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A few annual questions


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5 minutes ago, Bob_Belville said:

Clarence, isn't the thread pitch of the ss a little different?

Why in the world would that be the case? Screws come in standard diameters and thread pitches, fine and coarse. Material of the screw doesn't matter. Custom applications where the fastener is turned on a lathe excepted, they can be anything. A 1/4-20 screw is 1/4" diameter and 20 threads per inch, whether made from nylon, aluminum, carbon steel or stainless.

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26 minutes ago, Hank said:

Why in the world would that be the case? Screws come in standard diameters and thread pitches, fine and coarse. Material of the screw doesn't matter. Custom applications where the fastener is turned on a lathe excepted, they can be anything. A 1/4-20 screw is 1/4" diameter and 20 threads per inch, whether made from nylon, aluminum, carbon steel or stainless.

You're the engineer. But I doubt a plated screw is identical to an unplated one. Is the cadmium or nickel plating uniformly .001 everywhere or is the profile of the thread different?

8-32 tells us diameter, major and minor and pitch as well as the pitch or tpi but that does not define the root, crest, or flank characteristics.

Perhaps UNF defines those attributes.

Just askin'

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A thousandth or two on the diameter won't affect fit. Threads typically engage only 75% of their depth anyway. When it comes to plating, it's a process I have done outside and the ones I generally use are 0.001" thickness or less (TiN, Teflon, diamond black and other wear-prevention coatings rather than protection from the elements or corrosion).

Many of them anymore are vapor deposition (with the notable exception of anodizing aluminum or powder coating instead of painting), and can be as thin as 0.0001" (on ten thousandth of an inch). I used to mold plastic parts that were coated on the inside with glass10 microns thick using high energy vapor deposition. These techniques provide very consistent coating thicknesses. Cadmium? I dunno, but I'd be surprised if it's highly variable, it's done rapidly to too many parts sold at tiny markups over unplated parts for the manufacturer to not have good control over cadmium usage.

Edited by Hank
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Bob,

Typical wing panel screws are AN 507-832R7' this is a non structural 8-32 thread, Phillips drive 7/16" long, cadmium plated.  The stainless steel version is AN 507C832R7.

I remember from school being told the cadmium imparted some lubricating qualities.  this may be the difference and explain why the stainless screws bind at times.

Clarence

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2 hours ago, M20Doc said:

Bob,

Typical wing panel screws are AN 507-832R7' this is a non structural 8-32 thread, Phillips drive 7/16" long, cadmium plated.  The stainless steel version is AN 507C832R7.

I remember from school being told the cadmium imparted some lubricating qualities.  this may be the difference and explain why the stainless screws bind at times.

Clarence

That's helpful Clarence.

When I did my 1st annual I found that the screws on the larger panels were 3/4". I've replaced all with 8-32R8 but I can see that R7 would be fine.

There were at least 4 different length screws in the one piece belly. 1/2" is all that's needed. 

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9 hours ago, Bob_Belville said:

That's helpful Clarence.

When I did my 1st annual I found that the screws on the larger panels were 3/4". I've replaced all with 8-32R8 but I can see that R7 would be fine.

There were at least 4 different length screws in the one piece belly. 1/2" is all that's needed. 

All of those incorrect length screws add a bunch of extra time on the end of a screwdriver.

Clarence

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Just now, M20Doc said:

All of those incorrect length screws add a bunch of extra time on the end of a screwdriver.

Clarence

Absolutely. And increases the chance of buggered screw heads. Or fatigue and carpel tunnel. And adds to aircraft empty weight.

Seriously, we want to see at least one full thread of screw beyond the nut?

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I found today, putting my belly back on, that a few 3/4" long screws are useful for lining the belly pan up and getting started. The rest can be 1/2". Mine is a glorious mix, I've been replacing buggered up long screws with new, shorter ones. Don't think I could do it with all short screws, that long fiberglass belly is heavy, I need some long screws at the beginning.

My new IA (this is my 2nd annual with him) also balances props. So we put the cheek panels on, pulled outside and hooked up to check mine since it was last dynamically balanced in June '02. All compressions are 76-80, the tach reads 22 RPM low, and vibration registered at 0.01, so I shut down, pushed back into the hangar and finished cowling up then put on the spinner.

Everything finishes up tomorrow. It's been a busy weekend, and I opened all the panels last week after work. Annual started Friday morning, and I'm tired . . . The IA wants to make the Return to Service flight with me, so that'll be fun (weather permitting tomorrow; this morning's tornado warnings turned into nothing but rain, let's hope the same for tomorrow morning).

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10 hours ago, Hank said:

I found today, putting my belly back on, that a few 3/4" long screws are useful for lining the belly pan up and getting started. The rest can be 1/2". Mine is a glorious mix, I've been replacing buggered up long screws with new, shorter ones. Don't think I could do it with all short screws, that long fiberglass belly is heavy, I need some long screws at the beginning.

My new IA (this is my 2nd annual with him) also balances props. So we put the cheek panels on, pulled outside and hooked up to check mine since it was last dynamically balanced in June '02. All compressions are 76-80, the tach reads 22 RPM low, and vibration registered at 0.01, so I shut down, pushed back into the hangar and finished cowling up then put on the spinner.

Everything finishes up tomorrow. It's been a busy weekend, and I opened all the panels last week after work. Annual started Friday morning, and I'm tired . . . The IA wants to make the Return to Service flight with me, so that'll be fun (weather permitting tomorrow; this morning's tornado warnings turned into nothing but rain, let's hope the same for tomorrow morning).

Hank,

Prop balance with the spinner removed seems odd?  Normally they are installed during the balancing and indexed for future reference.

Clarence

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7 hours ago, M20Doc said:

Hank,

Prop balance with the spinner removed seems odd?  Normally they are installed during the balancing and indexed for future reference.

Clarence

The spinner and blade guards are indexed, have been since I bought the plane. The original balancing was done by the previous owner; this was a check to make sure it was still good. Every time I remove the spinner, I make sure the numbers are all legible for reinstall.

Honestly, I don't remember if I put the spinner on before or after . . . Last night when I wrote this up my back and forearms were too sore. Lots of screws, and I cleaned the entire belly before putting the belly pan back on.

Edited by Hank
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i feel like im interrupting my own thread here....  But the annual is finally over.  Swung the new compass this AM and the IA had one last look to make sure no jesus parts were falling off.  All good.  If it wasnt so nasty Id go fly, instead I closed up the hangar and went home for some warm chili. Its got to be at least 55deg here.  brrrrr.

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Mine's done too, but the ceiling yesterday was 500-1000' variable with horrible winds. May test fly it after work one evening this week once the winds calm down. Taking off in a Mooney with active tornado warnings just wasn't something I wanted to do, even between rain showers . . .

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Well, my annual is not quite over but very close. I'm waiting for grease for the guide blocks and jack screw. Should arrive from ASpruce tomorrow. Then I can put the belly pan on. We're going to weigh the plane. Then we'll be done -- except for the paper work... unless I can get Lynn to do some more painting. :P 

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1 minute ago, Bob_Belville said:

Well, my annual is not quite over but very close. I'm waiting for grease for the guide blocks and jack screw. Should arrive from ASpruce tomorrow. Then I can put the belly pan on. We're going to weigh the plane. Then we'll be done -- except for the paper work... unless I can get Lynn to do some more painting. :P 

you waiting on #7?  They finally get some in?  I was told to switch to #33 (i think , need to look at the tube again) which meets the same milspec and #7 wasnt anywhere to be found.  Been trying since I bought the plane in August to find #7.

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Just now, TheTurtle said:

you waiting on #7?  They finally get some in?  I was told to switch to #33 (i think , need to look at the tube again) which meets the same milspec and #7 wasnt anywhere to be found.  Been trying since I bought the plane in August to find #7.

Yeah, I'm in the same boat on a backordered #7. I finally asked DMax who said that AS is reformulating #7 and that he was using #33 which is probably overkill as I read the specs. I did not have #33 so I had Lynn order a tube for me - he was out of it himself.

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Just now, Bob_Belville said:

Yeah, I'm in the same boat on a backordered #7. I finally asked DMax who said that AS is reformulating #7 and that he was using #33 which is probably overkill as I read the specs. I did not have #33 so I had Lynn order a tube for me - he was out of it himself.

i heard the same thing from AS regarding the reformulation.  They actually told me a couple weeks ago it was supposed to be in on Dec 29th but the counterguy then said "but I dont believe it" so I just went with the 33.  The 33 is green.  I just cleaned my jack screw really well and used it.  Then I decrudded the guide plates as much as possible and smashed as much 33 as I could get between the rods and the plate.

I will say, though I havent flown it yet, all the controls feel like butter now.  Im not sure if the PO never greased anything or what but between the triflow on all the rod ends and the grease on the guide plates its slicker than snot on the ground.

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55 minutes ago, TheTurtle said:

 

I will say, though I havent flown it yet, all the controls feel like butter now.  Im not sure if the PO never greased anything or what but between the triflow on all the rod ends and the grease on the guide plates its slicker than snot on the ground.

I spray TriFlo under the belly, starting at the front and working my way towards the tail. That minimizes the amount that drips on me. If it ain't dripping, I didn't spray enough of it! Everything moves nicely.

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