A little piano hinge advice, please (help)

[Roly Nelson]

I just had to design and build another different kind of teardrop trailer. My latest creation is a teardrop shaped like the Good Year Blimp. However, I am having a real problem with the hatch lid and it's hinge. The hatchlid fits just fine, but when I bent the piano hinge around the curve on the roof and screwed it down to the roof and to the hatch lid, I can't get the damned thing open. No matter how I try, it seems to bind and won't move more than an inch or so. What am I doing wrong? Piano hinges may not be the answer, besides they leak, due to their joints every 1/2 inch or so.

All of the piano hinges on my other TDs have worked just fine, but this one has me stumped. I guess I flunked engineering, so I may have to trash the whole thing, if someone can't fill me in about my bendable, curved, impossable hatch-lid lifting proceedures. Another problem I fear I will have would be fighting this same situation when I build the door on the curved side. Ugh, this stinks and trying to solve this problem makes my head hurt, I'm too old for this crap.
Roly

[Dean in Ct.]

I don't believe you can bend a piano hinge and have it work. Picture how much the 2 sides of the joint have to move to go from closed to open. Maybe a single heavy narrow hinge in the middle would do it.

[Kody]

If you can use two but hinges about 3" long, mount them about 4 inches in from the outside edge. The hinge pins themselves must be parallel and on the same plane. This may mean not mounting the hinges following the curve (Curve? what curve?) of the pivot joint where the piano hinge was/is. Check out the hinge pin on your closet door. The pins are parallel and mounted on the same plane. The hinges must be mounted in the same format for your hatch to pivot upwards.

Kody

[Gage]

Well Roly, I guess you need to check with Dale and see how he did it.

[Gage]

A piano hinge wont work if you bend it, way too much stress on it and they're not meant to go around corners.
Find the most usable straight part to mount your hinge and you're good to go.

Wonder how this door hinges? Just something to think about.

[Dean in Ct.]

That yellow one reminds me of the door on an airliner where the 2 hinges pop the door out and then swing giving some clearance. It also looks like the hatch has a straight joint for about 18". Would love to see more details there!

[Gage]

Looks to me like one hinge, the door handle doesn't count as a hinge.
Be nice to see this pic expanded for a better look at it.

Well, it belongs to a member here and is in the 'Hall of Fame'. Guess you need to take a little time and look for it. Oh it's listed as 'Del's Jelly Belly'.

[pohukai]

Looks like the top of the hatch is straight for the hinge.

That build is EXTREME! great job.

[eamarquardt]

If you can use two but hinges about 3" long, mount them about 4 inches in from the outside edge. The hinge pins themselves must be parallel and on the same plane. This may mean not mounting the hinges following the curve (Curve? what curve?) of the pivot joint where the piano hinge was/is. Check out the hinge pin on your closet door. The pins are parallel and mounted on the same plane. The hinges must be mounted in the same format for your hatch to pivot upwards.

Kody

Correct! Look at old cars with curved doors and the hinges on the outside of the vehicle. A classic VW bug is a perfect example. In order to get the hinges to work you have to have the hinge pins perfectly aligned (well almost perfect will probably work). You should be able to insert a one piece straight rod through both hinges where the normal pins go.

Or, like aircraft doors you can come up with elaborate systems for getting a curved door to close. It wouldn't be difficult to make some custom hinges to do the job or perhaps you can find some strap hinges you can adapt. Gimme a shout if you wanna make some as I'm not that far away and we could do so in a couple of hours.

Cheers,

Gus

[rmclarke]

Here's a couple of pics from his album, showing how Del did that 'door with the wicked hinge':

[Dean in Ct.]

What I said!
Way cool!

[Mukilteo]

the jelly belly was/is listed for sale.
http://www.tnttt.com/viewtopic.php?f=18&t=52317

[mezmo]

Hey Roly,

Scrap the piano hinge idea as that'd always bind - as
your experience shows.

Get a couple pair of car trunk lid hinges - the big "C" or "?" shaped kind -
[Google Image for "car trunk hinges" and you'll see what I mean.]
and use a pair each on the hatch and the entry door. They
shouldn't be too hard or expensive to find in any auto
junkyard. A Plymouth Acclaim I had a few years ago had
that type of trunk hinge. They're cheap to use so they are/should
be widely available. You'd just need to make sure the
mounting points for them are correct on your build. I'm
sure you could determine that by educated guessing and
trial-and-error without too much extraneous effort.

Here's a link to a company making a 'universal' hinge of
this type for hot-rodders:

http://www.weedetrstreetrod.com/item126548.ctlg

It shows the idea, but is a bit pricey. Recycling junkyard one's
should be much more affordable

Cheers,
Norm/mezmo

P.S. dandan's Roswell build dealt with this same problem too:

http://tnttt.com/viewtopic.php?f=50&t=2 ... well+build

pgs 23-24, and 27, show the large squared-off "C" hinges he made
for the gullwing door he has. Junkyard car trunk hinges are
on the same principle.

P.P.S.: It just occurred to me:
Hinges for the front engine hoods might also be a possibility. They
may be more compact and most seem to have a spring built in too.
Just Google Image "car engine hood hinges" to see examples.

[wagondude]

Ok. We are into two pages without Roly responding to any of the advice anyone has given. Is anyone besides me starting to think he is just pulling your chain? Is it really possible that a man with his skill set doesn't know that a hinge pin must be a straight line to work? I smell something funny going on here. Maybe I'm wrong, but i think not.

[rmclarke]

hmmm.....you might be onto something here Bill.......at the IRG, I fell for that 'electric' Chevy of his