I'm close to finishing my 2nd effort at building a blammo box. Going to use it for a rabbit production. The gimmick panel is going to be propelled down into place by the workigns of a mouse/rat trap. However, on testing it today, all four outside walls / panels are not falling. They just stand pretty much in place after the top is removed. I've used piano hinge on all four of them. Any suggestions on how to get them to fall quickly and reliably? Thanks.

Jim

Pull the original wire out of the piano hinge and replace it with a thinner diameter wire. Also, think of filing a little metal away from the edges of each of the fingers of the hinge to make it a little sloppier.

You can also drill a hole and put a spring loaded bullet catch on hinge. Or add a couple of springs right into the hinge itself. But I would guess that the thinner wire would do the trick.

You could also put a thin thickness of wood so you have to kind of spring the side up to put the lid on. That will leave some tension on the sides so when the lid is removed it will go down.

The bullet catches are a great idea. I have seen designs of boxes built so the walls taper outward at the top, but since your box is already built, you may want to look this over. (Spring Hinges) I put this up about a week ago for a friend who needed to make some.

With piano hinges, you will have to modify the idea somewhat, possibly dividing a longer hinge into two non-equal shorter sections and spring-loading the smaller of those.

~michael

The bullet catches are really good. They are a simple fix, too. Be sure to have some metal on the surface the bullet presses against to keep from denting the wood.

Michael already hinted at this idea.

I know it might be too late, but you might consider changing the piano hinge for a couple of regular hinges. Less resistance to natural movement.

Just make sure that the hinges are mounted in such a way that the panels are flush, when folded up or down. This way, they should want to fall.

At least, that is the way my full-sized blammo was made. Mine was made with pin hinges, which are fairly loose.

- Donald

Thanks for the article Michael,

You guys are great! Is this a terrific place or what. Thanks so much for all the solutions to a dilemma I am dealing with right now. Michael, amazing web page abotu making spring hinges!
Best,
Jim

PS: I think I know what the bullet catches are. I'll check at the hardware store.

Yes the spring ball, (bullet door latch), is what is in my Chalet Birds to Bunny.
as long as your box sides are on the inside when closed. Its the best way, or
you also could glue a small rubber strip, cut rubber band, along the hing to provide some pressure.

Bullet Catches along with pulling the pins on the piano hinges, replacing them with smaller diameter wire is the best solution. In my opinion.

The Piano hinge, normally has some small punch marks every few tangs. You have to drill these out and then you will be able to pull the pin. The replacement wire is available at your local Hobby Shop (The kind that sells Radio Controlled Airplanes). Just ask for the piano wire section and you'll find lengths and diameters that will work perfectly. This will make the sides swing very free.

If the sides swing very free, all the bullet catches have to do is get them past vertical, and gravity will do the rest.

The removeable pins will also allow you to take all the sides off and break the prop down to let it travel easier.

Also, the gimmick doesn't have to be spring loaded either. Gravity moves it pretty fast, and handling the lid properly will cover it's descent.

Michael Berends

Take a thin piece on spring steel, bend the end a little, then slightly round the rest. then you can put the screw in the end creating a spring to push it out.
or you can put one or two wmall washers on a couple of the screws, then it will have pressure when lifted up, so the sides will fall

The reason I mentioned sectioning the piano hinge is because it's a nightmare to knock the pins out of one of those. Cut off a short section and it's easy for that part. (I never thought about drilling the crimps!) The flat spring steel is a great idea, too.

I made a fullsize firebox Blammo a few years ago, and it had a similar problem. A quick remedy there was to have the assistant put pressure against the back and two sides with a foot, an elbow and a hand. The gimmick dropping created enough air pressure to blow the front open.

What's wrong with this world when you can't train a rabbit to even try to learn to do that? Sheesh!

~michael

Drilling out the crimps is not as bad as you may think. It really didn't take me long to drill them out, and extract the pins.

As for those darn rabbits....I too have had problems not being able to get them to do the simplest of tasks....LOL

Michael

I'll give it a shot. Thanks!

~michael

The photos that Michael Baker posted are great for making a spring hinge. I have a forgetful Frankie the the hinge is broken beyond repair. I have been trying to make a spring hinge for it but being that the hinge is small I can not remove as much of the hinge as I need to put a strong enough piano wire in that will pop his head up fast enough. Does any one know where I may be able to get a spring hinge for Frankie?

Thanks

I've never owned a Forgetful Anything, but would the spring from a mouse trap work?


As for the Blammo Box, I built one this spring for use in my library shows. Quite a bit of thinking went into it, and it (as usual) took longer than anticipated. But the results have been great. Having never seen one up close I never thought of using springs of any kind. Instead, everything is gravity fed. The sides lean out 1/2" at the top, and although the piano hinges are slightly "sticky", when the top is pulled off quickly, the trap falls into place and the sides kick out wonderfully. Even close up this is a great illusion.