The International Cessna^® 170 Association

My hinges were shot, ripped in two in a wreck... I looked andcould not find any replacement hinges....sooooooooo..
I tookthe original hinge and looked at it for a while. It is made from flat steel with the hinge part rolled, then silver soldered...quite the trick
I chopped 0ff the bad part, took a 10-32 bolt and drilled a .091 hole thru the middle. This is not easy to do as I had a pile of them around my ankles before I got two bolts with the holes thru the middle. Next I cut off the head adn the threaded part. THen I bead blasted the cad platingoff.Then the hard part, I tig weld the bolt to the hinge.I took a die grinder and cut out the part not needed so as to match the opposite hinge. It took a while as you can remove metal but it is real hard to put it back, so ground, checked fit, ground, checked fit etc utnil I had the right fit.I only TIG welded the bolt into one side.
ANyway I have fixed three different 170's this way and they are still working fine many years later. I used stainless hinge pin/rods.

Bravo! WAY TO GO! I love the idea that we can not be held up by the unavailability/high prices of production parts. I love your solution to the hinge problem. Perhaps an entirely new hinge can be fabricated that resists the flexing and bending when the door is closed on newly installed door seals? I'm sure you ran these hinges by the FAA man didn't you...ha just kidding...what they don't know can't hurt them

Mark what is the price from Cessna?
We have a pretty good machine shop available and I was thinking of making one--mine broke this weekend. It was loose at annual and apparently got caught by a gust at the gas pump (top hinge on the pilot's side)
ron williams
Wichita, KS
1950 170A N5486C

John, Mark IS an FAA man. Not that it matters. An owner can fabricate any part on his airplane he chooses, in accordance with the FARs.

To those of you with stainless door pins, Be aware that stanless is anodic to aluminium. (will cause corrosion on the aluminim)
The old boys that built this aircraft knew what they were doing when they used brass wire for the hinge.
Sure it wears out fast, but brass wire is far cheaper than a heat treated formed part.
Use the brass hinge pin. I think that there must be an aftermarket source for hinges. I have a few laying around the shop that would work but they are not a perfect match (337 required) they look real pretty though.
Anyone check spruce or univair for something similar?

scott

Scott,
Are you speaking of the pin or the hinge? When you ask "Anyone check spruce or univair for something similar?"
I needed a hinge and called Univair, they wanted $500. However, I find one at Wentworth for $95.
Did not know that about the brass pins. Where can I get those?
Curtis

scott wrote:To those of you with stainless door pins, Be aware that stanless is anodic to aluminium. (will cause corrosion on the aluminim)
The old boys that built this aircraft knew what they were doing when they used brass wire for the hinge.
Sure it wears out fast, but brass wire is far cheaper than a heat treated formed part.
Use the brass hinge pin. I think that there must be an aftermarket source for hinges. I have a few laying around the shop that would work but they are not a perfect match (337 required) they look real pretty though.
Anyone check spruce or univair for something similar?

scott

The original pin was not brass, it was mild steel. Brass is too soft for door hinge-pins. Unexpected loss of the door inflight might result. (It may even strike the tail.) Some stainless is indeed troublesome for aluminum, but I've not had any problem in 4 years of using AN415, corrosion resistant "lock pins", available from Aircraft Spruce and ordinary local hardware stores (sometimes called hitch-pins. They are shaped like the letter "R".) They are also available in cadmium-plated steel.

Addendum: The door hinges are not made of aluminum. They are made of steel. That may explain why there seems to be no "anodic" (corrosion) problem using stainless steel pins. If it's a big concern to you, use the cad plated steel AN415 pins.

P/N S1426-2 for pins with loop on top for easy removal.

gahorn wrote:

scott wrote:To those of you with stainless door pins, Be aware that stanless is anodic to aluminium. (will cause corrosion on the aluminim)
The old boys that built this aircraft knew what they were doing when they used brass wire for the hinge.
Sure it wears out fast, but brass wire is far cheaper than a heat treated formed part.
Use the brass hinge pin. I think that there must be an aftermarket source for hinges. I have a few laying around the shop that would work but they are not a perfect match (337 required) they look real pretty though.
Anyone check spruce or univair for something similar?

scott

The original pin was not brass, it was mild steel. Brass is too soft for door hinge-pins. Unexpected loss of the door inflight might result. (It may even strike the tail.) Some stainless is indeed troublesome for aluminum, but I've not had any problem in 4 years of using AN415, corrosion resistant "lock pins", available from Aircraft Spruce and ordinary local hardware stores (sometimes called hitch-pins. They are shaped like the letter "R".) They are also available in cadmium-plated steel.

The parts list on the original drawing calls out 3/32 brass welding rod as the hinge pin material.

To preserve the steel parts integrety the engineers called out brass pins peened over at each end. I use either brass or aluminum stock to make my removable pins to continue that softer on harder idea.

N4005V wrote:[...The parts list on the original drawing calls out 3/32 brass welding rod as the hinge pin material.

minton wrote:To preserve the steel parts integrety the engineers called out brass pins peened over at each end. I use either brass or aluminum stock to make my removable pins to continue that softer on harder idea.

I know neither what drawings are being referred, nor which engineers were being disregarded by Cessna-production people, but...
...I have four N.O.S. hinges mounted on N.O.S. doors. The hinge pins on all four are mild steel, bradded over on both ends. (Either that or they are made of a very unusually-hard, magnetic brass.)

Here's Cessna's instructions on spin bradding hinge pins.

H. Mark Smith wrote:My hinges were shot, ripped in two in a wreck... I looked andcould not find any replacement hinges....sooooooooo..
I tookthe original hinge and looked at it for a while. It is made from flat steel with the hinge part rolled, then silver soldered...quite the trick
I chopped 0ff the bad part, took a 10-32 bolt and drilled a .091 hole thru the middle. This is not easy to do as I had a pile of them around my ankles before I got two bolts with the holes thru the middle. Next I cut off the head adn the threaded part. THen I bead blasted the cad platingoff.Then the hard part, I tig weld the bolt to the hinge.I took a die grinder and cut out the part not needed so as to match the opposite hinge. It took a while as you can remove metal but it is real hard to put it back, so ground, checked fit, ground, checked fit etc utnil I had the right fit.I only TIG welded the bolt into one side.
ANyway I have fixed three different 170's this way and they are still working fine many years later. I used stainless hinge pin/rods.

Mark went to a lot of trouble to drill out bolts to make new hinges but I'm sure they came out very nice.

When the hinges went bad on my 1958 C180, my IA asked what I wanted to do. I asked him if he could just skip-weld a piece of steel tubing about the same size as the original and cut out the part where the other side of the hinge goes. He said that sounded like a design spec he could use for an owner produced part and that is what he did. We then found a piece of stainless steel welding rod to fit the tubing and made new loop hinge pins. That was in the mid 1990s and the hinges are still working just fine.

I personally would not use brass hinge pins.

MIne broke and my mechanic welded it.
We had to remove the hinge from the door, so the job took about a day, including reinstallation and paint.