This is always rather a difficult problem if you want to get it right. I have two options. The first is to rebore and fit new hardened and semi finish ground cups then to grind in situ. This takes much time to set up the case for grinding to get right and so unfortunately is expensive. The second less time consuming option is to make high tensile steel cups and fit as per normal Scott cups, then to skim out the semi finished bore to take a ball race and seals. This is quite a neat solution, but if using standard cranks, then these have to be supplied with an adapter ring on which to mount the ball race bore. I have made special cranks with a larger diameter mounting boss on the rear to use ball race main bearings for years, but these for my own use and the few new engines I make. I am on the point of ordering steel to make another batch of cranks, mostly, of course of long stroke type. I have made about 120 sets of long stroke and about 20 sets of short stroke in the last 15 years, so you can see the ratio. At this point I have about four original cases with ruined cups and I will have a small number of LS cranks made with the large back mounting so I can reclaim these cases using high tensile cups and ball races. This is to give notice that I will be committing orders within three weeks and if anyone is interested in recovering a valuable case by this method, let me know. The reality is that at 72 already, I can not be sure that there will ever be another batch. Nothing lasts forever! Kind Regards Roger
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