of 1-1/4" using the band saw. After this, I used the table saw to cut the piece to a width of 1-1/4".
The reason I used the band saw first is that my table saw struggles with cutting full 2" thick walnut, but it of course leave a much better finish than the band saw. By reducing the thickness to 1-1/4" first on the band saw, I was able to do a nicer final cut on my table saw.
I created 7 mortises (one extra just in case) every 1-1/2" on this piece. I used the router table to round off one bottom edge. Then I drilled holes thought the center of each mortise (and used a forstner bit to hide the screw head). I used the table saw's miter sled to cut this into individual buttons. Then I glued a Domino into each button, sanded, and put a coat of varnish oil on each one.
Step 21: Table Top Attachment
After the table top was placed on top of the legs, it was adjusted so that the overhang in all directions was equal. Then the top was attached with 4 screws in the middle cross member, and 1 screw in each of the 6 leg buttons.
Step 22: Final Thoughts
I have been talking about making a dining room table for years, and last Thanksgiving I decided I would finally get it done for 2014. Well, I finally finished it, and even with an entire day to spare before Thankgiving! Even though I have been wanting to do this for years, I feel like doing this project sooner would not have worked, because I would not have had the tools, skills, or design sense to do the table justice.
Also, originally I planned to make the chairs for the table as well - that turned out to be way too ambitious for my timeline. After making a prototype, I decided that chairmaking is a whole other specialty that will probably take me a lifetime to master. My prototype is sturdy and looks ok, but it's certainly not what I would call comfortable. My wife found these on Overstock.com, so I conceded to buy the chairs and move on to another project.
Thanks for viewing my Instructable on this table - I welcome any and all feedback or questions!