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Kadee skeleton log car kit truck/bunk screws work themselves loose, but maybe not!

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Kadee skeleton log car kit truck/bunk screws work themselves loose, but maybe not!
Posted by Lastspikemike on Sunday, September 19, 2021 7:20 PM

The car isn't running but the screws back out anyway which is odd.

The same screw holds the truck into the car by threading into the log bunk sandwiching the skeleton beam.

Loctite blue would work but that seems a bit permanent. Once loctited the truck can't be adjusted without breaking the loctite and restarting the problem.

There's no way to fit any type of lock washer. 

Silicone in the threaded hole in the bunk maybe? Just to provide enough resistance to the screw turning with the truck?

And I thought the main challenge was assembling the log stop levers and retaining chains into the ends of the bunks. I'm halfway done those challenging little beasties. 

Alyth Yard

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Posted by dstarr on Sunday, September 19, 2021 7:51 PM

Locktite is pretty permanent.  Duco cement will hold the screws in place and you can break it loose with a screwdriver should you need to.

 

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Posted by tstage on Sunday, September 19, 2021 7:58 PM

Loctite Blue is a medium-strength and is designed for disassembly.  I think it should work fine - even if you need to back the screw out slightly to adjust the fit.  Just make sure you let it cure a full 24 hrs on the screw threads before you insert it into the threaded hole.  What you do NOT want to use is the Loctite Red - That's permanent!

You could also try teflon tape to see if that offers enough resistance to keep the screw from backing out.

Tom

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Posted by gmpullman on Sunday, September 19, 2021 8:45 PM

I have small needlepoint applicators that I bought from Amazon. I keep PVA (slightly diluted Weldbond) in one of them. When I have a bolster screw or sometimes a draft gear cover plate screw that seems "loose" I'll apply a tiny drop of this.

Canopy cement is a similar product. Some of my Athearn Genesis coupler cover plates require the screw to be backed off a bit otherwise the coupler won't swing freely. A small dab of PVA on the flat head of the screw prevents any rotation.

Likewise, when mounting trucks there are times when the screw can not be completely snugged down if the mounting boss is too short (the screw head contacts the truck bolster) or, on some cars such as Walthers passenger cars, seating the screw limits the truck "rocking" ability too much so the screw has to be backed out a bit. The screws are notoriously short so they don't have much "bite". Same with their coupler swing draft gear.

A minimal application of PVA will keep the screw in place but will not inhibit removal when the time comes.

Good Luck, Ed

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Posted by PC101 on Sunday, September 19, 2021 10:17 PM

Dental Floss. Cut a short piece or two a hair longer then the depth of the hole and stick it down the screw hole.

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Posted by doctorwayne on Monday, September 20, 2021 12:26 AM

Another option is contact cement...apply it to the screws' threads, let it dry, then re-mount the trucks.  It won't prevent the truck from being removed when necessary, but will prevent the screws from working out due to the pivotting of the trucks due to the increased friction. 

Back in the mid-50s, I also used it to prevent the springs from accidentally popping out of the original K-type couplers...a little contact cement on the stationary spring-nub, and if the spring disengaged from the nub on the moveable portion of the knuckle, at least it wouldn't be lost.  The more recent Kadee couplers seldom need that fix nowadays.

Wayne

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Posted by snjroy on Monday, September 20, 2021 9:06 AM

PC101

Dental Floss. Cut a short piece or two a hair longer then the depth of the hole and stick it down the screw hole.

 

Using a similar technique, I use toothpick splints.

Simon

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Posted by Lastspikemike on Monday, September 20, 2021 10:37 AM

Once again, great ideas. Thanks. My issue ironically may result from me actually tapping the holes correctly. The bunks are white metal of some kind, very soft.  

I will try nylon screws from Kadee first to see if the plastic grips the white metal better. Then I'll try the dilute PVA as that will clean out easily if it doesn't work. Finally loctite blue and adjust the trucks carefully the first time.....I'll let you know what works for my skeleton car.

I really like the kit. Tricky little details to install but looks quite good so far. CPR only used these on Vancouver Island and they were painted black. Mine are unnumbered red oxide (so far anyway) so are protolance destined for a little logging branch line "owned" by a forestry outfit  and connecting to the CPR mainline Kettie Valley Division somewhere in Southern BC in the period from the 1930's to about 1970 depending on which period of my locomotives or rolling stock are on the line at the time. 

Alyth Yard

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Posted by Renegade1c on Monday, September 20, 2021 5:27 PM

They also make Pink (low strength) loctite which is used for parts that are frequently serviced. Its made to work like blue but requires less torque to break loose the connection. We use it all the time at work. Its defintely NOT permanent like the red stuff. 


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http://www.coloradofrontrangerr.com/

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Posted by Lastspikemike on Monday, September 20, 2021 6:10 PM

Thanks. I'll check for that before I resort to blue. Thread filler is what I need. 

Alyth Yard

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Posted by Lastspikemike on Tuesday, September 21, 2021 9:10 AM

And I'll read the assembly instructions just one more time.

Kadee includes two washers, one for each truck mounting right?

Apparently not. There is no reference in the assembly instructions for those washers.

Turns out if you put them under the truck mounting screw heads where you might normally fit washers they don't work. The washer doesn't fit down inside the truck mounting hole.

That means there's insufficient thread depth in the bunks.

Eliminate the washers and the mounting screws go deeper and seem to hold. 

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Posted by SROC99 on Tuesday, September 21, 2021 10:01 AM

Hello,  I've built many of these cars and run them to death and have never had the screws back out. That's really new to us.

Assembling the rings onto the chain ends is a real challenge. I've found that by clamping the end of the chain securely where the last link is held tight then you can use both hands (maybe a thrid) to get the ring into that last link. There are several ways to clamp the small chain links and it depends on what you have available. 

Sam Clarke  R&D Kadee Quality Products

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Posted by Lastspikemike on Tuesday, September 21, 2021 2:12 PM

It's probably new to me, thankfully, once I screw them up properly. On that note it now seems to me that it was me who added two washers to the kit and forgot why I did so. I used them to hold the bunks on using the truck screws without installing the trucks. That was for painting. In the time it took for the paint to dry it seems I forgot the washers didn't belong there. When I removed and reinstalled the washer and screw into the truck  it was the washer preventing the screw from securing the truck by reducing the thread engagement.  All seems normal now I've taken out the washers.  I used nylon screws but I'm betting the metal ones would be fine.

I appreciate all the input even though the problem resulted from my not reading the instructions fully. 

Yes, those rings and wire pins to affix the chain are, ahem, interesting.  The suggestion in the instructions was helpful but I reversed. I stuck the lever end into a piece of foam to hold it while I inserted the wire to hold the lever to the car. Two more to go and I'm done.

These are well worth putting together in my opinion.  

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Posted by snjroy on Thursday, September 23, 2021 1:18 PM

Nylon screws have their usages, but I try to avoid them to hold trucks. They tend to bend and can accentuate the lateral swings of cars.

Simon

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Posted by Lastspikemike on Thursday, September 23, 2021 2:04 PM

snjroy

Nylon screws have their usages, but I try to avoid them to hold trucks. They tend to bend and can accentuate the lateral swings of cars.

Simon

 

In this application there is really no unsupported section of threaded screw that can bend (well no that I figured out what I did wrong of course). There are definitely some applications which depend on the rigidity of the screw. 

Nylon is pretty strong but not as rigid ss brass or steel screws. The two useful features are easy adjustment of thread length and no conductivity.

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Posted by Overmod on Thursday, September 23, 2021 2:07 PM

Lastspikemike
The car isn't running but the screws back out anyway which is odd.

Differential expansion.  The Zamac or whatever expands more than the screw.  As it contracts back down it forces the inclined thread a little along...

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Posted by Lastspikemike on Thursday, September 23, 2021 2:13 PM

Overmod

 

 
Lastspikemike
The car isn't running but the screws back out anyway which is odd.

 

Differential expansion.  The Zamac or whatever expands more than the screw.  As it contracts back down it forces the inclined thread a little along...

 

 

Thanks. Probably yes. But the actual cause of this particular situation turns out to be operator error. Probably. I'll know in a while once I get two more pesky chains installed and take the car over to our DC layout for testing.  Of course I bought the DC only version of this car, probably a mistake. 

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Posted by Overmod on Thursday, September 23, 2021 2:25 PM

Lastspikemike
Of course I bought the DC only version of this car, probably a mistake. 

Enlighten me.  What other options are there, and technically how is that implemented?

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Posted by maxman on Thursday, September 23, 2021 4:00 PM

Overmod

 

 
Lastspikemike
Of course I bought the DC only version of this car, probably a mistake. 

 

Enlighten me.  What other options are there, and technically how is that implemented?

 

 

Probably doesn't have sound.

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Posted by Water Level Route on Thursday, September 23, 2021 4:03 PM

maxman

 

 
Overmod

 

 
Lastspikemike
Of course I bought the DC only version of this car, probably a mistake. 

 

Enlighten me.  What other options are there, and technically how is that implemented?

 

 

 

 

Probably doesn't have sound.

 

Laugh

Mike

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Posted by Lastspikemike on Friday, September 24, 2021 8:00 AM

Overmod

 

 
Lastspikemike
Of course I bought the DC only version of this car, probably a mistake. 

 

Enlighten me.  What other options are there, and technically how is that implemented?

 

 

I do wonder occasionally how far the tongue needs to be in one's cheek, virtually speaking.

Alyth Yard

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Posted by Overmod on Friday, September 24, 2021 8:32 AM

Lastspikemike
I do wonder occasionally how far the tongue needs to be in one's cheek, virtually speaking.

As I wonder occasionally that an ex-English schoolboy does not recognize actual sarcasm when practiced in America.

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Posted by Lastspikemike on Friday, September 24, 2021 4:10 PM

Overmod

 

 
Lastspikemike
I do wonder occasionally how far the tongue needs to be in one's cheek, virtually speaking.

 

As I wonder occasionally that an ex-English schoolboy does not recognize actual sarcasm when practiced in America.

 

 

Two nations separated by a common language.

 

Alyth Yard

Canada

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