Looking for KFC225 autopilot red disconnect button

Hi,

Someone has lost the red "disconnect" button onmy KFC225 autopilot.

Honeywell want a lot of money for a whole new switch. Would anyone know who makes this switch? It looks like a standard pushbutton switch, with a button about 9mm diameter.

I could make a new button easily enough if I knew the thread used in the centre of the button (the button has a male screw on it). It certainly isn't metric.

The switch manufacturer is probably one of the well known names...

Any info would be much appreciated.

Peter.

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Hmmm....I must be out of sorts. A person needs a button with a male thread. He could make it himself if he knew the size. The makers price is too high. He wants someone like Rich to tell him the thread size. Have I got the facts right so far?

So the hardware store has some screws at 5 cents each or so for him to try. Let's say he might buy 5 different sizes. That's a quarter. Is that getting too costly, already?

Brian (sour-grapes) Whatcott, Altus, OK

No, it's just that in the UK, inch parts (apparently) are kind of few and far between. Didn't they used to refer to them as "English" vs metric? Ironic, ain't it? :-)

The existing shaft on the switch has a male threaded stud. The button (or knob) needs a female thread. But I'd think that even in UK, there's _somebody_ _somewhere_ who has a 4-40 nut or a

6-32 nut on hand, just to check. As Peter said, if he knows the thread size, he can make a button. According to , A #4 screw is about .112" OD, which is mumble-mumble millimeters - whaddaya, multiply by 25.4? And #6 is .138". The -40 or -32 is just number of threads per inch, which divided by 25.4 is number of threads per millimeter. With a magnifier and decent scale, it's trivially easy to measure them. He could theoretically even get the right sized tap, and just drill and tap a piece of plastic. What would international mail be on a 2-ounce, $3.00 tap?

For that matter, he could make a little form, add some mold release, and pour some epoxy into it and make a knob in place.

Cheers! Rich

I am in the UK, but the autopilot is a Honeywell one, made in the USA. The switch could be Grayhill, for example, or one of the other well known old U.S. names. It isn't a dirt cheap sort; probably $2 rather than $0.2.

I may have found a button - will be back if nothing turns up. Thank you all!

Peter.

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Rich Grise wrote

It certainly isn't 4-40 (which I assume is 4-40 UNC, same as commonly used on D-connector male screwlocks) as that is too big. The thread OD is slightly less than 3mm.

Sure I could get some screws...

BTW the price of the whole switch was quoted at US$72... but this is AVIATION :) Naturally, it would come with a batch number and an 8130-3 form with a nice rubber stamp on it.

Peter.

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Oh, dear. That's a tiny little bugger. I was thinking of the ones I'd seen many years ago, in the US military. For what it's worth, the next smaller common sizes are 3-48 and 2-56, but I imagine you've looked them up by now.

Yeah, for that price, at least in my case, it's worth doing a little bit of sculpture or what-not. Do they have "Sculpey" over there? It behaves a lot like modeling clay (which I believe the Brits call "plasticine"), but when you mold it to the shape you want, you can bake it and it hardens to the consistency of bulk HDPE, or a little harder.

I'm also a little surprised that by this time somebody hasn't come up with a knob from their junque box and dropped it in an envelope yet.

Good Luck! Rich

I bet they have one at SkyCraft Parts and Surplus in Winter Park Florida. email me a good closeup picture of the unit or the switch.

I've just got one sent to me by a very kind person - thank you all!