LettersFromFlyoverCountry

LettersFromFlyoverCountry

Well Known Member
Now that the project is mostly done, I have one remaining "problem:" getting the hinge pins on the cowling to fit.

For the last year or so, I've been using a drill to turn the side pins to get them to span the length of the hinge pieces on the cowling, but now I'm finishing up, having bought the two hinge pins Van's sells with the welded tab on the end.

The problem here, of course, is you can't use a drill to install these.

I can't get them in about 3/4 of the way with muscle, but that's about it. I've lubricated them and used a scotchbrite pad on them, but no luck.

Anyone got a foolproof way of treating the pins (or hinges) so that these things can fit properly?
 
Bob,
First, look very closely for a pinched eyelet in the vicinity where the pin starts to bind. If you find one pinched, re-expand it. Also look for dripped epoxy in some eyelets. If that fails, then take one of the pins you've been using with the drill and make it into a long "drill bit", slightly flattening the tip with a hammer and vice top. Grind it to a sharp point and also a sharp edge. The tip will look slightly teardrop shaped. Chuck it in the drill and run it in and out a few times.
This will clean out any epoxy and slightly expand a tight eyelet. Of course you could go too far and flatten the tip too much and and wind up breaking eyelets, but I've had good success with this method and haven't lost any eyelets yet!
Good luck,
 
Hinge Pins May Not Be The Problem

Sounds like the problem I had. Turns out the upper and lower cowl pieces were too closely fitted, and were creating tension as the pins were fitted. Used a drill motor to drive them in and out during Phase I, but they never really loosened. Paint shop I used after the test period pointed out the too-tight fit would lead to chipping along the seam. With both pieces in place, he used a hacksaw blade held in hand and worked along the seam. Resulted in a perfectly uniform gap and no more drill needed to drive the pins home.
Terry, CFI
RV9 N323TP
 
If your plane is not yet painted:
I agree with the previous suggestions but here is one more to try.
With the old pin installed gently heat the cowling with a heat gun in the hinge area. DO NOT use too much heat. I have found this to help on occasion. Typically after 10 or 20 hours of flight time this happens naturally due to engine heating and cooling but in your case it might not yet have occurred.

Again only if the cowling is not painted.
 
Another thing to look for is an eyelet slightly out of line. It just takes one. Note where the pin stops and start looking there. It's amazing how easy the pin slides in when everything aligns properly.
 
LettersFromFlyoverCountry said:
Now that the project is mostly done, I have one remaining "problem:" getting the hinge pins on the cowling to fit.

For the last year or so, I've been using a drill to turn the side pins to get them to span the length of the hinge pieces on the cowling, but now I'm finishing up, having bought the two hinge pins Van's sells with the welded tab on the end.

The problem here, of course, is you can't use a drill to install these.

I can't get them in about 3/4 of the way with muscle, but that's about it. I've lubricated them and used a scotchbrite pad on them, but no luck.

Anyone got a foolproof way of treating the pins (or hinges) so that these things can fit properly?
Click to expand...

I had a similar problem. Mine turned out to not be any of the things previously mentioned but rather a small dab of epoxy which had squeezed out just enough to interfere with the rod. Removing it allowed the hinge pins to be installed by hand w/o a drill, lube, or anything like that.
 
Make a drill bit from an old pin

Grind a flat about 1/2" long on one end of your old pin. Then chuck it up in the variable speed drill. The flattened end of the pin will bore (scrape) it's way through the eyelets and leave a nice tunnel for your new Vans pins.
 
What helped me was a slight de-burring of the entry side of each eyelet then with the cowling removed push the hinge pin in each cowling half and watch as it goes from eyelet to eyelet and fix any that are out of alignment. Going from eyelet to eyelet will help eyeball any immediate problems. The two halves fitting too tightly together could be an issue. Also be sure the pin is somewhat tapered at the insertion end.
 
i ordered the next size up of pin from McMaster-Carr. Two foot section which reaches total hinge if you come in from each end.

Used this to ream and ever so slightly widen pin holes.

Tom Hanaway
 
I was stuck with this same problem yesterday, so the timing of this hint was perfect. I made the "drill bit pin", ran it through both sides, and now it goes together "like butter". Thanks!
 
Dang hinge pins !

I found a very old thread when building my -4, that has you do a "chisel cut "on the pin end, grinding a basic flat over approx. 1/2" tapering to a smooth polished and slightly rounded end. You would think a more pointed approach would be better, but with the chisel cut, a slight twist while inserting the pin lets it step up over the conflicting eyelet. I have a very small loop at the forward end that is secured by a screw after fully inserted,and also find that if I gently push inward at the seam with one hand about mid-cowl as the the pin is being inserted, it goes much easier. Never needed a drill, hammer or plier to insert mine. I use a tiewrap looped through for removal and just put a rag over the end while inserting. I use a lubricant called "door ease" that looks like a big stick of chapstick, and is pretty much just parafin wax. After 100 hrs of flight time, they have really become easy to install...good luck !
 
At 140hrs mine are still a bear to get in and out...have to use vice-grips both ways and going in I've had them buckle from the pressure needed on a couple of occaisions even when I was trying to prevent it. I've cleaned them, lubed them, run emery cloth on them, bullet pointed them... What I haven't done is looked at the eyelet part of the equation...thanks for the ideas:)

Jeremy
 
Did the hacksaw trick. It's a little bit better (I have VERY little gap on my cowling). I was actually able to get the pins in by hand....of course it took about 20 minutes, but, hey, that's an improvement.

Will now try the "chisel cut" approach.
 
I took a grinder and cut a few shallow 'slots' angled back 45 degrees or so on the leading end of my pins (from near the tip back about 6"-8" or so). Wiped the end (to fill the slots) with some grinding compound and chucked the pins in a big 18 volt screw gun. A few 'in's and out's' with that setup once in awhile and (assuming everything is lined up properly and none of your hinge elements are out of line), that makes installation and removal pretty easy most of the time. Just wipe them down when done, apply a light coat of penetrating oil and they should slide in and out pretty easily. If not, repeat a couple of times.

Regards,


Lee...
 
Rubbing compound (as in old fashioned paint completion)

I agree with Mel that you need to take a close look at the individual loops to make sure they are "in line",..... looking at only upper or lower side at a time,....slowly push the rod in and look how it hits "the next" loop,... check each and every one..... small tweaks will make a big difference. (you get not only twist,... but some can be "up or down" don't really know how they get there... but it happens)

Even after I did that I still had some problems. Used a "dab" of rubbing compound on the hinge pin and ran them in and out a few times with the drill motor.... then worked several times without compound to try and remove all the compound. It helped a lot on getting the final fit and ease of removal.
 
You must log in or register to reply here.