Let’s try that again!

Sometimes you just have to face the fact that things are not going well – and lift the lid off the scrap bin and cast out that the bit you have been carefully crafting and toiling over, in the knowledge that it’s for the greater good 😦

And so it was with the crank and main bearings…

The fabricated main bearings were just not a good solution, and the approach I had taken to machining them had resulted in dimensional errors that needed “uncouth” solutions (shimming etc.) to get them right. Moreover the crank would not press up straight (even after peening the webs to remove post-press distortions.

After much soul-searching I concluded that I needed to bite the bullet and re-cut the main bearing journals after assembling the crank – this means that the bearings would be oversize, so would need re-making. Having reached that point I decided that I should re-make them from a block of solid gunmetal (a 62mm square block 7-inches long, only £160!) as the cast blocks from Camden were too small to fit the over-size housings that the base castings arrived from France with….

Cutting the main-bearing material in half, to fit it back together!

Cutting the main-bearing material in half, to fit it back together!

As always, coming to these “scrap and start over” decisions is accompanied by much wringing of hands, but delivers a calmness that lets you sleep better….

Pictures and progress in following posts…

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