Con Rod and Valve Gear screws

[ColinB]

A thing that surprised me yesterday was valve gear screws. I was fixing a Royal Scot that has lots of issues, seems to be a thing with this model. Anyway the previous owner said that it had bent the valve gear but he straightened it out. When I started running it I noticed every so often the valve gear would jam. Eventually I found the front con rod screw head was hitting the valve gear piston rod occasionally. When I further investigated I found the offending screw had a rather large head (lengthwise) so I searched through my old left over ones and found that their heads differed in length by a lot. The ones I eventually fitted heads were half the length of the original ones. Now seeing as the real prototypes don't have large screws to hold the con rods and valve gear on, you would have though Hornby would go with one sort. Anyway if your valve gear has the same issues examine you con rod screws.

[atom3624]

If/when I pull out a 'steamie' after a while in storage, I check the lubrication / listen to the motor (often prefer not to have to remove the body, as you explained), but always check out those pesky coupling / conrod screws.

They can easily work loose and cause absolute chaos.

Also, if/as/when I receive an addition, I check the valvegear slop and rod alignments. It's a very convenient place to hold locomotives, particularly with the increasing amount of external detail being added these days, and rods can very easily deform.

Al.