Can you critique these prototpe boxes please?

[julianf]

Im wanting to make a small number of boxes, so ive made up a few prototypes.


Below is the first unit i made -










This seems a pretty basic box, however, it seems to be more stable than the following units.
The base was routed out on my cnc machine to recess the sides, hence you see the base from the side. This aids me in gluing too (although ive since made a jig anyhow)





The second unit is, i think, more attractive, but ive got a failed joint -









I made this without the cnc machine. The center is just laminated, and then the ends and base cut from this sheet. I like the way the grain follows round. As i say, i think this is a nicer look than the first unit.



I then made a third. I intended the grain to follow round the sides and across the base, but i assembled the job wrong, so it does not.
I made the base on the cnc machine, and cut the sides to have more complex joints (i dont know the name of any of these!)







But the unit warped, as i left it on a heater, so i did not bother finishing it up. I do not think its a good design at all anyway, as the metal rails that have to be fitted will never work with the grain in this direction.




What im asking from you is basic advice. Im pretty novice with this stuff (i do cnc metal work normally)

Ive worked out for myself that #3 has the grain wrong, but, certainly #1 seems the most stable, but less interesting. #2 is made from thinner material, so i wonder if that is some of my issue? Id like them to be about 12.4mm ish (which #1 is, but #2 is less than 10mm i think)

There will be metal plates screwed on across the rails - so the whole top will be a metal sheet, so the rails will not be able to move relative to one another either.

The size of the opening on the top is 426mm x 128mm

Thank you!

 

[julianf]

ps.

Im keen on using the cnc machine for these. Little things like i need holes at specific places on the base - i can print out a template, and do them on the drill press, but as i have a cnc machine, i may as well just load the job to that, and get it to cut all the parts, IKEA style (although i dont want IKEA style at all, hence the stock choice!)

My point is, i can do the CAD for more complex joints than it may be viable for me to make by hand, if they would be considered better? Im quite keen on these looking nice, but they have to not fall apart also!

 

[MikeG.]

What's it for?

If you want it looking nice, then proper joints at the corners is going to help a lot. And sloshing glue all over the place is an issue if the interior is visible.

 

[Mr T]

If I understand the designs correctly I think you may have problems with movement on the first and third. On the first the bottom grain is across the grain in the ends. As it is only 128 wide you might get away with it but, as mentioned on another thread, it's a risk. On the third there will be a fair bit of movement length ways you would need to allow for that if you are screwing metal rails into the sides. The second looks OK and is less risky IMO.

Chris

 

[Jacob]

The tongue and groove corner joint is good for a basic box. It helps to have the tongue slightly short (fraction of a mm) of the full depth of the slot so that when clamped up you can be sure of a tight fit on the outside.
The bottom is too thick - any movement will pull the sides about. Various options - it could be say 4mm thick and floating loose in slots, or in slips, or clapped on to the bottom, perhaps just screwed so that movement would be possible. Or use 3 or 4 mm ply for stability.

PS The grain needs to go lengthways around the sides - that cross grain long side is doomed to distort

PPS to clean up the glue - take an ordinary 1/2" paint brush but trim it short to a stiff wedge shape. Use it wet but dry up with a cloth immediately after.

 

[julianf]

Thank you for the comments so far -

The glue - theyre just prototypes, ill take more care when the design is sorted. The inside wont be visible, but, if theyre done on the cnc machine, ill probably cut a logo into the inner face of the base (wont be seen in use, but, hey...)

re: base -

The job will actually be held by the base, either with little screw on feet, or on a metal frame. So the base will be structural also.


I realise i should have been clearer on their purpose!

This kind of thing -



Not exactly that, but that kind of idea. I CNC cut the panels, and i want to make wooden boxes for them to go into. So the top surface will be immovable.

The wood is reclaimed. It would be way less effort to go out and buy stock, but that is not the look im wanting.

(the unit in the photo above was just done on my RAS, no cnc machine for the wood, but i used the CNC for the anodised top panel)

 

[Ttrees]

I'd cut a dado or slot in the bottom of the sides to house a floating panel, if it were me.
This will stop the panel expanding and breaking apart the sides, whatever way you wish to assemble it, be it
regular dovetails, houndstooth, half blind, finger joints, dowels or whatever
you could make dovetail keys (or whatever you call'em) like on Ian Hawthorne's boxes

The Japanese hidden corner joints would be my choice....I can't remember what the name is.
Mitch Peacock might have made one on his channel.

Tom

 

[julianf]

If i have a floating base, that means that the sides will, effectively, just be a "hoop" of wood.

Im thinking that would fall apart on the first knock?

I cant rely on the metal parts being in place all the time - ie i have the problem of them limiting movement if they are in place, but can not depend on the gain of them providing structual support either!

 

[custard]

I make boxes like this quite regularly,

they don't "fall apart at the first knock"!

Wood moves across the grain, along the grain it remains very stable. So you can screw the metal panel into the top without any problems, and for the base just use plywood and glue it in place. No floating panels required. If plywood isn't attractive enough then apply veneer to both sides of it. Simple veneering isn't hard, you can even use on iron sheets of glue or pre-coat with PVA and then iron veneer to that, small scale veneering like that is a breeze.

 

[Brandlin]

If i have a floating base, that means that the sides will, effectively, just be a "hoop" of wood.

Im thinking that would fall apart on the first knock?

You're asking for advice.
You're being given sound advice about how almost all wooden boxes are made.
And you're doubting it.

Good joins at the corners like the tongue and groove you showed or even a splined mitre, made well will be plenty strong. You are using fairly substantial thickness for your material.

As to your face panel and how to mount it. There's a good reason that most electronics that were housed in wooden boxes are suspended by screwing the face plate to the top of the box sides, and all the connections or entrances for cables are through the sides and not the bottom.

 

[julianf]

From reading the comments, would this design -

negate the need for a floating base? Im thinking that the expansion would be the same on the base as on the ends (as mr t eludes to).

Would this be acceptable over the 128mm span? I dont know the wood being used, as its reclaimed, but its some sort of indian hardwood.

I see that #3 is no good at all really - the metal bar will not work across the grain, but will the metal top work across the grain on #2?

I could cut a metal base, but its not really the look im after.


If i go for the #2 design, should i have the base as per #1 and #3 - ie profiled so as the sides are recessed into it?

I need to google the names of some of the joints people have mentioned!

 

[MikeG.]

With a sheet of steel fixed to a steel frame you're worried about your box falling apart?

Will the bottom ever be seen? Does it need a base at all?

 

[julianf]

You're asking for advice.
You're being given sound advice about how almost all wooden boxes are made.
And you're doubting it.

Or a less aggressive way would be to suggest im trying to understand the advice being given.

I wouldn't be asking for advice if i knew what i was doing, would i?

 

[julianf]

With a sheet of steel fixed to a steel frame you're worried about your box falling apart?

Will the bottom ever be seen? Does it need a base at all?

It will need a base. It will get moved about, and the boards will be exposed without a base. And it may well be mounted at a non-horizontal angle, so the base would be seen in that instance.

If the plan works, they wont be shipped with electronics - i wont have control over the top panel being fitted or not, so they need to be able to survive until it is fitted.

 

[El Barto]

I always thought a box/carcass should have the grain orientated lengthways, in this case that’d be horizontal rather than vertical on the ends :-s

 

[Mr T]

My impression is that Julian wants something he can produce fairly easily. Mention of hidden japanese and houndstooth joints is over elaboration. The easiest way to do this with strength is to have the grain running round the sides/ends with tongue joints (or whatever they're called) at the corners and a ply bottom glued into a groove or rebate. If he is set on a solid bottom then it should be floating.

IMO!

Chris

 

[custard]

You're making this far more complicated than necessary.

Make the sides out of solid timber with the grain running all the way around.

Screw the metal top directly into the sides, or if necessary screw it into wooden battens attached to the inside of the sides.

Make the base out of plywood that glued into either a groove or a rebate (the choice might be influenced on how you choose to joint the sides). Forget using solid wood for the base unless you're prepared to open another can of worms.

The decision on how to joint the sides together at the corners is a separate issue that will be guided by your skill and your available tools and equipment. Share that information and you'll get some options.

 

[julianf]

Im sorry to seem to disagree with you, but ive mentioned that i cant screw the top to the sides. I cant rely on the top to even be in place.

The top, when present (again, it cant be relied upon) needs to mount to the metal rails that are show in the photos. The metal rails always need to be in place.

 

[julianf]

Available tools -

Planer thickener
Old dewalt RAS
CNC machine
Trend t4 router

That's probably about it.

 

[ColeyS1]

What's the attraction to using solid wood ? Why not painted mdf or birch ply ? If this is having a metal top, I see no reason it has to be solid wood...or am I missing something ?
What are you using the box for?

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