Favorite 3-way corner joint?

driftin

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I built my canopy on the quick and dirty some 15 years ago. A light 1x2 frame with a thin plywood skin. It's held up great considering, but I didn't do any interior paint etc and the wood is starting to rot after years of getting wet by my carelessness. I'd like to rebuild it and basically use the same construction - but do it "right" this time. So painting the wood, but I'd also like to use real joinery methods. I butt-joined pretty much everything on the last one, with a few cross braces, and deck screws to hold it all together. I think it was really the skin that has held it square...

What's your favorite corner joinery methods? 3-way corners especially. A lot of what I see is for square wood, not rectangular.
 
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Townes_Van_Camp

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Dovetails on a router table. Mitre joints with a spline are also outstanding joints. Spline jigs for the table saw aren’t terribly expensive. I used to know an old dude who worked in my uncles cabinet shop who would cut spline joints with a handsaw. I don’t recommend that at all. He was a pro and had done it for over 50 years.

simple dado joints are also quite strong when glued.
 
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Lost in the Sauce

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I would imagine a lap joint or pocket holes would be good options.
Pocket holes are not real joinery. It's a gimmick that holds a bit at an angle on a butt joint. No different than butt joint reinforced with screws.

I built my canopy on the quick and dirty some 15 years ago. A light 1x2 frame with a thin plywood skin. It's held up great considering, but I didn't do any interior paint etc and the wood is starting to rot after years of getting wet by my carelessness. I'd like to rebuild it and basically use the same construction - but do it "right" this time. So painting the wood, but I'd also like to use real joinery methods. I butt-joined pretty much everything on the last one, with a few cross braces, and deck screws to hold it all together. I think it was really the skin that has held it square...

What's your favorite corner joinery methods? 3-way corners especially. A lot of what I see is for square wood, not rectangular.
For a frame, nothing beats good ol fashion mortise and tenon (except a festool domino and that's just for speed)

On panels, If you have a router or dado blade, my favorite 3 way joint only needs rabbets. Cut rabbets into your "L" pieces do fit together, rabbet the third wall into the first two. Don't assemble anything with glue (Titebond 3 or epoxy) until all are cut. As long as your panels were square to begin, the entire side will be self squaring. This joinery method is easy and has a massive amount of surface area for adhesion.
 

Staghorn

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Honestly if your looking for a strong glue joint you want to use a lap joint or just buy joints. Miters look cleaner if you have a good saw that can cut them properly but they really don’t glue well and if not cut precisely the will always have gaps. If you bought everything together glue it and fasten it well. You can veneer over the joints if you’re familiar with veneer or you can simply cut some moulding or strips to cover the joints. If done right it can look attractive.
 
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Lost in the Sauce

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Honestly if your looking for a strong glue joint you want to use a lap joint or just buy joints. Miters look cleaner if you have a good saw that can cut them properly but they really don’t glue well and if not cut precisely the will always have gaps. If you bought everything together glue it and fasten it well. You can veneer over the joints if you’re familiar with veneer or you can simply cut some moulding or strips to cover the joints. If done right it can look attractive.
I've got WAY more into my shop than my tanks. When I build another base, it will be 2x4 construction frame, nice veneer moulded panels to hide the frame. All panels will be removable and held on with magnets. I wouldn't even M&T my own base; )
 

Staghorn

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I've got WAY more into my shop than my tanks. When I build another base, it will be 2x4 construction frame, nice veneer moulded panels to hide the frame. All panels will be removable and held on with magnets. I wouldn't even M&T my own base; )
Yeah I’ve got a few machines that hurt allot more to buy than all my aquarium stuff put together. But thankfully it pays for salt!
 

Lost in the Sauce

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Yeah I’ve got a few machines that hurt allot more to buy than all my aquarium stuff put together. But thankfully it pays for salt!
People think red sea is an expensive addiction. Try Festool. . . Red sea doesn't drop new tanks every 90 days
 
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driftin

driftin

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Thanks everyone, appreciate the ideas so far. I'm looking at this as a potential summer project - will post up photos as I go (if it turns out nicely ha)
 

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Man such a simple topic but will probably have a very large number of different opinions.

I'll attempt a few facts or commonly held beliefs...
Fact 1) miter joints look better but are one of the more difficult joints to close up tight and be square. This does not even consider how you want to do your top.

Fact 2) butt joints are easier, maybe don't look as nice, and have less surface stress for glue so generally are not as strong. Enter the simple options to make it stronger... Dowels and pocket holes. Unless you buy a cheap dowl jig, which is not worth it in my mind, the cost is about the same. Dowls are more of a purist woodworking joint but pocket holes are quite simple and really help get a strong square corner. You can save on clamping time too as the screw is the clamp in a way.

Fact 3) most other options such as dovetail joints require specialized tools or jigs you make yourself and or really require a table saw.

I did see some really interesting router bits online that are specifically made for 45° miter joints that looked crazy easy but I do not have any personal experience with. Also still need to consider how the top would be fastened to hide the cheating. See below.


For my final vote I find the simplicity, strength and ease of using pocket holes and glue on butt joints where I router the top edges to be a great compromise.
 
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NabberNate

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Pocket holes are not real joinery. It's a gimmick that holds a bit at an angle on a butt joint. No different than butt joint reinforced with screws.


For a frame, nothing beats good ol fashion mortise and tenon (except a festool domino and that's just for speed)

On panels, If you have a router or dado blade, my favorite 3 way joint only needs rabbets. Cut rabbets into your "L" pieces do fit together, rabbet the third wall into the first two. Don't assemble anything with glue (Titebond 3 or epoxy) until all are cut. As long as your panels were square to begin, the entire side will be self squaring. This joinery method is easy and has a massive amount of surface area for adhesion.
Can you send a picture or link to what you're describing? I'm having a hard time picturing.

Thanks
 

Townes_Van_Camp

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Man such a simple topic but will probably have a very large number of different opinions.

I'll attempt a few facts or commonly held beliefs...
Fact 1) miter joints look better but are one of the more difficult joints to close up tight and be square. This does not even consider how you want to do your top.

Fact 2) butt joints are easier, maybe don't look as nice, and have less surface stress for glue so generally are not as strong. Enter the simple options to make it stronger... Dowels and pocket holes. Unless you buy a cheap dowl jig, which is not worth it in my mind, the cost is about the same. Dowls are more of a purist woodworking joint but pocket holes are quite simple and really help get a strong square corner. You can save on clamping time too as the screw is the clamp in a way.

Fact 3) most other options such as dovetail joints require specialized tools or jigs you make yourself and or really require a table saw.

I did see some really interesting router bits online that are specifically made for 45° miter joints that looked crazy easy but I do not have any personal experience with. Also still need to consider how the top would be fastened to hide the cheating. See below.


For my final vote I find the simplicity, strength and ease of using pocket holes and glue on butt joints where I router the top edges to be a great compromise.
locking miters kick all sorts of butt, miter joint with a "built in spline" yeah its good to go. That said, when I am being lazy and want a quick joint; dado and depending on the depth of material I'll use a couple of dowels and some bar clamps to hold it all together and keep it aligned while the glue sets.
 
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Lost in the Sauce

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Can you send a picture or link to what you're describing? I'm having a hard time picturing.

Thanks
Sure
Step one
Screenshot_20210507-064128.png

Step two: rabbets are cut where the red lines are going down each side. Panel sits it and squares to this edges.
Screenshot_20210507-064230.png



Does that help?
 

Lost in the Sauce

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I think so. You basically have a rabbit on 2 sides of every board. Ends are for the joint and the top is like a shelf. 50% more surface area on joint than standard butt joint and makes it easier to nail in with a brad or trim. Thanks...
Correct although I'd bypass brads and go straight to pilot hole and countersunk fastener for anything supporting any weight.
 
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Sleepydoc

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Pocket holes are not real joinery. It's a gimmick that holds a bit at an angle on a butt joint. No different than butt joint reinforced with screws.


For a frame, nothing beats good ol fashion mortise and tenon (except a festool domino and that's just for speed)

On panels, If you have a router or dado blade, my favorite 3 way joint only needs rabbets. Cut rabbets into your "L" pieces do fit together, rabbet the third wall into the first two. Don't assemble anything with glue (Titebond 3 or epoxy) until all are cut. As long as your panels were square to begin, the entire side will be self squaring. This joinery method is easy and has a massive amount of surface area for adhesion.
I’ll disagree with you on pocket screws - they are a perfectly acceptable method, depending on what your goals are. Ultimately, they are a reinforced butt joint but I’ve seen them used essentially as a clamping method for face grain joints that weren’t amenable for clamping. Many people don‘t like them, but if you’re going to deride them because they don’t require skill, then you need to throw out the domino, too.

To the OP, Are you planning on making a frame and skinning it or is your joint going to be visible? When you say ”3 way miters, is it just for the top to attach to the frame? Without seeing your design it’s hard to comment. It’s also helpful to know what tools you have available. Festool domino is great for making floating tenon joints but they’re $1000, so unless you truly have a use for one you’re not going to go out and buy one just for this, and in the end it’s still a butt Joint, just a stronger one.

There are many ways of doing joinery; the best way depends on what you need in terms of strength and appearance and what your skills and available tools are.
 

Lost in the Sauce

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I’ll disagree with you on pocket screws - they are a perfectly acceptable method, depending on what your goals are. Ultimately, they are a reinforced butt joint but I’ve seen them used essentially as a clamping method for face grain joints that weren’t amenable for clamping. Many people don‘t like them, but if you’re going to deride them because they don’t require skill, then you need to throw out the domino, too.

A perfectly acceptable method of what? As you said, an alignment aid, sure. For creating a strong joint, no. For building anything structural, no. Building something that will have to securely hold hundreds or thousands of pounds, no way in my shop. I can tear a kreg drilled frame apart easily. I've done it. Can't break apart a m&t without destroying the work piece.

The domino is also a crutch tool that creates a time tested joint. Mortise and tenon construction goes way back. A floating long grain tenon adds strength to the overall joint.

Kreg jig has its place. Picture frames, cabinetry. I have it and use it.

Building an aquarium frame, I'll stick to what I know works. We all have our opinion of workflow. No one right way.
 

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