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Looking for tips to get the hinge pin in all of the way

McFly

McFly

Well Known Member
I am having a really hard time getting the hinge pin all of the way in on the cowl to firewall connection (long pin). The pin simply will not make the radius. I am using the undersized pin and have chiseled the tip and then deburred the chisel. The hinge on the firewall is not yet riveted, the hinge on the cowl is. Thanks.
 
Lube it up, then chuck it up, in the drill and slowly spin it in. Also make sure the eyes of the hinge aren't clogged with epoxy (if used), or bent. It'll get easier with time.
 
If you are having that much trouble, chances are that you have an "eye" out of alignment. Try puting the pin in each hinge half without the cowl in place. When it stops, you have found the offending eye. If the pin will go in each half individually, it should go in assembled. If not, something is badly missaligned.
 
You may also need to chamfer the inside edges of the hinges so they mesh better, allowing the pin to snake around. I also prebent the pins to assist in following the curve. Another thing is to polish the tip into a nice round point. Epoxy leaching into the hinge can aggravate the pin, and as mentioned, bent and misaligned hinge eyes. They do get better with time, especially after the engine is run and the cowl seems to conform better with the heat.

Roberta
 
If you haven't yet done so, put a rather noticable bend in the pin quite close to the end, maybe about 1/4" from the rounded end. You may be surprised how much you need to bend it in this location. And, be sure that you know which way to orient the end you are pushing to insure that this acute bend is pointing towards the inside of the curve.
 
Camlocks?

Hi Hugh and others,
I'm assuming that you're speaking of the upper cowl/firewall interface. This is the reason why most of my buddies and I installed camlocks up there at 4" intervals. As I understood it, the hinge pins are supposed to be .090" fitting in the .125" holes in order to make the bend easier.........am I wrong here?
Regards,
Pierre
 
I have a loop & puller

That particular hinge pin is the toughest one to get in. I had a 0.125" dia. aluminum hinge pin that I acquired with a hinge purchase that I found could be formed into a very effective hinge pin puller. I formed a hook (about 1/4" bent back past 90 degrees (120 pehaps) and a finger loop on the other end. I have a loop formed in the end of all my stainless steel flight hinge pins and my puller has made the job painless for all the years since they were first installed. Another couple of points with the particular hinge pin you are having trouble with: (1) when you are inserting it and it seems to hit an obstruction rotating it just a fraction of a turn with insertion pressure will allow it continue (2) when the insertion stalls pressing in on the cowl on the far side where the radius tightens up while maintaining insertion pressure on the hinge pin also worked for me. As Roberta stated mine has gotten easier to install with time. I still use my little puller though.

I still have the original hinge installation hardware everywhere on the cowl except the attachment at the bottom of the fuselage. I ended up installing extension plates containing #8 platenuts, from the firewall flange (with appropriate spacers) inside the cowl. The cowl is attached with flathead screws and dimpled washers at this point. Mel advised me via this forum when I reported the rivet heads working in the glass over time and poping off. I had reinstalled the hinges with larger diameter rivets and was seeing the head working problem again before this fix. The new configuration is working out very well.

Near the front of the cowl, I have a small notch cut in the upper cowl half for the small loop on the hinge pin for the upper/lower cowl interface to rotate into when it is fully inserted. Over this I have a 0.016" aluminum cover that is attached with three flathead screws, one in the inlet that goes through both halves and two on the outside in the upper and lower halves respectively. The cover is dimpled for the screws so no washers are required. Platenut are mounted inside to receive the screws. In addition to avoiding the hinge pin tang screwed to the outside of the cowl, it takes the inflight clamshell separation load off of the side hinges and it eliminates the leading edge gap between the cowl halves.

My airplane is an RV-6A but the cowl installations look similar so hopefully the information will be of some use to you.

Bob Axsom
 
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No joy yet

Thanks for all of the great suggestions. It sure acts like a couple of eyes are out of alignment but I?ll be darned if I can see it. I did chamber the offending eyes, checked for epoxy obstructions (there were none) and polished the rod end, and oiled everything but no joy yet. I have not tried Bob?s trick of pushing on the cowl, which seems like an obvious trick now.


Pierre: Way back when, I ordered the Skybolt camlock fastener kit. After three plus months all I got was an envelope with a few parts and large backorder list along along with lame excuses and attitudes. Seems like a great solution but I'll go with duct tape first. I?ve ranted about it before on this list so that?s all I?ll say about it.

I?ll keep trying. I must be missing something. Thanks.
 
Hugh,
I had the same problem, turns out I had one to many eyelets to the front (to much curve) cut off the frist eyelet on each side and it goes in much better
Frank K
N Mn
 
After you get the hinge pin in take a heat gun to the cowling where the hinge is. Heat it up till it is too hot to touch, go do the other side. Let it cool down then do it all over again. This will relieve the stress points on the hinge and the cowling will take the required shape. After it cools down to room temperature you will be able to remove the pins with ease. This is what happens to the cowl after several hours of flying anyway and it will make your life much easier removing the pins. This trick I developed four planes ago and hasn't failed me yet.
 
Hello Hugh

The pins will get easyer with use.

I started out using pliers to push the top pin in and had a friend thump on the curved portion of the cowl as I inserted the pin. The more times that I have inserted the pin the easyer it gets. I can now insert the pin myself and once I didn't even need to ues pliers.

Kent
RV9A with 18 hours of flight testing.
 
They?re in!

Thanks for all of the suggestions, I used all of them.


I finally and reluctantly came back to this and I can put a check in the ?done? box.

Here is what I think made the difference
1) Use a clecoe in every hole (the cowl side is riveted but not the boot cowl side)
2) Use a good lubricant. I was using ?3 in1? oil and not having any luck. I ended up heating the pin and then passing the pin over a stick of BoeLube. The BoeLube melts like candle wax and coats the pin nicely.

I did use NormanCYYS suggestion of heating the cowl after pin insert with great results. Thanks all!
 
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