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Getting hinge pins to fit
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.
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Quote:
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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.
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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.
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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 |
IF ALL ELSE FAILS YOU CAN GO TO YOUR LOCAL HOBBY SHOP AND BUY PIANO WIRE A COUPLE OF THOUSANDS SMALLER
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