I have a confession to make. I have started to dismantle my Austin Seven engine so that I can start designing the half size model. (Is it half size or half scale?) Today I wanted to remove the flywheel which is held onto the crankshaft by a taper and large nut. The nut was easy to remove and I have a flywheel puller. It consists of a bar of steel an inch wide by ¾” thick by about 2 ½” long. It has a threaded hole in the middle and 2 holes that line up with 2 blind threaded holes in the flywheel. All threads are ½” BSF. My puller was missing the central bolt. I remembered that the last time I used it to remove a flywheel I had to use a lot of heat, brute force and swearing. It took several days to get that particular flywheel off, and the middle bolt was beyond saving. So, I had a puller, but no very important bolt and ½” BSF isn’t available locally. I found a piece of steel rod about the right diameter, and I had a ½” BSF die. What I didn’t have was the correct die holder. I had bigger and smaller, but not the right size. There was only one thing I could do. Sorry, you might want to cover your ears. With the steel rod clamped in the vice I used a pair of water pump pliers to turn the die. I cut about 1 ½” of (wonky) thread and screwed the puller into the 2 flywheel holes and tightened down my home made bolt. It seemed to be working until I realised that one of the flywheel bolts was pulling out of its thread. The flywheel threaded holes are only about ½” deep at the most. I removed the bolts and cleaned out the holes as much as I could. Re-assembled and tightened I started to hit the middle bolt very hard. Several moments later the flywheel sprung off the taper and I could remove it. I still have the crankshaft to remove, then I can measure the crankcase and produce a 3D drawing before 3D printing it.

Bob, the engine is about 1930, two bearing with dynamo.

brian jones 11, An Austin Seven flywheel can "fly" off the taper if you are not carefull. The suggested way is to leave the nut on the crankshaft, but loosened. I didn't do that!

Russell, The flywheel taper and rear hub taper are both a bit suspect. I lapped a flywheel onto its taper many years ago. That quietened it down.

Lee

Even with the nut in place the puller bolt locates on the end of the crankshaft without touching the threads. Mind you, a badly alligned puller could damage the threads. I think the crankshaft is OK, they are prone to breaking, but I won't know until I remove it. It could be a spare engine for someone once I have finished with it.