M20C rigging problem

[Guest]

Many Piper aircraft models have drawings at the end of the flight control section in the maintenance manual to make your own rigging fixture, on to which you place your bubble protractor to check travels.  Here’s the one for the Comanche stabilator.

Clarence

[Matt Hall]

On 4/4/2022 at 10:41 AM, Jcmtl said:

what happens to the ball if you take your feet off of the rudder pedals and hold the yoke to keep wings level?

 

Not sure I’m going to try tomorrow morning will report back!

[Matt Hall]

Also couple questions about the travel boards. Are they model specific? Also how does one go about renting them? Are they for all control surfaces or only certain ones?

[RLCarter]

6 minutes ago, Matt Hall said:

Also couple questions about the travel boards. Are they model specific? Also how does one go about renting them? Are they for all control surfaces or only certain ones?

There are 3, ailerons/flaps, elevator and rudder, and yes they are model specific….there are a few sets floating around here, I would think a MSC would be required to have them but not sure if they would rent them out… Rumor has it that Don Maxwell in North East Texas is the guy to GO to for rigging issues.

[PT20J]

 

4 hours ago, M20Doc said:

most of us older guys can read both, where as the younger ones can’t read a vernier or a micrometer.

Or a clock with hands.

[cliffy]

AND its a "vernier" NOT a caliper

A "caliper" is a different animal all together.

As was beaten into my head by my Father who could make any (and I mean ANY) machine shop machine sing and dance and did so for 75 years.

[ShuRugal]

AND its a "vernier" NOT a caliper
A "caliper" is a different animal all together.
As was beaten into my head by my Father who could make any (and I mean ANY) machine shop machine sing and dance and did so for 75 years.

Strictly speaking, a Vernier is any scale which measures small divisions by interpolation. Calipers and Micrometers are both available in Vernier, dial indicating, and digital flavors.

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[carusoam]

Calipers look very similar… but don’t do the measuring…

More for comparing..?

-a-

[ShuRugal]

Calipers look very similar… but don’t do the measuring…
More for comparing..?
-a-

Calipers, regardless of the indication method, are only for rough measurements. Even if the scale used reads in a precision of tenths (as in, one ten thousandth of an inch), the sliding mechanism calipers are only repeatable to a few thou. If you're doing something where your tolerance is measured in single digit thou or smaller, you have to use a micrometer (and take the measurement at a calibrated temperature, or adjust your measurements based on the ambient temperature)

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[cliffy]

3 minutes ago, ShuRugal said:

Calipers, regardless of the indication method, are only for rough measurements. Even if the scale used reads in a precision of tenths (as in, one ten thousandth of an inch), the sliding mechanism calipers are only repeatable to a few thou. If you're doing something where your tolerance is measured in single digit thou or smaller, you have to use a micrometer (and take the measurement at a calibrated temperature, or adjust your measurements based on the ambient temperature)

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Yes I agree with the above except in "old school machinists world" they were just called verniers before electronic scales came to be. I was corrected several times before I got the idea. This was back in the 50s

[ShuRugal]

Yes I agree with the above except in "old school machinists world" they were just called verniers before electronic scales came to be. I was corrected several times before I got the idea. This was back in the 50s

Maybe a regional thing. Calipers and Micrometers have both been available with dial indicator gauges for a century, though. It would be pretty silly to call a caliper without a Vernier on it a "Vernier".

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[cliffy]

Inside calipers, outside calipers and hermaphrodite calipers are what I grew up with as calipers (two legs each, each with a different job- for ROUGH sizing and scribing only). 

Caliper looking like verniers without scales were a kid's tool box item 

Just the way I was brought up in the machine shop. 

AH  I love the smell of Black Cutting Oil in the morning. :-)

[Hank]

20 minutes ago, ShuRugal said:

Maybe a regional thing. Calipers and Micrometers have both been available with dial indicator gauges for a century, though. It would be pretty silly to call a caliper without a Vernier on it a "Vernier".

I never cared for dial calipers! Give me a good set of vernier calipers and I'm a happy man. They're accurate to about 0.003". If you need better, grab a micrometer (once again I'll take one with the rotating vernier scale).

Digital units are easier to read (and convert standard to metric and back at the touch of a button), but so many people think that digital calipers are actually accurate to the limit of the display, often 0.0005". They're still +/- 0.003" no matter what the digital readout says. I've been explaining this at work for a decade . . . . to people of all ages.

P.S.--I came up through tool and die, where part tolerances are often +/- 0.001" or less.

Edited April 7, 2022 by Hank

[cliffy]

I was using a mic on parts coming off an automatic lathe when I was 10 years old!!   :-) :-)

At 8 I would sit for hours at a flat belt Buffalo drill press drilling holes in scrap aluminum blocks while my Dad ran the machines in his production shop. 

Got rid of his last lathe 2 years ago. 

[carusoam]

Calipers (vernier in style) is what I used for measuring machine parts…. 1 mil was close enough for my needs… selecting from tools that were already made… or defining their wear…

Micrometer is what I used for the plastic parts the machine made….  Measuring plastic films are often less than 1 mil… and up to 10 mil… above 10 mil, that’s plastic sheet… 

If new to measuring…. 1 mil = 1/k of an inch… not much to do with millimeters… even though they sound related…

 

PP thoughts only, not a mechanical engineer..

Best regards,

-a-

[RLCarter]

9 hours ago, M20Doc said:

For the purposes of flight control rigging, I’m not sure that a digital level is any better than a bubble protractor or a propeller protractor or a travel board.  They might be simpler to read for those who can’t work other tools.  Look at a digital caliper versus a vernier caliper, most of us older guys can read both, where as the younger ones can’t read a vernier or a micrometer.

Clarence

I know guys in there 40’s that can’t even read a tape measure, can’t tell you many times I’ve heard something like 4 and 2 lines past the little bigger line……