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Stripped coupler screws Locos and rolling stock
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Regular poster 300 posts ajcaptain Regular poster 300 posts
ajcaptain

As careful as I try to be, I've managed to strip a couple of coupler screws in two of my locos.  Actually,  the screws are just fine.  The threaded plastic they screw into is the problem.  I've always managed to figure some convoluted way to make things work, but was wondering what other more skilled folks do to deal with this issue.  

Any input will be greatly appreciated! 

Thanks 

John C 

John C
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ajcaptain Regular poster 300 posts
ajcaptain

Double post

Thought i made a duplicate post. Guess not. 

 

John C
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joef MRH Founder 17,606 posts
joef

Easy

Easy ... get some styrene rod that just fits into the hole, then glue it in and soak it good with styrene solvent. Once it sets up (I like to give it a couple hours) trim the top flat with a sharp Xacto knife. Next drill and retap the hole with screw threads. For that you need to know the screw and thread size ... 2-56 is a common size. Once you know the screw size, you can get a drill and tap to make the new hole and add threads to it.

Joe Fugate​
Publisher, Model Railroad Hobbyist magazine

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Don Mitchell donm Super User 880 posts
Don Mitchell donm

Quick and easy

Just put a drop or 2 of CA on the stripped threads and hit with a spray of accelerator.  Put the screw back in with a reasonably gentle twist and the CA will be enough to hold the screw.  Can be redone if necessary but, for screws that are used frequently, use Joe F's method.

Don Mitchell

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ctxmf74 Super User 16,003 posts
ctxmf74

"Just put a drop or 2 of CA

Quote:

"Just put a drop or 2 of CA on the stripped threads and hit with a spray of accelerator."

    Yep, I do the same but don't even bother with an accelerator. I just put some CA or loctite in the hole and install the screw and wait for a while to use it. The load on coupler boxes is shear not tension it doesn't take much to keep them in place....DaveB 

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ajcaptain Regular poster 300 posts
ajcaptain

Both ideas sound good

The CA idea seems quick and easy.  

The styrene rod method is more work, but also more permanent.  With the styrene rod, I imagine the hole needs to be drilled out a bit to get a snug fit for whatever size rod is used.  Any recommendation on the rod diameter? 

Thanks for the ideas. 

John C 

John C
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joef MRH Founder 17,606 posts
joef

Ideally

Assuming this is a 2-56 screw, then the outside diameter of the screws are 0.086". Ideally, you'll get some rod that's slightly larger and drill out the hole to match the rod. You'll want styrene rod that's larger that 0.086", which would be 0.100" and a #38 drill. Evergreen sells 0.100" styrene rod.

Joe Fugate​
Publisher, Model Railroad Hobbyist magazine

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Graham Line Prolific poster 1,199 posts
Graham Line

Styrene rod

Among my boxes of thingsthatwillbeusefulsomeday is a shoebox of leftover plastic sprue. Some of them actually have a minute hole at the center to guide your drill. Comes in lots of colors, too, and easy to turn to size with a plastic drill and a file.
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ircman2003 Active Member 30 posts
ircman2003

Stripped Coupler Screws

Instead of styrene rod, I use 1/8" styrene tube. Drill out the hole with a 1/8" bit, push in the tube and glue it. When dry, cut it off flush. I have found that I don't need to tap the threads; it will take a 2-56 machine screw as is.
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ajcaptain Regular poster 300 posts
ajcaptain

Nice

Thanks, 

John C 

John C
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Metrolink Frequent poster 705 posts
Metrolink

What's a good length for N-scale trucks?

Thanks for posting the screw size, Joe! Would this be the same size (2-56) for N-scale? Also, what are the appropriate lengths to buy for attaching trucks to N-scale rolling stock?

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emodeler New member 26 posts
emodeler

Rethreading

Joe, I would wait a full 24 hrs before drilling & tapping.The rod will be rock solid by then and no worries of rod slipping or turning.That's my experience. Eric
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rickam1 Active Member 83 posts
rickam1

getting the center of the rod

I've also had some issues in the past with getting the drill started in the center of a rod but I found if I chuck it up in the drill press or the hand drill and run it while using a file or #11 X-acto knife blade it will cut around the perimeter of the rod surface and not cut the center until you cut down to the point where the center breaks off. That should guide your drill to stay centered. 

Enjoying the hobby!

Rick Melcher

Warminster Pa.
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Backshophoss Regular poster 198 posts
Backshophoss

Might be better to go up 1 screw size

This might work  for cars than locos,If the hardware was 2/56,drill and tap for 4/40 hardware

This works for HO scale.

Another possible option,fill the screw hole with Woodland scenics Hob-E tac glue,wait a coupe of minutes

then drive the screw in and let it set hard overnight.the screw should stay in place but if needed can be

removed if the coupler needs replacing.
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