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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.