I thought I would share my foibles of the Shelley 12DL rebuild, since this is the hands down best thread on the subject. First, here is a great video on rebuilding Shelley jacks:
https://www.youtube.com/watch?v=TuOwiwNPdM8 his is a 10DL, but same parts as the Cobra jacks. I combined two jacks, a 12DL with an L saddle, and a cheap Shelley, with the correct cast curved saddle. Not being the brightest bulb in the room, I took the L bracket off the 12DL first, messed that up but good, then I took the curved saddle off, that one came off perfect! I wanted to stake the saddle like the original Shelley, so I turned down the inner screw a little on the lathe so the curved saddle would fit. After rebuilding the jack fallowing the video and this thread, painting it Rust-Oleum Gloss Winter Grey, looks pretty close to original. Now for the staking, I followed the method in the video, no joy, and I gave up! I thought about welding like was done here, or drilling and tapping like others have done, but I wanted staking! Fortunately, I fallowed the immortal words of Fred Sanford, "never put off tell tomorrow, what you can do better, the day after." I realized, I tried to hammer on my wood bench, so the shock of the hammer was being absorbed by the wood. The next day, I put the jack on concrete, got the punch out and my big Whitworth hammer, and started tapping around like the video. After a minute or so, success, the saddle was on for good! If you look at photos of the staking on originals, it is really crude, must have been the first job for the poor apprentices. Here is a photo of my staking job. Not bad, should look good in the boot of which ever small block Cobra I end up with soon I hope. The price of the two jacks, shipped from the UK, plus the jack handles from Action, I gave up trying to find originals, still came out to less then $500, so not bad. Cheers, Dennis