I had occasion recently to rejoin a pair of HO Steam Loco steam boxes to a chassis [thank you Kwik J-D Weld], & to my pleasant surprise, the loco runs.
Fits were an eyeball job & I suspect I have some slight binding of the valve gear in the steam boxes.
I would like to free up the fit a tad, preferably without having to strip the valve gear again.
We have metal running back & forth in a plastic hole - I was considering a touch of jeweler’s rouge or cutting compound on the valve gear so it could ‘cut’ itself into a comfortable fit.
You might want to try a little bit of LaBelle gear grease (the one in the tube) applied with a toothpick to the spot where the rod goes into the steamchest. It might eliminate the binding without having to use jewlers rouge to cut the hole larger.
I’d NEVER glue any valve gear joins. All those little ‘thingamawhichits’ need to move freely, otherwise they’ll transfer down to the main rods and you’ll have more problems than you ever cared for, LOL! Valve gear in a steamer should be free and loose within their specs. They’re not called “Eccentric” gears for nothing. That’s why I recommend the grease where the rods enter the steamchest. The smoother those rods work, the less transfer you have down to the main rods, and the smoother your loco will run. It might take a little running in to do it. I’d suggest that you turn your loco upside down in a foam cradle, apply power to it (after greasing those rods) and run it forward and back at about half-speed for ten or twenty minutes. Hopefully, any binds will have worked themselves out by then. If they have, increase to full speed back and forth for about five minutes each way. That should clear out any little ‘bugs’ that are present.
And make sure that you lube all of those little rod connections with a drop of very light oil. That should keep it running smooth.
I didn’t express myself very well - I wasn’t talking about gluing the valve gear - hells teeth, those moving bits are the most fascinating part of the Loco![:)]
What I meant was the Cab Forward I have just repaired involved gluing the steam chests back on to the rear truck frame. I did this with the valve gear pulled up out of the way.
I was pondering if I have to do it again in the future whether to try & glue the steam chests to the truck frame with the valve gear in situ, so the alignments are held.
It doesn’t matter if you pull the valve gear out of the cylinders while you’re doing the repair, so long as you reinsert them when you’re done. You should be able to get them back in by unscrewing the valve gear hanger. Have you zeroed in on what’s binding? One thought I had is that if you didn’t reposition the cylinders properly and they are too far back, one crosshead (or both) may be striking them once per revolution.
When the cylinders were broken away from the frame, was there a rivet or something that made their proper location obvious? I never had a Crab Forward, but Rivarossi usually attached the steamchest with a big brass rivet.