Thread locking

[Deleted]

This may seem a rather elementary question, but should I be using thread locking compound on the nuts and bolts of my Modelworks Britannia, and if so, what sort?

Regards, John

[baggo]

Hi JJ,

Reading Suzy's website about the building of her Black 5 would imply that every kit for that loco came with a tube of Loctite! I presume though that your Britannia kits don't.

I think I would be tempted to use it on frame fixings that are not going to have to come to bits again (hopefully). It's fixings such as the horn bolts that are liable to work loose with time and it would probably be a pig of a job to get at some of them after the loco is complete.

Have a look at:

www.loctite.us/int_henkel/loctite_us/index.cfm?&pageid=114&layout=3

Go to Assembly Products and you'll be able to compare all the types of threadlock available along with the relevant data sheets. Loctite make several 'wicking' grades (290, 294) which can be used on already assembled nuts and bolts which saves the hassle of having to undo everything again.

John

[jgb7573]

I must admit I'm not sure about this one, but how did locos stay together in the days before thread lock was commonly available? There were (and probably still are) all sorts of systems for locking threads ranging from castle nuts, special washers, locknuts and even 'damaging' the thread so the nut won't come undone. These were used in those places where the thread was more likely to come undone, or would be particularly catastrophic if they did so. For other places, the bolts or nuts were just done up tight, and they stayed that way.
If you want to use a thread lock compound then by all means do so. I'm not convinced it's entirely necessary though.

[Jo]

I use Loctite 222 thread lock for standard nuts and bolts. Good stuff comes apart with hand tools but not through vibration around the track. There is nothing worse than a nut comming off in a totally inaccessible place, gaining a nasty rattle and subsequently having to strip down half the loco to get it back on.

[Deleted]

Thanks for all the advice. It definitely sounds worth locking the threads. Modelworks do provide tubes of Loctite 638 with many of the kits but this is for permanent bonding of bushes, crankpins etc - I wanted a thread lock that could be undone without a blowtorch if necessary. There's a bewildering choice of threadlocking compounds on the Loctite website that Baggo mentions. I intend to dismantle for painting once I've tested on air, so I'll use the Loctite 222 that Jo recommends at that stage. Although painting wouldn't involve dismantling stretchers, hornblocks and cylinders, I can remove these bolts one at a time to lock them, or perhaps try the 'wicking' compounds on them.

Regards, John

[baggo]

As John B suggests, it may well not be necessary but I tend to be one of the belt and braces fraternity!

I think nowadays we tend to use much smaller fasteners than in say LBSC's era in the interest of scale appearance and it's very easy to strip threads if you are a bit over zealous with the spanner! On my 2-1/2" gauge locos I use a lot of 8, 10, and 12BA fasteners (haven't quite got to 14BA yet!) so I'm very careful about not over tightening these sizes and prefer to use threadlock on them instead. I'm also a big fan of using Loctite on built up cranks and for fitting wheels on axles etc. (probably because I find it easier than getting the correct press fit!)

John