The Ford Barn

burner31 · 11-13-2017, 11:52 AM

I want to clean up a original Stewart/Warner Model A Horn, but can't get the nut off the ratchet so I can pull the armature out.
Lefthand or righthand threads?
And how do I hold the armature while removing the nut?
I don't want to mess things up, so I'm asking...how do you get that dang thing off without destroying the whole thing?

SeaSlugs · 11-13-2017, 12:03 PM

i believe its a left hand thread. There may be 1 or 2 threads sticking out that you can closely examine. They typically arent stuck very hard - soak in some kroil or PB blaster or something for a day or so. Ive used a soft towel around the armature core (not the brush area) in my hand and a box wrench on the nut. You dont want to risk damaging anything on the armature so i wouldnt use any tools just your hand and a towel to protect your hand.

Whatever you do dont force it - i think theres one horn maker out there that uses standard right hand threads...

Kevin in NJ · 11-13-2017, 12:58 PM

Left hand threads!!!!! The SW horns use left hand threads and yes the stud does break easy if you go the wrong way.

Yes, I learned how to make left hand threads on my lathe.

Bill G · 11-13-2017, 02:06 PM

I join the crowd. Left hand threads!

Bill G · 11-13-2017, 02:17 PM

One more thought....I would say that the best way is to leave it alone.

Even after I boogered it up by wrenching the nut off, I still went ahead and tried to clean up the armature shaft where it goes through the bushings at each end to make it spin more freely. After all that, I did not accomplish much.

Wishing now I had just lubricated it without messing with it.

Years ago I worked in a Hi Fi shop and took many motors apart for repair. Mostly AC induction motors, but some DC motors. The motor in the Model A looks alarmingly simple and one would think it would be an easy dis-assemble and re-assemble. For the most part, yes, but that dang left-hand thread really soured me on the whole idea of rejuvenating the horn.

Proceed with caution.

30ccpickup · 11-14-2017, 05:52 AM

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Quote:

Originally Posted by burner31

I want to clean up a original Stewart/Warner Model A Horn, but can't get the nut off the ratchet so I can pull the armature out.
Lefthand or righthand threads?
And how do I hold the armature while removing the nut?
I don't want to mess things up, so I'm asking...how do you get that dang thing off without destroying the whole thing?

I use a screwdriver to hold the armature by gently placing it between the outer metal parts of the motor and leaning it against the bracket.

Here is a simple tune up
http://modelabasics.com/horn.htm

burner31 · 11-19-2017, 02:16 AM

Got the horn working good now.
Used the horn tune-up from "30ccpickup" post 6...thank you
and I put in a new diaphram and some gaskets that were not in the horn when I got it.
Also installed the horn relay, all together it worked a miracle.
If your horn is dragging and weak I would recommend the horn relay, PITA the hook up but well worth it.
Thank You All

11-13-2017, 12:03 PM	#2
SeaSlugs Senior Member Join Date: May 2010 Location: Central, IL Posts: 3,968	Re: How to remove horn ratchet? i believe its a left hand thread. There may be 1 or 2 threads sticking out that you can closely examine. They typically arent stuck very hard - soak in some kroil or PB blaster or something for a day or so. Ive used a soft towel around the armature core (not the brush area) in my hand and a box wrench on the nut. You dont want to risk damaging anything on the armature so i wouldnt use any tools just your hand and a towel to protect your hand. Whatever you do dont force it - i think theres one horn maker out there that uses standard right hand threads... __________________ 1929 Model AA - Need long splash aprons!

11-13-2017, 12:58 PM	#3
Kevin in NJ Senior Member Join Date: May 2010 Location: South East NJ Posts: 3,398	Re: How to remove horn ratchet? Left hand threads!!!!! The SW horns use left hand threads and yes the stud does break easy if you go the wrong way. Yes, I learned how to make left hand threads on my lathe.

11-13-2017, 02:06 PM	#4
Bill G Senior Member Join Date: Jun 2017 Location: Walla Walla, WA Posts: 1,045	Re: How to remove horn ratchet? I join the crowd. Left hand threads!

11-13-2017, 02:17 PM	#5
Bill G Senior Member Join Date: Jun 2017 Location: Walla Walla, WA Posts: 1,045	Re: How to remove horn ratchet? One more thought....I would say that the best way is to leave it alone. Even after I boogered it up by wrenching the nut off, I still went ahead and tried to clean up the armature shaft where it goes through the bushings at each end to make it spin more freely. After all that, I did not accomplish much. Wishing now I had just lubricated it without messing with it. Years ago I worked in a Hi Fi shop and took many motors apart for repair. Mostly AC induction motors, but some DC motors. The motor in the Model A looks alarmingly simple and one would think it would be an easy dis-assemble and re-assemble. For the most part, yes, but that dang left-hand thread really soured me on the whole idea of rejuvenating the horn. Proceed with caution.

11-19-2017, 02:16 AM	#7
burner31 Senior Member Join Date: Dec 2014 Location: Shawnee, Ok Posts: 3,471	Re: How to remove horn ratchet? Got the horn working good now. Used the horn tune-up from "30ccpickup" post 6...thank you and I put in a new diaphram and some gaskets that were not in the horn when I got it. Also installed the horn relay, all together it worked a miracle. If your horn is dragging and weak I would recommend the horn relay, PITA the hook up but well worth it. Thank You All __________________ Keith Shawnee OK '31 SW 160-B