Author Topic: Need photo/info on Key brass PRR M1a drawbar attachment  (Read 1053 times)

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mmagliaro

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Need photo/info on Key brass PRR M1a drawbar attachment
« on: September 19, 2012, 12:44:19 PM »
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I am working on someone's Key brass 4-8-2 PRR M1a.
The electrical pickup is shoddy, and the problem is where the drawbar attaches under the cab
with a shoulder screw.  It looks like a pretty standard design, where there should be a spring over
that screw so that it can be fully tightened, but allow the drawbar to swing freely, and be held
against the head of the screw by a spring over the screw.
But there is no spring on this one.  I suspect it's missing.

If anyone has one of these, can you take a photo, or tell me if there is a spring over the screw on yours?

Thanks!


Bob Bufkin

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Re: Need photo/info on Key brass PRR M1a drawbar attachment
« Reply #1 on: September 19, 2012, 02:39:35 PM »
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Just checked mine and there is a spring.

mmagliaro

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Re: Need photo/info on Key brass PRR M1a drawbar attachment
« Reply #2 on: September 19, 2012, 03:31:48 PM »
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Thank you.  I figured there had to be.  Pretty much every brass steam loco I've seen with a drawbar attachment
like this works that way.


robert3985

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Re: Need photo/info on Key brass PRR M1a drawbar attachment
« Reply #3 on: September 19, 2012, 07:31:08 PM »
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I'm in the process of stripping, detailing and painting a friend's old Key GS-3, and it has the typical Key drawbar arrangement, with spring, screw and drawbar, and a bronze spring wire to contact the pin attached to the tender offset from the center of the pin hole in the drawbar.

This particular drawbar was bent up pretty bad and the spring around the mounting screw between the drawbar and the body was squashed and otherwise deformed badly.  When I removed the drawbar, the spring actually was in two pieces, and since this is a critical electrical connection, I decided to mount a new spring when I re-attach the drawbar again, but I'm soldering a super-flexy black wire from the drawbar to the loco body for a more robust electrical connection.

I've got a resistance solderer, so soldering the stranded wire to the brass body will be easy.  I'm not sure it would be as easy with just a hot iron.

I'm also considering blackening the nickel silver drawbar and bronze spring with Neolube, which will also enhance the parts' conductivity.

Cheers!!
Bob Gilmore
« Last Edit: September 19, 2012, 07:34:01 PM by robert3985 »

mmagliaro

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Re: Need photo/info on Key brass PRR M1a drawbar attachment
« Reply #4 on: September 20, 2012, 01:22:04 AM »
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I am considering such an improvement.   Even though I don't have a resistance soldering rig, I have had success doing this just by drilling and tapping a 00-90 hole into the body or frame somewhere unobtrusive,
soldering the wire to a 00-90 brass washer, and then putting the screw through the washer tightly into the frame.

Even though the spring/pressure wire drawbar is almost defacto in steam locos, plastic and brass alike, I do not like them.  They are just too darn unreliable.  A soldered wire always works.  I am willing to give up the convenience of being able to separate the tender from the engine.  I don't think I've ever had a wire break off yet, but if it does, oh well.  I'll just solder it back.