Spent Saturday night doing a complete breakdown, clean, add new brushes, and lube to a PW 675. Finally got it on the layout for a test run around 1:30am. Runs great, nice and quiet, looks like it’s ready for another 60 years.
Problem: In putting the side rods back on I broke one of the hex head screws in the hole, don’t know if it was cross threaded or what. But question is, what do I do now? Any tricks short of finding a tap that size? (and if I need to get a tap, where would I find one that size?)
I found a small tap for a Lionel General which I was upgrading at a local R/C model plane hobby shop.They had to order it but nobody else could even imagine one that size.
I think that screw is a 3-48, which is an uncommon size.
Were you able to get the broken piece out? If you cross-threaded it, that may be hard to do. But, if you perhaps just caught the shoulder of the screw on the side rod, the broken piece may turn easily enough that you can tease it out by turning it with a pin or needle on the exposed surface.
If you do get it out, you may not need a tap at all–just put in a new screw. If you did need a tap, it would have to be a bottom tap; or you would have to drill through the wheel before tapping.
I had the same thing happen with one of my 675s this winter. I had a spare driver, so I gave the broken one a shot. said a prayer, then drilled it out with a slightly smaller bit. tried a new screw, and it fit perfectly. good luck with yours.
If you have to drill it out, try to find a left-hand twist drill bit. Heaven only knows whether one is avilable in that tiny size, but the mere act of drilling may back out the shank of the screw. This method works well on much larger sizes. . . .