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Annett's Key
We’re seeing signs of spring around Tilford now, and I spotted a little rabbit sitting by a pile of sleepers in the Old Kiln yard when I arrived. The peace and quiet didn’t last long: I got a colleague to fire up the arc welder and weld together the pieces of the Annett’s key I made last weekend. After some cleaning up of the welds with an angle grinder and a couple of files we took our new key over to the yard ground frame to test it. It went in the keyhole first try, but wouldn’t turn: I’d deliberately left it oversized so I could adjust it to fit.
I used a hacksaw to cut thin slivers of metal—about 1/32″—from the “teeth” of the bit, filed the edges smooth and tried the fit again in the ground frame lock: success! It unlocked the frame and we were able to operate the levers. Feeling rather pleased with myself, my colleague and I took the key down to the bottom end of the line to try it in the Reeds Road ground frame. I opened the cover, inserted the key, turned it, and…
It stuck after turning about 45 degrees. I gave it a firm twist, and the T-bar of the handle came off in my hand as the weld failed, leaving the shaft of the key stuck in the lock. Oops! Too tight to get out by hand, so it was back to the workshop for a pair of pliers and mole grips. A quick trip back down to retrieve the key from the lock, and it was back to the welding shed to clamp the pieces together and weld them again. My colleague used a heavier gauge rod this time, and after hammering off the slag we left the key to cool while we had our lunch break.
After lunch we headed back down to the frame to work out what was making it stick. I inked the bit of the key with a Sharpie marker and tried it in the lock again so that the ink would be rubbed off where it was catching. This didn’t show anything conclusive, but we did notice that the shank of the key seemed to rub against the edge of the keyhole, so back to the workshop again to grind down the shank. This time we took a selection of files down to the frame with us, and tried again to determine which part of the key was sticking. Although we did get the key to turn a fraction further, we weren’t successful, so went to plan B.
Another trip to the workshop and back, this time with spanners to unbolt the lock so we could take it into the shop and see what was going on inside. This did the trick: with the lock open I was able to see the key moving the bars inside the mechanism, and finally determined that I needed to file down the front tooth. It hadn’t shown when I inked it because it left black grease where it had touched: maybe I should invest in some engineer’s blue! With that done the lock operated smoothly, and we took it back down the line to bolt it back onto the ground frame. After a last test to check everything was properly aligned we could move on to the third and last of our ground frames up at Mills Wood.
After a leisurely stroll across the museum we walked along the station platform and down to the frame where, feeling slightly nervous, I put the key into the lock and turned it. It turned easily, appearing to work perfectly, but when I tried to operate the first lever in the frame I couldn’t shift it. After my brief moment of despair my colleague had a go and the lever did move: it was simply a stiff latch on the lever itself that I’d not pulled hard enough.
The back and forth to get the key working in the second frame had used up half the day on its own and it was now 4:30pm, so I decided it was too late to start grinding, filing and sanding to finish off the key before handing it over to the S&T (Signals and Telegraph) department. We locked it away safely in a cupboard for next time. We’ve got other things in the diary for next weekend, so it’ll probably be a couple of weeks until my next update.
