Alternatives to .089 hinge pin

[LettersFromFlyoverCountry]

I am giving up on the idea of using the .089 hinge pin in attaching the cowling to the top of firewall (the long piece). It is just too steep a curve that last 4 or so inches and I'm cracking and delaminating the cowling edge where it enters the hinge.
I'd like to find a thinner pin and see if that might work better but, unfortunately, I cannot find a supplier. All of the hinge pins on all of the hinge material on Aircraft Spruce is .089".
Is there anybody who's gone this route who can help me?
The other option, I suppose, is modify things and cut the hinge and have that section be two pieces, but I'd have to create another entry point and I really don't feel like doing that.

 

[seagull]

If you bend the pin to the final radius it should go in with no issues.

 

[Ironflight]

McMaster has steel rod in all sorts of sizes - try searching “steel rod” and then pick your diameter.

 

[LettersFromFlyoverCountry]

If you bend the pin to the final radius it should go in with no issues.

Perhaps. I've tried all sorts of permutations without success.

 

[LettersFromFlyoverCountry]

McMaster has steel rod in all sorts of sizes - try searching “steel rod” and then pick your diameter.

I'll keep looking; not seeing anything that fits the bill.

 

[Stevea]

If you bend the pin to the final radius it should go in with no issues.

This is important.

I have no experience on a 12 cowl. But by bull nosing and tapering the end of pin, and pre shaping it as closely as possible to the cowl curve, I managed to install a full diameter stainless steel pin across the top edge of a 6 cowl. Probably took a day of just not giving up on shaping it. And there is a technique to installing and removing the pilot side. But all it takes is about 4 drops of liquid Boelube on a wiped clean pin, and it goes in without any hammering or colorful words.

Update: if anyone wants details (photos, wire diameter used, etc, I can post those in a few days….probably Saturday. Sorry no can do until then.

 

[rockyfatcat]

For the hinges that curve it is acceptable to step down one size. I spent some time adjusting the angle between each eyelet as it goes around the curve.

I don’t have a whole lot of patience for stuffing a pin that won’t go. I taper the end (not sharpened) that goes in first. Put on a little Boelube and chuck it up in a drill. Spin the drill and push gently. Much less frustration and foul language.

For a variety or reasons, I used hinge material to attach my wingtips to my wings. Do you think you can easily slip two 5 foot hinge pins in each wingtip? The drill makes it easy.

 

[Tony Kirk]

You could try the .063 cowl pin or an equivelent from McMaster.

.063" Stainless Steel Pin 3'

store.vansaircraft.com

McMaster #8934K43

 

[johnbright]

I'll keep looking; not seeing anything that fits the bill.

Perhaps piano wire, it comes in rolls so it’ll have to be straightened. In 304 SS McMaster has 0.075 and 0.080 diameters for instance. The shorter rolls are ~15’ and cheap enough to buy a roll of each.

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[gasman]

IF I had that problem, I would try 5/64" cable with the end welded over and polished.... or just use JB weld to see if it works.

 

[rockyfatcat]

Google MS20257 pin diameter of 0.063"

 

[rv8or]

Here in the UK I go to my local model shop and buy piano wire, my one carries various sizes.

Good luck
Rob

 

[Carl Froehlich]

I am giving up on the idea of using the .089 hinge pin in attaching the cowling to the top of firewall (the long piece). It is just too steep a curve that last 4 or so inches and I'm cracking and delaminating the cowling edge where it enters the hinge.
I'd like to find a thinner pin and see if that might work better but, unfortunately, I cannot find a supplier. All of the hinge pins on all of the hinge material on Aircraft Spruce is .089".
Is there anybody who's gone this route who can help me?
The other option, I suppose, is modify things and cut the hinge and have that section be two pieces, but I'd have to create another entry point and I really don't feel like doing that.

I use standard 1/8”. SS hinge pins. I did not like the play in the hinges when using the 3/32” hinge pins in the 1/8” hinge as it allows the top cowl to flex out in flight.

But, these pins must be modified to make this happen. I chucked a longer than needed pin in the drill press, turning at a low speed. I used a rotary file in a die grinder to taper the ~8” or so directly below the drill press chuck. Take your time and measure often, and you will have a uniform taper to ~3/32” over this section. Use some sand paper to dress up the area before taking the pin out of the drill press. Cut of the end of the pin that was in the chuck, then fit to the cowl for length.

I also add a touch of LPS-2 to all pins when inserting.

This process has worked well on a RV-8 and RV-10.

Carl

 

[GaryK]

Here in the UK I go to my local model shop and buy piano wire, my one carries various sizes.

Good luck
Rob

I am giving up on the idea of using the .089 hinge pin in attaching the cowling to the top of firewall (the long piece). It is just too steep a curve that last 4 or so inches and I'm cracking and delaminating the cowling edge where it enters the hinge.
I'd like to find a thinner pin and see if that might work better but, unfortunately, I cannot find a supplier. All of the hinge pins on all of the hinge material on Aircraft Spruce is .089".
Is there anybody who's gone this route who can help me?
The other option, I suppose, is modify things and cut the hinge and have that section be two pieces, but I'd have to create another entry point and I really don't feel like doing that.

I know McMaster has already been mentioned but that is where I got them.

 

[Tag]

Update: if anyone wants details (photos, wire diameter used, etc, I can post those in a few days….probably Saturday. Sorry no can do until then.

Please do Steve; I’m struggling with wingtip hinges…

 

[Stevea]

Please do Steve; I’m struggling with wingtip hinges…

Hey Tag. Just to be clear, I'm talking about the hinge pins (1/16" nominal diameter and 1/8" nominal diameter) holding the cowl top and bottom together, and to the firewall. I ended up using screws and nut plates to attach my wingtips. But, my cowl side seam hinges are the same AN257 piano hinge part others use for the wingtips....so some hints may apply.

Also, there are others who have successfully used the piano hinges to mount the wing tips. Maybe you can locate some of those posts.
edit: try looking for the thread by wirejock. I seem to recall he wrote up his experience doing this.

Like I said earlier, I'll post photos and pin diameters once I get them.

 

[Stevea]

As promised, tips and photos of how I managed to make a full sized pin work on a -6 cowl are posted here:

Cowl to firewall hinge attachment using full diameter pins

Starting a new thread so as not to totally hijack this one: https://vansairforce.net/threads/alternatives-to-089-hinge-pin.241031/#post-1908125 The above discussion is about trying to fit a 0.089" diameter pin in the top cowl to firewall hinge attachment on a -12. Maybe someone has been able...

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