I feel so stupid

[steingar]

My buddy and I did an oil change on the airplane last weekend.  A royal pain, we wound up having to pound a wood chisel into the oil filter to get enough oomph on it to get it turning, but we got it off, got the new one on, safety wired and everything.

We went to put the cowlings back on the nose and made the most unpleasant discovery.  The screws aren't all the same the way there were on the Cherokee.  Every screw doesn't fit every hole, not by a long shot.

Well, we worked with it and by the end we had every hole filled with a screw but three that didn't fit our remaining screws.  We were both tired and frustrated, so I figured I could play musical screws with the airplane another day.  They all came off, they should all go back on.  We put the remaining screws in a baggie on the hangar shelves.

Where I couldn't find them today for the life of me.  They're 

Criminy, do I feel like a boob.

 

[Guitarmaster]

Ahhhh.... Welcome to the MSC... Mooney Screw Company!

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[mooniac15u]

I probably have some extras but I'm not sure I'll be able to make it out to Bolton today. Do you know what sizes they are?

[cnoe]

I love hearing of other people's mistakes. Just the other day I was reinstalling both the top and bottom cowlings and was down to the last screw inside the air inlet when my fingers fumbled. Tink tink tink and there lodged the screw and washer between the engine baffling and the ram-air horn at the bottom of the lower cowl. After removing the upper cowl again I could see it with an inspection mirror. My magnet-on-a-stick would lightly adhere to the washer but the SS screw said no way. My claw pick-up tool was 35 miles away so I had no choice but to then remove the lower cowl too and start all over again. Sigh.

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[steingar]

9 minutes ago, mooniac15u said:

I probably have some extras but I'm not sure I'll be able to make it out to Bolton today. Do you know what sizes they are?

I swear some look like wood screws.  No idea.  But I was planning to hit the airport tomorrow for a bit to see if I can find the damn things. Hey, if I'm successful maybe I'll take you for a ride in mine.  If not maybe you'll take me for a ride in yours.  Non pilot buys lunch?

[steingar]

31 minutes ago, cnoe said:

I love hearing of other people's mistakes. 

Glad I could make your day that much better. 

[MyNameIsNobody]

It is better to feel stupid than to be stupid and I, like you, have felt marvelously stupid...from time to time.

[Guest]

Older Moonies are assembled with a variety of different screws, they must have owned a screw manufacturing company.  Most older cowls had #8X1/2" self tapping screws holding the side panels on.  Over the years the Tinnerman nuts break, instead of replacing the nuts people jamb in a #10 screw and so on as the nut continues to break..  The belly suffers the same fate.

Clarence

[takair]

1 hour ago, steingar said:

My buddy and I did an oil change on the airplane last weekend.  A royal pain, we wound up having to pound a wood chisel into the oil filter to get enough oomph on it to get it turning, but we got it off, got the new one on, safety wired and everything.

We went to put the cowlings back on the nose and made the most unpleasant discovery.  The screws aren't all the same the way there were on the Cherokee.  Every screw doesn't fit every hole, not by a long shot.

Well, we worked with it and by the end we had every hole filled with a screw but three that didn't fit our remaining screws.  We were both tired and frustrated, so I figured I could play musical screws with the airplane another day.  They all came off, they should all go back on.  We put the remaining screws in a baggie on the hangar shelves.

Where I couldn't find them today for the life of me.  They're 

Criminy, do I feel like a boob.

 

Soon after I got the plane I bought a new stainless screw kit and tinnermans.  Replaced any oddball or bad tinnermans and this reduced the frustration.  Bad enough having to do it when it's right, miserable when mismatched.  The belly is an order of magnitude worse.

[gsxrpilot]

$10 at Aircraft Spruce will get you a bucket of replacement screws and tinnermans. 

[mooniac15u]

2 hours ago, steingar said:

I swear some look like wood screws.  No idea.  But I was planning to hit the airport tomorrow for a bit to see if I can find the damn things. Hey, if I'm successful maybe I'll take you for a ride in mine.  If not maybe you'll take me for a ride in yours.  Non pilot buys lunch?

I've got a bunch of #8 and #10 screws. We should be able to get it put back together. I'm not exactly sure what my schedule looks like tomorrow. I'll PM you my cell phone number. 

[carusoam]

If you get the screws that match the tinnermans they don't have a really pointy end.  The maintenance manual kind of gives a hint of which size screws go where.

Follow Clarence's reasoning of why the screws all seam to be /are mismatched.

Fresh tinnermans with fresh screws do an amazing job of keeping things simple.

Best regards,

-a-

[kris_adams]

Been there and done that

[bradp]

The front part of my firewall must be like the island in the black hole in lost.  I don't know how many times I've heard something go clunk to be forever invisible until the next time I come into the hangar and the hangar elf has conveniently placed it where I swear I had looked last time.  

[Yetti]

Develop the quick look and scan coupled with the tink tink directional finder.   Just the other day in Homer Dan someone dropped a small part, I was on it like a retriever on a duck.  Reached under the edge of the cabinets picked up the part and handed to the person without breaking step.

[steingar]

Well, the Mooniac came by and gave huge help in putting the Lucky Strike back to rights. Mondo thanks.  Also put my mind at ease.  I had no idea there were so many different screws in my airplane.  Definitely stocking up.

[Vance Harral]

7 minutes ago, steingar said:

I had no idea there were so many different screws in my airplane.  Definitely stocking up.

It's worth referencing your parts manual to see what's supposed to be there.

Speaking only for the 1976 F model, I used to think the airplane was designed with dozens of different screws, too.  Then I looked at the parts manual one year and found almost all of them are spec'd as one of two types: AN526-832R8 or AN526-1032R8 truss head machine screws.  The exhaust tunnel panels are oddball (coarse sheet metal screws), and the belly panel where the nose gear doors close have a small number of flush head screws.  But even with those additions, that's just four types to cover every cowl, inspection panel, and belly panel screw on the whole airplane.

At that year's annual, I looked closely and found every "odd" screw I'd been carefully tracking over the years was actually the wrong screw.  In some cases a random screw had been improperly jammed and self-threaded into a tinnerman plate of a different size than the screw itself.  In others, a speed nut that was supposed to capture the screw had been lost, and someone tried to deal with it it by jamming in the next-size-up sheet metal screw with no capture nut.

In the case of riveted nut plates, I was fortunately able to clean them up with a tap.  For removable and lost nut plates, I replaced them with the actual spec'd parts.  It was tedious work - especially working speed nuts into tight spots - but not especially difficult.  Now we have a stock of "standard" screws and nut plates in just a few sizes.  Minimal hassle, and easy to replace lost or buggered screws.  Worth the effort, IMO.

[steingar]

To be honest, the only parts that weren't supposed to be there were from a couple number 6 screws that fit into previously replaced nut plates.  Don't know why, but I'm not going to loose sleep over two screws, especially since they're securing the avionics bay where I shouldn't have to go playing any time soon.  Those were definitely my magic screws.

It was just a shock to go from one airplane where they were all the same to another where there were a several different ones.  Now that I know I doubt it will ever again be much of a deal.