Making a case

[Kevin Hendrick]

...a lid position stop (right word?).

I believe you are referring to the "valance", the interfacing rim around the opening that aligns to two halves as the case is closed.

So, when you close and latch the lid, you have a "co-valant bond"?

[Joe Baker]

As to the lid stop, I was actually referring to the part that holds it in a position that's part way open, whatever that's called is what I'm putting on there. I shouldn't need anything to help align the halves as long as I weld correctly.

Gotcha. I'd be inclined to use a gas strut like they use on car hoods and trunks these days. How cool would that be: you free the latches and the lid just rises to an open position all by itself!

FWIW, I'd still want a valance. The pieces of a good valance interlock in such a way as to give greater structural integrity. All the torsion that is applied to a case of this mass will work to distort the halves, and to do so unevenly. The valance causes each half to reinforce the other when potentially distorting forces are applied. Think of it this way: the best case makers in the world still use a valance. If they weren't necessary, why would case makers use them?

Valance or no valance, I'm intrigued by your project, and look forward to reading more about it as it progresses.
__________________________
Joe Baker, who has made a case for using valances when... making a case.

[trseaman]

If you can find a company in your area that uses aluminum in their fabrication they might sell at a discounted price for a small project. I used to work for a firetruck manfacturer and they sold scrap metal all the time.

An aluminum frame covered with plywood would still be heavy... I like the idea of an all aluminum case and allowing the 1/8" skin to actually be a structural part of the case. Using a hydraulic press to form & bend corners would reduce welding and help maintain strength. You'd still need some internal bracing & re-enforcing but you could scale down a bit and use angle instead of boxed tube.

I've never seen a case made from all aluminum so I can't say for sure that everything would work properly. As stated in previous posts, the testing process would need to be pretty extensive to prove it's capabilities of flight protection. Something I'm not willing to do with my tuba... For me, I wanted to build a case for my King 2341 and get away from the two cases it originally came with! No plans for flying, just a solid case to protect it from myself and daily travel around town.

Maybe someday I'll get around to my project...

Regards, Tim

[Bandmaster]

Oh, 1 more thing, does anyone know where to get some crazily strong latches? I still need a source for those.

Try this website:

http://www.odyssey-parts.com

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I am thinking about making something like this for the York Master that I bought a month ago. It is a copy of the old York in this photo, so why not?



Some one posted this photo here a while back and I thought this case was really nice.

[Art Hovey]

The best padding material that I have been able to find is sold as "Kneeling pads". It's a resilient plastic foam about an inch thick. You can cut it easily with a sharp knife and glue it onto wood. Here is one source:
http://www.homedepot.com/prel80/HDUS/EN ... eeling_Pad

[ThomasDodd]

FWIW, I'd still want a valance. the best case makers in the world still use a valance. If they weren't necessary, why would case makers use them?

Most of my case have had latches like this. There's a stub on the lower half the fit into the upper half to aling the latch halves on 2 aixes. Never had much trouble with them.


I wouldn'y use a full length, paino style hing. This structur will be strong enough to use an interior hinge. Something like this.

I used these on a toy box that has a strong lid/frame. The hinges are completely inside when the box is closed, and it'll open with the back flush to the wall. For a case, you need the height of the top away for the wall, but when closed, the hinge would be conceled. That makes them less likely to be damaged.

Also solves the issue of the case opening too far, since this hinge won't open more that 90*. No need for another stop. Most hold in the open position too.

[Art Hovey]

Hey Engineer,
I am looking forward to seeing your tuba case construction details. You may get a chuckle out of my own crude attempt, but it works for me:
http://www.galvanizedjazz.com/tuba/tubacase.html
I wonder about the use of aluminum rather than wood or carbon fiber because aluminum tends to become permanently deformed upon impact, while wood tends to bounce back. But I am sure that you will find a way to design around that.
I sure would like to learn how to work with carbon fiber! Any suggestions?

[ThomasDodd]

I'd use those but I don't see that fitting in to the design (with the frame and all). I've never had great luck with things that are completely hidden, they always break and you have to take everything apart to fix it.

Dunno. When I did the box It too some planning to get them to work, but I pick the hinges first, and designed around them. You build the to halves, then align the hinges. You might need mounting blocks for them. I think I did. You just weld a short piece of tube to the frame where the hinges mount. I think Metal would work better than wood since the screw are less likely to pull out. That was my concern on the wood, that the weight of the lid was too much for the screws into the wood. With your tube, you could use a nut and bolt(or machine screw) and it'll be much stronger.

FWIW, I used 4 of them. The lid is 2ft x 4 ft. frame is 1x1 pine, covered with 1/4" plywood.
It was originally just a box with a screwd on lid, sort of a shipping crate. I made it witha singkle sheet of plywood and scrap 1 bys. Later needed a toybox, so it was remodled. Added a full frame to the lower box, and moved the lid frame. Took some work to make the hinges work, but they were better than other stuff I could find.

I'll get you a picture of the hinges in use so you can see what I mean.