6
Your initial thinking is correct. You're much better loading the sides directly than transferring the load through a joint in a shearing manner.
The first method of construction is more typical in cabinetry because the load isn't usually directly on the top sheet, it is on a countertop that spans the sides. This effectively transforms it into the ...
5
I'm thinking that it would be better to strengthen it in some way
You likely don't need this to be any stronger than the glue-only joint, if you do it right. Think of the stresses this is put under in use, the joints won't actually have to endure strong forces since the normal forces go straight down the length of the boards to the ground. And as I mention ...
5
In that particular video, the guy is working with particle board. There is no grain structure in particle board (or MDF for that matter), so there really isn't a 'good' way to make a butt joint.
The screws that are used in most particle board construction are specialty 'confimat' screw (as listed here on Amazon). These screws have very wide threads and ...
3
Scribe, saw and pare until you get a good fit, fix in place. It really is about as simple as that. Remember the tight fit only has to be right at the edge, it can be undercut away from the edge and won't make any difference — which based on the third photo it appears is how the original is done.
But this joint doesn't have to be done this way. You can cut ...
3
Professional woodworker here. I have to admit when I first answered this, I was thinking about face to face wood joints (rather than end to face) so most of this answer is talking about that BUT a lot of these points apply to all types of glued joints:
There's a lot to go over here so I'll cover each point in turn:
1 - Moisture content. This can certainly ...
3
Graphus mentioned the strength of the joint as being one major issue. If it's strong enough, it's fine, but pocket holes are not for every joint. Casework is a good example of where they shine (especially on shop furniture).
Another problem is similar to downsides of regular butt-joints: alignment. I found alignment to be a larger issue with butt joints ...
3
The top board will expand left to right, but not significantly in the relatively small area of the glue joint itself. The bottom board will expand up and down, but not significantly in thickness.
You can do the joint purely with glue if you desire - joints were glued only for a long time. Screws can be added but aren't necessary. Think of them as additional ...
2
The second, by a substantial margin.
The claims of strength from purveyors of pocket-screw jigs have been tested by many woodworkers, including numerous pros (e.g. Bob Van Dyke of the Connecticut Valley School of Woodworking), and these tests often confirm that when used for a standard 90° joint between two boards strength can rival or exceed that of mortise-...
2
Short Answer
I like @Graphus' comment where he/she states that Set B is mainly intended as shown in the image, for attaching solid-wood trim to the front edge of plywood or other manmade boards. However if you are using these bits for jointing solid-wood, there are applications where Set B could be better than Set A.
More surface area within the joint = ...
2
A pocket drill jig will allow you to drill holes at an angle to board 2 into board 2 and engaging board 1.
The jig guides the drill into the work, which would otherwise skip off due to the extreme angle and also provides for a clean "pluggable" hole if desired.
This is mostly the opposite of what you ask, but a doweling jig is the answer to your question. ...
2
Since the joint is pulling apart where it should be tightest it seems unlikely to me that the concavity is causing the problem. Rather, it seems that I might be making the concavity too subtle. Thoughts?
You're doing what are called sprung joints, or a spring joint in other places. These should do exactly what you want them to do, help the two ends not come ...
2
If you go to your local big box home center, they have metal brackets with which you can attach 2x4s and 4x4s in almost any configuration you can imagine. I used some of them several years ago to attach 4x4 legs for a balcony to the stage floor. This removes the need to screw at a 45 degree angle or to try to get access from underneath (and screw into end ...
2
For something that could be disassembled and reassembled each year, I would give strong consideration to carriage bolts.
A single carriage bolt could serve for both braces where they meet the upright. An oversized washer underneath would mitigate any possibility of pulling through the plywood, although I'd be inclined to think a regular-sized washer would ...
2
Edge gluing is a very popular way to get big panels without needing very wide lumber (which usually comes at a premium price). Your calculations are correct, in that you will need 7 1x4 boards to achieve a 24 1/2" wide panel. You'd need 8 and some extra to get the full 29 5/8".
One option to reduce the number of glue joints you'll need is to use wider ...
1
If you use pocket screws for all the major joints here you don't have to have any particular worries about strength, they are very very strong if everything is done right1.
Since this will see exposure to some weather (and the water from watering the plants I guess) be sure to use exterior-rated screws in the pocket holes.
How do I prevent it from tipping ...
1
I think a much more common approach would be to make the upper cabinet a stand-alone unit with its own bottom. Then, when you assemble the two units, you'd use short screws driven up through the top of the lower unit.
This would have a secondary benefit as well. As you currently envisage it, getting the doors right on the upper unit will be a very, very ...
1
Pocket screws are a popular method because you are fastening long-grain to long-grain. This is the strongest combination possible. If pocket holes don’t fit your needs, the long grain bond can be achieved through a number of more traditional methods like a mortise & tenon, half lap, or even dowels.
A butt joint is extremely weak unless the woodworker ...
1
The question is, just exactly what is included in your "router with a set of bits". If you have a bit which is longer than your boards are thick, you can use this to do the job.
Start by getting a guide board which is longer than your bench boards. It should be as straight as possible, but don't worry about small deviations. Using a couple of clamps, tie it ...
1
A lot of good points were commented but as a solution (much appreciated) I chose to use a 3/16" rabbet joint on the bottom board and then pocket screw and glue it in. The rabbet joint provided a nice grove to keep the the box square. The pocket screws I just used were 1" and the plywood is 3/4" so I had to be delicate with not over drilling ...
1
You mention that the bottom is plywood, which leads me to think that the sides are plywood also. It is never a good idea to drive screws into the edge of plywood. Not even if the joint is not carrying a particularly big load as in option number one.
You should use solid wood gluing blocks to reinforce the joint. The blocks are placed in the corner and ...
1
The first thing you will need for this project is a lot of bar clamps capable of spanning the width of the finish panel (29 5/8"). You should plan on clamping the width of the panel at least every 24" so you will need at least eight or nine clamps to spread across the 16' length. Other answers have offered good advise in starting with smaller widths of 2 or ...
1
I don't quite understand how you're getting from 24 1/2" to 29 5/8", but...
Typically when you're gluing up large, thin panels (and at 3/4" thick, 1x stock would be considered thin in a piece this size) you want to have some kind of alignment aids. These typically take two forms, external cauls or internal splines/biscuits/dowels/dominos.
For an external ...
1
It's likely you can dispense with any reinforcement here and achieve strong enough joints. It's even possible that if this piece were subject to much greater stress you could use glue only.
As mentioned in one or more previous Answers, the known weakness of end-grain glue joints primarily refers to when end grain meets end grain, as in the classic mitre ...
1
Although mortise and tenons would be better for strength, I would say glue and pocket screws would be OK. As you say, most of the load is vertical (I just did the trig, it's actually 99.6% of the load is vertical (cos(5deg)). Keep in mind that glue on end grain does not produce a very strong joint. So you definitely want some good pocket screws to help ...
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