I'm designing and building an outfeed table... and because I want to learn how to do several different things, it is overly complicated. With that disclaimer stated, I am not sure how to cut a board lengthwise at an angle. Here are some photos to better help understand what I'm doing.
The first rendering is the table completely assembled.
The second rendering provides and example of why I want to cut a board at an angle. This triangular-shaped board will sit on top of the bottom shelf and support the upper shelf support frame.
The bottom and upper support frames are exactly the same and they are rendered in image three.
The last rendering is simply to show the shelf on top of the support frame and the joinery.
Currently, the best (only?) way I can think to cut the board is to create a jig of some kind and cut it on the table saw. I do not own a band saw so that is out of the question. The only other option is to use a hand saw and I am not sure that cut would be very "clean".
I was not able to view your pictures.
Are you cutting large pieces of sheet material at an angle? If so, I cut the sheet first with my portable circular saw. I can then run the cut edge over the joiner for a smooth edge. If you don't have a CS, you can use a hand held jig saw. And if you don't have a joiner, you'll need to true up the cut with a hand plane.
Once I posted, your pictures came through. I see you are talking about the legs. A picture is always best.
There should be only one cut. Make it on the table saw. If the blade is too short to cut completely through, make the cut anyway and use your handsaw to complete the cut. The deep kerf made with the tablesaw will be your guide for a nice handsaw finishing cut.
The joints you are making in Sketch Up look pretty but they are not structurally sound. The best way to design this table is to make mockups of the corners and all the joints. You don't need to make a mockup of the entire table, but that won't hurt. You will find all the flaws in your structural engineering that way.
A frame only design puts all the stresses at the joints, so they need to be rigid all on their own. A frame and panel design turns the panels into structural elements, like diagonals which are invisible. A triangle is the strongest geometric shape used in construction and you will find them used for bracing in timber frame construction in addition to the mortise and tenons.
Racking occurs when the joints and not strong enough all on their own to resist lateral movement. When you add a diagonal or a panel across the frames corners it becomes incredibly strong. An open frame design is the weakest. Diagonals don't look the greatest, so a panel is the next best thing. Book cases have back panels to keep them from racking. If you have and open shelf bookcase without a back, it will eventually collapse.
The wedged shape leg only complicates the construction and will not be strong enough because of the tricky way you would need to make the attachments. Don't try things that are "different" just for the sake of being different. Things are the way they are for hundreds of years, because that's what works best. Industrial Design schools teach structural engineering as well as art and design for a reason. Things you design must be structurally sound as well as good looking. BTW, I have a Masters in Industrial Design from a University so I can speak with some experience. We always made mockups of our designs before making the finished models. The "design critiques" were tough on the students, but they always improved their designs. :wink2:
Thanks. This is not Sketchup (junk toy software). This is AutoDesk's Fusion 360 Parametric Modelling software which also has stress analysis (and a ton of other features).
That said, I understand what you're saying but I'm really not sure what to change. I took the design from the "The Wood Whisperer's" YouTube video:
What changes should I make to the design to ensure it is structurally sound?
Mortise and tenon are the strongest joints used in woodworking and also timber frame construction. The Roubo style workbenches all over the net use these joints. However, having said that there are other joints that will work well. A half lap joint uses the shoulders on each piece to resist rotation like no. 2:
Other common joints are shown here;
Your bench will need joints where the horizontal aprons or the shelf supports join to the vertical legs. For example 2, 4 7, or 8. above. Dowels will also work for those. If you choose a mortise and tenon joint, it will mean lots of hand work with chisels. Loose tenons are and easier method where you just make equal size mortises on each mating piece and then use a slip fit "tenon" in
between.
Your video will probably show you how to make those joints, if not there are a zillion others on You Tube.
I made a very sturdy workbench that supports hundreds of pounds using 2" x 6" s in an "L" in each corner. It's easy to nail or screw them together and they are super strong. You can attach your aprons inside or on the outside that way.
Thanks @woodnthings. The design I have is all mortise and tenon so I'm not sure where it is that you're saying I need to make a change. The "legs" are joined with tongue and groove (just two vertical 1"x3" boards).
I thought you were referring to the center support beam so I redesigned it with two diagonal cross members that have a lap joint. Does that make it "better"? Note, dowels are not shown in this drawing (it's not complete).
And yes, I know it is going to be a lot of work with hand tools... but that is the point... can't learn if I'm always taking the easy way out. Who ever learned anything useful by using pocket holes and screws?!
Maybe I'm misunderstanding. Are you questioning the stability of how the bottom and top (horizontal) support frames are going to be joined to the four vertical legs? @woodnthings
@woodnthings. I re-read your post again and I've made another change which is just to extend the tenons all the way through the legs as shown below. I'm fairly certain that is what you were saying I needed to do... ? I changed the look of all of the boards so you could easily see what was going where and I also hid the part of the leg closest to you.
@GeorgeC you clearly have nothing positive to contribute on this thread so just go be a jerk on some other thread.
@woodnthings. I re-read your post again and I've made another change which is just to extend the tenons all the way through the legs as shown below. I'm fairly certain that is what you were saying I needed to do... ? I changed the look of all of the boards so you could easily see what was going where and I also hid the part of the leg closest to you.
@GeorgeC you clearly have nothing positive to contribute on this thread so just go be a jerk on some other thread.
That software is really awesome! I haven't seen better on this forum ever. If it will also do stress analysis that's a real plus and way over my skill set. We don't need to get too technical, because a strong joint in theory, is also strong in practice. Speaking of practice .... ust make some of those joints in scrap wood and see what they do and how easy/hard they are to get precise. Practice, practice and then make your actual bench. It's like ridin' a Harley... it ain't about the destination, it's about the journey. :smile3:
What exactly is the purpose of the triangular legs when square or rectangular legs would be much easier to construct and probably much stronger?
Perhaps I'm missing something here, but it seems that the aesthetics is more important than the utilitarian use of the table. It's a work bench intended to work on or am I missing something here?
My work bench doubles as my outfeed and assembly table. I don't have unlimited space here in my half a garage shop..
Uh-oh..being mean to George is never a good idea.. Well, maybe it could be under the right circumstances.. Let's find out. George, your mother was a hamster and your father smelt of elderberries.
Yes, I'm trying to learn a lot of things all at once since I have no experience in this area. Learning Fusion 360 as well because, well, I'm an engineer and I work well in a 3D environment. It helps me visualise and keeps me from making mistakes. I figured I might as well start with the simplest table in the shop and learn some joinery and how to use all the tools. If I screw it up, it's not really a big deal. Just need to keep learning and hopefully, I will make something decent in the next few years.
I've got 4 of these in my shop now. Love them. But I do have a 5' outfeed table on my tablesaw. I've been doing lots of moldings and long stock lately, 16 footers. I set them up on the infeed of my jointer and the outfeed of my planer. Makes it very easy to get good results easy. Nice to be able to not have to rush from the infeed to the outfeed of the planer to catch the board before it sags to much.
Thanks Leo. That would be good for a few things in the shop but it doesn't do much for being an "assembly" table. Basically, I wanted an assembly table that doubles as an outfeed table. This would clean up the shop and give me a place to work since I have no "bench" of any kind.
Well, one leg down... sort of. I thought it might be fun to try to see how finger joints work but ultimately, I do not think they're going to work into this design due to the through-tenons. Oh well, it had fun and I learned quite a lot. That's what matters right?!
- Wil
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