a_10lodr Posted January 8, 2011 Report Share Posted January 8, 2011 I am attempting my project build of a hall bench that has some storage locations on the bottom. I am working off a plan I downloaded just to kind of get my ideas flowing. The plan calls for birch plywood, however I would prefer to make this out of a hardwood instead. My question is, will the top be strong enough with just the boards glued together or would I need to tongue and groove or dowel the boards together to add more stability? The bench will be about 48" long and about 15-18 deep with a center support. Any thoughts would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Dan S Posted January 8, 2011 Report Share Posted January 8, 2011 opps , I had to update my post, i read that as a half workbench the first time. A Butt joint will be fine for something like a hall table. Quote Link to comment Share on other sites More sharing options...
Sac Posted January 8, 2011 Report Share Posted January 8, 2011 Like Dan said, a glued butt joint is very strong. How thick is the top going to be? Do you have a pic of the plan or a link where we can see what you are building? Quote Link to comment Share on other sites More sharing options...
Beechwood Chip Posted January 8, 2011 Report Share Posted January 8, 2011 People are going to be sitting on it (you said "bench", right?), and some people are heavy. Which way does the center support run - are we talking two 48" x 9" spans, or two 24" x 18" spans? What thickness of hardwood? I think the long grain butt joint should be OK. The tricky part is how the top is supported, and if the rest of the design worked with plywood, it should also work with hardwood. Quote Link to comment Share on other sites More sharing options...
a_10lodr Posted January 8, 2011 Author Report Share Posted January 8, 2011 I am planning on building it from 3/4 oak and the center support runs perpendicular to the seating surface. The plan link is below: http://www.popularwoodworking.com/article/storage_bench/ Quote Link to comment Share on other sites More sharing options...
Pete Bennett Posted January 8, 2011 Report Share Posted January 8, 2011 I am planning on building it from 3/4 oak and the center support runs perpendicular to the seating surface. The plan link is below: http://www.popularwoodworking.com/article/storage_bench/ There should be no problem with good butt joints on any of the pieces but, for me I would definitely not use slotted screw joints for anything. I would mortice and tenon the base and dado house the rest. A plywood back would be fine. Quote Link to comment Share on other sites More sharing options...
WoodClips Posted January 8, 2011 Report Share Posted January 8, 2011 I built a bench with similar dimensions and a glued up red oak top and didn't have any problems with deflection in the top. Mine didn't have any support in the center, and with that support I don't think you have anything to be concerned about if you're going to use solid hardwood vs. plywood. You'll need to make sure that the grain in all your pieces (sides, center divider, top, bottom) is oriented in the same direction so they all expand and contract together. The real problem I see with this design is joining the top and bottom to the sides. The typical methods of joining panels (dadoes, dowels, pocket screws) do not really offer enough glue area or strength IMO to resist the forces that are going to be put on those joints if someone heavy sits on the middle of the bench. You'll need a joint that not only supports the downward forces, but also that will keep the front of the sides from pulling away from the top and bottom. One such joint would be a sliding dovetail. Since the back is going to hold everything together in the rear, the majority of the joint could be a dado with the sliding dovetail only spanning the front three inches or so to make it easier to assemble. These joints are traditionally used to join the sides and dividers on chests of drawers, so look for an article on solid wood chest of drawers construction for instructions on how to cut it. Finally, I think I'd consider adding a horizontal rail underneath the bottom to stiffen up the front. It could be 2.5 or 3 inches wide and inset a bit (half an inch?) from the front. The back will do a good job of stiffening everything up, but I'd still expect the front to deflect a little bit and the L-girder you'll create with the bottom and the rail glued together will help prevent that and reduce the stress on your joints. Rory 1 Quote Link to comment Share on other sites More sharing options...
a_10lodr Posted January 8, 2011 Author Report Share Posted January 8, 2011 Thanks for the tips...I really appreciate the insight. As a beginner I had not thought about some of the joint construction and the forces that would be put upon the bench had a heavier set individual sat on it. Rory, if I read your post correctly I definitely had not thought about a sliding dovetail front and dadoed back. Again thanks for the insight...you guys are only making me a better informed and hopefully proficient woodworker. Larry Quote Link to comment Share on other sites More sharing options...
Dan S Posted January 8, 2011 Report Share Posted January 8, 2011 I second this. Finally, I think I'd consider adding a horizontal rail underneath the bottom to stiffen up the front. It could be 2.5 or 3 inches wide and inset a bit (half an inch?) from the front. The back will do a good job of stiffening everything up, but I'd still expect the front to deflect a little bit and the L-girder you'll create with the bottom and the rail glued together will help prevent that and reduce the stress on your joints. Rory Quote Link to comment Share on other sites More sharing options...
WoodClips Posted January 8, 2011 Report Share Posted January 8, 2011 Thru mortise and tenons are another option that only require some basic hand tools and careful layout and patience to cut (imagine the top of the stool is the side of your bench). The exposed joinery isn't for everyone or every piece, but it can be a source of visual interest and is virtually indestructible. Quote Link to comment Share on other sites More sharing options...
a_10lodr Posted January 8, 2011 Author Report Share Posted January 8, 2011 OK, here is a question about the mortise and tenons, if I use the that joinery concept should I only use that on the sides or a combination of dado's and M&Ts? I know this may sound like an oddball question but I want this to be a strong and attractive piece, but don't have the background to be able to judge the strength of a wood joint. Once again thanks for all of the posts, they have made me think of things I would not have thought of before. Larry Quote Link to comment Share on other sites More sharing options...
WoodClips Posted January 8, 2011 Report Share Posted January 8, 2011 If you are using mortises and tenons I don't think a dado is really required, but a shallow dado (like an 1/8") will give you a clean looking joint and save you some time because you don't have to be super careful when cutting the tenon shoulders (they'll be hidden in the dado). The number, size and spacing is mainly a matter of aesthetics. If you like the look, you can cut a thin kerf in the tenons and drive in a wedge (or two) during glue-up. Just make sure the wedge is perpendicular to the grain so you don't split the sides. This makes for a super strong joint and if you taper the sides of the mortises slightly it wouldn't even need glue to stay together (not that I recommend skipping the glue). The tenons also don't need to go all the way through the sides if you don't want them showing--you just have to increase the quantity to achieve the same glue area/strength because they won't be as deep. At some point sliding dovetails start looking like less work. Lot's of options. Rory Quote Link to comment Share on other sites More sharing options...
Pete Bennett Posted January 9, 2011 Report Share Posted January 9, 2011 If you are using mortises and tenons I don't think a dado is really required, but a shallow dado (like an 1/8") will give you a clean looking joint and save you some time because you don't have to be super careful when cutting the tenon shoulders (they'll be hidden in the dado). The number, size and spacing is mainly a matter of aesthetics. If you like the look, you can cut a thin kerf in the tenons and drive in a wedge (or two) during glue-up. Just make sure the wedge is perpendicular to the grain so you don't split the sides. This makes for a super strong joint and if you taper the sides of the mortises slightly it wouldn't even need glue to stay together (not that I recommend skipping the glue). The tenons also don't need to go all the way through the sides if you don't want them showing--you just have to increase the quantity to achieve the same glue area/strength because they won't be as deep. At some point sliding dovetails start looking like less work. Lot's of options. Rory The very best advice so far. However, foxtail wedging as you suggest will never need glue if it's done right. Look at all the Elizabethan furniture that's still around that was built exactly in this way. Plus, if you want you can add attractive features like contrasting timber for the wedges. Your idea of a shallow dado is excellent it will give great rigidity and prevent there ever being any possibility of sagging in the top. Pete Quote Link to comment Share on other sites More sharing options...
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